SC TO-T/A

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE TO

Tender Offer Statement under Section 14(d)(1) or 13(e)(1)

of the Securities Exchange Act of 1934
(Amendment No. 7)

LAFARGE NORTH AMERICA INC.

(Name of Subject Company (issuer))

EFALAR INC.

a wholly owned subsidiary of

LAFARGE S.A.

(Names of Filing Persons (Offerors))

COMMON STOCK, PAR VALUE $1.00 PER SHARE

(Title of Class of Securities)

505862-10-2

(CUSIP Number of Class of Securities)

Laurent Alpert

Cleary Gottlieb Steen & Hamilton LLP

One Liberty Plaza

New York, New York 10006

Telephone: (212) 225-2340

(Name, address, and telephone numbers of person authorized

to receive notices and communications on behalf of filing persons)

Calculation of Filing Fee

Transaction valuation*
$2,610,174,308 Amount of filing fee**
$279,288.65

*Estimated for purposes of calculating the amount of filing fee only. The calculation assumes the purchase of all outstanding shares of common stock, par value $1.00 per share, of Lafarge North America Inc., a Maryland corporation, other than the shares owned by Lafarge S.A. and its subsidiaries, at a purchase price of $82.00 per share, net to the seller in cash. As of December 31, 2005 there were 71,436,455 shares of common stock outstanding, of which 39,605,061 shares are owned by Lafarge S.A. and its subsidiaries. As a result, this calculation assumes the purchase of 31,831,394 shares.

**the amount of filing fee is calculated in accordance with Rule 240.0-11 of the Securities Exchange Act of 1934, as amended, and Fee Rate Advisory No. 5 for fiscal year 2006 issued by the Securities and Exchange Commission on November 23, 2005. Such fee equals 0.010700% of the transaction value.

x Check the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

Amount Previously Paid:	$255,446.94
Form or Registration No.:	Schedule TO-T
Filing Party:	Lafarge S.A.
Date Filed:	February 21, 2006

o Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

      Check the appropriate boxes below to designate any transactions to which the statement relates:

x           third-party tender offer subject to Rule 14d-1.

o           issuer tender offer subject to Rule 13e-4.

x           going-private transaction subject to Rule 13e-3.

o           amendment to Schedule 13D under Rule 13d-2.

SEC2559(6-05) Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

Check the following box if the filing is a final amendment reporting the results of the tender offer:     o

     This Amendment No. 7 amends and supplements the Tender Offer Statement and Rule 13E-3 Transaction Statement filed under cover of Schedule TO (this “Schedule TO”) with the Securities and Exchange Commission (“SEC”) on February 21, 2006, by Lafarge S.A., a French société anonyme (“Parent”) and Efalar Inc., a Delaware corporation and direct, wholly-owned subsidiary of Parent (“Purchaser”). This Schedule TO relates to the amended offer by Purchaser to purchase all outstanding shares of common stock, par value $1.00 per share (“Common Shares”), of Lafarge North America Inc., a Maryland corporation (the “Company”) not owned by Parent and its subsidiaries, at a purchase price of $82.00 per Common Share, net to the seller in cash, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated February 21, 2006 (as amended by amendments to the Schedule TO filed by Parent with the SEC prior to the date hereof, the “Offer to Purchase”), the Supplement to the Offer to Purchase dated April 7, 2006 (the “Supplement”), a copy of which is attached hereto as Exhibit (a)(1)(xviii) and the related revised (pink) Letter of Transmittal, a copy of which is attached hereto as Exhibit (a)(1)(xix) (which, as amended or supplemented from time to time, together constitute the “Amended Offer”).

Item 1. Summary Term Sheet.

     Reference is made to the information set forth in the Supplement under the headings “SUMMARY TERM SHEET” and “QUESTIONS AND ANSWERS ABOUT THE AMENDED OFFER,” which is incorporated herein by reference.

Item 2. Subject Company Information.

     (b) Reference is made to the information set forth in the Supplement under the headings “INTRODUCTION,” and “THE OFFER — Section 12. Effect of the Amended Offer on the Market for the Common Shares; NYSE and TSX Quotation; Exchange Act Registration and Margin Regulations,” which is incorporated herein by reference.

     (c) Reference is made to the information set forth in the Supplement under the heading “THE OFFER — Section 6. Price Range of the Shares; Dividends,” which is incorporated herein by reference.

Item 4. Terms of the Transaction.

     (a) Reference is made to the information set forth in the Supplement under the headings “SUMMARY TERM SHEET,” “QUESTIONS AND ANSWERS ABOUT THE AMENDED TENDER OFFER,” “INTRODUCTION,” “THE OFFER — Section 1. Terms of the Amended Offer,” “THE OFFER — Section 3. Procedure for Accepting The Amended Offer and Tendering Common Shares,” and “THE OFFER — Section 11. Conditions to the Amended Offer,” which is incorporated herein by reference.

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Item 5. Past Contacts, Transactions, Negotiations and Agreements.

     (b) Reference is made to the information set forth in the Supplement under the headings “INTRODUCTION,” and “SPECIAL FACTORS — Section 1. Background,” which is incorporated herein by reference.

Item 6. Purposes of the Transaction and Plans or Proposals.

     (a) Reference is made to the information set forth in the Supplement under the headings “SUMMARY TERM SHEET,” “QUESTIONS AND ANSWERS ABOUT THE AMENDED TENDER OFFER,” “INTRODUCTION,” and “SPECIAL FACTORS — Section 1. Background,” which is incorporated herein by reference.

Item 7. Source and Amount of Funds or Other Consideration.

     (a), (b) and (d) Reference is made to the information set forth in the Supplement under the headings “SUMMARY TERM SHEET” and “THE OFFER — Section 9. Source and Amount of Funds,” which is incorporated herein by reference.

Item 11. Additional Information.

     (a)(2) through (a)(4) Reference is made to the information set forth in the Supplement under the headings “QUESTIONS AND ANSWERS ABOUT THE AMENDED TENDER OFFER” and “THE OFFER — Section 13. Certain Legal Matters; Regulatory Approvals,” which is incorporated herein by reference.

     (a)(5) Reference is made to the information set forth in the Supplement under the heading “THE OFFER — Section 13. Certain Legal Matters; Regulatory Approvals,” which is incorporated herein by reference.

     (b) Reference is made to the information set forth in the Supplement and the related revised Letter of Transmittal, which is incorporated herein by reference.

Item 12. Exhibits.

(a)(1)(xviii)	Supplement to the Offer to Purchase, dated April 7, 2006.
(a)(1)(xix)	Revised Letter of Transmittal.
(a)(1)(xx)	Revised Notice of Guaranteed Delivery.
(a)(1)(xxi)	Revised Letter to Brokers, Dealers, Banks, Trust Companies and Other Nominees.

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(a)(1)(xxii)	Revised Letter to Clients for use by Brokers, Dealers, Banks, Trust Companies and Other Nominees.
(a)(1)(xxiii)	Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9.
(a)(1)(xxiv)	Revised MJDS Take-Over Bid Circular, dated February 21, 2006.
(a)(1)(xxv)	Certification of Foreign Status of Beneficial Owner for United States Tax Withholding.
(b)(iii)	Consent by Mandated Lead Arrangers Under the $2,800,000,000 Credit Facility, dated February 5, 2006, to Increase Offer Price.

Item 13. Information Required by Schedule 13E-3.

Item 2. Subject Company Information.

     (d) Reference is made to the information set forth in the Supplement under the heading “THE OFFER — Section 6. Price Range of the Shares; Dividends,” which is incorporated herein by reference.

Item 4. Terms of Transaction.

     (d) Reference is made to the information set forth in the Supplement under the heading “SUMMARY TERM SHEET,” which is incorporated herein by reference.

Item 5. Past Contacts, Transactions, Negotiations and Agreements.

     (c) Reference is made to the information set forth in the Supplement under the headings “INTRODUCTION,” and “SPECIAL FACTORS — Section 1. Background,” which is incorporated herein by reference.

Item 7. Purposes, Alternatives, Reasons and Effects.

     (a) through (c) Reference is made to the information set forth in the Supplement under the headings “SUMMARY TERM SHEET,” “QUESTIONS AND ANSWERS ABOUT THE AMENDED TENDER OFFER,” and “INTRODUCTION,” which is incorporated herein by reference.

Item 8. Fairness of the Transaction.

     (a) through (e) Reference is made to the information set forth in the Supplement under the headings “SUMMARY TERM SHEET,” “QUESTIONS AND ANSWERS ABOUT THE AMENDED TENDER OFFER,” “INTRODUCTION,” and “SPECIAL FACTORS — Section 3. Position of Parent and Purchaser Regarding Fairness of the Amended Offer and the Merger”, which is incorporated herein by reference.

Item 16. Exhibits.

     (c) Report of JPMorgan and BNP Paribas to the Lafarge S.A. Board of Directors, dated April 3, 2006 filed herewith as Exhibit (c)(ii).

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SIGNATURES

     After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

LAFARGE S.A.

By: /s/ Michel Bisiaux

Michel Bisiaux

Corporate Secretary

EFALAR INC.

By: /s/ Michel Bisiaux

Michel Bisiaux

Secretary

Dated: April 7, 2006

EXHIBIT INDEX

EXHIBIT	DESCRIPTION
(a)(1)(xviii)	Supplement to the Offer to Purchase, dated April 7, 2006.
(a)(1)(xix)	Revised Letter of Transmittal.
(a)(1)(xx)	Revised Notice of Guaranteed Delivery.
(a)(1)(xxi)	Revised Letter to Brokers, Dealers, Banks, Trust Companies and Other Nominees.
(a)(1)(xxii)	Revised Letter to Clients for use by Brokers, Dealers, Banks, Trust Companies and Other Nominees.
(a)(1)(xxiii)	Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9.
(a)(1)(xxiv)	Revised MJDS Take-Over Bid Circular, dated February 21, 2006.
(a)(1)(xxv)	Certification of Foreign Status of Beneficial Owner for United States Tax Withholding.
(b)(iii)	Consent by Mandated Lead Arrangers Under the $2,800,000,000 Credit Facility, dated February 5, 2006, to Increase Offer Price.
(c)(ii)	Report of JPMorgan and BNP Paribas to the Lafarge S.A. Board of Directors, dated April 3, 2006.

EX-99.A.1.XVIII

Exhibit (a)(1)(xviii)

Supplement

to

OFFER TO PURCHASE FOR CASH

All Outstanding Shares of Common Stock

of

LAFARGE NORTH AMERICA INC.

at

$82.00 Net Per Share

by

EFALAR INC.

a wholly-owned subsidiary of

LAFARGE S.A.

THE AMENDED OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON FRIDAY, APRIL 28, 2006, UNLESS THE AMENDED OFFER IS EXTENDED.

       The Amended Offer is conditioned upon, among other things, (i) there being validly tendered and not withdrawn a number of shares of common stock, par value $1.00 per share (the “Common Shares”), of Lafarge North America Inc. (the “Company”) which, when taken together with the Exchangeable Preference Shares (as defined in the INTRODUCTION to this Supplement) validly tendered and not withdrawn pursuant to the Amended EPS Offer (as defined in the INTRODUCTION to this Supplement), will constitute at least a majority of the outstanding Common Shares and Exchangeable Preference Shares, taken together as a single class, as of the date the Common Shares are accepted for payment pursuant to the Amended Offer, excluding Common Shares and Exchangeable Preference Shares beneficially owned by Lafarge S.A. and certain other persons as set forth in the INTRODUCTION to this Supplement (the “Minimum Tender Condition”) and (ii) there being validly tendered and not withdrawn a sufficient number of Common Shares such that, upon acceptance for payment and payment for the tendered Common Shares pursuant to the Amended Offer (and taking into account any Exchangeable Preference Shares to be accepted for payment in the Amended EPS Offer), Lafarge S.A. will, directly or through wholly-owned subsidiaries, own a number of Common Shares and Exchangeable Preference Shares representing at least 90% of the issued and outstanding Common Shares and Exchangeable Preference Shares, taken together as a single class, as of the date the Common Shares are accepted for payment pursuant to the Amended Offer. The Minimum Tender Condition is not waivable. The Amended Offer is also subject to certain other conditions set forth in this Supplement. See “THE OFFER — Section 11. Conditions to the Amended Offer” in this Supplement. You should read this entire Supplement and the Offer to Purchase carefully before deciding whether to tender your Common Shares.

      None of the Securities and Exchange Commission, any state securities commission or the securities regulatory authority of any other jurisdiction has: (i) approved or disapproved of the Amended Offer; (ii) passed upon the merits or fairness of the Amended Offer; or (iii) passed upon the adequacy or accuracy of the disclosure in the Offer to Purchase or this Supplement. Any representation to the contrary is a criminal offense.

The Information Agent for the Amended Offer is:

The Dealer Managers for the Amended Offer are:

April 7, 2006

IMPORTANT

      Any shareholder of the Company who desires to tender all or any portion of such shareholder’s Common Shares pursuant to the Amended Offer must do one of the following, as applicable: (a) complete and sign the original (yellow) or the revised (pink) Letter of Transmittal for the Amended Offer, which is enclosed with this Supplement to the Offer to Purchase, in accordance with the instructions contained in the Letter of Transmittal (having such shareholder’s signature on the Letter of Transmittal guaranteed if required by Instruction 1 to the Letter of Transmittal), mail or deliver the original (yellow) or revised (pink) Letter of Transmittal (or a manually executed facsimile thereof) (or, in the case of a book-entry transfer, an Agent’s Message (as defined herein) in lieu of the Letter of Transmittal) and any other required documents to Computershare Shareholder Services, Inc., the “Depositary” for the Amended Offer, and either deliver the certificates for such Common Shares to the Depositary along with the Letter of Transmittal (or a manually executed facsimile thereof) or tender such Common Shares by book-entry transfer by following the procedures described in “THE OFFER — Section 3. Procedure for Accepting the Amended Offer and Tendering Common Shares” in this Supplement, in each case on or prior to the Expiration Date (as defined herein) of the Amended Offer, or (b) request such shareholder’s broker, dealer, commercial bank, trust company or other nominee to effect the transaction for such shareholder. Any shareholder of the Company with Common Shares registered in the name of a broker, dealer, commercial bank, trust company or other nominee must contact that institution in order to tender such Common Shares pursuant to the Amended Offer.

      Although the original (yellow) Letter of Transmittal and the original (blue) Notice of Guaranteed Delivery previously circulated with the Offer to Purchase refer only to the Offer to Purchase, shareholders using such documents to tender their Common Shares will nevertheless be deemed to be tendering pursuant to the Amended Offer and will receive the Amended Offer Price of $82.00 per Common Share described in this Supplement, if Common Shares are accepted for payment and paid for by Efalar Inc. (“Purchaser”), pursuant to the Amended Offer. Common Shares previously validly tendered and not withdrawn constitute valid tenders for purposes of the Amended Offer. Shareholders are not required to take any further action with respect to such tendered Common Shares in order to receive the Amended Offer Price if Common Shares are accepted for payment and paid for by Purchaser pursuant to the Amended Offer, except as may be required by the guaranteed delivery procedure if such procedure was utilized.

      Any shareholder of the Company who desires to tender Common Shares pursuant to the Amended Offer and whose certificates representing such Common Shares are not immediately available, or who cannot comply in a timely manner with the procedures for tendering Common Shares by book-entry transfer, or who cannot deliver all required documents to the Depositary prior to the Expiration Date, may tender such Common Shares pursuant to the Amended Offer by following the procedures for guaranteed delivery described in “THE OFFER — Section 3. Procedure for Accepting the Amended Offer and Tendering Common Shares” in this Supplement.

      Holders of Exchangeable Preference Shares wishing to tender such shares should follow the instructions in the separate materials sent to them along with this Supplement.

      Questions and requests for assistance may be directed to the Information Agent or the Dealer Managers at their respective addresses and telephone numbers set forth on the back cover of this Supplement. Requests for additional copies of this Supplement, the Offer to Purchase, the revised (pink) Letter of Transmittal, the revised (green) Notice of Guaranteed Delivery, the Amended EPS Offer and other tender offer materials may also be directed to the Information Agent. A shareholder may also contact such shareholder’s broker, dealer, commercial bank or trust company for assistance.

TABLE OF CONTENTS

SUMMARY TERM SHEET	1
QUESTIONS AND ANSWERS ABOUT THE AMENDED TENDER OFFER	4
INTRODUCTION	7
SPECIAL FACTORS	10
1.  Background	10
2.  Purpose and Reasons for the Amended Offer; Plans for the Company After the Amended Offer and the Merger	10
3.  Position of Parent and Purchaser Regarding Fairness of the Amended Offer and the Merger	10
4.  Summary of JPMorgan and BNP Paribas Presentation to Parent’s Board of Directors	13
5.  Certain Projected Company Financial Information	16
6.  Effects of the Amended Offer and the Merger	16
7.  Conduct of the Company’s Business if the Amended Offer is not Completed	16
8.  Dissenters’ Appraisal Rights; Rule 13e-3	17
9.  Transactions and Arrangements Concerning the Common Shares and Exchangeable Preference Shares	17
10.  Related Party Transactions; Certain Transactions Between Parent and the Company	17
THE OFFER	18
1.  Terms of the Amended Offer	18
2.  Acceptance for Payment and Payment for Common Shares	18
3.  Procedure for Accepting the Amended Offer and Tendering Common Shares	18
4.  Withdrawal Rights	18
5.  Material United States Federal Income Tax Consequences of the Amended Offer	19
6.  Price Range of Shares; Dividends	19
7.  Certain Information Concerning the Company	20
8.  Certain Information Concerning Purchaser and Parent	20
9.  Source and Amount of Funds	20
10.  Dividends and Distributions	20
11.  Conditions to the Amended Offer	21
12.  Effect of the Amended Offer on the Market for the Common Shares; NYSE and TSX Quotation; Exchange Act Registration and Margin Regulations	24
13.  Certain Legal Matters; Regulatory Approvals	24
14.  Fees and Expenses	26
15.  Miscellaneous	27

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SUMMARY TERM SHEET

      This summary term sheet highlights important and material information contained in this Supplement but is intended to be an overview only. To fully understand the Amended Offer described in this document, and for a more complete description of the terms of the Amended Offer, you should read carefully this entire Supplement along with the original Offer to Purchase, dated February 21, 2006, as amended, the schedules and exhibits to this Supplement and the original Offer to Purchase, the documents incorporated by reference or otherwise referred to herein and in the original Offer to Purchase and the revised (pink) Letter of Transmittal. Section and heading references are included to direct you to a more complete description of the topics contained in this summary term sheet.

•   Lafarge S.A. (“Parent”) has amended its offer, through Efalar Inc. (“Purchaser”), a wholly-owned subsidiary of Parent incorporated in Delaware, to acquire all of the shares of common stock, par value $1.00 per share, of Lafarge North America Inc. (the “Company”) not owned by Parent and its subsidiaries, by increasing the offer price to $82.00 per share in cash, without interest, upon the terms and subject to the conditions set forth in this Supplement, the original Offer to Purchase and the revised (pink) Letter of Transmittal provided with this Supplement. All shareholders whose shares of Company common stock are validly tendered, not withdrawn and accepted for payment (including shares tendered prior to the date of this Supplement) will receive the increased offer price even if such shareholders have previously tendered their shares and take no further action. See the “INTRODUCTION” and “THE OFFER — Section 1. Terms of the Amended Offer” in this Supplement. Concurrently with this amended offer to purchase all of the shares of common stock of the Company, Parent, through another of its wholly-owned subsidiaries, is offering to acquire all of the exchangeable preference shares of Lafarge Canada Inc. (“Lafarge Canada”), a wholly-owned subsidiary of the Company, at the same increased per share price being offered for the common stock of the Company. That offer is subject to the conditions contained in this amended offer and Parent will not consummate the acquisition of such exchangeable preference shares unless Parent also consummates the acquisition of the common shares of the Company pursuant to this tender offer.

•   Parent currently owns, directly and through its 100% ownership interest in subsidiaries of Parent, approximately 55.4% of the outstanding shares of Company common stock, 10.7% of the outstanding exchangeable preference shares of Lafarge Canada and 53.2% of the outstanding shares of common stock of the Company and exchangeable preference shares of Lafarge Canada taken together as a single class. For a more detailed discussion of Parent’s ownership interests in the Company and Lafarge Canada see the “INTRODUCTION” to this Supplement.

•   The expiration date of the Amended Offer is 12:00 midnight, New York City time, on Friday, April 28, 2006, unless such date is extended further. See “THE OFFER — Section 1. Terms of the Amended Offer” in this Supplement.

•   The amended offer is conditioned upon, among other things:

•  there being validly tendered and not withdrawn a number of shares of Company common stock which, when taken together with the exchangeable preference shares of Lafarge Canada validly tendered and not withdrawn in the amended exchangeable preference share offer, will constitute at least a majority of the outstanding shares of Company common stock and exchangeable preference shares of Lafarge Canada, taken together as a single class, as of the date the shares of Company common stock are accepted for payment pursuant to the amended offer, excluding shares of Company common stock and exchangeable preference shares of Lafarge Canada beneficially owned by Parent and certain other persons as set forth in the “INTRODUCTION” to this Supplement, which we refer to as the “minimum tender condition;” and

•  there being validly tendered and not withdrawn a sufficient number of shares of Company common stock such that, upon acceptance for payment and payment for the tendered shares of Company common stock pursuant to the amended offer (and taking into account any

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exchangeable preference shares of Lafarge Canada to be accepted for payment in the amended exchangeable preference share offer), Parent will, directly or indirectly through wholly-owned subsidiaries, own a number of shares of Company common stock and exchangeable preference shares of Lafarge Canada representing at least 90% of the issued and outstanding shares of Company common stock and exchangeable preference shares of Lafarge Canada, taken together as a single class, as of the date the shares of Company common stock are accepted for payment pursuant to the amended offer.

      The minimum tender condition is not waivable. See “THE OFFER — Section 11. Conditions to the Amended Offer” in this Supplement for a complete description of all conditions to the amended offer.

•   Parent and Purchaser expect to have sufficient funds to purchase the common shares of the Company tendered and to complete the merger. The amended offer price of $82.00 per share implies a total value of approximately $3.3 billion for all of the common shares of the Company and exchangeable preference shares of Lafarge Canada not owned by Parent, including shares obtainable pursuant to the exercise of options and warrants. In order to finance the offer and related transactions, Parent has entered into a $2,800,000,000 credit agreement with J.P. Morgan plc and BNP Paribas. Pursuant to the terms of the $2,800,000,000 Credit Facility, Parent obtained the consent of BNP Paribas and J.P. Morgan plc to increase the price offered to shareholders in the tender offer from $75.00 per share to $82.00 per share. In addition, Parent expects to borrow under an existing € 1,850,000,000 credit facility agreement with a syndicate of banks. The ability of Parent to borrow under each of these facilities is subject to customary conditions. Parent and Purchaser expect that the funds available pursuant to these arrangements will be sufficient to consummate the tender offer. The tender offer is not conditioned on obtaining these funds. See “THE OFFER — Section 9. Source and Amount of Funds” in this Supplement.

•   If the amended offer is completed, Parent will cause Purchaser and the Company to merge pursuant to a “short-form” merger, unless it is not lawful to do so. Under Section 3-106 of the Maryland General Corporation Law and Section 253 of the Delaware General Corporation Law, Purchaser may effect a “short-form” merger without the affirmative vote of the Company’s shareholders if Purchaser owns at least 90% of the securities entitled to vote with respect to a merger. See “SPECIAL FACTORS — Section 6. Effects of the Amended Offer and the Merger” in this Supplement.

•   After the merger:

•  Parent would own directly or indirectly all of the equity interests in the Company;

•  the Company’s current minority shareholders would no longer have any interest in the Company’s future earnings or growth;

•  the Company’s common stock would no longer trade on the New York Stock Exchange and the Toronto Stock Exchange; and

•  the Company’s financial statements may no longer be publicly available.

      See “THE OFFER — Section 12. Effect of the Amended Offer on the Market for the Common Shares; NYSE and TSX Quotation; Exchange Act Registration and Margin Regulations” in this Supplement.

•   The tender offer commenced without obtaining the prior approval or recommendation of the Company’s board of directors. Neither the approval nor the recommendation of the Company’s board of directors is required under applicable law for this tender offer transaction to be commenced or completed. See the “INTRODUCTION” in this Supplement.

•   Position of the Company with respect to the amended offer:

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•  The special committee of the Company’s board of directors has not yet taken a position with respect to the amended offer.

•   Position of the Company with respect to the original offer:

•  The Company filed a “Solicitation/Recommendation Statement” on Schedule 14D-9 with the SEC on March 6, 2006 stating that at that time the special committee of its board of directors was unable to take a position with respect to the original offer; thereafter, on March 24, 2006, the Company issued a press release and filed with the SEC Amendment No. 2 to the “Solicitation/Recommendation Statement” on Schedule 14D-9 stating that the original offer is inadequate and not in the best interests of the shareholders of the Company, other than Parent and its affiliates, and recommending that the shareholders of the Company reject the original offer and not tender their shares.

•   Shareholders who sell their shares of Company common stock in the tender offer will, if the tender offer is completed, receive cash for their shares sooner than shareholders who wait for the merger.

•   Appraisal rights are not available in connection with the amended offer, and will not be available in connection with the merger.

•   Parent and Purchaser both believe that the tender offer and the subsequent “short-form merger” are fair to the shareholders of the Company who are unaffiliated with Parent and Purchaser.

•  Parent and Purchaser believe that the price being offered in the tender offer and that unaffiliated shareholders will receive in the merger is fair based on a number of factors, including: that this price represents a premium over historical trading levels of the Company’s common stock; that the Company’s common stock was trading at close to an all time high at the time the tender offer was announced; the analyses contained in the presentation provided by JPMorgan and BNP Paribas and described in the original Offer to Purchase and in the supplement to that presentation described in “SPECIAL FACTORS — Section 4. Summary of JPMorgan and BNP Paribas Presentation to Parent’s Board of Directors” in this Supplement; that the tender offer will provide an opportunity for the unaffiliated shareholders of the Company to sell their shares of Company common stock without incurring typical transaction costs; that the consideration in the tender offer and the merger is entirely cash; and that the tender offer and the merger will provide additional liquidity to the unaffiliated shareholders of the Company.

•  Parent and Purchaser also believe that the corporate process by which the tender offer and the merger are being pursued is fair to the unaffiliated shareholders based on a number of factors, including: that the minimum tender condition is not waivable and amounts to a “public referendum” on the tender offer; that each unaffiliated shareholder will be able to decide voluntarily whether or not to tender and all shareholders that do not tender will receive the same consideration in the merger (if the merger is completed) as in the tender offer; and that the special committee of the board of directors of the Company has retained financial and legal advisors to assist it in reviewing and making a recommendation with respect to the tender offer.

      See “SPECIAL FACTORS — Section 3. Position of Parent and Purchaser Regarding Fairness of the Amended Offer and the Merger” in this Supplement.

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QUESTIONS AND ANSWERS ABOUT THE AMENDED TENDER OFFER

      Parent, through Purchaser, is offering to purchase all of the issued and outstanding shares of common stock of the Company not owned by Parent or its subsidiaries at an increased price of $82.00 per share in cash, without interest, upon the terms and subject to the conditions described in this Supplement, the original Offer to Purchase and the revised (pink) Letter of Transmittal provided with this Supplement. The following are some of the questions you, as a shareholder of the Company, may have and answers to those questions. We urge you to read carefully this entire Supplement along with the original Offer to Purchase, as amended, the schedules and exhibits to this Supplement and the original Offer to Purchase, the documents incorporated by reference or otherwise referred to herein and in the original Offer to Purchase and the revised (pink) Letter of Transmittal because the information in these questions and answers is not complete and is intended to be only an overview. Additional important information is contained in the remainder of this Supplement, the original Offer to Purchase and the revised (pink) Letter of Transmittal.

Who is offering to buy my shares?

      Purchaser is offering to purchase your shares of Company common stock. Purchaser is a Delaware corporation and a wholly-owned subsidiary of Parent. See “THE OFFER — Section 8. Certain Information Concerning Purchaser and Parent” in this Supplement.

Why is Purchaser amending its tender offer?

      Purchaser is amending its tender offer to increase the offer price from $75.00 per share to $82.00 per share, in cash. The increased offer price represents an increase of 9.3% over the original $75.00 per share tender offer price, a premium of approximately 27.6% to the closing price of $64.25 for the Company’s common stock on February 3, 2006, the last trading day before the Company announced its intention to commence the Original Offer, and a premium of approximately 43.2% to the average closing price of $57.27 for the Company’s common stock during the three months prior to February 3, 2006. You should obtain a recent quotation for shares of Company common stock in deciding whether to tender your shares in the amended offer.

Has the expiration date of the tender offer been changed?

      Yes. The expiration date of the amended offer is 12:00 midnight, New York City time, on Friday, April 28, 2006, unless further extended. See “THE OFFER — Section 1. Terms of the Offer” in this Supplement.

If I already tendered my shares in the original offer, do I have to do anything now?

      No. Company shareholders do not have to take any action regarding any shares previously validly tendered and not withdrawn. If the amended offer is completed, these shares will be accepted for payment and such shareholders will receive the amended offer price of $82.00 per share.

What are the most significant conditions to the amended offer?

      We are not obligated to accept for payment or to purchase any shares that are validly tendered unless:

•   that number of shares of Company common stock validly tendered and not withdrawn, when taken together with the exchangeable preference shares of Lafarge Canada validly tendered and not withdrawn in the amended exchangeable preference share offer, constitutes at least a majority of the outstanding shares of Company common stock and exchangeable preference shares of Lafarge Canada, taken together as a single class, as of the date the shares of Company common stock are accepted for payment pursuant to the amended offer, excluding shares of Company common stock and exchangeable preference shares of Lafarge Canada beneficially owned by Parent and certain

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other persons as set forth in the “INTRODUCTION” to this Supplement (which we call the “minimum tender condition”); and

•

there have been validly tendered and not withdrawn a sufficient number of shares of Company common stock such that, upon acceptance for payment and payment for the tendered shares of Company common stock in the amended offer (and taking into account any exchangeable preference shares of Lafarge Canada to be accepted for payment pursuant to the amended exchangeable preference share offer), Parent will, directly or through wholly-owned subsidiaries, own a number of shares of Company common stock and exchangeable preference shares of Lafarge Canada representing at least 90% of the issued and outstanding shares of Company common stock and exchangeable preference shares of Lafarge Canada, taken together as a single class, as of the date the shares of Company common stock are accepted for payment pursuant to the tender offer.

      The minimum tender condition is not waivable.

      The tender offer is also subject to a number of other conditions described below in this Supplement. We do not believe that we need to obtain any material antitrust, regulatory or other governmental approvals, consents or clearances in order to complete this amended offer. For a complete description of all conditions to which the amended offer is subject, see “THE OFFER — Section 11. Conditions to the Amended Offer” in this Supplement.

Do you think that the amended offer and the merger are fair to the shareholders of the Company that are not affiliated with Parent and Purchaser?

      Yes. Parent and Purchaser believe that the tender offer and the subsequent “short-form merger” are fair to the shareholders of the Company that are not affiliated with Parent and Purchaser.

      Parent and Purchaser believe that the price being offered in the tender offer and that unaffiliated shareholders will receive in the merger is fair based on a number of factors, including: that this price represents a premium over historical trading levels of the Company’s common stock; that the Company’s common stock was trading at close to an all time high at the time the tender offer was announced; the analyses contained in the presentation provided by JPMorgan and BNP Paribas and described in the original Offer to Purchase and the supplement to that presentation described in “SPECIAL FACTORS — Section 4. Summary of JPMorgan and BNP Paribas Presentation to Parent’s Board of Directors” in this Supplement; that the tender offer will provide the unaffiliated shareholders of the Company an opportunity to sell their shares of Company common stock without incurring typical transaction costs; that the consideration in the tender offer and the merger is entirely cash; and that the tender offer and the merger will provide additional liquidity to the unaffiliated shareholders of the Company.

      Parent and Purchaser also believe that the corporate process by which the tender offer and the merger are being pursued is fair to the unaffiliated shareholders based on a number of factors, including: that the minimum tender condition is not waivable and amounts to a “public referendum” on the tender offer; that each unaffiliated shareholder will be able to decide voluntarily whether or not to tender and all shareholders that do not tender will receive the same consideration in the merger (if the merger is completed) as in the tender offer; and that the special committee of the board of directors of the Company has retained financial and legal advisors to assist it in reviewing and making a recommendation with respect to the tender offer.

      See “SPECIAL FACTORS — Section 3. Position of Parent and Purchaser Regarding Fairness of the Amended Offer and the Merger” in this Supplement.

What does the Company’s Board of Directors recommend regarding the tender offer?

      The tender offer commenced without obtaining the prior approval or recommendation of the Company’s board of directors. Neither the approval nor the recommendation of the Company’s board of directors is required under applicable law for the tender offer to be commenced or completed. See the “INTRODUCTION” to this Supplement.

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•   Position of the Company with respect to the amended offer:

•  The special committee of the Company’s board of directors has not yet taken a position with respect to the amended offer.

•   Position of the Company with respect to the original offer:

•  The Company filed a “Solicitation/ Recommendation Statement” on Schedule 14D-9 with the Securities and Exchange Commission on March 6, 2006 stating that at that time the special committee of its board of directors was unable to take a position with respect to the original offer; thereafter, on March 24, 2006, the Company issued a press release and filed with the Securities and Exchange Commission Amendment No. 2 to the “Solicitation/ Recommendation Statement” on Schedule 14D-9 stating that the original offer is inadequate and not in the best interests of the shareholders of the Company, other than Parent and its affiliates, and recommending that the shareholders of the Company reject the original offer and not tender their shares.

What is the market value of my shares as of a recent date?

      On February 3, 2006, the last trading day before we announced our intention to commence the original offer, the per share closing price of Company common stock as reported on the New York Stock Exchange was $64.25. On February 17, 2006, the last trading day before we commenced the original offer, the per share closing price of Company common stock as reported on the New York Stock Exchange was $82.35. On April 3, 2006, the last trading day before we announced our intention to commence the amended offer, the per share closing price of Company common stock as reported on the New York Stock Exchange was $84.36. On April 6, 2006, the last trading day before we commenced the amended offer, the per share closing price of Company common stock as reported on the New York Stock Exchange was $85.19. We encourage you to obtain a recent quotation for your shares of Company common stock. See “THE OFFER — Section 6. Price Range of the Shares; Dividends” in this Supplement.

Who can I talk to if I have questions about the Amended Offer?

      You may call Innisfree M&A Incorporated at (877) 825-8730 (toll free) for English speakers or (877) 825-8777 (toll free) for French speakers. Innisfree is acting as the information agent for the tender offer. You may also call J.P. Morgan Securities Inc. at (800) 488-6809 (toll free) and BNP Paribas Securities Corp. at (212) 841-3204. J.P. Morgan Securities Inc. and BNP Paribas Securities Corp. are acting as the dealer managers for the tender offer. See the back cover of this Supplement for additional contact information.

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To All Holders of Common Stock of the Company:

INTRODUCTION

      The following information amends and supplements the Offer to Purchase, dated February 21, 2006, of Purchaser, as amended by certain amendments to the Schedule TO filed with the Securities and Exchange Commission (the “SEC”) by Parent (the “Offer to Purchase”). Purchaser hereby offers to purchase all the issued and outstanding shares of common stock, par value $1.00 per share (the “Common Shares”), of the Company, other than Common Shares owned by Parent or its subsidiaries, at an increased price of $82.00 per Common Share (the “Amended Offer Price”), in cash, without interest, upon the terms and subject to the conditions set forth in this Supplement to the Offer to Purchase (this “Supplement”) and the revised (pink) Letter of Transmittal provided with this Supplement (which, as amended or supplemented from time to time, collectively constitute the “Amended Offer”).

      Concurrently with this Amended Offer, Parent, through another of its wholly-owned subsidiaries (“Canadian Merger Sub”), is offering to acquire all of the exchangeable preference shares (the “Exchangeable Preference Shares” and, such offer, the “Amended EPS Offer”) of Lafarge Canada. The Exchangeable Preference Shares are exchangeable into Common Shares on a 1-for-1 basis (subject to adjustment in accordance with their terms), and the per share offer price in the Amended EPS Offer is the same as the Amended Offer Price. The Amended EPS Offer is subject to the conditions contained in this Amended Offer, and Parent will not consummate the acquisition of such Exchangeable Preference Shares unless Parent also consummates the acquisition of the Common Shares pursuant to the Amended Offer. See “THE OFFER — Section 1. Terms of the Offer” in this Supplement.

      Tendering shareholders who are the record owners of Common Shares will not be obligated to pay brokerage fees or commissions or, except as set forth in Instruction 6 of the revised (pink) Letter of Transmittal, stock transfer taxes on the purchase of Common Shares by Purchaser pursuant to the Amended Offer. Shareholders who hold their Common Shares through a bank or broker should check with such institution as to whether the institution will charge any service fees. However, if you fail to complete and sign IRS Form W-9, you may be subject to a required backup federal income tax withholding of 28% of the gross proceeds payable in the Amended Offer. See “THE OFFER — Section 3. Procedure for Accepting the Amended Offer and Tendering Common Shares” and “THE OFFER — Section 5. Material United States Federal Income Tax Consequences of the Amended Offer” in this Supplement. Parent and Purchaser will pay all charges and expenses of J.P. Morgan Securities Inc. (“JPMorgan”) and BNP Paribas Securities Corp. (“BNP Paribas” and, together with JPMorgan, the “Dealer Managers”), Computershare Shareholder Services, Inc. (the “Depositary”) and Innisfree M&A Incorporated (the “Information Agent”) incurred in connection with the Amended Offer and in accordance with the terms of the agreements entered into by and between Purchaser and/or Parent and each such person. See “THE OFFER — Section 14. Fees and Expenses” in this Supplement.

      Except as otherwise expressly set forth in this Supplement and in the revised (pink) Letter of Transmittal, the terms and conditions previously set forth in the Offer to Purchase remain applicable in all respects to the Amended Offer. This Supplement should be read carefully in conjunction with the Offer to Purchase and the revised (pink) Letter of Transmittal. Capitalized terms used herein and not otherwise expressly defined shall have the meanings set forth in the Offer to Purchase. As used herein, the term “Original Offer” shall mean Parent’s and Purchaser’s original offer to purchase the Common Shares at $75.00 per share pursuant to the Offer to Purchase.

      Procedures for tendering Common Shares are set forth in “THE OFFER — Section 3. Procedure for Accepting the Amended Offer and Tendering Common Shares” in this Supplement. Tendering shareholders may continue to use the original (yellow) Letter of Transmittal and the original (blue) Notice of Guaranteed Delivery previously circulated with the Offer to Purchase, or they may use the revised (pink) Letter of Transmittal and the revised (green) Notice of Guaranteed Delivery circulated with this Supplement. Although the original (yellow) Letter of Transmittal and the original (blue) Notice of Guaranteed Delivery previously circulated with the Offer to Purchase refer only to the Original Offer,

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shareholders using such documents to tender their Common Shares will nevertheless be deemed to be tendering pursuant to the Amended Offer and will receive the Amended Offer Price described in this Supplement if Common Shares are accepted for payment and paid for by Purchaser pursuant to the Amended Offer.

      Common Shares previously validly tendered and not withdrawn constitute valid tenders for purposes of the Amended Offer. Shareholders are not required to take any further action with respect to such Common Shares in order to receive the Amended Offer price if Common Shares are accepted for payment and paid for by Purchaser pursuant to the Amended Offer, except as may be required by the guaranteed delivery procedure if such procedure was utilized. See “THE OFFER — Section 4. Withdrawal Rights” in this Supplement for the procedures for withdrawing Common Shares tendered pursuant to the Amended Offer.

      THE AMENDED OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, (I) THERE BEING VALIDLY TENDERED AND NOT WITHDRAWN A NUMBER OF COMMON SHARES WHICH, WHEN TAKEN TOGETHER WITH THE EXCHANGEABLE PREFERENCE SHARES VALIDLY TENDERED AND NOT WITHDRAWN PURSUANT TO THE AMENDED EPS OFFER, WILL CONSTITUTE AT LEAST A MAJORITY OF THE OUTSTANDING COMMON SHARES AND EXCHANGEABLE PREFERENCE SHARES, TAKEN TOGETHER AS A SINGLE CLASS, AS OF THE DATE THE COMMON SHARES ARE ACCEPTED FOR PAYMENT PURSUANT TO THE AMENDED OFFER, EXCLUDING COMMON SHARES AND EXCHANGEABLE PREFERENCE SHARES BENEFICIALLY OWNED BY PARENT AND CERTAIN OTHER PERSONS, AS SET FORTH BELOW (THE “MINIMUM TENDER CONDITION”) AND (II) THERE BEING VALIDLY TENDERED AND NOT WITHDRAWN A SUFFICIENT NUMBER OF COMMON SHARES SUCH THAT, UPON ACCEPTANCE FOR PAYMENT AND PAYMENT FOR THE TENDERED COMMON SHARES PURSUANT TO THE AMENDED OFFER (AND TAKING INTO ACCOUNT ANY EXCHANGEABLE PREFERENCE SHARES TO BE ACCEPTED FOR PAYMENT IN THE AMENDED EPS OFFER), PARENT WILL, DIRECTLY OR THROUGH WHOLLY-OWNED SUBSIDIARIES, OWN A NUMBER OF COMMON SHARES AND EXCHANGEABLE PREFERENCE SHARES REPRESENTING AT LEAST 90% OF THE ISSUED AND OUTSTANDING COMMON SHARES AND EXCHANGEABLE PREFERENCE SHARES, TAKEN TOGETHER AS A SINGLE CLASS, AS OF THE DATE THE COMMON SHARES ARE ACCEPTED FOR PAYMENT PURSUANT TO THE AMENDED OFFER (THE “90% CONDITION”). THE MINIMUM TENDER CONDITION IS NOT WAIVABLE. THE AMENDED OFFER IS ALSO SUBJECT TO CERTAIN OTHER CONDITIONS DESCRIBED IN “THE OFFER — SECTION 11. CONDITIONS TO THE AMENDED OFFER” IN THIS SUPPLEMENT.

      The purpose of the Amended Offer is to acquire for cash as many outstanding Common Shares not owned by Parent and Purchaser as possible as a first step in acquiring the entire equity interest in the Company. If the Amended Offer is completed and Parent holds, directly or through wholly-owned subsidiaries, at least 90% of the issued and outstanding Common Shares and Exchangeable Preference Shares, taken together as a single class, Parent will cause the “short-form” merger of Purchaser and the Company (the “Merger”) in accordance with the applicable provisions of the Maryland General Corporation Law (the “MGCL”) and the Delaware General Corporation Law (the “DGCL”), unless it is not lawful to do so. The Merger would be effected without a vote of the shareholders of the Company. In the Merger, each then issued and outstanding Common Share (other than Common Shares held by Purchaser or Parent) will be converted into and represent the right to receive the Amended Offer Price. See “SPECIAL FACTORS — Section 2. Purpose and Reasons for the Amended Offer; Plans for the Company After the Amended Offer and the Merger” in this Supplement.

      If, after the Amended Offer is completed but prior to the completion of the Merger, the aggregate beneficial ownership by Parent and Purchaser of the outstanding Common Shares should fall below 90% for any reason, if Purchaser waives the 90% Condition or if the Amended Offer is not completed for any reason (including a failure to satisfy the Minimum Tender Condition), Purchaser may decide to acquire additional Common Shares and/or Exchangeable Preference Shares on the open market or in privately

8

negotiated transactions to the extent required for the beneficial ownership interest of Purchaser and Parent to equal or exceed 90% of the Common Shares and Exchangeable Preference Shares, taken together as a single class. Any such purchases would be made at market prices or privately negotiated prices at the time of purchase, which may be higher or lower than, or the same as, the Amended Offer Price. For a discussion of other actions that Parent and Purchaser may take if the Amended Offer is not completed, see “SPECIAL FACTORS — Section 7. Conduct of the Company’s Business if the Amended Offer Is Not Completed” in this Supplement.

      The board of directors of the Company has not been asked by Parent or Purchaser to approve or recommend the Amended Offer. Under applicable law, no approval or recommendation by the Company’s board is necessary for Parent and Purchaser to commence or complete the Amended Offer. The special committee of the Company’s board of directors has not taken a position with respect to the Amended Offer. With respect to the Original Offer, the Company filed a “Solicitation/ Recommendation Statement” on Schedule 14D-9 with the SEC on March 6, 2006 stating that at that time the special committee of its board of directors was unable to take a position with respect to the Original Offer; thereafter, on March 24, 2006, the Company issued a press release and filed with the SEC Amendment No. 2 to the “Solicitation/ Recommendation Statement” on Schedule 14D-9 stating that the Original Offer is inadequate and not in the best interests of the shareholders of the Company, other than Parent and its affiliates, and recommending that the shareholders of the Company reject the Original Offer and not tender their shares.

      This Supplement, the Offer to Purchase and the documents incorporated by reference in this Supplement and the Offer to Purchase include certain forward-looking statements. These statements appear throughout this Supplement and the Offer to Purchase and include statements regarding the intent, belief or current expectations of Parent and Purchaser, including statements concerning Parent’s and Purchaser’s plans with respect to the Common Shares or their actions if they do not complete the Amended Offer and/or the Merger. Such forward-looking statements are not guarantees of future performance or events and involve risks and uncertainties. Actual results may differ materially from those described in such forward-looking statements as a result of various factors. Factors that might affect such forward-looking statements include:

•   whether the conditions to the Amended Offer will be satisfied;

•   following the completion of the Amended Offer and the consummation of the Merger, the ability to integrate successfully the Company into Parent’s operations;

•   general economic, capital market and business conditions;

•   competitive factors in the industries and markets in which each of the Company and Parent operates and general industry trends;

•   the effect of war, terrorism or catastrophic events;

•   changes in government regulation;

•   changes in tax law requirements, including tax rate changes, new tax laws and revised tax law interpretations; and

•   the ability of Parent to execute fully on its business strategy after taking the Company private, including future expenditures on capital projects.

      The information contained in this Supplement and the Offer to Purchase concerning the Company was supplied by the Company or obtained from publicly available sources.

      THIS SUPPLEMENT, THE OFFER TO PURCHASE AND THE REVISED (PINK) LETTER OF TRANSMITTAL CONTAIN IMPORTANT INFORMATION AND SHOULD BE READ CAREFULLY BEFORE ANY DECISION IS MADE WITH RESPECT TO THE AMENDED OFFER.

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SPECIAL FACTORS

1. Background

      The discussion set forth in “SPECIAL FACTORS — Section 1. Background” in the Offer to Purchase is hereby amended and supplemented with the information concerning the position of the Company with respect to the Original Offer and the Amended Offer and Merger contained in the “INTRODUCTION” to this Supplement. Such discussion is also supplemented as follows:

      On April 3, 2006, a meeting of Parent’s board of directors was convened in Paris to discuss whether or not to increase the price offered for the publicly held Common Shares and Exchangeable Preference Shares. At that meeting, JPMorgan and BNP Paribas provided a supplement to the presentation that they had previously made to the Parent’s board of directors in connection with the Original Offer. Such supplement is described under “SPECIAL FACTORS — Section 4. Summary of JPMorgan and BNP Paribas Presentation to Parent’s Board of Directors” in this Supplement. The presentation given on February 5, 2006 and the supplement to that presentation given on April 3, 2006 constitute the only materials presented to Parent’s board of directors by the financial advisors of Parent and thus the only such materials that Parent’s board of directors factored into its decision to proceed with the Amended Offer. Parent’s board of directors did not receive any appraisal in connection with its consideration of the Amended Offer. The supplemental presentation provided by JPMorgan and BNP Paribas contained various financial analyses at potential offer prices ranging from $75.00 to $84.00. Following discussions and questions by the board members to Parent’s management and Parent’s financial advisors and the recommendation of Parent’s management, Parent’s board authorized Parent’s management to increase the offer price for the Common Shares and the Exchangeable Preference Shares not held by Parent and its subsidiaries to $82.00 per share in cash. In authorizing Parent’s management to proceed with the Amended Offer, and in determining the Amended Offer Price, Parent considered the analyses contained in the presentation provided by JPMorgan and BNP Paribas, the supplement thereto, the recommendation made by Parent’s management and the other factors described in “SPECIAL FACTORS — Section 2. Purpose and Reasons for the Amended Offer; Plans for the Company After the Amended Offer and the Merger” and “SPECIAL FACTORS — Section 3. Position of Parent and Purchaser Regarding Fairness of the Amended Offer and the Merger” in this Supplement.

2. Purpose and Reasons for the Amended Offer and the Merger; Plans for the Company After the Amended Offer and the Merger

      A discussion of the purpose and reasons for the Amended Offer and the Merger and for Parent’s plans with respect to the Company after the Amended Offer and the Merger is set forth in “SPECIAL FACTORS — Section 2. Purpose and Reasons for the Offer; Plans for the Company After the Offer and the Merger” in the Offer to Purchase.

3. Position of Parent and Purchaser Regarding Fairness of the Amended Offer and the Merger

      The discussion set forth in “SPECIAL FACTORS — Section 3. Position of Parent and Purchaser Regarding Fairness of the Offer and the Merger” in the Offer to Purchase is hereby amended and supplemented as follows:

      Fairness of the Original Offer — Parent and Purchaser continue to believe that the Original Offer Price offered to the unaffiliated shareholders of the Company pursuant to the Original Offer and the Merger is fair to such unaffiliated shareholders. Parent and Purchaser base their belief on the following factors, each of which, in their judgment, supports their views as to the fairness of the Original Offer and the Merger:

•   The Original Offer Price represents a premium of approximately 16.7% to the closing price of $64.25 for the Common Shares on February 3, 2006, the last trading day prior to the date on which Parent’s intention to make the Original Offer was announced, and a premium of approximately 31.0% to the average closing price of $57.27 for the Common Shares during the three months prior

10

	to February 3, 2006. Parent and Purchaser do not believe that the post-announcement trading price of the Common Shares is indicative of the fair value of the Common Shares, and thus did not consider it when making an assessment as to the fairness of the Original Offer and the Merger.”
•	The Common Shares were, prior to the announcement of Parent’s intention to launch the Original Offer, trading at close to an all time high closing price and the Common Shares appreciated by 20% in the twelve months prior to February 3, 2006, by 128% in the three years prior to February 3, 2006 and by 145% in the five years prior to February 3, 2006. This demonstrates that the Original Offer Price is at a premium to a last prior trading price that already reflected favorable investor sentiment towards the Company’s performance and prospects and thus is at a premium to historical market prices. The premium of the Original Offer Price over historical market prices will allow long-term shareholders of the Company to realize significant capital gains.
•	Both the Original Offer Price and the trading price of the Common Shares immediately prior to announcement of the Original Offer imply a valuation of the Company (as shown by the ratio of firm value to EBITDA) that is materially higher than during most periods over the past five years. The ratio of firm value to 2005 EBITDA is 6.5x when firm value is calculated based on the closing price per Common Share on February 3, 2006 and 7.7x when firm value is calculated using the Original Offer Price, in comparison with an average ratio of firm value to last twelve months EBITDA of 4.9x over the period between September 1998 and February 2006.
•	The analyses contained in the presentation provided by JPMorgan and BNP Paribas described below, which include a comparison of certain financial, operating and stock market data and forecasted financial information for selected publicly-traded companies in the building materials industry to similar information for the Company and an overview of premiums paid in other buy-in transactions. A summary of the JPMorgan and BNP Paribas presentation, which does not express an opinion with respect to the fairness of the Original Offer Price, is set forth in the Offer to Purchase under “SPECIAL FACTORS — Section 4. Summary of JPMorgan and BNP Paribas presentation to Parent’s Board of Directors.” In particular, Parent and Purchaser considered the following:

•  that the Original Offer Price was above the upper end of each of the trading ranges for the 6-month, 52-week, two-year, three-year and five-year ranges as described under “SPECIAL FACTORS — Section 4. Summary of JPMorgan and BNP Paribas presentation to Parent’s Board of Directors — Historical Stock Price Performance” on page 20 of the Offer to Purchase;

•  that over the twelve months prior to February 3, 2006, 95.2% of the traded volume in the Common Shares traded below $68.00 and 87.1% traded below $66.00, and thus the Original Offer Price was significantly above the price at which the bulk of trading had occurred over the past twelve months as described under “SPECIAL FACTORS — Section 4. Summary of JPMorgan and BNP Paribas presentation to Parent’s Board of Directors — Trading Prices of the Common Shares” on page 20 of the Offer to Purchase;

•  that the Original Offer Price represented a premium of 17.9% to the 1-week average share price prior to the announcement of the transaction of $63.64, which was higher than the median 1-week premium of 15% paid in US acquisitions by majority or controlling stockholders between January 1, 2005 and November 17, 2005 as described under “SPECIAL FACTORS — Section 4. Summary of JPMorgan and BNP Paribas presentation to Parent’s Board of Directors — Historical Acquisition by Majority or Controlling Stockholders Premia” beginning on page 22 of the Offer to Purchase.

•   The Original Offer provides the Company’s unaffiliated shareholders who are considering selling their Common Shares with the opportunity to sell their shares at the Original Offer Price without incurring the transaction costs typically associated with market sales.

•   The form of consideration to be paid to the Company’s unaffiliated shareholders is entirely in cash.

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•   The Original Offer and the Merger provide additional liquidity for the unaffiliated shareholders of the Company.

      Fairness of the Amended Offer — The rules of the SEC require Parent and Purchaser to express their belief as to the fairness of the Amended Offer and the Merger to shareholders of the Company who are not affiliated with Parent and Purchaser. Parent and Purchaser, as discussed above, continue to believe that the Original Offer Price offered to unaffiliated shareholders of the Company pursuant to the Original Offer and the Merger is fair to such unaffiliated shareholders. Therefore Parent and Purchaser believe that the Amended Offer Price, which represents an increase of $7 per share over the Original Offer Price, is fair to the unaffiliated shareholders of the Company.

      In addition to the factors set forth above that support Parent and Purchaser’s determination that the Original Offer Price is fair to unaffiliated shareholders of the Company, Parent and Purchaser considered the following factors in their determination that the Amended Offer Price is fair to unaffiliated shareholders of the Company:

•   The Amended Offer Price of $82.00 represents an increase of 9.3% over the Original Offer Price of $75.00, a premium of approximately 27.6% to the closing price of $64.25 for the Common Shares on February 3, 2006, the last trading day prior to the date on which Parent’s intention to make the Original Offer was announced, and a premium of 43.2% to the average closing price of $57.27 for the Common Shares during the three months prior to February 3, 2006. Parent and Purchaser do not believe that the post-announcement trading price of the Common Shares is indicative of the fair value of the Common Shares, and thus did not consider it when making an assessment as to the fairness of the Amended Offer and the Merger.

•   The supplemental materials provided by JPMorgan and BNP Paribas and summarized under “SPECIAL FACTORS — Section 4. Summary of JPMorgan and BNP Paribas Presentation to Parent’s Board of Directors” in this Supplement.

      In addition, Parent and Purchaser believe that the corporate process by which the Amended Offer and Merger are being pursued is fair to shareholders of the Company who are not affiliated with Parent and Purchaser, based on the following factors:

•   The Amended Offer is conditioned upon the tender of a number of Common Shares which, when taken together with the Exchangeable Preference Shares tendered pursuant to the Amended EPS Offer, constitute at least a majority of the Common Shares and Exchangeable Preference Shares, taken together as a single class, not owned by Parent, Purchaser, the Company, their respective officers and directors and the Lafarge Canada Stock Fund. This Minimum Tender Condition is not waivable. Parent and Purchaser believe that the Company’s unaffiliated shareholders are therefore able to evaluate the terms of the Amended Offer and its fairness without coercion. The effect of the Minimum Tender Condition is that the Amended Offer will not close unless the holders of a majority of the Common Shares and Exchangeable Preference Shares held by the unaffiliated shareholders of the Company tender their shares, which amounts to a “public referendum” on the Amended Offer.

•   Each of the Company’s unaffiliated shareholders will be able to decide voluntarily whether or not to tender such shareholder’s Common Shares in the Amended Offer and, if the Amended Offer and the Merger are completed and such shareholder elected not to tender, such shareholder will receive exactly the same type and amount of consideration in the Merger that such shareholder would have received in the Amended Offer.

•   The Company has appointed the Special Committee to evaluate the tender offer and the Special Committee has retained Merrill Lynch as it financial advisor and Simpson Thacher and Venable as its legal advisors.

      To the best of Parent’s and Purchaser’s knowledge, a majority of the directors of the Company who are not employees of the Company have not retained an unaffiliated representative to act solely on behalf

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of unaffiliated shareholders for purposes of preparing a report concerning the fairness of the transaction. However, based on the Company’s public disclosure that the Special Committee has retained Merrill Lynch as its financial advisor and Simpson Thacher and Venable as its legal advisors to assist it in considering the tender offer and in light of the procedural safeguards discussed above, Parent and Purchaser do not believe the failure to retain such a representative to be material.

      Neither Parent nor Purchaser found it practicable to assign, nor did either of them assign, relative weights to the individual factors considered in reaching their conclusion as to fairness. In reaching their conclusion as to fairness, neither Parent nor Purchaser considered the liquidation value of the Company’s assets because they consider the Company to be a viable going concern. In addition, the liquidation of the Company’s assets was not considered to be a viable course of action based on Parent’s desire for the Company to continue to conduct its business as a subsidiary of Parent and remain an integral component of Parent’s overall strategy. Therefore, no appraisal of liquidation value was sought for purposes of valuing the Common Shares, and Parent and Purchaser believe that the liquidation value of the Company is irrelevant to a determination as to whether the Amended Offer is fair to unaffiliated shareholders. Further, Parent and Purchaser did not consider net book value, which is an accounting concept, as a factor because they believed that net book value is not a material indicator of the value of the Company as a going concern but rather is indicative of historical costs. The Company’s net book value per share as of December 31, 2005, calculated by dividing shareholders’ equity by the number of shares of common stock outstanding, was $42.98. This value is substantially below the Amended Offer Price. Parent and Purchaser are not aware of any firm offers made for the Company during the two years prior to the Amended Offer and in any event have no intention of selling the Common Shares or Exchangeable Preference Shares owned by them, and therefore did not consider any such offers in reaching their conclusion as to fairness.

      Parent and Purchaser did not calculate a stand-alone going concern value of the Company, but did consider a comparison of certain financial, operating and stock market data and forecasted financial information for selected publicly traded companies to similar information for the Company, each of which supported the fairness determination of Parent and Purchaser. Parent considered that the going concern value was not a viable method of determining the value of the Common Shares for the purpose of this transaction. A valuation that contemplates the sale of a company as a going concern incorporates into that valuation a premium for the control of that company. In light of the fact that Parent already has, and will continue to have, control of the Company, Parent does not believe that it would be appropriate for the securities of the unaffiliated shareholders to be valued on a basis that includes a control premium. For the foregoing reasons, Parent does not believe that a “going concern” valuation would be a viable or appropriate method of determining the value of the Common Shares for the purposes of this transaction.

      The foregoing discussion of the information and factors considered by Parent and Purchaser is believed to include the material factors considered by Parent and Purchaser. Parent and Purchaser’s views as to the fairness of the Original Offer and Amended Offer to shareholders of the Company should not be construed as a recommendation to any shareholder as to whether that shareholder should tender such shareholder’s Common Shares or Exchangeable Preference Shares in the Amended Offer.

      Purchaser was formed solely for the purpose of engaging in the Original Offer and the Merger and, as such, did not perform a fairness determination with respect to either the Original Offer or the Amended Offer separate from that performed by Parent. In making a determination as to fairness, Purchaser relied entirely on and expressly adopted the analyses and conclusions of Parent.

4. Summary of JPMorgan and BNP Paribas Presentation to Parent’s Board of Directors

      A summary of the presentation of JPMorgan and BNP Paribas to the Parent’s board of directors on February 5, 2006 (the “February 5th Presentation”) is set forth in “SPECIAL FACTORS — Section 4. Summary of JPMorgan and BNP Paribas Presentation to the Parent’s Board of Directors” in the Offer to Purchase.

      The following is a summary of the material financial analyses contained in the supplemental presentation made by JPMorgan and BNP Paribas to Parent’s board of directors on April 3, 2006 (the

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“April 3rd Supplemental Presentation”). However, it does not purport to be a complete description of the analyses performed by JPMorgan and BNP Paribas or of their discussions with the board of directors of Parent.

      While JPMorgan and BNP Paribas were not asked to, nor did they, opine as to the fairness of the transaction to the unaffiliated shareholders of the Company, the financial analyses described below were provided to Parent with the understanding that Parent would use such analyses as part of its process of making its determination as to the fairness of the Amended Offer and the Merger. Had JPMorgan and BNP Paribas been requested to provide an opinion or recommend or provide support for a fair or appropriate valuation of the Common Shares not held by Parent and its affiliates, the information, comparisons and analyses presented by JPMorgan and BNP Paribas in the April 3rd Supplemental Presentation might have been different.

      The following summary is included here only for informational purposes and to comply with applicable disclosure requirements. The analyses described herein and the order in which they are presented and the results of the analyses do not represent relative importance or weight given to these analyses by JPMorgan and BNP Paribas. The full text of the April 3rd Supplemental Presentation summarized below is set forth in Exhibit (c)(ii) to Amendment No. 7 to the Schedule TO filed with the SEC on April 7, 2006 in connection with the Amended Offer. Copies of the February 5th Presentation and the April 3rd Supplemental Presentation may be made available for inspection and copying during regular business hours by any shareholder or its representative who has been designated in writing by contacting the Information Agent. Holders of Common Shares are urged to, and should, read such presentation materials in their entirety. Neither the April 3rd Supplemental Presentation nor this summary constitutes a recommendation as to whether holders of Common Shares should tender their shares in the Amended Offer or as to any other action any holder should take or refrain from taking in connection with the Amended Offer or the Merger.

      In preparing the April 3rd Supplemental Presentation, JPMorgan and BNP Paribas relied upon the accuracy and completeness of all of the financial, accounting and other information reviewed by them and assumed such accuracy and completeness for purposes of the April 3rd Supplemental Presentation and its presentation, and have not assumed any responsibility or liability therefor. JPMorgan and BNP Paribas were not asked to make, and did not assume responsibility for making, any independent verification of the information reviewed by them. In addition, JPMorgan and BNP Paribas did not conduct any valuation or appraisal of any assets or liabilities, nor have any such valuations or appraisals been provided to them. JPMorgan and BNP Paribas also assumed that there have been no material changes in the Company’s condition, results of operations, business or prospects since the date of the most recent financial statements made available to JPMorgan and BNP Paribas and JPMorgan and BNP Paribas do not have any obligation to update, revise or reaffirm the materials presented by them to Parent. JPMorgan and BNP Paribas based their analyses on assumptions that they deemed reasonable, including assumptions concerning general business and economic conditions and industry-specific factors. JPMorgan’s and BNP Paribas’ analyses are not necessarily indicative of actual values or actual future results that might be achieved, which values may be higher or lower than those indicated.

      In providing financial advice and preparing financial analysis, JPMorgan and BNP Paribas, among other things:

•   reviewed certain publicly available business and financial information concerning the Company and the sector in which the business operates;

•   compared the equity market capitalization and other current and historical financial metrics and multiples for the Company and certain other building materials companies;

•   reviewed the historical trading volumes and market prices of the Common Shares;

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•   reviewed the premia at various illustrative prices over certain historical prices, implied multiples and other financial metrics; and

•   performed such other financial studies and analyses and considered such other information as JPMorgan and BNP Paribas deemed appropriate during the course of providing financial advice.

      Some of the summaries of financial analyses described below include information presented in tabular format. In order to understand fully the financial analyses performed by JPMorgan and BNP Paribas, the tables must be read together with the text of each summary. The tables alone do not constitute a complete description of the financial analyses performed by JPMorgan and BNP Paribas. The following quantitative information, to the extent it is based on market data, is based on market data as it existed at or prior to March 31, 2006 and is not necessarily indicative of current or future market conditions.

      Analysis of Trading After Announcement of the Original Offer — JPMorgan and BNP Paribas analyzed the historic trading activity of the Company’s Common Shares between February 6, 2006 (the day of the public announcement of the Offer) and March 31, 2006. This analysis showed that, during this period, 32.8 million of the Company’s Common Shares were traded, representing 92.8% of the free float. A summary of the results follows:

Price range	<$81.00	$81.00 - $81.49	$81.50 - $81.99	$82.00 - $82.49	$	82.50 - $82.99	$	83.00 - $83.49	$	83.50 - $83.99	$	84.00 - $84.49	$	84.50 - $84.99	³$	85.00
% of total volume traded since Feb 6, 2006	6.5%	5.6%	35.8%	19.3%		19.1%		2.9%		8.0%		2.8%		0.0%		0.0%

	Volume weighted
Date range	average price		Volume traded		% total volume traded
Feb. 7, 2006	$	81.40		10,559,000		32.2%
8 days (Feb. 6, 2006 - Feb. 16, 2006)	$	81.92		11,501,900		35.1%
10 days (Feb. 17, 2006 - Mar. 3, 2006)	$	82.76		3,729,500		11.4%
10 days (Mar. 6, 2006 - Mar. 17, 2006)	$	83.10		4,679,500		14.3%
10 days (Mar. 20, 2006 - Mar. 31, 2006)	$	83.77		2,293,800		7.0%
Total period (Feb. 6, 2006 - Mar. 31, 2006)	$	82.15		32,763,700		100.0%

      Comparisons of Selected Publicly Traded Building Materials Companies — JPMorgan and BNP Paribas provided an updated version of the analysis in the February 5th Presentation in which they compared certain financial information of the Company and Parent with that of other listed building materials companies. A summary of the results follows:

	Metrics as of March 31, 2006
	FV/EBITDA						P/E
	2005A			2006E			2006E
U.S. company median		13.3	x		9.9	x		19.3	x
U.S. company mean		13.0	x		10.2	x		19.2	x
Non-U.S. company median		8.8	x		7.4	x		13.7	x
Non-U.S. company mean		8.8	x		7.8	x		14.1	x
Parent		7.7	x		6.9	x		13.1	x
Company	not meaningful

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      Analysis at Various Prices — JPMorgan and BNP Paribas reviewed the premia at various hypothetical stock prices over certain historical prices, implied multiples and other financial metrics. A summary of the results follows:

						Illustrative Price Per Share
	As of		Original Offer
	Feb. 3, 2006		$75.00			$80.00			$81.00			$82.00			$83.00			$84.00
Implied premium over pre-Original Offer prices:
Feb. 3, 2006	$	64.25		16.7	%		24.5	%		26.1	%		27.6	%		29.2	%		30.7	%
3 month average		57.27		31.0	%		39.7	%		41.4	%		43.2	%		44.9	%		46.7	%
30-calendar day average		60.83		23.3	%		31.5	%		33.2	%		34.8	%		36.4	%		38.1	%
1-week average		63.64		17.9	%		25.7	%		27.3	%		28.8	%		30.4	%		32.0	%
Implied multiples:
FV/ 2005A EBITDA				7.7	x		8.2	x		8.3	x		8.4	x		8.5	x		8.6	x
FV/ 2006E EBITDA				7.2	x		7.7	x		7.8	x		7.9	x		8.0	x		8.1	x
P/ 2005A EPS				17.6	x		18.8	x		19.1	x		19.3	x		19.6	x		19.8	x
P/ 2006E EPS				16.5	x		17.6	x		17.9	x		18.1	x		18.3	x		18.6	x

      Each of JPMorgan and BNP Paribas, as part of its investment banking business, is continually engaged in the valuation of businesses and their securities in connection with mergers and acquisitions, negotiated underwritings, competitive biddings, secondary distributions of listed and unlisted securities, private placements and valuations for corporate and other purposes. Each of JPMorgan and BNP Paribas is familiar with Parent, having acted as its financial advisor in connection with the Amended Offer and has also provided certain investment banking services to Parent from time to time, and may provide investment banking services to Parent in the future. Each of JPMorgan and BNP Paribas provides a full range of financial advisory and securities services and, in the course of its normal trading activities, may from time to time effect transactions and hold securities, including derivative securities, of Parent and the Company for its own account and for the account of customers. In selecting JPMorgan and BNP Paribas to represent Parent as its financial advisors, Parent considered primarily JPMorgan’s and BNP Paribas’ qualifications and knowledge of the business affairs of Parent, as well as the reputations of JPMorgan and BNP Paribas as internationally recognized investment banking firms that have substantial experience in transactions similar to the Amended Offer.

      A description of the compensation that JPMorgan and BNP Paribas are entitled to receive in connection with their service to Parent as financial advisors and Dealer Managers is set forth in “SPECIAL FACTORS — Section 4. Summary of JPMorgan and BNP Paribas Presentation to the Parent’s Board of Directors” in the Offer to Purchase. JPMorgan and BNP Paribas have agreed to provide financing for the Amended Offer, as described in “The OFFER — Section 9. Source and Amount of Funds” in this Supplement, for which they will receive customary compensation.

5. Certain Projected Company Financial Information

      A discussion of certain projected financial information is set forth in “SPECIAL FACTORS — Section 5. Certain Projected Financial Data” in the Offer to Purchase.

6. Effects of the Amended Offer and the Merger

      A discussion of certain effects of the Amended Offer and the Merger is set forth in “SPECIAL FACTORS — Section 6. Effects of the Offer and the Merger” in the Offer to Purchase.

7. Conduct of the Company’s Business if the Amended Offer is not Completed

      A discussion of the conduct of the Company’s business if the Amended Offer is not completed is set forth in “SPECIAL FACTORS — Section 7. Conduct of the Company’s Business if the Offer is not Completed” in the Offer to Purchase.

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8. Dissenters’ Appraisal Rights; Rule 13e-3

      A discussion of dissenters’ appraisal rights and rules under the Exchange Act applicable to “going private” transactions is set forth in “SPECIAL FACTORS — Section 8. Dissenters’ Appraisal Rights; Rule 13e-3” in the Offer to Purchase.

9. Transactions and Arrangements Concerning the Common Shares and Exchangeable Preference Shares

      The final paragraph of the discussion of certain transactions and arrangements concerning the Common Shares and Exchangeable Preference Shares set forth in “SPECIAL FACTORS — Section 9. Transactions and Arrangements Concerning the Common Shares and Exchangeable Preference Shares” in the Offer to Purchase is hereby amended and supplemented as follows:

      Parent and Purchaser believe that Messrs. Bertrand P. Collomb, Bruno Lafont, Bernard L. Kasriel and Michel Rose, who are affiliates of Parent and members of the Company’s Board of Directors, will tender their Common Shares in the Amended Offer. As of the date hereof, (i) to the best of their knowledge, neither Parent nor Purchaser knows whether any other executive officer, director or affiliate of the Company intends to tender Common Shares in the Amended Offer or Exchangeable Preference Shares in the Amended EPS Offer, (ii) the Company has recommended that the shareholders of the Company reject the Original Offer and not tender their Common Shares, (iii) none of the Company, its executive officers, directors or affiliates have made any public recommendation with respect to the Amended Offer and (iv) the Company has not made public any appraisal, report or opinion on the fairness of this transaction. The Amended Offer and Merger have not been approved by a majority of the directors of the Company who are not employees of the Company.

10. Related Party Transactions; Certain Transactions Between Parent and the Company

      A discussion of related party transactions and certain transactions between Parent and the Company is set forth in “SPECIAL FACTORS — Section 10. Related Party Transactions; Certain Transactions Between Parent and the Company” in the Offer to Purchase.

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THE OFFER

1. Terms of the Amended Offer

      The discussion set forth in “THE OFFER — Section 1. Terms of the Offer” is hereby amended and supplemented as follows:

      Purchaser has amended the Original Offer to purchase the Common Shares. The price per Common Share to be paid has been increased from $75.00 per Common Share in the Original Offer to $82.00 per Common Share in the Amended Offer, net to seller in cash, without interest, upon the terms and subject to the conditions of the Amended Offer. All shareholders whose Common Shares are validly tendered (including Common Shares tendered and not withdrawn prior to the date of this Supplement), not withdrawn and accepted for payment on or prior to the Expiration Date will receive the Amended Offer Price.

      Upon the terms and subject to the conditions of the Amended Offer (including, if the Amended Offer is extended or amended, the terms and conditions of any such extension or amendment), Purchaser will accept for payment and will pay for all Common Shares validly tendered prior to the Expiration Date and not withdrawn in accordance with “THE OFFER — Section 4. Withdrawal Rights” in this Supplement. The term “Expiration Date” means 12:00 midnight, New York City time, on Friday, April 28, 2006, or, if the Amended Offer is extended, the latest time and date at which the Amended Offer, as extended, will expire.

2. Acceptance for Payment and Payment for Common Shares

      Purchaser will accept for payment, and will pay for, the Common Shares in the Amended Offer as set forth in “THE OFFER — Section 2. Acceptance for Payment and Payment for Common Shares” in the Offer to Purchase.

3. Procedure for Accepting the Amended Offer and Tendering Common Shares

      The discussion set forth in “THE OFFER — Section 3. Procedure for Accepting The Offer and Tendering Common Shares” is hereby amended and supplemented as follows:

      Shareholders tendering shares may use the original (yellow) Letter of Transmittal that was distributed with the Offer to Purchase or the revised (pink) Letter of Transmittal distributed with this Supplement and will nevertheless receive $82.00 per Common Share, upon the terms and subject to the conditions of the Amended Offer. Although the original (yellow) Letter of Transmittal and the original (blue) Notice of Guaranteed Delivery previously circulated with the Offer to Purchase refer only to the Offer to Purchase, shareholders using such documents to tender their Common Shares will nevertheless be deemed to be tendering pursuant to the Amended Offer and will receive the Amended Offer Price described in this Supplement, if Common Shares are accepted for payment and paid for by Purchaser pursuant to the Amended Offer. Shares previously validly tendered and not withdrawn constitute valid tenders for purposes of the Amended Offer. Shareholders are not required to take any further action with respect to such Common Shares in order to receive the Amended Offer Price of $82.00 per Common Share, if Common Shares are accepted for payment and paid for by Purchaser pursuant to the Amended Offer, except as may be required by the guaranteed delivery procedure if such procedure was utilized.

4. Withdrawal Rights

      The withdrawal rights pursuant to the Amended Offer are set forth in “THE OFFER — Section 4. Withdrawal Rights” in the Offer to Purchase.

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5. Material United States Federal Income Tax Consequences of the Amended Offer

      Material United States federal tax income consequences of the Amended Offer are summarized in “THE OFFER — Section 5. Material United States Federal Income Tax Consequences of the Offer” in the Offer to Purchase.

6. Price Range of Shares; Dividends

      The discussion set forth in “THE OFFER — Section 6. Price Range of Shares; Dividends” in the Offer to Purchase is hereby amended and supplemented as follows:

      The Common Shares are listed on the NYSE and the TSX under the symbol “LAF”. The following table sets forth, for each of the fiscal quarters indicated, the high and low closing prices per Common Share on the NYSE.

		Common Stock
		High		Low
Fiscal Year 2004
	First Quarter	$	43.39	$	39.80
	Second Quarter		45.03		40.88
	Third Quarter		47.42		41.30
	Fourth Quarter		51.55		47.65
Fiscal Year 2005
	First Quarter	$	63.75	$	50.72
	Second Quarter		62.59		52.47
	Third Quarter		69.78		62.99
	Fourth Quarter		69.02		53.27
Fiscal Year 2006
	First Quarter	$	84.14	$	57.57
	Second Quarter (through April 6)	$	85.28	$	84.36

      On February 3, 2006, the last trading day prior to the public announcement of the Offer, the per share closing price of the Common Shares on the NYSE was $64.25. On February 17, 2006, the last trading day prior to the commencement of the Original Offer, the per share closing price of the Common Shares on the NYSE was $82.35. On April 3, 2006, the last trading day prior to the public announcement of the Amended Offer, the per share closing price of the Common Shares on the NYSE was $84.36. On April 6, 2006, the last trading day prior to the commencement of the Amended Offer, the per share closing price of the Common Shares on the NYSE was $85.19. Shareholders are urged to obtain a current market quotation for the Common Shares.

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      The following table sets forth, for each of the fiscal quarters indicated, dividend paid by the Company on the Common Shares.

		Common Stock
		Dividends Paid
Fiscal Year 2004
	First Quarter	$	0.20
	Second Quarter		0.20
	Third Quarter		0.22
	Fourth Quarter		0.22
Fiscal Year 2005
	First Quarter	$	0.22
	Second Quarter		0.22
	Third Quarter		0.24
	Fourth Quarter		0.24
Fiscal Year 2006
	First Quarter	$	0.24

      The Company currently pays a quarterly dividend of $0.24; however, the declaration and payment of dividends on Common Shares by the Company is subject to the discretion of the Company’s board of directors and there can be no assurance whether or when dividends will be paid. In addition, a subsidiary of Lafarge Canada issued certain redeemable preferred shares in connection with its 2000 acquisition of Warren Paving and Materials Group, which preferred shares are entitled to receive cumulative, preferential cash dividends at the annual rate of 6.0% of the issue price (the issue price being C$166.4 million). The Company has also agreed not to pay any dividends on the Common Shares unless it also declares a dividend in the same amount on the Exchangeable Preference Shares. The Company is also party to a five-year revolving credit facility that imposes certain limitations on the ability of the Company to pay dividends. Each of the foregoing may impact the ability of the Company to pay dividends in the future.

7. Certain Information Concerning the Company

      Certain information concerning the Company is set forth in “THE OFFER — Section 7. Certain Information Concerning the Company” in the Offer to Purchase.

8. Certain Information Concerning Purchaser and Parent

      Certain information concerning Purchaser and Parent is set forth in “THE OFFER — Section 8. Certain Information Concerning Purchaser and Parent” in the Offer to Purchase.

9. Source and Amount of Funds

      The discussion set forth in “THE OFFER — Section 9. Source and Amount of Funds” of the Offer to Purchase is hereby amended and supplemented as follows:

      Pursuant to the terms of the $2,800,000,000 Credit Facility, Parent obtained the consent of BNP Paribas and J.P. Morgan plc to increase the price offered to shareholders in the tender offer from $75.00 per share to $82.00 per share.

10. Dividends and Distributions

      The treatment of dividends and distributions with respect to the Common Shares pursuant to the Amended Offer is set forth in “THE OFFER — Section 10. Dividends and Distributions” in the Offer to Purchase.

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11. Conditions to the Amended Offer

      The discussion set forth in “THE OFFER — Section 11. Conditions to the Offer” of the Offer to Purchase is hereby amended and restated as follows:

      Notwithstanding any other provision of the Amended Offer, and in addition to (and not in limitation of) Purchaser’s rights to extend and amend the Amended Offer at any time in its sole discretion, Purchaser will not be required to accept for payment any tendered Common Shares, and may amend or terminate the Amended Offer, if (i) at the Expiration Date the Minimum Tender Condition has not been satisfied or (ii) at any time on or after February 5, 2006 and prior to the Expiration Date, any of the following events has occurred:

•   there has not been validly tendered and not withdrawn a sufficient number of Common Shares such that, upon acceptance for payment and payment for the tendered Common Shares pursuant to the Amended Offer (and taking into account any Exchangeable Preference Shares to be accepted for payment pursuant to the Amended EPS Offer), Parent will, directly or through wholly-owned subsidiaries, own a number of Common Shares and Exchangeable Preference Shares representing at least 90% of the issued and outstanding Common Shares and Exchangeable Preference Shares, taken together as a single class, as of the date the Common Shares are accepted for payment pursuant to the Amended Offer (as defined in the “INTRODUCTION”);

•   any change (or any condition, event or development involving a prospective change) has occurred in the business, properties, assets, liabilities, capitalization, shareholders’ equity, condition (financial or otherwise), cash flows, licenses, franchises, permits, authorizations, operations, results of operations or prospects of the Company that has or is reasonably expected to have a material adverse effect on the Company (an “Adverse Effect”), or results or is reasonably expected to result in a material diminution in the value of the Common Shares or the benefits expected to be derived by Purchaser or Parent as a result of the transactions contemplated by the Amended Offer or the Merger (a “Diminution in Value”);

•   there has been instituted by, or there is pending before, any government or governmental authority or agency or other regulatory or administrative agency or commission, whether domestic (local, state or federal), foreign or supranational, court or arbitral panel or any self-regulatory organization (a “Governmental Entity”), any action, proceeding, application, claim or counterclaim or any judgment, ruling, order or injunction sought or any other action taken by any person or entity which (i) challenges the acquisition by Parent or Purchaser of any Common Shares pursuant to the Amended Offer or the Merger, seeks to restrain, prohibit, delay or increase the cost of the making or completion of the Offer or consummation of the Merger, or would otherwise adversely affect the Amended Offer or the Merger, (ii) seeks to prohibit or materially limit the ownership or operation by the Company, Parent or Purchaser (or any other affiliate of Parent) of all or any material portion of the business or assets of the Company or of Parent and its affiliates taken as a whole, or to compel the Company, Parent or Purchaser (or any other affiliate of Parent) to dispose of or to hold separate all or any material portion of the business or assets of Parent and its affiliates taken as a whole or of the Company as a result of the transactions contemplated by the Amended Offer or the Merger, (iii) seeks to impose any material limitation on the ability of the Company, Parent or Purchaser (or any other affiliate of Parent) to conduct their respective businesses or own such assets, (iv) seeks to impose or confirm any material limitation on the ability of Parent or Purchaser (or any other affiliate of Parent) to acquire or hold, or to exercise full rights of ownership of, any Common Shares, including the right to vote such Common Shares on all matters properly presented to the shareholders of the Company, (v) seeks to require divestiture by Parent or Purchaser (or any other affiliate of Parent) of any or all of the Common Shares, (vi) otherwise has or is reasonably expected to have an Adverse Effect, or results or is reasonably expected to result in a Diminution in Value, or (vii) seeks to impose any condition to the Amended Offer materially burdensome to Parent or Purchaser;

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•   there has been entered or issued any preliminary or permanent judgment, order, decree, ruling or injunction or any other action taken by any Governmental Entity, whether on its own initiative or the initiative of any other person, which (i) restrains, prohibits or delays or increases the cost of the making or completion of the Amended Offer or consummation of the Merger, or otherwise adversely affects the Offer or the Merger, (ii) prohibits or materially limits the ownership or operation by the Company, Parent or Purchaser (or any other affiliate of Parent) of all or any material portion of the business or assets of the Company or of Parent and its affiliates taken as a whole, or compels the Company, Parent or Purchaser (or any other affiliate of Parent) to dispose of or to hold separate all or any material portion of the business or assets of Parent and its affiliates taken as a whole or of the Company as a result of the transactions contemplated by the Amended Offer or the Merger, (iii) imposes any material limitation on the ability of the Company, Parent or Purchaser (or any other affiliate of Parent) to conduct their respective businesses or own such assets, (iv) imposes or confirms any material limitation on the ability of Parent or Purchaser (or any other affiliate of Parent) to acquire or hold, or to exercise full rights of ownership of, any Common Shares, including the right to vote such Common Shares on all matters properly presented to the shareholders of the Company, (v) requires divestiture by Parent or Purchaser (or any other affiliates of Parent) of any or all of the Common Shares, (vi) otherwise has or is reasonably expected to have an Adverse Effect, or results or is reasonably expected to result in a Diminution in Value, or (vii) imposes any condition to the Amended Offer materially burdensome to Parent or Purchaser

•   there has been any statute, rule or regulation enacted, promulgated, entered, enforced, or deemed applicable or asserted to be applicable to the Amended Offer or the Merger by any Governmental Entity or by the Company, or any other action has been taken by any Governmental Entity or the Company, that results or would result in any of the consequences referred to in clauses (i) through (vii) of the paragraph above;

•   there has occurred (i) any general suspension of trading in, or limitation on times or prices for, securities on any United States national securities exchange, or in the over-the-counter market, (ii) any extraordinary or material adverse change in the United States financial markets generally, including without limitation, a decline of at least 20% in either the Dow Jones average of industrial stocks or the Standard & Poor’s 500 index from February 5, 2006, (iii) any declaration of a banking moratorium or any suspension of payments in respect of banks in the United States, (iv) any material limitation by any Governmental Entity or any court that materially affects the extension of credit generally by lenders that regularly participate in the United States or European market in loans, (v) any commencement or escalation of war, terrorist acts, armed hostilities or other national or international calamity directly or indirectly involving the United States or Europe, (vi) a suspension of, or limitation (whether or not mandatory) on, the currency exchange markets or the imposition of, or material changes in, any currency or exchange control laws in the United States or France or (vii) in the case of any of the foregoing occurrences existing on or at the time of the commencement of the Original Offer, a material acceleration or worsening thereof;

•   the Company and Purchaser or Parent have reached an agreement or understanding that the Amended Offer be terminated or amended or Parent or Purchaser (or one of their respective affiliates) have entered into a definitive agreement or an agreement in principle to acquire the Company by merger or other business combination, or purchase of Common Shares or assets of the Company;

•   the Company has (i) issued, distributed, pledged, sold or authorized, or proposed the issuance of or distribution, pledge or sale to any person of any (A) shares of its capital stock of any class, including, without limitation, the Common Shares or the Exchangeable Preference Shares (other than the issuance of Common Shares upon the exercise of stock options and warrants outstanding on February 5, 2006 and the exchange of Exchangeable Preference Shares) or securities convertible into or exchangeable for any such shares of capital stock, or any rights, warrants or options to acquire any such shares or convertible securities or any other securities of the Company or any

22

	other person, (B) other securities in respect of, in lieu of or in substitution for Shares outstanding on February 5, 2006, or (C) debt securities or any securities convertible into or exchangeable for debt securities or any rights, warrants or options entitling the holder thereof to purchase or otherwise acquire any debt securities, (ii) purchased or otherwise acquired, or proposed or offered to purchase or otherwise acquire, any outstanding Common Shares or other securities, (iii) proposed, recommended, authorized, declared, issued or paid any dividend or distribution on any Common Shares or any other security, whether payable in cash, securities or other property, other than the payment of the dividend in the amount of $0.24 already declared by the Company and paid on March 1, 2006, (iv) altered or proposed to alter any material term of any outstanding security, (v) incurred, agreed to incur or announced its intention to incur, any debt other than in the ordinary course of business and consistent with past practice, (vi) authorized, recommended, proposed or publicly announced its intent to enter into any merger, consolidation, liquidation, dissolution, business combination, acquisition or disposition of assets or securities other than in the ordinary course of business, any material change in its capitalization or business operations, any release or relinquishment of any material contractual or other rights or any comparable event, or taken any action to implement any such transaction previously authorized, recommended, proposed or publicly announced or (vii) entered into or amended any other agreement or otherwise effected any other arrangement with any other party or with its officers or other employees of the Company that might, individually or in the aggregate, have an Adverse Effect or result in a Diminution in Value;
•	the Company has amended, or proposed or authorized any amendment to, its certificate of incorporation or by-laws or similar organizational documents or Purchaser has learned that the Company has proposed, adopted or recommended any such amendment which has not previously been publicly disclosed by the Company and also set forth in filings with the SEC;
•	a tender or exchange offer for some portion or all of the Common Shares and/or Exchangeable Preference Shares has been commenced or publicly proposed to be made by another person (including the Company), or it shall have been publicly disclosed or Purchaser has learned that (i) any person (including the Company), entity or “group” (as defined in Section 13(d)(3) of the Exchange Act) has acquired or proposed to acquire more than five percent of the Common Shares and Exchangeable Preference Shares, taken together as a single class, or has been granted any option or right, conditional or otherwise, to acquire more than five percent of the Common Shares or Exchangeable Preference Shares, taken together as a single class, other than acquisitions for bona fide arbitrage purposes and other than acquisitions by persons or groups who have publicly disclosed in a Schedule 13D or 13G (or amendments thereto on file with the SEC) such ownership on or prior to February 5, 2006, (ii) any such person, entity or group who has publicly disclosed any such ownership of more than five percent of the Common Shares and Exchangeable Preference Shares, taken together as a single class, prior to such date has acquired or proposed to acquire additional Common Shares and or Exchangeable Preference Shares constituting more than one percent of the Common Shares and Exchangeable Preference Shares, taken together as a single class, or has been granted any option or right to acquire more than one percent of the Common Shares and Exchangeable Preference Shares, taken together as a single class, (iii) any such person, entity or group shall have entered into a definitive agreement or an agreement in principle or made a proposal with respect to a tender offer or exchange offer for some portion or all of the Common Shares and/or Exchangeable Preference Shares, or a merger, consolidation or other business combination or sale of assets (other than in the ordinary course of business) with or involving the Company or (iv) any person has filed a Notification and Report Form under the HSR Act (as defined herein) or made a public announcement reflecting an intent to acquire the Company or assets or securities of the Company;
•	any change (or any condition, event or development involving a prospective change) has occurred or is threatened in the general economic, financial, currency exchange or market conditions in the

23

United States or abroad that has or might have an Adverse Effect or results or might result in a Diminution in Value;

•

the Company has transferred into trust, escrow or similar arrangement any amounts required to fund any existing benefit, employment or severance agreements with any of its employees or shall have entered into with its employees or otherwise effected any additional benefit, employment, severance or similar agreements, arrangements or plans other than in the ordinary course of business, or entered into or amended any agreements, arrangements or plans with an employee or employees so as to provide for increased benefits as a result of or in connection with the transactions contemplated by the Amended Offer or the Merger, which in each case with respect to every matter referred to above makes it inadvisable to proceed with the Amended Offer or with the acceptance for payment of, or the payment for, the Common Shares.

      The foregoing conditions are for the sole benefit of Parent, Purchaser and their respective affiliates (other than the Company) and may be asserted by Parent or Purchaser regardless of the circumstances (including any action or inaction by Parent or Purchaser) giving rise to any such conditions or may be waived by Parent or Purchaser, in whole or in part, at any time and from time to time in the sole discretion of Parent or Purchaser. The Minimum Tender Condition may not be waived by Parent or Purchaser. The failure by Parent or Purchaser at any time to exercise its rights under any of the foregoing conditions will not be deemed a waiver of any such rights and each such right will be deemed an ongoing right which may be asserted at any time or from time to time prior to the Expiration Date of the Amended Offer.

12. Effect of the Amended Offer on the Market for the Common Shares; NYSE and TSX Quotation; Exchange Act Registration and Margin Regulations

      The discussion set forth in “THE OFFER — Section 12. Effect of the Offer on the Market for the Common Shares; NYSE and TSX Quotation; Exchange Act Registration and Margin Regulations” in the Offer to Purchase is hereby amended and supplemented as follows:

      According to the Company’s shareholder list, as of April 4, 2006, there were 73,362,967 Common Shares outstanding held by 3,130 holders of record.

13. Certain Legal Matters; Regulatory Approvals

      The discussion of certain legal matters set forth in “THE OFFER — Section 13. Certain Legal Matters; Regulatory Approvals” is amended and supplemented as follows:

      The eight pending cases filed by shareholders in the Circuit Court for Baltimore City, Maryland, were transferred to the Circuit Court for Montgomery County, Maryland, where two other cases were pending. Nine of these outstanding ten Maryland cases, each involving claims by holders of Common Shares, have been consolidated under the caption Rice v. Lafarge v. Lafarge North America Inc., et al. (268974-V). The tenth case, Sheldon and Esther Schwartz v. Lafarge North America Inc. et al. (270410) involves holders of Exchangeable Preference Shares and has not been consolidated. The complaint filed in the Circuit Court for Fairfax County Virginia, captioned Alaska Electrical Pension Fund v. Lafarge, S.A. (C.A. No. CL 2006 2118) has not been consolidated.

      Plaintiffs in the Rice case filed an amended complaint on March 28, 2006, and on March 29, 2006 filed a motion for a temporary restraining order and/or a preliminary injunction to enjoin the Offer. On March 31, 2006, the Circuit for Montgomery County denied plaintiffs’ motion.

      The outstanding complaints allege (1) breaches of fiduciary duty by the Parent, the Company and the members of the Company board in connection with the Offer and Merger; (2) that the consideration the Parent is offering is inadequate; (3) that the Parent is acting to further its own interests at the expense of the Company’s minority shareholders; (4) that the Special Committee lacks sufficient independence to protect the Company’s minority shareholders; and (5) that the Offer is materially misleading.

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      The complaints generally allege that the consideration the Parent is offering is inadequate because (1) the Parent dominates and controls the Company, and is in possession of private corporate information about the Company’s assets, businesses and future prospects; (2) $75 is only a 6.4% premium over the highest trading price the Company’s common stock reached in the 52 weeks up to February 3, 2006; (3) prior to February 3, 2006, the Company’s trading price for its common shares had been close to its level of book value and cash per share; (4) it does not adequately take into account the significant value of the Company’s technologies and/or patents; (5) it does not adequately reflect the expected growth in the Company’s profitability, in light of its continued growth in sales and profits; (6) on February 16, 2006, the Company informed Parent that it was expecting to exceed its 2006 Budget numbers which had just recently been formulated and which had been very positive, and that projections used by Parent for the Company in formulating the Offer were based on a discount to the original 2006 Budget numbers sent to Parent by the Company; (7) the recent projections by various securities analysts following the Company based on the Company’s own publicly announced financials and projections, as well as industry-wide projections and statements by the Company’s competitors, are far more optimistic about the Company’s and the North American marketplace’s future prospects than those used by Parent’s financial advisors in formulating the Offer; (8) in October, 2005, just one month prior to engaging its financial advisors, Parent announced that it would have trouble meeting its full-year profit target as a result of a decline in North American demand, which announcement allegedly sent the Company’s stock price lower by 9.2%, as compared to the Bloomberg Europe index, which was flat, and Bloomberg US index, which fell 2.1%. The Company’s stock price eventually recovered, in line with the US index, but from a lower base; (9) the analyses by the Parent’s financial advisors are flawed because they rely on comparisons of the Company to European rather than North American companies; (10) the emphasis by Parent’s financial advisors on the fact that the Company had lower total shareholder returns than other U.S. building material companies, among other comparables, is flawed in that it ignores that, unlike most other U.S. building companies, the Company is a majority-controlled company which explains such lower comparables; and (11) the analyses by the Parent’s financial advisors of the premiums paid in precedent transactions by controlling shareholders are incomplete, and, thus of limited utility, because, while they purport to show implied multiples, they do not show transaction multiples for precedent transactions, nor do they contain multiples, there is not enough detail provided to verify the summary results, nor do they provide transaction multiples for precedent industry transactions.

      The Complaints allege the Offer is materially misleading because, among other things, they assert that: (1) the Offer omits the Company’s current financial projections and instead reports the reliance by JPMorgan and BNP Paribas on highly questionable financial projections; (2) JPMorgan and BNP Paribas did not prepare an independent set of financial projections for the Company, but instead relied upon the Company’s 2006 Budget numbers, the Parent’s 2006 financial projections for the Company, and the Parent’s pessimistic financial projections for the Company based on a “sensitivity analysis” which assumes a severe erosion of conditions in the North American market; (3) when compared to those of various analysts whose estimates concerning the Company were recently published, the projections employed by JPMorgan and BNP Paribas are the lowest; (4) the Company’s 2006 Budget numbers relied upon by JPMorgan and BNP Paribas were stale by the time the Offer was made, and the Parent’s 2006 projections less credible, because on February 16 the Company advised the Parent that its financial performance in 2006 would likely exceed the numbers in the 2006 budget; (5) continuing favorable conditions in North America, including higher prices and strong demand, are expected to generate earnings growth for the Company and its competitors, including Vulcan and Florida Rock, making highly suspect the “sensitivity analysis” prepared by Parent relative to its 2007 projections for the Company, which assumes an erosion of conditions in the North American marketplace; (6) the valuations in the Offer misleadingly fail to disclose the Company’s recently improved financial results, as in the Company’s announced Fourth Quarter and year-end 2005 financial results, which reported a 14% increase in net sales and a 27% increase in operating income from the same quarter of the prior year, with full-year sales up 15% and operating income up 18%; (7) the analyses by JPMorgan and BNP Paribas are also misleading, and flawed, because they rely on comparisons of the Company to European rather than North American companies and, at least according to some analysts, the Company has exposure to markets more similar to other U.S. and North American

25

and not European peers. Furthermore, a comparison of the daily stock price returns for the Company to (a) the Bloomberg Europe Building Materials Index and (b) the Bloomberg U.S. Building Materials Index indicates a much stronger correlation with the Company’s North American competitors. Using an EV/ EBITDA multiple of 8X (a U.S. industry multiple) results in an implied value for the Company’s common stock in the $90 per share range; (8) the Offer is misleading because Parent and Purchaser fail to disclose the positive aspects of the Company’s geographic presence such as the facts that (i) the Company’s presence in Western Canada, where oil prices have triggered a surge in construction markets, is a positive; (ii) a major aggregate operation on Texada Island, B.C. shipping aggregate into the California market addresses a growth market; (iii) the Company has a strong presence in the Chicago market, which is a good market with significant upside potential and (iv) the Company’s primary presence in the interior of North America is actually a significant plus-factor in that the interior market is protected from imports; (9) the Offer fails to disclose the true reasons for the Company’s historically depressed multiples, namely, that by virtue of the fact that Parent controls in excess of 50% of the Company’s shares, no other third party buyer would be interested, nor able, to make a bid for control of the Company; (10) the Offer omits key information regarding precedent going-private transactions analysis. The Offer describes an analysis done by JPMorgan and BNP Paribas of the premiums paid in purported precedent going-private transactions by controlling shareholders, but there is no disclosure as to which specific transactions they considered, and no details on these transactions, such as who the targets were, or the multiples to sales, EBITDA, or earnings at which the transactions were priced, are provided. Further, a review of Mergerstat data on “going-private” transactions allegedly performed by consultants to shareholder plaintiffs shows that from 1999-2005, the median premium price ultimately paid above the 1-week prior trading price was 35%. A 35% premium over the Company’s 1-week price of $64.00 indicates a fair premium value in excess of $86.00 per share; (11) the Offer omits any precedent industry transactions analysis, and a recent analysis allegedly prepared by consultants to shareholder plaintiffs demonstrates that the median EV/ EBIT and EV/ EBITDA multiples paid for transactions announced between 2/1/00-2/1/06, were 12.1x and 8.8x, respectively. Applying these multiples to the Company’s 2005 EBIT and EBITDA results in an implied value of $86.00-$90.00 per share; (12) the Offer is not credible because it states Parent and Purchaser “believe that the Offer Price to be received by the unaffiliated shareholders of the Company pursuant to the Offer and the Merger is fair to such unaffiliated shareholders” notwithstanding that the “Offer Price” is $75 per share and the Company’s stock currently trades at about $83 per share; (13) JPMorgan and BNP Paribas have not taken any position on the fairness of the price and have not provided any fairness opinion stating that they actually believe that $75 per share is a fair price to the Company’s minority shareholders; (14) the Offer omits material information with respect to the fees to be paid to JPMorgan and BNP Paribas for their work in connection with the Tender Offer. In addition to acting as the financial advisor to Parent and providing it with valuations used in the Offer JPMorgan and BNP Paribas have also entered into credit agreements with Parent. These agreements contemplate that JPMorgan and BNP Paribas will provide financing to complete the Offer and Merger for which they will be handsomely paid. There is no disclosure regarding the additional compensation JPMorgan and BNP Paribas will receive for financing the Offer and Merger; (15) the Offer fails to include much of the data used in the financial evaluations prepared by Parent, JPMorgan and BNP Paribas for which Parent claims that $75 per share is fair; (16) the Offer fails to present any discounted cash flow analysis for the Company, even though such an analysis is a standard measure used by valuation professionals to determine a present value of a company’s projections for future growth.

14. Fees and Expenses

      A discussion of fees and expenses with respect to the Amended Offer is set forth in “THE OFFER — Section 14. Fees and Expenses” in the Offer to Purchase.

26

15. Miscellaneous

      The discussion set forth in “THE OFFER — Section 15. Miscellaneous” in the Offer to Purchase is hereby amended and supplemented as follows:

      The Amended Offer is being made solely by this Supplement, the Offer to Purchase and the revised (pink) Letter of Transmittal and is being made to the holders of Common Shares other than Parent and its subsidiaries. Purchaser is not aware of any state where the making of the Amended Offer is prohibited by administrative or judicial action pursuant to any valid state statute. If Purchaser becomes aware of any valid state statute prohibiting the making of the Amended Offer or the acceptance of the Common Shares pursuant thereto, Purchaser will make a good faith effort to comply with such statute or seek to have such statute declared inapplicable to the Amended Offer. If, after such good faith effort, Purchaser cannot comply with such state statute, the Amended Offer will not be made to (nor will tenders be accepted from or on behalf of) holders of Common Shares in such state.

      NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY REPRESENTATION ON BEHALF OF PARENT OR PURCHASER NOT CONTAINED HEREIN, IN THE OFFER TO PURCHASE OR IN THE REVISED (PINK)LETTER OF TRANSMITTAL AND, IF GIVEN OR MADE, SUCH INFORMATION OR REPRESENTATION MUST NOT BE RELIED UPON AS HAVING BEEN AUTHORIZED.

      Purchaser and Parent have filed with the SEC Amendment No. 7 to the Tender Offer Statement on Schedule TO pursuant to Rule 14d-3 under the Exchange Act, together with all exhibits thereto, furnishing certain additional information with respect to the Amended Offer, which includes the information required by Schedule 13E-3. Such Schedule TO and any amendments thereto, including exhibits, should be available for inspection and copies should be obtainable in the same manner described in “THE OFFER — Section 7. Certain Information Concerning the Company — Available Information” in the Offer to Purchase.

      EXCEPT AS OTHERWISE SET FORTH IN THIS SUPPLEMENT AND IN THE REVISED (PINK) LETTER OF TRANSMITTAL, THE TERMS AND CONDITIONS PREVIOUSLY SET FORTH IN THE OFFER TO PURCHASE REMAIN APPLICABLE IN ALL RESPECTS TO THE AMENDED OFFER, AND THIS SUPPLEMENT SHOULD BE READ IN CONJUNCTION WITH THE OFFER TO PURCHASE AND RELATED LETTER OF TRANSMITTAL, AS THE SAME HAVE BEEN AMENDED.

Efalar Inc.

April 7, 2006

27

      Manually-executed facsimile copies of the original (yellow) or revised (pink) Letter of Transmittal, properly completed and duly executed, will be accepted. The original (yellow) or revised (pink) Letter of Transmittal, Share Certificates and any other required documents should be sent or delivered by each shareholder of the Company or such shareholder’s broker, dealer, commercial bank, trust company or other nominee to the Depositary, at the applicable address set forth below:

The Depositary for the Amended Offer is:

By Mail:	By Hand:	By Overnight Courier:
Computershare	Computershare	Computershare
Attn: Corp. Actions	Attn: Corp. Actions	Attn: Corp. Actions
PO Box 43014	250 Royall St.	250 Royall St.
Providence, RI 02940-3014	Canton, MA 02021	Canton, MA 02021

      Any questions or requests for assistance or additional copies of this Supplement, the original (yellow) or revised (pink) Letter of Transmittal, the revised (green) Notice of Guaranteed Delivery and the other tender offer materials may be directed to the Information Agent at its address and telephone number set forth below. Shareholders may also contact their broker, dealer, commercial bank, trust company or other nominee for assistance concerning the Amended Offer.

The Information Agent for the Amended Offer is:

501 Madison Avenue, 20th Floor

New York, New York 10022

Shareholders Call Toll-Free:

(877) 825-8730 (English speakers)

(877) 825-8777 (French speakers)

Banks & Brokers Call Collect: (212) 750-5833

The Dealer Managers for the Amended Offer are:

J.P. Morgan Securities Inc.
277 Park Avenue
New York, NY 10172
Toll Free: (800) 488-6809
BNP Paribas Securities Corp.
The Equitable Tower, 787 Seventh Avenue
New York, NY 10019
(212) 841-3204

EX-99.A.1.XIX

Exhibit (a)(1)(xix)

THIS DOCUMENT IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION.

Letter of Transmittal

To Tender Shares of Common Stock

of

LAFARGE NORTH AMERICA INC.

at $82.00 Net Per Share

Pursuant to the Offer to Purchase Dated February 21, 2006

and

the Supplement Thereto Dated April 7, 2006

by

EFALAR INC.

a wholly-owned subsidiary of

LAFARGE S.A.

THE AMENDED OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT

12:00 MIDNIGHT, NEW YORK CITY TIME, ON FRIDAY, APRIL 28, 2006,

UNLESS THE AMENDED OFFER IS EXTENDED.

The Depositary for the Amended Offer is:

By Mail:

Computershare
Attn: Corp. Actions
PO Box 43014
Providence, RI 02940-3014 By Hand:

Computershare
Attn: Corp. Actions
250 Royall St.
Canton, MA 02021 By Overnight Courier:

Computershare
Attn: Corp. Actions
250 Royall St.
Canton, MA 02021

     DELIVERY OF THIS REVISED LETTER OF TRANSMITTAL TO AN ADDRESS OTHER THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY TO THE DEPOSITARY. YOU MUST SIGN THIS REVISED LETTER OF TRANSMITTAL WHERE INDICATED BELOW AND, IF YOU ARE A U.S. HOLDER, (AS THAT TERM IS DEFINED UNDER “IMPORTANT U.S. FEDERAL TAX INFORMATION”), YOU MUST COMPLETE THE ATTACHED SUBSTITUTE W-9. IF YOU ARE A NON U.S.-HOLDER, YOU MUST OBTAIN AND COMPLETE A FORM W-8BEN OR OTHER FORM W-8, AS APPLICABLE.

     PLEASE READ THE INSTRUCTIONS ACCOMPANYING THIS REVISED LETTER OF TRANSMITTAL CAREFULLY BEFORE COMPLETING THIS REVISED LETTER OF TRANSMITTAL.

DESCRIPTION OF COMMON SHARES TENDERED
Name(s) and Address(es) of Registered Owner(s)
(If blank, please fill in exactly as name(s)	Common Shares Tendered
appear(s) on share certificate(s))	(Attach additional list if necessary)
		Total Number
		of Common
		Shares
		Represented	Number of	Dividend
	Share	By	Common	Reinvestment
	Certificate	Share	Shares	Shares
	Number(s)*	Certificate(s)*	Tendered**	Tendered***
	Total Common Shares Tendered
* Need not be completed by shareholders who deliver common shares by book-entry transfer.
** Unless otherwise indicated, it will be assumed that all Lafarge North America Inc. common shares represented by certificates described above are being tendered hereby. See Instruction 4.
*** If any common shares being tendered are common shares held by the Transfer Agent pursuant to Lafarge North America Inc.’s dividend reinvestment plan, the shareholder should so indicate on page 4.

      You have received this revised (pink) Letter of Transmittal in connection with the amended offer of Efalar Inc., a Delaware corporation and a wholly-owned subsidiary of Lafarge S.A., a French société anonyme, to purchase all outstanding common shares, par value $1.00 per share, of Lafarge North America Inc., a Maryland corporation, other than common shares owned by Lafarge S.A. or its subsidiaries, at the increased price of $82.00 per share, net to the seller in cash, without interest, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated February 21, 2006, as amended by amendments to the Schedule TO filed by Lafarge S.A. with the Securities and Exchange Commission, the Supplement to the Offer to Purchase, dated April 7, 2006, and this revised (pink) Letter of Transmittal.

      Either this revised (pink) Letter of Transmittal or the original (yellow) Letter of Transmittal previously circulated may be used by shareholders of Lafarge North America Inc. to deliver to the Depositary common shares of Lafarge North America Inc. represented by stock certificates for tender and to deliver uncertificated common shares held by the Lafarge North America Inc.’s transfer agent pursuant to Lafarge North America Inc.’s dividend reinvestment plan. If you are delivering your Lafarge North America Inc. common shares by book-entry transfer to an account maintained by the Depositary (as defined below) at The Depository Trust Company (“DTC”), you may use either this revised (pink) Letter of Transmittal or the original (yellow) Letter of Transmittal previously circulated or you may use an Agent’s Message (as defined in Instruction 2 below). In this document, shareholders who deliver certificates representing their Lafarge North America Inc. common shares are referred to as “Certificate Stockholders.” Shareholders who deliver their Lafarge North America Inc. common shares through book-entry transfer are referred to as “Book-Entry Stockholders.”

      Holders of common shares who have previously validly tendered common shares using the original (yellow) Letter of Transmittal or (blue) Notice of Guaranteed Delivery, and who have not withdrawn such common shares, have validly tendered such common shares for purposes of the amended offer and need not take any further action in order to receive the increased price of $82.00 per common share pursuant to the amended offer. Tendering shareholders may continue to use the original (yellow) Letter of Transmittal and the original (blue) Notice of Guaranteed Delivery previously circulated with the Offer to Purchase or they may use the revised (pink) Letter of Transmittal and the revised (green) Notice of Guaranteed Delivery circulated with the Supplement (as defined herein). Although the original (yellow) Letter of Transmittal previously circulated with the Offer to Purchase refers only to the Offer to Purchase (and not the Supplement), shareholders using such document to tender their common shares will nevertheless be deemed to be tendering pursuant to the amended offer and will receive the amended offer price of $82.00 per common share described in the Supplement if common shares are accepted for payment pursuant to the amended offer.

      If certificates for your Lafarge North America Inc. common shares are not immediately available or you cannot deliver your certificates and all other required documents to the Depositary on or prior to the expiration date of the amended offer, or you cannot comply with the book-entry transfer procedure on a timely basis, you may nevertheless tender your Lafarge North America Inc. common shares according to the guaranteed delivery procedure set forth in “THE OFFER — Section 3. Procedure for Accepting The Amended Offer and Tendering Common Shares” in the Supplement. See Instruction 2. The term “Expiration Date” means 12:00 midnight, New York City time, on Friday, April 28, 2006, or, if the Amended Offer is extended, the latest time and date at which the Amended Offer, as extended, will expire. Delivery of documents to DTC will not constitute delivery to the Depositary.

o  CHECK HERE IF TENDERED COMMON SHARES ARE BEING DELIVERED BY BOOK-ENTRY TRANSFER TO THE ACCOUNT MAINTAINED BY THE DEPOSITARY WITH DTC AND COMPLETE THE FOLLOWING (ONLY FINANCIAL INSTITUTIONS THAT ARE PARTICIPANTS IN DTC MAY DELIVER SHARES BY BOOK-ENTRY TRANSFER):

Name of Tendering Institution:

DTC Participant Number:

Transaction Code Number:

o  CHECK HERE IF TENDERED COMMON SHARES ARE BEING DELIVERED PURSUANT TO A NOTICE OF GUARANTEED DELIVERY PREVIOUSLY SENT TO THE DEPOSITARY AND COMPLETE THE FOLLOWING. PLEASE ENCLOSE A PHOTOCOPY OF SUCH NOTICE OF GUARANTEED DELIVERY.

Name(s) of Registered Owner(s):

Window Ticket Number (if any) or DTC Participant Number:

Date of Execution of Notice of Guaranteed Delivery: 

Name of Institution which Guaranteed Delivery: 

NOTE: SIGNATURES MUST BE PROVIDED BELOW

PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY

2

Ladies and Gentlemen:

      The undersigned hereby tenders to Efalar Inc., a Delaware corporation (“Purchaser”) and a wholly-owned subsidiary of Lafarge S.A., a French société anonyme (“Parent”), the above-described shares of common stock, par value $1.00 per share (the “Common Shares”), of Lafarge North America Inc., a Maryland corporation (the “Company”), pursuant to Purchaser’s offer to purchase all outstanding Common Shares not already owned by Parent or its subsidiaries, at a price of $82.00 per Common Share, net to the seller in cash, without interest thereon, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated February 21, 2006, as amended by amendments to the Schedule TO filed by Parent with the Securities and Exchange Commission (as so amended, the “Offer to Purchase”), the Supplement to the Offer to Purchase, dated April 7, 2006 (the “Supplement”) and in this revised (pink) Letter of Transmittal (which, together with the Offer to Purchase, as amended or supplemented from time to time, collectively constitute the “Amended Offer”). Receipt of the Amended Offer is hereby acknowledged. Purchaser reserves the right to transfer or assign, in whole or in part and from time to time, to one or more of its affiliates, the right to purchase all or any portion of the Common Shares tendered herewith.

      On the terms and subject to the conditions of the Amended Offer (including, if the Amended Offer is extended or amended, the terms and conditions of such extension or amendment), subject to, and effective upon, acceptance for payment and payment for the Common Shares validly tendered herewith in accordance with the terms of the Amended Offer, the undersigned hereby sells, assigns and transfers to, or upon the order of, Purchaser, all right, title and interest in and to all of the Common Shares being tendered hereby and any and all cash dividends, distributions, rights, other Common Shares or other securities issued or issuable in respect of such Common Shares on or after the date hereof, other than the regular quarterly dividend of $0.24 per Common Share already declared and paid on March 1, 2006 (collectively, “Distributions”). In addition, the undersigned irrevocably appoints Computershare Shareholder Services, Inc. (the “Depositary”) the true and lawful agent and attorney-in-fact of the undersigned with respect to such Common Shares and any Distributions with full power of substitution (such power of attorney being deemed to be an irrevocable power coupled with an interest) to the fullest extent of such shareholder’s rights with respect to such Common Shares and any Distributions (a) to deliver certificates representing Common Shares (“Share Certificates”) and any Distributions, or transfer ownership of such Common Shares and any Distributions on the account books maintained by DTC, together, in either such case, with all accompanying evidence of transfer and authenticity, to or upon the order of Purchaser, (b) to present such Common Shares and any Distributions for transfer on the books of the Company and (c) to receive all benefits and otherwise exercise all rights of beneficial ownership of such Common Shares and any Distributions, all in accordance with the terms and subject to the conditions of the Amended Offer.

      The undersigned hereby irrevocably appoints each of the designees of Purchaser the attorneys-in-fact and proxies of the undersigned, each with full power of substitution, to the full extent of such shareholder’s rights with respect to the Common Shares tendered hereby which have been accepted for payment and with respect to any Distributions. The designees of Purchaser will, with respect to the Common Shares and any associated Distributions for which the appointment is effective, be empowered to exercise all voting and any other rights of such shareholder, as they, in their sole discretion, may deem proper at any annual, special, adjourned or postponed meeting of the Company’s shareholders, by written consent in lieu of any such meeting or otherwise. This proxy and power of attorney shall be irrevocable and coupled with an interest in the tendered Common Shares. Such appointment is effective when, and only to the extent that, Purchaser accepts the Common Shares tendered with this revised Letter of Transmittal for payment pursuant to the Amended Offer. Upon the effectiveness of such appointment, without further action, all prior powers of attorney, proxies and consents given by the undersigned with respect to such Common Shares and any associated Distributions will be revoked and no subsequent powers of attorney, proxies, consents or revocations may be given (and, if given, will not be deemed effective). Purchaser reserves the right to require that, in order for Common Shares to be deemed validly tendered, immediately upon Purchaser’s acceptance for payment of such Common Shares, Purchaser must be able to exercise full voting, consent and other rights, to the extent permitted under applicable law, with respect to such Common Shares and any associated Distributions, including voting at any meeting of shareholders or executing a written consent concerning any matter.

      The undersigned hereby represents and warrants that the undersigned has full power and authority to tender, sell, assign and transfer the Common Shares and any Distributions tendered hereby and, when the same are accepted for payment by Purchaser, Purchaser will acquire good, marketable and unencumbered title thereto, free and clear of all liens, restrictions, charges and encumbrances and the same will not be subject to any adverse claim. The undersigned hereby represents and warrants that the undersigned is the registered owner of the Common Shares or the Share Certificate(s) have been endorsed to the undersigned in blank or the undersigned is a participant in DTC whose name appears on a security position listing as the owner of the Common Shares. The undersigned will, upon request, execute and deliver any additional documents deemed by the Depositary or Purchaser to be necessary or desirable to complete the sale, assignment and transfer of the Common Shares and any Distributions tendered hereby. In addition,

3

the undersigned shall promptly remit and transfer to the Depositary for the account of Purchaser any and all Distributions in respect of the Common Shares tendered hereby, accompanied by appropriate documentation of transfer and, pending such remittance or appropriate assurance thereof, Purchaser shall be entitled to all rights and privileges as owner of any such Distributions and may withhold the entire purchase price or deduct from the purchase price the amount or value thereof, as determined by Purchaser in its sole discretion.

      It is understood that the undersigned will not receive payment for the Common Shares unless and until the Common Shares are accepted for payment and until the Share Certificate(s) owned by the undersigned are received by the Depositary at the address set forth above, together with such additional documents as the Depositary may require, or, in the case of Common Shares held in book-entry form, ownership of Common Shares is validly transferred on the account books maintained by DTC, and until the same are processed for payment by the Depositary. It is understood that the method of delivery of the Share Certificate(s) and all other required documents is at the option and risk of the undersigned and that the risk of loss of such Share Certificate(s) shall pass only after the Depositary has actually received the Share Certificate(s).

      All authority conferred or agreed to be conferred pursuant to this revised Letter of Transmittal shall not be affected by, and shall survive, the death or incapacity of the undersigned and any obligation of the undersigned hereunder shall be binding upon the heirs, executors, administrators, trustees in bankruptcy, personal representatives, successors and assigns of the undersigned. Except as stated in the Offer to Purchase and the Supplement, this tender is irrevocable.

      Acceptance for payment by Purchaser of Common Shares tendered pursuant to the procedure described under “THE OFFER — Section 3. Procedure for Accepting The Amended Offer and Tendering Common Shares” in the Supplement will constitute a binding agreement between the undersigned and Purchaser upon the terms and subject to the conditions of the Amended Offer. Without limiting the foregoing, if the Amended Offer Price to be paid in the Amended Offer is amended, the price to be paid to the undersigned will be the amended price notwithstanding the fact that a different price is stated in this revised Letter of Transmittal. Under certain circumstances set forth in the Offer to Purchase and the Supplement, Purchaser may not be required to accept for payment any of the Common Shares tendered hereby.

      Unless otherwise indicated herein under “Special Payment Instructions,” please issue the check for the purchase price and/or return any Share Certificates representing Common Shares not tendered or accepted for payment in the name(s) of the registered owner(s) appearing under “Description of Common Shares Tendered.” Similarly, unless otherwise indicated under “Special Delivery Instructions,” please mail the check for the purchase price and/or return any Share Certificates representing Common Shares not tendered or accepted for payment (and accompanying documents, as appropriate) to the address(es) of the registered owner(s) appearing under “Description of Common Shares Tendered.” In the event that both the Special Delivery Instructions and the Special Payment Instructions are completed, please issue the check for the purchase price and/or issue any Share Certificates representing Common Shares not tendered or accepted for payment (and any accompanying documents, as appropriate) in the name of, and deliver such check and/or return such Share Certificates (and any accompanying documents, as appropriate) to, the person or persons so indicated. Unless otherwise indicated herein in the box titled “Special Payment Instructions,” please credit any Common Shares tendered hereby or by an Agent’s Message and delivered by book-entry transfer, but which are not purchased, by crediting the account at DTC designated above. Purchaser has no obligation pursuant to the Special Payment Instructions to transfer any Common Shares from the name of the registered owner thereof if Purchaser does not accept for payment any of the Common Shares so tendered. The “Special Payment Instructions” and the “Special Delivery Instructions” are not applicable to Common Shares tendered pursuant to the Company’s dividend reinvestment plan, which Common Shares may be tendered hereby.

      THE UNDERSIGNED TENDER ALL UNCERTIFICATED SHARES THAT MAY BE HELD IN THE NAME OF THE REGISTERED HOLDER(S) BY THE COMPANY’S TRANSFER AGENT PURSUANT TO THE COMPANY’S DIVIDEND REINVESTMENT PLAN.

                     Yes            No

      Note: If you do not check either of the spaces above, uncertificated Common Shares, if any, held in the name of the registered holder(s) by the Company’s transfer agent pursuant to the Company’s dividend reinvestment plan will NOT be tendered.

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SPECIAL PAYMENT INSTRUCTIONS

(See Instructions 1, 5, 6 and 7)

      To be completed ONLY if Share Certificate(s) representing Common Shares not tendered or not accepted for payment and/or the check for the purchase price of Common Shares accepted for payment are to be issued in the name of someone other than the undersigned or if Common Shares tendered by book-entry transfer which are not accepted for payment are to be returned by credit to an account maintained at DTC other than that designated above.

Issue: o Check and/or o  Share Certificates to:

Name: 

(Please Print)

Address: 

(Include Zip Code)

(Tax Identification or Social Security Number)

o  Credit Common Shares tendered by book-entry transfer that are not accepted for payment to the DTC account set forth below.

(DTC Account Number)

SPECIAL DELIVERY INSTRUCTIONS

(See Instructions 1, 5, 6 and 7)

      To be completed ONLY if Share Certificate(s) representing Common Shares not tendered or not accepted for payment and/or the check for the purchase price of Common Shares accepted for payment are to be sent to someone other than the undersigned or to the undersigned at an address other than that shown in the box titled “Description of Common Shares Tendered” above.

Deliver: o Check and/or o  Share Certificates to:

Name: 

(Please Print)

Address: 

(Include Zip Code)

5

IMPORTANT — SIGN HERE

(U.S. Holders Please Also Complete Substitute Form W-9 Below)

(Non-U.S. Holders Please Obtain and Complete Form W-8BEN or Other Form W-8)

(Must be signed by registered owner(s) exactly as name(s) appear(s) on Share Certificate(s) or on a security position listing or by person(s) authorized to become registered owner(s) by certificates and documents transmitted herewith. If signature is by trustees, executors, administrators, guardians, attorneys-in-fact, officers of corporations or others acting in a fiduciary or representative capacity, please set forth full title and see Instruction 5.)

Signature(s) of Stockholder(s)

Dated: ______________________________ , 2006

Name(s) 

(Please Print)

Capacity (full title): 

Address: 

(Include Zip Code)

Area Code and Telephone Number: 

Tax Identification or

Social Security No.: 

GUARANTEE OF SIGNATURE(S)

For use by Eligible Institutions only. Place medallion guarantee in space below.

See Instructions 1 and 5

Name of Firm: 

Address: 

(Include Zip Code)

Authorized Signature: 

Name: 

(Please Type or Print)

Area Code and Telephone Number: 

Dated: ______________________________ , 2006

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INSTRUCTIONS

Forming Part of the Terms and Conditions of the Amended Offer

      1.     Guarantee of Signatures. Except as otherwise provided below, all signatures on this revised Letter of Transmittal must be guaranteed by a financial institution (including most commercial banks, savings and loan associations and brokerage houses) that is a member in good standing of a recognized Medallion Program approved by the Securities Transfer Association, Inc., including the Security Transfer Agents Medallion Program, the New York Stock Exchange Medallion Signature Program and the Stock Exchange Medallion Program (each, an “Eligible Institution”). Signatures on this revised Letter of Transmittal need not be guaranteed (a) if this revised Letter of Transmittal is signed by the registered owner(s) (which term, for purposes of this document, includes any participant in DTC whose name appears on a security position listing as the owner of the Common Shares) of Common Shares tendered herewith and such registered owner has not completed the box titled “Special Payment Instructions” or the box titled “Special Delivery Instructions” on this revised Letter of Transmittal or (b) if such Common Shares are tendered for the account of an Eligible Institution. See Instruction 5.

      2.     Delivery of this revised Letter of Transmittal and Certificates or Book-Entry Confirmations. This revised Letter of Transmittal is to be used (a) if Share Certificates are to be forwarded herewith, or (b) if uncertificated Common Shares held by the Company’s transfer agent pursuant to the Company’s dividend reinvestment plan are to be tendered, or (c) unless an Agent’s Message is utilized, if tenders are to be made pursuant to the procedure for tender by book-entry transfer set forth in “THE OFFER — Section 3. Procedure for Accepting The Offer and Tendering Common Shares.” A manually executed facsimile of this document may be used in lieu of the original. Share Certificates representing all physically tendered Common Shares, or confirmation of any book-entry transfer into the Depositary’s account at DTC of Common Shares tendered by book-entry transfer (“Book Entry Confirmation”), as well as this revised Letter of Transmittal properly completed and duly executed with any required signature guarantees, unless an Agent’s Message in the case of a book-entry transfer is utilized, and any other documents required by this revised Letter of Transmittal, must be received by the Depositary at one of its addresses set forth herein on or prior to the expiration date. Please do not send your share certificates directly to Parent, Purchaser or the Company.

      Shareholders whose Share Certificates are not immediately available or who cannot deliver all other required documents to the Depositary (other than uncertificated Common Shares held by the Company’s transfer agent pursuant to the Company’s dividend reinvestment plan) on or prior to the Expiration Date or who cannot comply with the procedure for book-entry transfer on a timely basis, may nevertheless tender their Common Shares by properly completing and duly executing either the original (blue) Notice of Guaranteed Delivery circulated with the Offer to Purchase or the revised (green) Notice of Guaranteed Delivery circulated with the Supplement pursuant to the guaranteed delivery procedure set forth in “THE OFFER — Section 3. Procedure for Accepting The Offer and Tendering Common Shares” in the Offer to Purchase. Pursuant to such procedure: (a) such tender must be made by or through an Eligible Institution, (b) a properly completed and duly executed Notice of Guaranteed Delivery (either the original (blue) or revised (green) version) substantially in the form provided by Purchaser must be received by the Depositary prior to the expiration date and (c) Share Certificates representing all tendered Common Shares, in proper form for transfer (or a Book Entry Confirmation with respect to such Common Shares), as well as a revised Letter of Transmittal, properly completed and duly executed with any required signature guarantees (unless, in the case of a book-entry transfer, an Agent’s Message is utilized), and all other documents required by this revised Letter of Transmittal, must be received by the Depositary within three New York Stock Exchange trading days after the date of execution of such Notice of Guaranteed Delivery.

      A properly completed and duly executed revised (pink) Letter of Transmittal or original (yellow) Letter of Transmittal must accompany each such delivery of Share Certificates to the Depositary.

      The term “Agent’s Message” means a message, transmitted by DTC to, and received by, the Depositary and forming part of a Book-Entry Confirmation, which states that DTC has received an express acknowledgment from the participant in DTC tendering the Common Shares which are the subject of such Book-Entry Confirmation that such participant has received and agrees to be bound by the terms of the revised Letter of Transmittal and that Purchaser may enforce such agreement against the participant.

7

      THE METHOD OF DELIVERY OF THE COMMON SHARES, THIS REVISED LETTER OF TRANSMITTAL AND ALL OTHER REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH DTC, IS AT THE ELECTION AND RISK OF THE TENDERING SHAREHOLDER. DELIVERY OF ALL SUCH DOCUMENTS WILL BE DEEMED MADE AND RISK OF LOSS OF THE SHARE CERTIFICATES SHALL PASS ONLY WHEN ACTUALLY RECEIVED BY THE DEPOSITARY (INCLUDING, IN THE CASE OF A BOOK-ENTRY TRANSFER, RECEIPT OF A BOOK-ENTRY CONFIRMATION). IF SUCH DELIVERY IS BY MAIL, IT IS RECOMMENDED THAT ALL SUCH DOCUMENTS BE SENT BY PROPERLY INSURED REGISTERED MAIL WITH RETURN RECEIPT REQUESTED. IN ALL CASES, SUFFICIENT TIME SHOULD BE ALLOWED TO ENSURE TIMELY DELIVERY.

      No alternative, conditional or contingent tenders will be accepted and no fractional Common Shares will be purchased. All tendering shareholders, by execution of this Letter of Transmittal, waive any right to receive any notice of the acceptance of their Common Shares for payment.

      All questions as to validity, form and eligibility of the surrender of any Share Certificate hereunder will be determined by Purchaser (which may delegate power in whole or in part to the Depositary) and such determination shall be final and binding. Purchaser reserves the right to waive any irregularities or defects in the surrender of any Share Certificate(s). A surrender will not be deemed to have been made until all irregularities have been cured or waived. Purchaser and the Depositary shall make reasonable efforts to notify any person of any defect in any Letter of Transmittal submitted to the Depositary.

      3.     Inadequate Space. If the space provided herein is inadequate, the certificate numbers and/or the number of Common Shares and any other required information should be listed on a separate schedule attached hereto and separately signed on each page thereof in the same manner as this revised Letter of Transmittal is signed.

      4.     Partial Tenders (Applicable to Certificate Stockholders Only). If fewer than all the Common Shares evidenced by any Share Certificate delivered to the Depositary are to be tendered, fill in the number of Common Shares that are to be tendered in the box titled “Number of Common Shares Tendered.” In such cases, new certificate(s) for the remainder of the Common Shares that were evidenced by the old certificate(s) but not tendered will be sent to the registered owner, unless otherwise provided in the appropriate box on this revised Letter of Transmittal, as soon as practicable after the Expiration Date. All Common Shares represented by Share Certificates delivered to the Depositary will be deemed to have been tendered unless otherwise indicated.

      5.     Signatures on Revised Letter of Transmittal; Stock Powers and Endorsements. If this revised Letter of Transmittal is signed by the registered owner(s) of the Common Shares tendered hereby, the signature(s) must correspond with the name(s) as written on the face of the Share Certificate(s) without alteration, enlargement or any other change whatsoever.

      If any of the Common Shares tendered hereby are owned of record by two or more joint owners, all such owners must sign this revised Letter of Transmittal.

      If any of the tendered Common Shares are registered in the names of different holder(s), it will be necessary to complete, sign and submit as many separate revised Letters of Transmittal as there are different registrations of such Common Shares.

      If this revised Letter of Transmittal or any certificates or stock powers are signed by trustees, executors, administrators, guardians, attorneys-in-fact, officers of corporations or others acting in a fiduciary or representative capacity, such persons should so indicate when signing, and proper evidence satisfactory to Purchaser of their authority so to act must be submitted.

      If this revised Letter of Transmittal is signed by the registered owner(s) of the Common Shares listed and transmitted hereby, no endorsements of Share Certificates or separate stock powers are required unless payment is to be made to, or Share Certificates representing Common Shares not tendered or accepted for payment are to be issued in the name of, a person other than the registered owner(s). Signatures on such Share Certificates or stock powers must be guaranteed by an Eligible Institution.

      If this revised Letter of Transmittal is signed by a person other than the registered owner(s) of the Common Share(s) listed, the Share Certificate(s) must be endorsed or accompanied by the appropriate stock powers, in either case, signed exactly as the name or names of the registered owner(s) or holder(s) appear(s) on the Share Certificate(s). Signatures on such Share Certificates or stock powers must be guaranteed by an Eligible Institution.

8

      6.     Stock Transfer Taxes. Purchaser will pay any stock transfer taxes with respect to the transfer and sale of Common Shares to it or to its order pursuant to the Amended Offer. If, however, payment of the purchase price is to be made to, or (in the circumstances permitted hereby) if Share Certificates representing Common Shares not tendered or accepted for payment are to be registered in the name of, any person other than the registered owner(s), or if tendered Share Certificates are registered in the name of any person other than the person signing this revised Letter of Transmittal, the amount of any stock transfer taxes (whether imposed on the registered owner(s) or such person) payable on account of the transfer to such person will be deducted from the purchase price if satisfactory evidence of the payment of such taxes, or exemption therefrom, is not submitted.

      Except as provided in this Instruction 6, it will not be necessary for transfer tax stamps to be affixed to the Share Certificates listed in this revised Letter of Transmittal.

      7.     Special Payment and Delivery Instructions. If a check is to be issued in the name of, and/or Share Certificates representing Common Shares not tendered or accepted for payment are to be issued or returned to, a person other than the signer(s) of this revised Letter of Transmittal or if a check and/or such certificates are to be mailed to a person other than the signer(s) of this revised Letter of Transmittal or to an address other than that shown in the box titled “Description of Common Shares Tendered” above, the appropriate boxes on this revised Letter of Transmittal should be completed. Shareholders delivering Common Shares tendered hereby or by Agent’s Message by book-entry transfer may request that Common Shares not purchased be credited to an account maintained at DTC as such shareholder may designate in the box titled “Special Payment Instructions” herein. If no such instructions are given, all such Common Shares not purchased will be returned by crediting the same account at DTC as the account from which such Common Shares were delivered.

      8.     Requests for Assistance or Additional Copies. Questions or requests for assistance may be directed to the Information Agent at its address and telephone number set forth below or to your broker, dealer, commercial bank or trust company. Additional copies of the Supplement, the Offer to Purchase, this revised Letter of Transmittal, the revised (green) Notice of Guaranteed Delivery and other tender offer materials may be obtained from the Information Agent as set forth below, and will be furnished at Purchaser’s expense.

      9.     Backup Withholding. In order to avoid U.S. federal “backup withholding” at a rate of 28 percent with respect to cash received in exchange for Common Shares pursuant to the Amended Offer, a shareholder submitting Common Shares must (i) provide the Depositary with a properly completed Substitute Form W-9, included in this revised Letter of Transmittal, and sign such form under penalties of perjury, (ii) provide the Depositary with a properly completed IRS Form W-8BEN or other Form W-8, and sign such form under penalties of perjury or (iii) otherwise establish an exemption. IRS Form W-8BEN and other Forms W-8 are available from the Depositary or from the Internal Revenue Service web site, at http://www.irs.ustreas.gov. Please see “Important U.S. Federal Tax Information” below.

      10.     Lost, Destroyed, Mutilated or Stolen Share Certificates. If any Share Certificate has been lost, destroyed, mutilated or stolen, the shareholder should promptly notify the Company’s stock transfer agent, Computershare, 250 Royall St., Canton, MA 02021, Attention: Corporate Actions, Telephone 800-633-4236. The shareholder will then be instructed as to the steps that must be taken in order to replace the Share Certificate. This revised Letter of Transmittal and related documents cannot be processed until the procedure for replacing lost, mutilated or destroyed Share Certificates have been followed.

      11.     Waiver of Conditions. Subject to the terms and conditions set forth in “THE OFFER — Section 11. Conditions to the Amended Offer” in the Supplement, and the applicable rules and regulations of the Securities and Exchange Commission (the “Commission”), the conditions of the Amended Offer (other than the Minimum Tender Condition, as defined in the Offer to Purchase and the Supplement to the Offer to Purchase) may be waived by Purchaser in its discretion in whole or in part at any applicable time or from time to time prior to expiration of the Amended Offer, in each case subject to the applicable rules and regulations of the Commission.

      IMPORTANT: THIS REVISED (PINK) LETTER OF TRANSMITTAL OR THE ORIGINAL (YELLOW) LETTER OF TRANSMITTAL OR AN AGENT’S MESSAGE, TOGETHER WITH SHARE CERTIFICATES OR BOOK-ENTRY CONFIRMATION OR A PROPERLY COMPLETED AND DULY EXECUTED REVISED (GREEN) NOTICE OF GUARANTEED DELIVERY OR ORIGINAL (BLUE) NOTICE OF GUARANTEED DELIVERY AND ALL OTHER REQUIRED DOCUMENTS, MUST BE RECEIVED BY THE DEPOSITARY ON OR PRIOR TO THE EXPIRATION DATE.

9

IMPORTANT U.S. FEDERAL TAX INFORMATION

      For the purpose of this summary, a “U.S. holder” is a holder of the Common Shares that is an individual who is a citizen or resident of the United States, a U.S. domestic corporation, or any other person that is subject to U.S. federal income tax on a net income basis in respect of its investment in the Common Shares. A “non-US holder” is a holder of the Common Shares who is not a U.S. holder.

      Under United States federal income tax laws, we are generally required to report any cash payment made to a holder of Common Shares surrendered in the Merger to you and to the United States Internal Revenue Service (“IRS”) and we may be required to “backup withhold” 28 percent of any such payment. To avoid such backup withholding, a U.S. holder whose Common Shares are submitted herewith should provide the Depositary a properly completed Substitute Form W-9, which is attached hereto, signed under penalties of perjury, including such shareholder’s current Taxpayer Identification Number (“TIN”) and other certifications. A U.S. holder of Common Shares is required to give the Depositary the social security number or employer identification number of the record owner of the Common Shares being submitted for payment in connection with the Amended Offer. If the Common Shares are in more than one name or are not in the name of the actual owner, please consult the enclosed Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9 for additional guidance on which number to report. If the holder does not have a TIN, the holder should write “Applied For” in the space provided for the TIN. In such case, the Depositary will retain 28 percent of all payments made to the holder, until such holder provides a TIN to the Depositary. If the holder does not provide the Depositary with a certified TIN within 60 days, the Depositary will remit such retained amounts to the IRS as backup withholding.

      Certain holders (including, among others, corporations and non-U.S. holders) are exempt from these backup withholding and reporting requirements. Exempt persons who are not non-U.S. holders are not subject to backup withholding and should indicate their exempt status on Substitute Form W-9 by entering their correct TIN, marking the appropriate box and signing and dating the Substitute Form W-9 in the space provided.

      A non-U.S. holder should submit to the Depositary the appropriate version of an IRS Form W-8, properly completed, including certification of such individual’s foreign status, and signed under penalty of perjury. Form W8BEN is the version of Form W-8 most likely to apply to foreign persons claiming exemption from backup withholding. Non-U.S. persons should carefully read the instructions to Form W-8BEN and, if applicable, complete the required information, sign and date the Form W-8BEN and return the form to the Depositary with the completed Letter of Transmittal. In certain cases, Form W-8BEN may not be the proper IRS form to be completed and returned, depending on the status of the foreign person claiming exemption from backup withholding. If you are a non-U.S. holder, you must complete and return the appropriate version of Form W-8. Form W-8BEN and other Forms W-8 are available from the Depositary or from the IRS web site, at http://www.irs.ustreas.gov.

      If the Depositary is not provided with a properly completed Substitute Form W-9 or an IRS Form W-8BEN or other Form W-8, the holder may be subject to a $50 penalty imposed by the IRS. In addition, the Depositary may be required to withhold 28 percent of any cash payment made to the holder with respect to Common Shares submitted in connection with the Amended Offer as backup withholding. Backup withholding is not an additional tax. Rather, the tax liability of a person subject to backup withholding may be reduced by the amount of tax withheld. If withholding results in an overpayment of taxes, a refund from the IRS may be obtained.

      Please consult your accountant or tax advisor for further guidance regarding the completion of Substitute Form W-9, Form W-8BEN, or another version of Form W-8 to claim exemption from backup withholding, or contact the Depositary.

10

TO BE COMPLETED BY ALL TENDERING U.S. HOLDERS

(See Instruction 9)

PAYER: COMPUTERSHARE

SUBSTITUTE
Form W-9
Department of the Treasury
Internal Revenue Service

Request for Taxpayer
Identification Number (TIN)
and Certification Name:
Address:
Check appropriate box:
Individual/Sole Proprietor o              Corporation                          o
Partner  o                                           Other (specify)                      o
                                             Exempt from Backup Withholding    o

Part I.  Please provide your taxpayer identification number in the space at right. If awaiting TIN, write “Applied For” in space at right and complete the Certificate of Awaiting Taxpayer Identification Number below.	SSN: Or EIN:
Part II.  For Payees exempt from backup withholding, see the enclosed “Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9” and complete as instructed therein.
Part III. CERTIFICATION
Under penalties of perjury, I certify that:
(1) The number shown on this form is my correct Taxpayer Identification Number (or, as indicated, I am waiting for a number to be issued to me); and
(2) I am not subject to backup withholding because: (a) I am exempt from backup withholding, or (b) I have not been notified by the IRS that I am subject to backup withholding as a result of a failure to report all interest or dividends, or (c) the IRS has notified me that I am no longer subject to backup withholding.
(3) I am a U.S. person (including a U.S. resident alien).
Certification instructions — You must cross out item (2) above if you have been notified by the IRS that you are subject to backup withholding because you have failed to report all interest or dividends on your tax return. However, if after being notified by the IRS that you were subject to backup withholding you received another notification from the IRS that you are no longer subject to backup withholding, do not cross out item (2).
Signature:                                                  Date:                                             2006

YOU MUST COMPLETE THE FOLLOWING CERTIFICATE IF YOU WROTE

“APPLIED FOR” IN PART I

OF THIS SUBSTITUTE FORM W-9

CERTIFICATE OF AWAITING TAXPAYER IDENTIFICATION NUMBER

     I certify under penalties of perjury that a taxpayer identification number has not been issued to me, and either (a) I have mailed or delivered an application to receive a taxpayer identification number to the appropriate Internal Revenue Service Center or Social Security Administration Office or (b) I intend to mail or deliver an application in the near future. I understand that, notwithstanding the information I provided in Part III of the Substitute Form W-9 (and the fact that I have completed this Certificate of Awaiting Taxpayer Identification Number), 28 percent of all payments made to me pursuant to this Amended Offer shall be retained until I provide a Tax Identification Number to the Payor and that, if I do not provide my Taxpayer Identification Number within sixty (60) days, such retained amounts shall be remitted to the IRS as backup withholding.

Signature:                                                                                                     Date:                                                                                           2006

NOTE: FAILURE TO COMPLETE AND RETURN THIS FORM MAY RESULT IN BACKUP WITHHOLDING OF 28% OF ANY PAYMENTS MADE TO YOU PURSUANT TO THE AMENDED OFFER. PLEASE REVIEW THE ENCLOSED GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION NUMBER ON SUBSTITUTE FORM W-9 FOR ADDITIONAL DETAILS.

      MANUALLY SIGNED FACSIMILE COPIES OF THE REVISED (PINK) OR ORIGINAL (YELLOW) LETTER OF TRANSMITTAL WILL BE ACCEPTED. THE REVISED (PINK) OR ORIGINAL (YELLOW) LETTER OF TRANSMITTAL, CERTIFICATES FOR SHARES AND ANY OTHER REQUIRED DOCUMENTS SHOULD BE SENT OR DELIVERED BY EACH SHAREHOLDER OF THE COMPANY OR SUCH SHAREHOLDER’S BROKER, DEALER, COMMERCIAL BANK, TRUST COMPANY OR OTHER NOMINEE TO THE DEPOSITARY AT ONE OF ITS ADDRESSES SET FORTH ON THE FIRST PAGE.

11

The Depositary for the Amended Offer is:

By Mail:	By Hand:	By Overnight Courier:
Computershare	Computershare	Computershare
Attn: Corp. Actions	Attn: Corp. Actions	Attn: Corp. Actions
PO Box 43014	250 Royall St.	250 Royall St.
Providence, RI 02940-3014	Canton, MA 02021	Canton, MA 02021

The Information Agent for the Amended Offer is:

501 Madison Avenue, 20th Floor

New York, New York 10022

Shareholders Call Toll-Free:

(877) 825-8730 (English speakers)

(877) 825-8777 (French speakers)

Banks & Brokers Call Collect: (212) 750-5833

The Dealer Managers for the Amended Offer are:

J.P. Morgan Securities Inc.
277 Park Avenue
New York, NY 10172
Toll free: (800) 488-6809  

BNP Paribas Securities Corp.
The Equitable Tower, 787 Seventh Avenue
New York, NY 10019
(212) 841-3204

EX-99.A.1.XX

Exhibit (a)(1)(xx)

Notice of Guaranteed Delivery

for

Tender of Shares of Common Stock

of

LAFARGE NORTH AMERICA INC.

at $82.00 Net Per Share

to

EFALAR INC.

a wholly-owned subsidiary of

LAFARGE S.A.

Do not use for signature guarantees

THE AMENDED OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON FRIDAY, APRIL 28, 2006, UNLESS THE AMENDED OFFER IS EXTENDED.

     This revised (green) Notice of Guaranteed Delivery, or a form substantially equivalent to this form (including the original (blue) Notice of Guaranteed Delivery), must be used to accept the Amended Offer (as defined below) if:

•  certificates representing Common Shares (as defined below) are not immediately available;

•  the procedures for book-entry transfer cannot be completed prior to the expiration date of the Amended Offer; or

•  if time will not permit all required documents to reach Computershare Shareholder Services, Inc. (the “Depositary”), the Depositary for the Amended Offer, prior to the expiration date.

     The term “Expiration Date” means 12:00 midnight, New York City time, on Friday, April 28, 2006, unless Purchaser (as defined below) has extended the Amended Offer, in which event the term “Expiration Date” shall mean the latest time and date at which the Amended Offer, as so extended by Purchaser, will expire. Such form may be delivered by hand or transmitted via facsimile or mailed to the Depositary and must include a guarantee by an Eligible Institution (as defined below). See “THE OFFER — Section 3. Procedure for Accepting The Offer and Tendering Common Shares” in the Offer to Purchase (as defined below).

The Depositary for the Amended Offer is:

By Mail: Computershare Attn: Corp. Actions PO Box 43014 Providence, RI 02940- 3014	By Hand: Computershare Attn: Corp. Actions 250 Royall St. Canton, MA 02021 By Facsimile Transmission: (for Eligible Institutions only) (781) 575-2901	By Overnight Courier: Computershare Attn: Corp. Actions 250 Royall St. Canton, MA 02021
	To Confirm Facsimile Transmission by Telephone: (781) 575-3839

     DELIVERY OF THIS REVISED NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER THAN ONE SET FORTH ABOVE, OR TRANSMISSION OF INSTRUCTIONS VIA FACSIMILE TO A NUMBER OTHER THAN ONE SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY.

     This revised (green) Notice of Guaranteed Delivery is not to be used to guarantee signatures. If a signature on a Letter of Transmittal is required to be guaranteed by an Eligible Institution under the instructions thereto, such signature guarantee must appear in the applicable space provided in the signature box on the Letter of Transmittal.

     The Eligible Institution that completes this form must communicate the guarantee to the Depositary and must deliver the revised (pink) Letter of Transmittal or the original (yellow) Letter of Transmittal or an Agent’s Message (as defined in “The Offer — Section 3. Procedure for Accepting the Offer and Tendering Common Shares” in the Offer to Purchase) and certificates for Common Shares to the Depositary within the time period shown herein. Failure to do so could result in a financial loss to such Eligible Institution.

Ladies and Gentlemen:

      The undersigned hereby tenders to Efalar Inc., a Delaware corporation (“Purchaser”) and a wholly-owned subsidiary of Lafarge S.A., a French société anonyme (“Parent”), upon the terms and subject to the conditions set forth in the Offer to Purchase, dated February 21, 2006, as amended by amendments to the Schedule TO filed by Parent with the Securities and Exchange Commission (as so amended, the “Offer to Purchase”), the Supplement to the Offer to Purchase, dated April 7, 2006 (the “Supplement”) and the related revised (pink) Letter of Transmittal (which, together with the Offer to Purchase, as amended or supplemented from time to time, collectively constitute the “Amended Offer”), receipt of which is hereby acknowledged, the number of Common Shares indicated below pursuant to the guaranteed delivery procedure set forth in “THE OFFER — Section 3. Procedure for Accepting The Offer and Tendering Common Shares” in the Offer to Purchase.

Number of Common Shares Tendered:	Name(s) of Record Owner(s):
Share Certificate Numbers (if available):
	(Please Type or Print)
If Common Shares will be delivered by book-entry transfer:	Address(es):
	(Including Zip Code)
Name of Tendering Institution:
DTC Participant Number:	Area Code and Telephone Number:
Transaction Code Number:
Date:     , 2006	Signature(s):

GUARANTEE

(Not to be used for signature guarantee)

          The undersigned, a member in good standing of a recognized Medallion Program approved by the Securities Transfer Association, Inc., including the Security Transfer Agents Medallion Program, the New York Stock Exchange Medallion Signature Program and the Stock Exchange Medallion Program (each, an “Eligible Institution”), hereby guarantees that either the Share Certificates representing the Common Shares tendered hereby, in proper form for transfer, or timely confirmation of a book-entry transfer of such Common Shares into the Depositary’s account at The Depository Trust Company (pursuant to the procedures set forth in “THE OFFER — Section 3. Procedure for Accepting The Offer and Tendering Common Shares” in the Supplement), together with a properly completed and duly executed revised (pink) Letter of Transmittal or original (yellow) Letter of Transmittal with any required signature guarantees (or, in the case of a book-entry transfer, an Agent’s Message (as defined in the Offer to Purchase)) and any other documents required by the Letter of Transmittal, will be received by the Depositary at one of its addresses set forth above within three (3) New York Stock Exchange trading days after the date of execution hereof.

          The Eligible Institution that completes this form must communicate the guarantee to the Depositary and must deliver the revised (pink) Letter of Transmittal or the original (yellow) Letter of Transmittal, Share Certificates and/or any other required documents to the Depositary within the time period shown above. Failure to do so could result in a financial loss to such Eligible Institution.

Name of Firm:

Address:

(Including Zip Code)

Area Code and

Telephone Number:

Authorized Signature:

Name:

(Please Type or Print)

Title:

Dated: ______________________________ , 2006

NOTE: DO NOT SEND SHARE CERTIFICATES WITH THIS NOTICE OF GUARANTEED DELIVERY. SHARE CERTIFICATES ARE TO BE DELIVERED WITH THE LETTER OF TRANSMITTAL.

EX-99.A.1.XXI

Exhibit (a)(1)(xxi)

Amended Offer to Purchase for Cash

All Outstanding Shares of Common Stock

of

LAFARGE NORTH AMERICA INC.

at

$82.00 Net Per Share

by

EFALAR INC.

a wholly-owned subsidiary of

LAFARGE S.A.

THE AMENDED OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT

12:00 MIDNIGHT, NEW YORK CITY TIME, ON FRIDAY, APRIL 28, 2006, UNLESS

THE AMENDED OFFER IS EXTENDED.

April 7, 2006

To Brokers, Dealers, Commercial Banks

Trust Companies and Other Nominees:

      We have been engaged by Lafarge S.A., a French société anonyme (“Parent”), and Efalar Inc., a Delaware corporation (“Purchaser”) and a wholly-owned subsidiary of Parent, to act as Dealer Managers in connection with Purchaser’s amended offer to purchase all of the outstanding shares of common stock, par value $1.00 per share (the “Common Shares”), of Lafarge North America Inc., a Maryland corporation (the “Company”), not already owned by Parent or its subsidiaries, at an increased purchase price of $82.00 per Common Share, net to the seller in cash, without interest thereon, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated February 21, 2006, as amended by amendments to the Schedule TO filed by Parent with the Securities and Exchange Commission (as so amended, the “Offer to Purchase”), the Supplement to the Offer to Purchase, dated April 7, 2006 (the “Supplement”) and in the related revised (pink) Letter of Transmittal (which, together with the Offer to Purchase, as amended or supplemented from time to time, collectively constitute the “Amended Offer”).

      Concurrently with the Amended Offer, Parent, through another of its wholly-owned subsidiaries, is offering to acquire all of the exchangeable preference shares (the “Exchangeable Preference Shares” and, such offer, as amended and supplemented, the “Amended EPS Offer”) of Lafarge Canada Inc. (“Lafarge Canada”). The Exchangeable Preference Shares are convertible into Common Shares on a 1-for-1 basis, subject to adjustment in accordance with their terms, and the per share offer price in the Amended EPS Offer is the same as the per share price offered for the Common Shares in the Amended Offer. That offer is subject to the conditions contained in the Supplement, and Parent will not consummate the acquisition of such Exchangeable Preference Shares unless Parent also consummates the acquisition of the Common Shares pursuant to the Amended Offer.

      The Amended Offer is conditioned upon, among other things, (i) there being validly tendered and not withdrawn a number of Common Shares which, when taken together with the Exchangeable Preference Shares validly tendered and not withdrawn pursuant to the Amended EPS Offer, will constitute at least a majority of the outstanding Common Shares and Exchangeable Preference Shares, taken together as a single class, as of the date the Common Shares are accepted for payment pursuant to the Amended Offer, excluding Common Shares and Exchangeable Preference Shares beneficially owned by Parent and certain other persons as set forth in the Introduction of the Offer to Purchase (the “Minimum Tender Condition”) and (ii) there being validly tendered and not withdrawn a sufficient number of Common Shares such that, upon acceptance for payment and payment for the tendered Common Shares pursuant to the Amended Offer (and taking into account any Exchangeable Preference Shares to be accepted for payment in the Amended EPS Offer), Parent will, directly or through wholly-owned subsidiaries, own a number of Common Shares and Exchangeable Preference Shares representing at least 90% of the issued and outstanding Common Shares and Exchangeable Preference Shares, taken together as a single class, as of the date the Common Shares are accepted for payment pursuant to the Amended Offer. The Minimum Tender Condition is not waivable. The Amended Offer is also subject to certain other conditions set forth in the Supplement. See “THE OFFER — Section 11. Conditions to the Amended Offer” in the Supplement.

      Please furnish copies of the enclosed material to those of your clients for whose accounts you hold Common Shares registered in your name or in the name of your nominee.

      Enclosed herewith are the following documents:

1.	The Supplement, dated April 7, 2006;
2.	The revised (pink) Letter of Transmittal for your use in accepting the Amended Offer and tendering Common Shares and for the information of your clients;
3.	The revised (green) Notice of Guaranteed Delivery to be used to accept the Amended Offer if Share Certificates are not immediately available or if such certificates and all other required documents cannot be delivered to the Depositary, or if the procedures for book-entry transfer cannot be completed on a timely basis;
4.	A printed form of a letter that may be sent to your clients for whose account you hold Common Shares in your name or in the name of your nominee, with space provided for obtaining such clients’ instructions with regard to the Amended Offer; and
5.	Return envelope addressed to the Depositary (as defined below); and
6.	Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9.

      Upon the terms and subject to the conditions of the Amended Offer (including, if the Amended Offer is extended or amended, the terms and conditions of any such extension or amendment), Purchaser will be deemed to have accepted for payment, and will pay for, all Common Shares validly tendered and not properly withdrawn by the Expiration Date if and when Purchaser gives written notice to Computershare Shareholder Services, Inc. (the “Depositary”) of the Purchaser’s acceptance of the tenders of such Common Shares for payment pursuant to the Amended Offer. Payment for Common Shares tendered and accepted for payment pursuant to the Amended Offer will be made only after timely receipt by the Depositary of (a) certificates for such Common Shares or a Book-Entry Confirmation (as defined in the Offer to Purchase) with respect to such Common Shares pursuant to the procedures set forth in the Offer to Purchase, (b) a revised (pink) Letter of Transmittal or an original (yellow) Letter of Transmittal, properly completed and duly executed, with any required signature guarantees (or, in the case of a book-entry transfer, an Agent’s Message (as defined in the Offer to Purchase) in lieu of the Letter of Transmittal) and (c) any other documents required by the revised (pink) Letter of Transmittal or original (yellow) Letter of Transmittal. Accordingly, tendering shareholders may be paid at different times depending upon when certificates for Common Shares or Book-Entry Confirmations with respect to Common Shares are actually received by the Depositary. Under no circumstances will interest be paid on the purchase price for Common Shares, regardless of any extension of the Amended Offer or any delay in payment for Common Shares.

      The Amended Offer is not being made to (nor will tenders be accepted from or on behalf of) holders of Common Shares in any jurisdiction in which the making or acceptance of the Amended Offer would not be in compliance with the laws of such jurisdiction. However, Purchaser may, in its sole discretion, take such action as it may deem necessary to make the Amended Offer in any such jurisdiction and extend the Amended Offer to holders of Common Shares in such jurisdiction. Neither Purchaser nor Parent is aware of any jurisdiction in which the making of the Amended Offer or the acceptance of Common Shares in connection therewith would not be in compliance with the laws of such jurisdiction. An envelope in which to return your instructions to us is enclosed. If you authorize tender of your Common Shares, all such Common Shares will be tendered unless otherwise indicated in such instruction form. Please forward your instructions to us as soon as possible to allow us ample time to tender Common Shares on your behalf prior to the expiration of the Amended Offer.

      In order to tender Common Shares pursuant to the Amended Offer, a properly completed and duly executed revised (pink) Letter of Transmittal or original (yellow) Letter of Transmittal, with any required signature guarantees, or an Agent’s Message (in the case of any book-entry transfer), and any other documents required by the revised (pink) Letter of Transmittal or original (yellow) Letter of Transmittal, should be sent to and timely received by the Depositary, and either certificates representing the tendered Common Shares should be delivered or such Common Shares must be delivered to the Depositary pursuant to the procedures for book-entry transfers, all in accordance with the instructions set forth in either the revised (pink) Letter of Transmittal or the original (yellow) Letter of Transmittal and the Offer to Purchase.

      Neither Parent nor Purchaser will pay any fees or commissions to any broker or dealer or other person (other than the Information Agent, the Depositary and the Dealer Managers as described in the Offer to Purchase) in connection with the solicitation of tenders of Common Shares pursuant to the Amended Offer. You will be reimbursed upon request for customary mailing and handling expenses incurred by you in forwarding the enclosed offering materials to your clients.

      Your prompt action is requested. We urge you to contact your clients as promptly as possible. The Amended Offer and withdrawal rights will expire at 12:00 midnight, New York City time, on Friday, April 28, 2006, unless the Amended Offer is extended.

2

      If holders of Common Shares wish to tender their Common Shares, but it is impracticable for them to deliver their certificates representing tendered Common Shares or other required documents or to complete the procedures for delivery by book-entry transfer prior to the Expiration Date, a tender may be effected by following the guaranteed delivery procedures specified in the Offer to Purchase and either the revised (pink) Letter of Transmittal or the original (yellow) Letter of Transmittal.

      Questions and requests for assistance or for additional copies of the enclosed materials may be directed to the Information Agent or the undersigned at the addresses and telephone numbers set forth below and in the Supplement. Additional copies of the enclosed materials will be furnished at Purchaser’s expense.

Very truly yours,

J.P. Morgan Securities Inc.

BNP Paribas Securities Corp.

      NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL RENDER YOU OR ANY PERSON THE AGENT OF PARENT, PURCHASER, THE COMPANY, THE INFORMATION AGENT, THE DEALER MANAGERS, THE DEPOSITARY OR ANY OF THEIR AFFILIATES, OR AUTHORIZE YOU OR ANY OTHER PERSON TO USE ANY DOCUMENT OR MAKE ANY REPRESENTATION ON BEHALF OF ANY OF THEM WITH RESPECT TO THE AMENDED OFFER OTHER THAN THE DOCUMENTS ENCLOSED HEREWITH AND THE STATEMENTS CONTAINED THEREIN.

The Information Agent for the Amended Offer is:

501 Madison Avenue, 20th Floor

New York, New York 10022

Shareholders Call Toll-Free:

(877) 825-8730 (English speakers)

(877) 825-8777 (French speakers)

Banks & Brokers Call Collect: (212) 750-5833

The Dealer Managers for the Amended Offer are:

J.P. Morgan Securities Inc.
277 Park Avenue
New York, NY 10172
Toll free: (800) 488-6809
BNP Paribas Securities Corp.
The Equitable Tower, 787 Seventh Avenue
New York, NY 10019
(212) 841-3204

3 EX-99.A.1.XXII 6 y19490exv99waw1wxxii.htm EX-99.A.1.XXII: REVISED LETTER TO CLIENTS

Exhibit (a)(1)(xxii)

Amended Offer to Purchase for Cash

All Outstanding Shares of Common Stock

of

LAFARGE NORTH AMERICA INC.

at

$82.00 Net Per Share

by

EFALAR INC.

a wholly-owned subsidiary of

LAFARGE S.A.

THE AMENDED OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT

12:00 MIDNIGHT, NEW YORK CITY TIME, ON FRIDAY, APRIL 28, 2006,

UNLESS THE AMENDED OFFER IS EXTENDED.

April 7, 2006 

To Our Clients:

      Enclosed for your information are the Supplement, dated April 7, 2006 (the “Supplement”), to the Offer to Purchase, dated February 21, 2006 (as previously amended by amendments to the Schedule TO filed by Lafarge S.A. with the Securities and Exchange Commission, the “Offer to Purchase”) and the related revised (pink) Letter of Transmittal (which, together with the Offer to Purchase, as amended and supplemented from time to time, collectively constitute the “Amended Offer”), relating to the Amended Offer by Efalar Inc., a Delaware corporation (“Purchaser”) and a wholly-owned subsidiary of Lafarge S.A., a French société anonyme (“Parent”), to purchase all of the outstanding shares of common stock, par value $1.00 per share (the “Common Shares”), of Lafarge North America Inc., a Maryland corporation (the “Company”), at an increased price of $82.00 per Common Share, net to the seller in cash, without interest thereon, upon the terms and subject to the conditions set forth in the Amended Offer.

      We are the holder of record (directly or indirectly) of Common Shares held by us for your account. A tender of such Common Shares can be made only by us as the holder of record and pursuant to your instructions. The revised (pink) Letter of Transmittal accompanying this letter is furnished to you for your information only and cannot be used by you to tender Common Shares held by us for your account.

      We request instructions as to whether you wish to tender any or all of the Common Shares held by us for your account, pursuant to the terms and conditions in the Amended Offer.

      Your attention is directed to the following:

1.	The increased offer price is $82.00 per Common Share, net to the seller in cash, without interest thereon, upon the terms and subject to the conditions set forth in the Offer to Purchase and the Supplement.
2.	The Amended Offer is being made for all of the outstanding Common Shares not already owned by Parent and its subsidiaries.
3.	Concurrently with the Amended Offer, Parent, through another of its wholly-owned subsidiaries, is offering to acquire all of the exchangeable preference shares (the “Exchangeable Preference Shares” and, such offer, the “Amended EPS Offer”) of Lafarge Canada Inc. (“Lafarge Canada”). The Exchangeable Preference Shares are convertible into Common Shares on a 1-for-1 basis, subject to adjustment in accordance with their terms, and the per share offer price in the Amended EPS Offer is the same as the

	per share price offered for the Common Shares in the Amended Offer. That offer is subject to the conditions contained in the Amended Offer, and Parent will not consummate the acquisition of such Exchangeable Preference Shares unless Parent also consummates the acquisition of the Common Shares pursuant to the Amended Offer.
4.	The Amended Offer is conditioned upon, among other things, (i) there being validly tendered and not withdrawn a number of Common Shares which, when taken together with the Exchangeable Preference Shares validly tendered and not withdrawn pursuant to the Amended EPS Offer, will constitute at least a majority of the outstanding Common Shares and Exchangeable Preference Shares, taken together as a single class, as of the date the Common Shares are accepted for payment pursuant to the Amended Offer, excluding Common Shares and Exchangeable Preference Shares beneficially owned by Parent and certain other persons as set forth in the Introduction of the Offer to Purchase (the “Minimum Tender Condition”) and (ii) there being validly tendered and not withdrawn a sufficient number of Common Shares such that, upon acceptance for payment and payment for the tendered Common Shares pursuant to the Amended Offer (and taking into account any Exchangeable Preference Shares to be accepted for payment in the Amended EPS Offer), Parent will, directly or through wholly-owned subsidiaries, own a number of Common Shares and Exchangeable Preference Shares representing at least 90% of the issued and outstanding Common Shares and Exchangeable Preference Shares, taken together as a single class, as of the date the Common Shares are accepted for payment pursuant to the Amended Offer. The Minimum Tender Condition is not waivable. The Amended Offer is also subject to certain other conditions set forth in the Supplement. See “THE OFFER — Section 11. Conditions to the Amended Offer” in the Supplement.
5.	The Amended Offer and withdrawal rights will expire at 12:00 midnight, New York City time, on Friday, April 28, 2006 (the “Expiration Date”), unless Purchaser has extended the period of time during which the Amended Offer is open, in which event the term “Expiration Date” shall mean the latest time and date at which the Amended Offer, as so extended by Purchaser, shall expire.
6.	Any stock transfer taxes applicable to the sale of Common Shares to Purchaser pursuant to the Amended Offer will be paid by Purchaser, except as otherwise provided in Instruction 6 of the revised (pink) Letter of Transmittal or the original (yellow) Letter of Transmittal.

      If you wish to have us tender any or all of the Common Shares held by us for your account, please so instruct us by completing, executing and returning to us in the enclosed envelope the instruction form set forth below. If you authorize the tender of your Common Shares, all such Common Shares will be tendered unless otherwise specified on the instruction form set forth below. Please forward your instructions to us in ample time to permit us to submit a tender on your behalf prior to the Expiration Date.

      Payment for Common Shares will be in all cases made only after such Common Shares are accepted by Purchaser for payment pursuant to the Amended Offer and the timely receipt by Computershare Shareholder Services, Inc. (the “Depositary”) of (a) certificates for such Common Shares or a Book-Entry Confirmation (as defined in the Offer to Purchase) with respect to such Common Shares (b) a revised (pink) Letter of Transmittal or an original (yellow) Letter of Transmittal, properly completed and duly executed, with any required signature guarantees (or, in the case of a book-entry transfer, an Agent’s Message (as defined in the Offer to Purchase) in lieu of the Letter of Transmittal and (c) any other documents required by the revised (pink) Letter of Transmittal or the original (yellow) Letter of Transmittal. Accordingly, tendering shareholders may be paid at different times depending upon when certificates for Common Shares or Book-Entry Confirmations with respect to Common Shares are actually received by the Depositary. Under no circumstances will interest be paid on the purchase price for Common Shares, regardless of any extension of the Amended Offer or any delay in payment for Common Shares.

      The Amended Offer is not being made to (nor will tenders be accepted from or on behalf of) holders of Common Shares in any jurisdiction in which the making or acceptance of the Amended Offer would not be in compliance with the laws of such jurisdiction. However, Purchaser may, in its sole discretion, take such action as it may deem necessary to make the Amended Offer in any such jurisdiction and extend the Amended Offer to holders of Common Shares in such jurisdiction. Neither Purchaser nor Parent is aware of any jurisdiction in which the making of the Amended Offer or the acceptance of Common Shares in connection therewith would not be in compliance with the laws of such jurisdiction.

2

Instructions with Respect to the

Amended Offer to Purchase for Cash

All Outstanding Shares of Common Stock

of

LAFARGE NORTH AMERICA INC.

at

$82.00 Net Per Share

by

EFALAR INC.

a wholly-owned subsidiary of

LAFARGE S.A.

      The undersigned acknowledge(s) receipt of your letter and the enclosed Supplement, dated April 7, 2006 (the “Supplement”), to the Offer to Purchase, dated February 21, 2006 (as previously amended by amendments to the Schedule TO filed by Lafarge S.A. with the Securities and Exchange Commission, the “Offer to Purchase”) and the related revised (pink) Letter of Transmittal (which, together with the Offer to Purchase, as amended and supplemented from time to time, collectively constitute the “Amended Offer”), relating to the Amended Offer by Efalar Inc., a Delaware corporation (“Purchaser”) and a wholly-owned subsidiary of Lafarge S.A., a French société anonyme (“Parent”), to purchase for cash all of the outstanding shares of common stock, par value $1.00 per share (the “Common Shares”), of Lafarge North America Inc., a Maryland corporation (the “Company”), at an increased price of $82.00 per Common Share, net to the seller in cash, without interest thereon, upon the terms and conditions set forth in the Amended Offer.

      This will instruct you to tender the number of Common Shares indicated below (or if no number is indicated below, all Common Shares) that are held by you for the account of the undersigned, upon the terms and subject to the conditions in the Amended Offer.

      The undersigned understands and acknowledges that all questions as to validity, form and eligibility of the surrender of any certificate representing Common Shares submitted on my behalf to the Depositary will be determined by Purchaser (which may delegate power in whole or in part to the Depositary) and such determination shall be final and binding.

Number of Common Shares to Be Tendered: ________________________Common Shares*

Sign Below

Account Number:	Signature(s):
Dated:                                                    , 2006

Please Type or Print Name(s)

Please Type or Print Address(es) Here

Area Code and Telephone Number

Taxpayer Identification or Social Security Number(s)

*  Unless otherwise indicated, you are deemed to have instructed us to tender all Common Shares held by us for your account.

      Please return this form to the brokerage firm or other nominee maintaining your account.

EX-99.A.1.XXII

EX-99.A.1.XXII

EX-99.A.1.XXIII

Exhibit (a)(1)(xxiii)

GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION

NUMBER ON SUBSTITUTE FORM W-9

      Guidelines for Determining the Proper Identification Number for the Payee (You) to Give the Payer—Social security numbers have nine digits separated by two hyphens: i.e. 000-00-0000. Employer identification numbers have nine digits separated by only one hyphen: i.e. 00-0000000. The table below will help determine the number to give the payer.

For this type of account:		Give the name and SOCIAL SECURITY number of—
1.	An individual’s account	The individual
2.	Two or more individuals (joint account)	The actual owner of the account or, if combined funds, the first individual on the account(1)
3.	Custodian account of a minor (Uniform Gift to Minors Act)	The minor(2)
4.	(a)  The usual revocable savings trust (grantor is also trustee)	The grantor-trustee(1)
	(b)  So-called trust account that is not a legal or valid trust under state law	The actual owner(1)
5.	Sole proprietorship account or single-owner LLC	The owner(3)
For this type of account:		Give the EMPLOYER IDENTIFICATION number of—
6.	A valid trust, estate, or pension trust	The legal entity(4)
7.	Corporate account or LLC electing corporate status on IRS Form 8832	The corporation
8.	Partnership account (or multiple-member LLC) member held in the name of the business	The partnership
9.	Association, club, or tax-exempt organization account	The organization
10.	A broker or registered nominee	The broker or nominee
11.	Account with the Department of Agriculture in the name of a public entity (such as a State or local government, school district, or prison) that receives agricultural program payments	The public entity
(1)	List first and circle the name of the person whose number you furnish. If only one person has a social security number, that person’s number must be furnished.
(2)	Circle the minor’s name and furnish the minor’s social security number.
(3)	Show the name of the owner. You must show your individual name, but you may also enter your business or “doing business as” name. Either your social security number or employer identification number (if you have one) may be used.
(4)	List first and circle the name of the legal trust, estate, or pension trust. (Do not furnish the taxpayer identification number of the personal representative or trustee unless the legal entity itself is not designated in the account title.)
Note:	If no name is circled when there is more than one name, the number will be considered to be that of the first name listed.

GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION

NUMBER ON SUBSTITUTE FORM W-9

         Obtaining a Number

     If you do not have a taxpayer identification number (“TIN”) you should apply for one immediately. You may obtain Form SS-5, Application for a Social Security Card, at the local office of the Social Security Administration or get this form online at www.socialsecurity.gov. You may obtain Form SS-4, Application for Employer Identification Number, or Form W7, Application for IRS Individual Taxpayer identification Number, from the Internal Revenue Service by calling 1-800-TAX-FORM (1-800-829-3676) or from the IRS’s Internet website at www.irs.gov. If you do not have a TIN, write “Applied For” in the space for the TIN.

Payees Exempt from Backup Withholding

     Payees specifically exempted from backup withholding on all dividend and interest payments and on broker transactions including the following:

•  A corporation.

•  A financial institution.

•  An organization exempt from tax under Section 501(a), or an individual retirement account, or a custodial account under Section 403(b)(7) if the account satisfies the requirements of Section 401(f)(2).

•  The United States or any agency or instrumentality thereof.

•  A state, the District of Columbia, a possession of the United States, or any subdivision or instrumentality thereof.

•  An international organization or any agency or instrumentality thereof.

•  A dealer in securities or commodities required to register in the United States, the District of Columbia or a possession of the United States.

•  A real estate investment trust.

•  A common trust fund operated by a bank under Section 584(a)

•  An entity registered at all times during the tax year under the Investment Company Act of 1940.

•  A foreign central bank of issue.

     Certain other payees may be exempt from either dividend and interest payments or broker transactions. You should consult your tax advisor to determine whether you might be exempt from backup withholding. Exempt payees described above should file the Substitute Form W-9 to avoid possible erroneous backup withholding. Complete the Substitute Form W-9 as follows:

     ENTER YOUR TAXPAYER IDENTIFICATION NUMBER, WRITE “EXEMPT” ACROSS THE FACE OF THE FORM, SIGN AND DATE THE FORM AND RETURN THE FORM TO THE PAYER.

     IF YOU ARE A NONRESIDENT ALIEN OR FOREIGN ENTITY NOT SUBJECT TO BACKUP WITHHOLDING, GIVE THE PAYER THE APPROPRIATE COMPLETED FORM W-8.

     Privacy Act Notice.—Section 6109 requires you to provide your correct taxpayer identification number to payers who must report the payments to the IRS. The IRS uses the number for identification purposes and may also provide this information to various government agencies for tax enforcement or litigation purposes. Payers must be given the numbers whether or not recipients are required to file tax returns. Payers must generally withhold 28% of taxable interest, dividend, and certain other payments to a payee who does not furnish a taxpayer identification number to a payer. Certain penalties may also apply.

Penalties

     (1) Penalty for Failure to Furnish Taxpayer Identification Number— If you fail to furnish your correct taxpayer identification number to a payer, you are subject to a penalty of $50 for each such failure unless your failure is due to reasonable cause and not to willful neglect.

     (2) Civil Penalty for False Information with Respect to Withholding—If you make a false statement with no reasonable basis which results in no imposition of backup withholding, you are subject to a penalty of $500.

     (3) Criminal Penalty for Falsifying Information—Willfully falsifying certifications or affirmations may subject you to criminal penalties including fines and/or imprisonment.

FOR ADDITIONAL INFORMATION CONTACT YOUR TAX CONSULTANT OR THE INTERNAL REVENUE SERVICE

EX-99.A.1.XXIV

Exhibit (a)(1)(xxiv)

     This Notice of Change and Variation to Efalar Inc.’s MJDS Take-Over Bid Circular dated February 21, 2006 (the “MJDS Take-Over Bid Circular”) incorporates the text of the accompanying Supplement to Offer to Purchase dated April 7, 2006 (the “Supplement,” and together with this notice of change and variation, the “Notice of Change and Variation”), as supplemented, modified or amended from time to time, used in connection with Efalar Inc.’s offer to purchase all outstanding Common Shares (as defined below). The details of the Amended Offer are set out in the Offer to Purchase dated February 21, 2006 (the “Offer to Purchase”) and the Supplement, each as supplemented herein, and any decision to participate in the Amended Offer should be based solely on information contained in this Notice of Change and Variation and in the MJDS Take-Over Bid Circular. Capitalized terms used but not defined herein have the meanings given to them in the Offer to Purchase and the Supplement.

     The information required to be disclosed by paragraph (d)(1) of Rule 14d-6 of the General Rules and Regulations under the Securities Exchange Act of 1934, as amended, is contained in the Offer to Purchase and the Supplement and is incorporated herein by reference. The Offer to Purchase, the Supplement, the revised Letter of Transmittal and the revised Notice of Guaranteed Delivery contain important information and should be read carefully and in their entirety before any decision is made with respect to the Amended Offer.

Notice of Change and Variation to

MJDS Take-Over Bid Circular

April 7, 2006

     This bid is made in Canada for securities of a U.S. issuer in accordance with U.S. federal securities laws. Securityholders should be aware that the U.S. requirements applicable to the bid may differ from those of the provinces and territories of Canada.

     All of the directors and officers of Lafarge S.A. and of the offeror and all of the experts named in this bid circular reside outside of Canada. Substantially all of the assets of these persons and of Lafarge S.A. and the offeror may be located outside of Canada. Lafarge S.A. and the offeror have appointed Blakes Services Inc., 199 Bay Street, Suite 2800, Toronto, Ontario, M5L 1A9, as their agent for service of process in Canada, but it may not be possible for securityholders to effect service of process within Canada upon the directors, officers and experts referred to above. It may also not be possible to enforce against Lafarge S.A., the offeror, their respective directors and officers and the experts named in this bid circular judgments obtained in Canadian courts predicated upon the civil liability provisions of applicable securities laws in Canada.

Notice of Change and Variation

to

OFFER TO PURCHASE FOR CASH

All Outstanding Shares of Common Stock

of

LAFARGE NORTH AMERICA INC.

at

US$82.00 Net Per Share

by

EFALAR INC.

a wholly-owned subsidiary of

LAFARGE S.A.

THE AMENDED OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT

12:00 MIDNIGHT, NEW YORK CITY TIME, ON FRIDAY, APRIL 28, 2006,

UNLESS THE AMENDED OFFER IS EXTENDED.

     The Amended Offer is conditioned upon, among other things, (i) there being validly tendered and not withdrawn a number of shares of common stock, par value US$1.00 per share (the “Common Shares”), of Lafarge North America Inc. (the “Company”) which, when taken together with the Exchangeable Preference Shares (as defined in the INTRODUCTION to the Supplement) validly tendered and not withdrawn pursuant to the Amended EPS Offer (as defined in the INTRODUCTION to the Supplement), will constitute at least a majority of the outstanding Common Shares and Exchangeable Preference Shares, taken together as a single class, as of the date the Common Shares are accepted for payment pursuant to the Amended Offer, excluding Common Shares and Exchangeable Preference Shares beneficially owned by Lafarge S.A. and certain other persons as set forth in the INTRODUCTION to the Supplement (the “Minimum Tender Condition”) and (ii) there being validly tendered and not withdrawn a sufficient number of Common Shares such that, upon acceptance for payment and payment for the tendered Common Shares pursuant to the Amended Offer (and taking into account any Exchangeable Preference Shares to be accepted for payment in the Amended EPS Offer), Lafarge S.A. will, directly or through wholly-owned subsidiaries, own a number of Common Shares and Exchangeable Preference Shares representing at least 90% of the issued and outstanding Common Shares and Exchangeable Preference Shares, taken together as a single class, as of the date the Common Shares are accepted for payment pursuant to the Amended Offer. The Minimum Tender Condition is not waivable. The Amended Offer is also subject to certain other conditions set forth in the Supplement. See “THE OFFER — Section 11. Conditions to the Amended Offer” in the Supplement.

     None of the Securities and Exchange Commission, any state securities commission or the securities regulatory authority of any other jurisdiction has: (i) approved or disapproved of the Amended Offer; (ii) passed upon the merits or fairness of the Amended Offer; or (iii) passed upon the adequacy or accuracy of the disclosure in the Offer to Purchase or the Supplement. Any representation to the contrary is a criminal offence.

     In addition, no securities regulatory authority of any province or territory of Canada has expressed an opinion about this transaction or the information contained in this document and it is an offence to claim otherwise.               

The Information Agent for the Amended Offer is:

The Dealer Managers for the Amended Offer are:

     Any questions or requests for assistance or additional copies of the Offer to Purchase, the Supplement to Offer to Purchase, the revised Letter of Transmittal, the revised Notice of Guaranteed Delivery and the other tender offer materials may be directed to the Information Agent at its address and telephone number set forth on the back cover of the Supplement to Offer to Purchase. Shareholders may also contact their broker, dealer, commercial bank, trust company or other nominee for assistance concerning the Amended Offer.

Securities legislation in certain of the provinces and territories of Canada provides securityholders of the offeree issuer with, in addition to any other rights they may have at law, remedies for rescission or, in some jurisdictions, damages if a circular or notice that is required to be delivered to such securityholders contains a misrepresentation or is not delivered to the securityholder, provided that such remedies for rescission or damages are exercised by the securityholder within the time limit prescribed by the securities legislation of the securityholder’s province or territory. The securityholder should refer to the applicable provisions of the securities legislation of the securityholder’s province or territory for particulars of these rights or consult with a legal adviser. Rights and remedies also may be available to securityholders under U.S. law; securityholders may wish to consult with a U.S. legal adviser for particulars of these rights.

VOLUME AND PRICE RANGE OF COMMON SHARES

The Common Shares are listed on the New York Stock Exchange (“NYSE”) and the Toronto Stock Exchange (“TSX”) under the symbol “LAF”. The following tables sets forth, for each of the calendar quarters indicated, the average daily volume of trading on the NYSE and the TSX and the high and low closing prices per Common Share on the NYSE and the TSX.

		Average Daily
		Volume of Trading
		of Common Shares
		NYSE		TSX
2005
	First Quarter		294,450		356
	Second Quarter		260,307		142
	Third Quarter		316,561		205
	Fourth Quarter		315,820		2,266
2006
	First Quarter		793,551		2,066
	Second Quarter (through April 6)		661,550		6,388

		Price Range of				Price Range of
		Common Shares				Common Shares
		on the NYSE				on the TSX
		(US$)				(CDN$)
		High		Low		High		Low
2005
	First Quarter		63.75		50.72		79.00		61.50
	Second Quarter		62.59		52.47		72.50		67.50
	Third Quarter		69.78		62.99		82.65		72.50
	Fourth Quarter		69.02		53.27		80.50		62.63
2006
	First Quarter		84.14		57.57		97.93		66.00
	Second Quarter (through April 6)		85.28		84.36		99.00		97.93

MATERIAL UNITED STATES WITHHOLDING TAX CONSIDERATIONS

In order to avoid U.S. federal “backup withholding” at a rate of 28 percent with respect to cash received in exchange for Common Shares pursuant to the Amended Offer, you should provide the Depositary with (i) a Substitute Form W-9 (included in the revised Letter of Transmittal) if you are a “U.S. holder” (as that term is defined under “Important U.S. Federal Tax Information” in the enclosed revised Letter of Transmittal), (ii) the applicable IRS Form W-8 if you are not a U.S. holder, or (iii) otherwise establish an exemption.

      The various IRS Forms W-8 are available from the Depositary or from the Internal Revenue Service website at http://www.irs.ustreas.gov. For your convenience, we enclose with the Supplement a IRS Form W-8BEN (the version of the IRS Form W-8 that is the most likely to apply to non-U.S. holders). For more information on this form and on IRS Forms W-8, see “Important U.S. Federal Tax Information” in the enclosed revised Letter of Transmittal.

CERTIFICATE OF LAFARGE S.A. AND EFALAR INC.

      The foregoing, together with the MJDS Take-Over Bid Circular and documents incorporated by reference, contains no untrue statement of a material fact and does not omit to state a material fact that is required to be stated or that is necessary to make a statement not misleading in the light of the circumstances in which it was made.

DATED: April 7, 2006

LAFARGE S.A.

(signed) Bruno Lafont	(signed) Jean-Jacques Gauthier
Chief Executive Officer	Chief Financial Officer

ON BEHALF OF THE BOARD OF DIRECTORS OF

LAFARGE S.A.

(signed) Bertrand Collomb	(signed) Bernard Kasriel
Director	Director

EFALAR INC.

AND

ON BEHALF OF THE BOARD OF DIRECTORS OF

EFALAR INC.

(signed) Jean-Jacques Gauthier	(signed) Michel Bisiaux
Chief Executive Officer and	Chief Financial Officer and
Director	Director

(signed) Benjamin Dornic

                                                                                               Director

EX-99.A.1.XXV

Exhibit (a)(1)(xxv)

W-8BEN            Certificate of Foreign Status of Beneficial Owner Form (Rev. December 2000) for United States Tax Withholding OMB No. 1545-1621 Department of the Treasury ³ Section references are to the Internal Revenue Code. ³ See separate instructions. Internal Revenue Service ³ Give this form to the withholding agent or payer. Do not send to the IRS. Do not use this form for: Instead, use Form: 3 A U.S. citizen or other U.S. person, including a resident alien individual            W-9 3 A person claiming an exemption from U.S. withholding on income effectively connected with the conduct of a trade or business in the United StatesW-8ECI 3 A foreign partnership, a foreign simple trust, or a foreign grantor trust (see instructions for exceptions) W-8ECI or W-8IMY 3 A foreign government, international organization, foreign central bank of issue, foreign tax-exempt organization, foreign private foundation, or government of a U.S. possession that received effectively connected income or that is claiming the applicability of section(s) 115(2), 501(c), 892, 895, or 1443(b) (see instructions) W-8ECI or W-8EXP Note: These entities should use Form W-8BEN if they are claiming treaty benefits or are providing the form only to claim they are a foreign person exempt from backup withholding. 3 A person acting as an intermediary W-8IMY Note: See instructions for additional exceptions. Part I            Identification of Beneficial Owner (See instructions.) 1 Name of individual or organization that is the beneficial owner 2 Country of incorporation or organization 3 Type of beneficial owner: IndividualCorporationDisregarded entityPartnership            Simple trust Grantor trust            Complex trust            Estate            Government            Internationa l organization Central bank of issue            Tax-exempt organization            Private foundation 4 Permanent residence address (street, apt. or suite no., or rural route). Do not use a P.O. box or in-care-of address. City or town, state or province. Include postal code where appropriate. Country (do not abbreviate) 5 Mailing address (if different from above) City or town, state or province. Include postal code where appropriate. Country (do not abbreviate) 6 U.S. taxpayer identification number, if required (see instructions) 7 Foreign tax identifying number, if any (optional) SSN or ITIN EIN 8Reference number(s) (see instructions) Part II            Claim of Tax Treaty Benefits (if applicable) 9 I certify that (check all that apply): a The beneficial owner is a resident of within the meaning of the income tax treaty between the United States and that country. b If required, the U.S. taxpayer identification number is stated on line 6 (see instructions). c The beneficial owner is not an individual, derives the item (or items) of income for which the treaty benefits are claimed, and, if applicable, meets the requirements of the treaty provision dealing with limitation on benefits (see instructions). d The beneficial owner is not an individual, is claiming treaty benefits for dividends received from a foreign corporation or interest from a U.S. trade or business of a foreign corporation, and meets qualified resident status (see instructions). e The beneficial owner is related to the person obligated to pay the income within the meaning of section 267(b) or 707(b), and will file Form 8833 if the amount subject to withholding received during a calendar year exceeds, in the aggregate, $500,000. 10Special rates and conditions (if applicable—see instructions): The beneficial owner is claiming the provisions of Article            of the treaty identified on line 9a above to claim a      % rate of withholding on (specify type of income): . Explain the reasons the beneficial owner meets the terms of the treaty article: Part III            Notional Principal Contracts 11 I have provided or will provide a statement that identifies those notional principal contracts from which the income is not effectively connected with the conduct of a trade or business in the United States. I agree to update this statement as required. Part IV Certification Under penalties of perjury, I declare that I have examined the information on this form and to the best of my knowledge and belief it is true, correct, and complete. I further certify under penalties of perjury that: 3 I am the beneficial owner (or am authorized to sign for the beneficial owner) of all the income to which this form relates, 3 The beneficial owner is not a U.S. person, 3 The income to which this form relates is not effectively connected with the conduct of a trade or business in the United States or is effectively connected but is not subject to tax under an income tax treaty, and 3 For broker transactions or barter exchanges, the beneficial owner is an exempt foreign person as defined in the instructions. Furthermore, I authorize this form to be provided to any withholding agent that has control, receipt, or custody of the income of which I am the beneficial owner or any withholding agent that can disburse or make payments of the income of which I am the beneficial owner. Sign Here 3 Signature of beneficial owner (or individual authorized to sign for beneficial owner) Date (MM-DD-YYYY) Capacity in which acting For Paperwork Reduction Act Notice, see separate instructions. Cat. No. 25047Z Form W-8BEN (Rev. 12-2000)

EX-99.B.III

Exhibit (b)(iii)

Lafarge SA
Attention: Head of Treasury Department

April 3, 2006

Dear Sirs,

We refer to the US$2,800,000,000 Facility Agreement dated 5 February 2006 (the “Facility Agreement”) between you, as Borrower, and the Finance Parties. All capitalized terms in this letter have the meaning ascribed to them in the Facility Agreement.

In our capacity as Mandated Lead Arrangers, we hereby confirm, pursuant to Section 20.10 (b) of the Facility Agreement, that we have been duly informed of your intention to increase the per share price offered for the Shares from US$75 to US$82, and that we give our consent to such increase.

Yours sincerely,

/s/ Ludovic de Montille	/s/ Olivier Grandry
BNP PARIBAS	JP MORGAN PLC
By: Ludovic de Montille	By: Olivier Grandry

EX-99.C.II

Exhibit c(ii)

A P R I L    3 ,    2 0 0 6

S T R I C T L Y    P R I V A T E    A N D    C O N F I D E N T I A L

  D I S C U S S I O N   M A T E R I A L S

D I S C U S S I O N     M A T E R I A L S

This presentation was prepared exclusively for the benefit and internal use of the JPMorgan and BNP Paribas (together the “Financial Advisers”) client to whom it is directly addressed and delivered (including such client’s subsidiaries, the “Company”) in order to assist the Company in evaluating, on a preliminary basis, the feasibility of a possible transaction or transactions and does not carry any right of publication or disclosure, in whole or in part, to any other party. This presentation is for discussion purposes only and is incomplete without reference to, and should be viewed solely in conjunction with, the oral briefing provided by the Financial Advisers. Neither this presentation nor any of its contents may be disclosed or used for any other purpose without the prior written consent of the Financial Advisers.

The information in this presentation is based upon any management forecasts supplied to us and reflects prevailing conditions and our views as of this date, all of which are accordingly subject to change. The Financial Advisers’ opinions and estimates constitute the Financial Advisers’ judgment and should be regarded as indicative, preliminary and for illustrative purposes only. In preparing this presentation, we have relied upon and assumed, without independent verification, the accuracy and completeness of all information available from public sources or which was provided to us by or on behalf of the Company or which was otherwise reviewed by us. In addition, our analyses are not and do not purport to be appraisals of the assets, stock, or business of the Company or any other entity. The Financial Advisers make no representations as to the actual value which may be received in connection with a transaction nor the legal, tax or accounting effects of consummating a transaction. Unless expressly contemplated hereby, the information in this presentation does not take into account the effects of a possible transaction or transactions involving an actual or potential change of control, which may have significant valuation and other effects.

Notwithstanding anything herein to the contrary, the Company and each of its employees, representatives or other agents may disclose to any and all persons, without limitation of any kind, the U.S. federal and state income tax treatment and the U.S. federal and state income tax structure of the transactions contemplated hereby and all materials of any kind (including opinions or other tax analyses) that are provided to the Company relating to such tax treatment and tax structure insofar as such treatment and/or structure relates to a U.S. federal or state income tax strategy provided to the Company by the Financial Advisers.

The Financial Advisers’ policies prohibit employees from offering, directly or indirectly, a favorable research rating or specific price target, or offering to change a rating or price target, to a subject company as consideration or inducement for the receipt of business or for compensation. The Financials Advisers also prohibit their research analysts from being compensated for involvement in investment banking transactions except to the extent that such participation is intended to benefit investors.

IRS Circular 230 Disclosure: The Financial Advisers do not provide tax advice. Accordingly, any discussion of U.S. tax matters included herein (including any attachments) is not intended or written to be used, and cannot be used, in connection with the promotion, marketing or recommendation by anyone not affiliated with the Financial Advisers of any of the matters addressed herein or for the purpose of avoiding U.S. tax-related penalties.

JPMorgan is a marketing name for investment banking businesses of JPMorgan Chase & Co. and its subsidiaries worldwide. Securities, syndicated loan arranging, financial advisory and other investment banking activities are performed by a combination of J.P. Morgan Securities Inc., J.P. Morgan plc, J.P. Morgan Securities Ltd. and the appropriately licensed subsidiaries of JPMorgan Chase & Co. in Asia-Pacific, and lending, derivatives and other commercial banking activities are performed by JPMorgan Chase Bank, N.A. JPMorgan deal team members may be employees of any of the foregoing entities.

This presentation does not constitute a commitment by any JPMorgan or BNP Paribas entity to underwrite, subscribe for or place any securities or to extend or arrange credit or to provide any other services.

D I S C U S S I O N     M A T E R I A L S

Tango trading summary post-announcement of the Offer

1

D I S C U S S I O N     M A T E R I A L S

Merrill Lynch provided JPMorgan with a revised
“2006 Outlook” for Tango on March 9, 2006

Comparison of 2005 actual vs. 2006 Budget vs. 2006 Outlook — as provided by Merrill Lynch

			2006 Budget					2006 Outlook
			Presented to Tango Board					Presented to Tango Special Committee
			on Jan 31, 2006					on March 1, 2006
	2005 Actual
	($mm)		($mm)		% vs. 2005			($mm)		% vs. 2005			% vs. budget
Sales		$4,309.6		$4,636.4		7.6	%		$4,744.7		10.1	%		2.3	%
EBIT		$565.2		$600.8		6.3	%		$662.6		17.2	%		10.3	%

2

D I S C U S S I O N     M A T E R I A L S

Analysis of Tango trading since February 6, 2006

Analysis of shares traded since Feb 6 (% of total volume)

Price range
< $81.00
$81.00—$81.49
$81.50—$81.99
$82.00—$82.49
$82.50—$82.99
$83.00—$83.49
$83.50—$83.99
$84.00—$84.49
$84.50—$84.99
> $85.00

Total volume traded since Feb 6:	32.8mm
% of free float traded since Feb 6 2:	92.8%

Source: Bloomberg intra-day data
¹ Free float = 35.3 million shares

Tango volume-weighted average price (VWAP)

					% Total
			Volume		Volume
Date range	VWAP		Traded		traded
Feb 6, 2006		$81.40		10,559,000		32.2%
(day of announcement)
8 days		$81.92		11,501,900		35.1%
(2/7/06—2/16/06)
10 days		482.76		3,729,500		11.4%
(2/17/06—3/3/06)
10 days		$83.10		4,679,500		14.3%
(3/6/06—3/17/06)
10 days		$83.77		2,293,800		7.0%
(3/20/06—3/31/06)
Total period post-ann.		$82.15		32,763,700		100.0%
(Feb-6, 06—Mar-31, 06)

Source: Tradeline

3

D I S C U S S I O N     M A T E R I A L S

Public market valuations of building materials companies

Building materials market valuations

	Price		% of 52-			Market			Firm			Historical metrics (Feb 3, 06 3)						Current metrics (Mar-31, 06)
	(local		week			cap.			Value			FV/EBITDA 1				P/E 2		FV/EBITDA 1				P/E 2
Market data as of Mar-31	currency)		high			US$mm			US$mm			2005A		2006E		2006E		2005A		2006E		2006E
U.S. companies
Vulcan Materials	$	86.65		97.2	%	$	9,032		$	9,177			11.4x		9.1x		17.9x		13.2x		9.9x		19.3x
Martin Marietta		107.03		99.3	%		5,129			5,738			11.2		9.1		17.5		13.3		10.4		20.0
Florida Rock		56.22		82.7	%		3,830			3,775			11.2		9.4		17.8		11.6		9.7		18.4
Eagle Materials		63.76		99.6	%		3,235			3,375			12.1		9.3		14.6		13.7		9.8		17.4
Texas Industries		60.49		86.4	%		1,443			1,737			12.1		9.9		18.4		13.4		11.0		21.1
Median													11.4x		9.3x		17.8x		13.3x		9.9x		19.3x
Average													11.6x		9.4x		17.2x		13.0x		10.2x		19.2x
Non-U.S. companies
Cemex	$	65.28		99.4	%	$	22,936		$	32,129			8.8x		7.7x		10.8x		9.0x		7.8x		12.3x
CRH	€	28.80		98.1	%		18,876			23,324			9.2		8.6		13.0		9.7		8.5		13.6
Holcim	SFr. 103.80			100.0	%		18,405			30,941			8.4		7.2		11.4		8.5		7.0		12.3
Heidelberg Cement	€	94.20		100.0	%		13,256			18,089			9.7		8.7		14.7		10.4		9.3		16.8
Rinker	AUD 19.85			100.0	%		12,969			13,191			10.2		8.7		15.7		11.4		9.4		16.7
Hanson	£	7.54		96.1	%		9,470			11,203			8.5		8.0		13.2		9.4		8.8		13.8
Ciments Francais	€	129.30		98.8	%		6,116			8,812			7.5		6.6		12.5		7.9		7.0		14.0
Italcementi	€	19.77		99.1	%		6,018			10,331			6.8		5.5		10.6		7.6		6.2		13.1
Cimpor	€	5.51		99.6	%		4,505			6,233			10.0		9.1		12.8		10.7		9.8		14.1
Buzzi Unicem	€	19.67		100.0	%		4,349			6,168			6.0		5.6		10.3		6.9		6.5		12.7
Cementos Portland	€	86.45		98.2	%		2,928			3,061			8.2		8.0		17.8		8.0		7.0		16.4
Cementir	€	5.95		94.4	%		1,152			1,508			6.3		5.5		12.4		6.7		5.8		13.6
Median													8.5x		7.8x		12.7x		8.8x		7.4x		13.7x
Average													8.3x		7.5x		12.9x		8.8x		7.8x		14.1x
Foxtrot	€	93.50		100.0	%	$	19,703		$	31,068			7.4x		6.8x		12.8x		7.7x		6.9x		13.1x
Tango	$	84.00		99.8	%	$	6,766	4	$	6,993	4		6.5x		6.2x		14.0x	Tango multiples non-meaningful

 
 
 
 

Note: Multiples not adjusted for pension/OPEB deficits, projections might not reflect recent improvements in earnings released over the past week. Estimates are used where actual results are not yet available

Source: Tradeline/Datastream as of March 31, 2006, I/B/E/S and equity research. Tango projections based on 2006 budget

1 Calendarized EBITDA	3 Market data as of Feb 3, 2006
2 Pre-goodwill amortization and pre-exceptionals	4 Based on fully diluted NOSH

4

D I S C U S S I O N     M A T E R I A L S

Illustrative analysis at various prices

Illustrative analysis at various prices

				As of		Current offer		Illustrative price
($mm except per share)				Feb-3		$75.00		$80.00		$81.00		$82.00		$83.00		$84.00
Implied premia over pre-offer prices
Pre-Announcement:
Feb 3, 2006 close					$64.25		16.7%		24.5%		26.1%		27.6%		29.2%		30.7%
over 1-year high					69.78		7.5%		14.6%		16.1%		17.5%		18.9%		20.4%
over 1-year low					52.47		42.9%		52.5%		54.4%		56.3%		58.2%		60.1%
over 1-year average					60.67		23.6%		31.9%		33.5%		35.2%		36.8%		38.5%
over 6-month average					60.81		23.3%		31.6%		33.2%		34.8%		36.5%		38.1%
over 3-month average					57.27		31.0%		39.7%		41.4%		43.2%		44.9%		46.7%
over last 30 calendar day average					60.83		23.3%		31.5%		33.2%		34.8%		36.4%		38.1%
over 1-week average					63.64		17.9%		25.7%		27.3%		28.8%		30.4%		32.0%
Basic number of shares					75.4		75.4		75.4		75.4		75.4		75.4		75.4
Implied Tango equity value					4,844		5,654		6,031		6,106		6,182		6,257		6,332
Implied fully diluted equity value					5,102		6,008		6,429		6,513		6,598		6,682		6,766
Implied buy-out amount 1					2,526		3,001		3,222		3,266		3,310		3,354		3,398
Implied buy-out amount (€mm)2					2,105		2,501		2,685		2,721		2,758		2,795		2,832
Net debt & minority interest 3					227
Implied firm value					5,329		6,235		6,656		6,741		6,825		6,909		6,993
	Base data ($mm)
FV/EBITDA		2005A	814		6.5x		7.7x		8.2x		8.3x		8.4x		8.5x		8.6x
		2006E	861		6.2x		7.2x		7.7x		7.8x		7.9x		8.0x		8.1x
P/E4		2005A	341		15.0x		17.6x		18.8x		19.1x		19.3x		19.6x		19.8x
		2006E	365		14.0x		16.5x		17.6x		17.9x		18.1x		18.3x		18.6x

Key financials — Tango

$mm	2005A		2006E		2007E
Sales		$4,310		$4,500		$4,800
EBITDA		814		861		940
% margin		18.9%		19.1%		19.6%
Net income4		341		365		408
% margin		7.9%		8.1%		8.5%

Net debt

$mm	Dec-05
Financial debt5		919
- Cash & equivalent		(692)
= Net debt (excl. off B/S liabilities)		227

Number of shares

mm
Common shares	75.4
Options o/s (estimate)	4.5
Warrants (estimate)	4.4
Diluted shares (at $64.25/share)	79.4

Source: Foxtrot guidance

1	46.8% of basic nosh + cash cost for buyback
2	Assumes Euro-to-Dollar exchange rate of 1.200
3	Excluding pensions/OPEB deficits

4	Pre-exceptionals
5	Including redeemable preferred shares

 5