SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 4)*

BUILDERS FIRSTSOURCE, INC.

(Name of Issuer)

Common stock, par value $0.01 per share

(Title of Class of Securities)

12008R-10-7

(CUSIP Number)

Robert B. Knauss, Esq.

Managing Director and General Counsel

Warburg Pincus LLC

450 Lexington Avenue

New York, New York 10017

(212) 878-0600

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

July 29, 2015

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.   ¨

NOTE: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

SCHEDULE 13D

SCHEDULE 13D

SCHEDULE 13D

SCHEDULE 13D

SCHEDULE 13D

SCHEDULE 13D

SCHEDULE 13D

SCHEDULE 13D

The Reporting Persons previously filed a Schedule 13D with the Securities and Exchange Commission (the “SEC”) on March 2, 2006, as amended by Amendment No. 1 thereto filed with the SEC on December 8, 2006 (“Amendment No. 1”), Amendment No. 2 thereto filed with the SEC on March 14, 2008 (“Amendment No. 2”), Amendment No. 3 thereto filed with the SEC on September 1, 2009 (“Amendment No. 3”), Amendment No. 4 thereto filed with the SEC on October 26, 2009 (“Amendment No. 4”), Amendment No. 5 thereto filed with the SEC on January 22, 2010 (“Amendment No. 5”), and Amendment No. 6 thereto filed with the SEC on June 24, 2010 (the Original Schedule 13D, as amended by Amendment No. 1, Amendment No. 2, Amendment No. 3, Amendment No. 4, Amendment No. 5, and Amendment No. 6 are collectively referred to herein as the “Original Schedule 13D”). As disclosed in Amendment No. 6 to the Original Schedule 13D, the Reporting Persons determined to no longer file amendments to the Original Schedule 13D jointly with the JLL Reporting Persons (as defined in the Original Schedule 13D). Accordingly, the Reporting Persons filed a separate Schedule 13D with the SEC on March 16, 2012, as amended by Amendment No. 1 thereto filed with the SEC on April 17, 2012, as amended by Amendment No. 2 thereto filed with the SEC on June 19, 2012, as amended by Amendment No. 3 thereto filed with the SEC on April 15, 2015 (the “Schedule 13D”). Pursuant to Rule 13d-2 promulgated under the Securities Exchange Act of 1934, as amended, the Reporting Persons are filing this Amendment No. 4 to the Schedule 13D. All capitalized terms used herein but not defined shall have the meaning set forth in the Schedule 13D.

Item 2. Identity and Background

Item 2(a) is hereby amended and supplemented by adding the following at the end thereof:

This Amendment No. 4 is filed by (i) Warburg Pincus Private Equity IX, L.P., a Delaware limited partnership (“WP IX”); (ii) Warburg Pincus IX GP L.P., a Delaware limited partnership (“WP IX GP”), the general partner of WP IX; (iii) WPP GP LLC, a Delaware limited liability company (“WPP GP”), the general partner of WP IX GP; (iv) Warburg Pincus Partners, L.P., a Delaware limited partnership (“WP Partners”), the sole member of WPP GP; (v) Warburg Pincus Partners GP LLC, a Delaware limited liability company (“WP Partners GP”), the general partner of WP Partners; (vi) Warburg Pincus & Co., a New York general partnership (“WP”), the managing member of WP Partners GP; (vii) Warburg Pincus LLC, a New York limited liability company (“WP LLC”), which manages WP IX; and (viii) Charles R. Kaye and Joseph P. Landy, who are Managing General Partners of WP and Managing Members and Co-Chief Executive Officers of WP LLC and may be deemed to control the entities listed in clauses (i) through (vii). Messrs. Kaye and Landy disclaim beneficial ownership of all shares held by such entities listed in clauses (i) through (vii). WP IX, WP IX GP, WPP GP, WP Partners, WP Partners GP, WP, WP LLC, Mr. Kaye and Mr. Landy collectively are referred to as the “Reporting Persons.”

The Reporting Persons are making this single, joint filing because they may be deemed to constitute a “group” within the meaning of Section 13(d)-3 of the Securities Exchange Act, as amended (the “Exchange Act”). The agreement among the Reporting Persons to file this Schedule 13D jointly in accordance with rule 13d-1(k)(1) of the Exchange Act is attached hereto as Exhibit A.

Item 4. Purpose of Transaction

Item 4 is hereby amended and supplemented by adding the following at the end thereof:

On July 29, 2015, WP IX entered into an underwriting agreement (the “Underwriting Agreement”) with the Company and Credit Suisse Securities (USA) LLC, Deutsche Bank Securities Inc. and Citigroup Global Markets Inc., as representatives of the underwriters (the “Underwriters”), relating to the previously announced public offering by the Company of 8,000,000 shares of Common Stock of the Company and secondary offering by WP IX of 4,000,000 shares of Common Stock of the Company. In connection with the offering, the Underwriters have also exercised an option granted pursuant to the Underwriting Agreement to purchase an additional 1,200,000 and 600,000 shares, respectively. The offering is expected to close on or about July 31, 2015, subject to customary closing conditions.

Pursuant to the Underwriting Agreement, the Company and WP IX agreed to indemnify the underwriters and certain of their controlling persons against certain liabilities and to pay certain expenses associated with the offering. The offering of the shares of Common Stock of the Company described above is registered under the Securities Act, of 1933, as amended (the “Securities Act”), pursuant to registration statements on Form S-3, as amended, including the prospectus dated July 24, 2015, the prospectus dated November 26, 2014, the preliminary prospectus supplement dated July 27, 2015 and a final prospectus supplement dated July 29, 2015.

Also on July 29, 2015, WP IX entered into a letter agreement (the “Lock-Up Agreement”) with the Underwriters, pursuant to which, subject to certain exceptions, WP IX will not offer, sell, contract to sell, pledge or otherwise dispose of, directly or indirectly, any Common Stock of the Company without, in each case, the prior written consent of Citigroup Global Markets Inc., Credit Suisse Securities (USA) LLC and Deutsche Bank Securities Inc. for a period beginning on the date of such Lock-Up Agreement and continuing for sixty (60) days after the date of the final prospectus used to sell shares of Common Stock of the Company pursuant to the Underwriting Agreement.

The foregoing description of the Underwriting Agreement and the Lock-Up Agreement is qualified in its entirety by reference to the full text of the Underwriting Agreement and the Lock-Up Agreement, copies of which are attached hereto as Exhibit B and Exhibit C, respectively, and incorporated by reference herein.

As of the date of this Amendment No. 4, except as set forth in this Schedule 13D, there are no current plans or proposals of the Reporting Persons that relate to or would result in any of the actions identified in Item 4(a) through Item 4(j).

Item 5. Interest in Securities of the Issuer

Section (a), Section (b), and Section (c) of Item 5 of the Schedule 13D are hereby amended and restated as follows:

(a) By virtue of its direct ownership of 24,863,266 shares of Common Stock of the Company, WP IX may be deemed to be the beneficial owner of 24,863,266 shares of Common Stock of the Company, which represents 25.0% of the outstanding shares of Common Stock of the Company. The percentages used in this Schedule 13D are calculated based upon a total of 99,326,375 shares of Common Stock of the Company issued and outstanding as of July 20, 2015, as disclosed in a prospectus supplement filed with the SEC on July 27, 2015, by the Company pursuant to Rule 424(b)(3) under the Securities Act.

(b) Each of WP IX GP, WPP GP, WP Partners, WP Partners GP, WP and WP LLC may be deemed to share with WP IX, the power to vote or to direct the vote and to dispose or to direct the disposition of the 24,863,266 shares of Common Stock of the Company, which WP IX may be deemed to beneficially own as of the date of this filing. Charles R. Kaye and Joseph P. Landy are Managing General Partners of WP and Managing Members and Co-Chief Executive Officers of WP LLC and may be deemed to control the other Reporting Persons. Messrs. Kaye and Landy disclaim beneficial ownership of all shares held by WP IX. Neither the filing of this Schedule 13D nor any of its contents shall be deemed to constitute an admission that any Reporting Person, other than WP IX, or any of its affiliates is the beneficial owner of any shares of Common Stock of the Company for purposes of Section 13(d) of the Exchange Act or for any other purpose. As a result of the voting arrangements set forth in the Stockholders’ Agreement (as defined in the Original Schedule 13D), JLL Holdings (as defined in the Original Schedule 13D) and the Reporting Persons may be deemed to have formed a group for purposes of Section 13(d) of the Exchange Act. Each of the Reporting Persons disclaims beneficial ownership of shares of Common Stock of the Company beneficially owned by the JLL Reporting Persons.¹

(c) During the last sixty (60) days there were no transactions in the Common Stock of the Company effected by the Reporting Persons, nor, to the best of their knowledge, any of their general partners, members or directors.

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer

Item 6 is hereby amended and supplemented by adding the following at the end thereof:

The information provided in Item 4 of this Amendment No. 4 is incorporated by reference to this Item 6.

Item 7. Material to be Filed as Exhibits

SIGNATURES

After reasonable 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.

Exhibit A

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1) of the Securities Exchange Act of 1934, as amended, each of the undersigned hereby agrees to the joint filing of the Schedule 13D to which this agreement is attached and to the joint filing of all amendments thereto.

This agreement may be executed in one or more counterparts, each of which shall be considered an original counterpart, and shall become a binding agreement when each of the parties designated as signatories has executed one counterpart.

Exhibit B

EXECUTION VERSION

12,000,000 Shares

BUILDERS FIRSTSOURCE, INC.

Common Stock

UNDERWRITING AGREEMENT

July 29, 2015

CREDIT SUISSE SECURITIES (USA) LLC

DEUTSCHE BANK SECURITIES INC.

CITIGROUP GLOBAL MARKETS INC.

As Representatives of the several Underwriters,

c/o Credit Suisse Securities (USA) LLC

Eleven Madison Avenue

New York, New York 10010

c/o Deutsche Bank Securities Inc.

60 Wall Street

New York, New York 10005

c/o Citigroup Global Markets Inc.

388 Greenwich Street

New York, New York 10013

Ladies and Gentlemen:

1. Introductory. Builders FirstSource, Inc., a Delaware corporation (the “Company”), agrees with the several Underwriters named in Schedule A hereto (“Underwriters”) to issue and sell to the Underwriters 8,000,000 shares of its common stock (the “Securities”) and Warburg Pincus Private Equity IX, L.P. (“Selling Stockholder”) agrees with the Underwriters to sell to the Underwriters an aggregate of 4,000,000 outstanding shares of the Securities (such shares of Securities being hereinafter referred to as the “Firm Securities”). The Company also agrees to sell to the Underwriters, at the option of the Underwriters, an aggregate of not more than 1,200,000 additional outstanding shares of its Securities and the Selling Stockholder also agrees to sell to the Underwriters, at the option of the Underwriters, an aggregate not more than 600,000 additional shares (the “Optional Securities”) of the Company’s Securities, as set forth below. The Firm Securities and the Optional Securities are herein collectively called the “Offered Securities”.

The Company has entered into a Securities Purchase Agreement, dated as of April 13, 2015 (as amended from time to time, the “Acquisition Agreement”), among the Company, ProBuild Holdings LLC, a Delaware limited liability company (“ProBuild”), FMR LLC, a Delaware limited liability company, ProBuild Capital LLC, a Delaware limited liability company, ProBuild Holdings, Inc., a

Delaware corporation, and Lanoga Corporation, a Minnesota Corporation, pursuant to which the Company will acquire all of the outstanding equity interests of ProBuild as described in the General Disclosure Package (as defined below). The term “Acquisition Agreement” as used herein shall refer to all exhibits, schedules and attachments to such Acquisition Agreement. The term “Acquisition” as used herein shall refer to the transactions contemplated by the Acquisition Agreement, including this offering of common stock and the other financing transactions. The Acquisition is expected to be completed substantially concurrently with the completion of this offering. However, the completion of the Acquisition is not a condition to this offering of common stock.

2. Representations and Warranties of the Company and the Selling Stockholder.

(a) Representations and Warranties of the Company. The Company represents and warrants to, and agrees with, the Underwriters that (it being understood and agreed that whenever reference is made to the subsidiaries of the Company in this agreement (the “Agreement”), such phrase will be understood to refer to and include (i) all of the subsidiaries of the Company and (ii) except as expressly stated herein, ProBuild and its consolidated subsidiaries):

(i) Filing and Effectiveness of Registration Statements; Certain Defined Terms. The Company has filed with the Commission a registration statement on Form S-3 (No. 333-203824), including a related prospectus or prospectuses and registration statements on Form S-3 filed pursuant to Rule 462(b) of the Rules and Regulations, covering the registration of the Offered Securities of the Company under the Act, which has become effective, and a registration statement on Form S-3 (No. 333-199955), including a related prospectus or prospectuses and registration statements on Form S-3 filed pursuant to Rule 462(b) of the Rules and Regulations, covering the registration of the Offered Securities of the Selling Stockholder under the Act, which has become effective. “Registration Statement” at any particular time means such registration statement in the form then filed with the Commission, including any amendment thereto, any document incorporated by reference therein and including all 430B Information with respect to such registration statement, that in any case has not been superseded or modified. “Registration Statement” without reference to a time means the Registration Statement as of the Effective Time. For purposes of this definition, 430B Information shall be considered to be included in the Registration Statement as of the time specified in Rule 430B.

For purposes of this Agreement:

“430B Information” means information included in a prospectus then deemed to be a part of a Registration Statement pursuant to Rule 430B(e) or retroactively deemed to be a part of a Registration Statement pursuant to Rule 430B(f).

“Act” means the Securities Act of 1933, as amended.

“Applicable Time” means 8:30 a.m. (Eastern time) on the date of this Agreement.

“Closing” means the time of closing of the Acquisition on the First Closing Date.

“Closing Date” has the meaning defined in Section 3 hereof.

“Commission” means the Securities and Exchange Commission.

“Effective Time” of a Registration Statement relating to the applicable Offered Securities means the time of the first contract of sale for such Offered Securities.

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“Exchange Act” means the Securities Exchange Act of 1934, as amended.

“Final Prospectus” means the Statutory Prospectus that discloses the public offering price, other 430B Information and other final terms of the applicable Offered Securities and otherwise satisfies Section 10(a) of the Act.

“General Use Issuer Free Writing Prospectus” means any Issuer Free Writing Prospectus that is intended for general distribution to prospective investors, as evidenced by its being so specified in Schedule B to this Agreement.

“Issuer Free Writing Prospectus” means any “issuer free writing prospectus,” as defined in Rule 433, relating to the Offered Securities in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Company’s records pursuant to Rule 433(g).

“Limited Use Issuer Free Writing Prospectus” means any Issuer Free Writing Prospectus that is not a General Use Issuer Free Writing Prospectus.

“Rules and Regulations” means the rules and regulations of the Commission.

“Securities Laws” means, collectively, the Sarbanes-Oxley Act of 2002, as amended, and the rules and regulations promulgated in connection therewith (“Sarbanes-Oxley”), the Act, the Exchange Act, the Rules and Regulations, the auditing principles, rules, standards and practices applicable to auditors of “issuers” (as defined in Sarbanes-Oxley) promulgated or approved by the Public Company Accounting Oversight Board and, as applicable, the rules of the NASDAQ Stock Market (“Exchange Rules”).

“Statutory Prospectus” with reference to any particular time means the prospectus relating to the applicable Offered Securities that is included in the applicable Registration Statement immediately prior to that time, including all 430B Information with respect to such Registration Statement. For purposes of the foregoing definition, 430B Information shall be considered to be included in the Statutory Prospectus only as of the actual time that form of prospectus (including a prospectus supplement) is filed with the Commission pursuant to Rule 424(b) and not retroactively.

Unless otherwise specified, a reference to a “rule” is to the indicated rule under the Act.

(ii) Compliance with Securities Act Requirements. (i) (A) At the time each Registration Statement initially became effective, (B) at the time of each amendment thereto for the purposes of complying with Section 10(a)(3) of the Act (whether by post-effective amendment, incorporated report or form of prospectus), (C) at the Effective Time relating to the Offered Securities and (D) on the Closing Date, each Registration Statement conformed and will conform in all respects to the requirements of the Act and the Rules and Regulations and did not and will not include any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein not misleading and (ii) (A) on its date, (B) at the time of filing pursuant to Rule 424(b) and (C) on the Closing Date, each Final Prospectus will conform in all respects to the requirements of the Act and the Rules and Regulations, and will not include any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from any such document based upon written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information is that described as such in Section 8(b) hereof.

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(iii) Shelf Registration Statement. The date of this Agreement is not more than three years subsequent to the more recent of the initial effective time of each Registration Statement or December 1, 2005. If, immediately prior to the third anniversary of the more recent of the initial effective time of each Registration Statement or December 1, 2005, any of the applicable Offered Securities remain unsold by the Underwriters, the Company will prior to that third anniversary file, if it has not already done so, a new shelf registration statement relating to such Offered Securities, in a form satisfactory to the Representatives, will use its best efforts to cause such registration statement to be declared effective within 180 days after that third anniversary, and will take all other action necessary or appropriate to permit the public offering and sale of such Offered Securities to continue as contemplated in the expired registration statement relating to such Offered Securities. References herein to a Registration Statement shall include such new shelf registration statement.

(iv) Ineligible Issuer Status. (i) At the earliest time after the filing of the Registration Statement that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2)) of the Offered Securities and (ii) at the date of this Agreement, the Company was not and is not an “ineligible issuer,” as defined in Rule 405, including (x) the Company or any other subsidiary in the preceding three years not having been convicted of a felony or misdemeanor or having been made the subject of a judicial or administrative decree or order as described in Rule 405 and (y) the Company in the preceding three years not having been the subject of a bankruptcy petition or insolvency or similar proceeding, not having had a registration statement be the subject of a proceeding under Section 8 of the Act and not being the subject of a proceeding under Section 8A of the Act in connection with the offering of the Offered Securities, all as described in Rule 405.

(v) General Disclosure Package. As of the Applicable Time, in connection with each Registration Statement neither (i) the General Use Issuer Free Writing Prospectus(es) issued at or prior to the Applicable Time, the preliminary prospectus supplement, dated July 27, 2015, including the base prospectus, dated as of its date, (which is the most recent Statutory Prospectus distributed to investors generally), and the other information, if any, stated in Schedule B to this Agreement to be included in the General Disclosure Package, all considered together (collectively, the “General Disclosure Package”; unless otherwise specified, “General Disclosure Package” shall refer to the foregoing materials in respect of all Offered Securities), nor (ii) any individual Limited Use Issuer Free Writing Prospectus, when considered together with the General Disclosure Package, included any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from any Statutory Prospectus or any Issuer Free Writing Prospectus in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8(b) hereof.

(vi) Issuer Free Writing Prospectuses. Each Issuer Free Writing Prospectus, as of its issue date and at all subsequent times through the completion of the public offer and sale of the Offered Securities or until any earlier date that the Company notified or notifies the Representatives as described in the next sentence, did not, does not and will not include any information that conflicted, conflicts or will conflict with the information then contained in the

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Registration Statements. If at any time following issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development as a result of which such Issuer Free Writing Prospectus conflicted or would conflict with the information then contained in a Registration Statement or as a result of which such Issuer Free Writing Prospectus, if republished immediately following such event or development, would include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, (i) the Company has promptly notified or will promptly notify the Representatives and (ii) the Company has promptly amended or will promptly amend or supplement such Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement or omission.

(vii) Good Standing of the Company. The Company has been duly incorporated and is existing and in good standing under the laws of the State of Delaware, with all requisite corporate power and authority to own its properties and conduct its business as described in the General Disclosure Package; and the Company is duly qualified to do business as a foreign corporation in good standing in all other jurisdictions in which its ownership or lease of property or the conduct of its business requires such qualification, except where the failure to be so qualified, in good standing or have such power or authority would not reasonably be expected to result in, individually or in the aggregate, a material adverse effect on the business, results of operations or condition (financial or otherwise) of the Company and its subsidiaries, taken as a whole, or materially and adversely affect the ability of the Company to perform its obligations under this Agreement (a “Material Adverse Effect”).

(viii) Subsidiaries. Each subsidiary of the Company (A) has been duly incorporated or organized and is existing and in good standing under the laws of the jurisdiction of its incorporation or formation, (B) has all requisite power and authority (corporate and other) to own its properties and conduct its business as described in the General Disclosure Package, and (C) is duly qualified to do business as a foreign corporation in good standing in all other jurisdictions in which its ownership or lease of property or the conduct of its business requires such qualification, except, in the case of clauses (B) and (C), where the failure to be so qualified, in good standing or have such power and authority would not reasonably be expected to result in, individually or in the aggregate, a Material Adverse Effect; all of the issued and outstanding capital stock of each subsidiary of the Company has been duly authorized and validly issued and is fully paid and nonassessable; and, except with regard to Dixieline Builders Fund Control, Inc., Builder’s Capital LLC and Pro-Build Real Estate Holdings, LLC (the “Transferred Subsidiaries”), the capital stock of any subsidiary owned by the Company, directly or through subsidiaries, is owned free from liens, encumbrances and defects (other than the credit agreements governing the New Senior Secured Credit Facilities (as described in each of the General Disclosure Package and the Final Prospectus) (the “Senior Credit Agreements”), the Existing Indenture (as described in each of the General Disclosure Package and the Final Prospectus), the security documents entered into in connection therewith and, prior to the Closing, pursuant to the documents governing the Existing ABL Facility (as defined in the General Disclosure Package) and the ProBuild Credit Agreement (as defined in the General Disclosure Package) (collectively, the “Existing Credit Agreements”), which will be terminated or released in connection with the repayment of the Existing ProBuild Indebtedness (as defined in the General Disclosure Package) and the Existing ABL Facility (the “Refinancing”)); none of the outstanding capital stock of any subsidiary owned by the Company, directly or through subsidiaries, has been issued in violation of any preemptive or similar rights of any security holder.

Upon completion of the transactions contemplated by the Contribution and Assignment Agreement (the “Contribution Agreement”), dated as of April 13, 2015, by and among

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ProBuild, Lanoga Corporation, a Minnesota corporation, ProBuild Capital LLC, a Delaware limited liability company, and ProBuild Holdings, Inc., a Delaware corporation, which will occur prior to the Closing, all of the outstanding shares of capital stock of the Transferred Subsidiaries will be owned, directly or indirectly, by ProBuild, free and clear of any Liens (other than the Senior Credit Agreements, and prior to the Closing, pursuant to the Existing Credit Agreements, which will be terminated or released in connection with the Refinancing); and all such securities have been duly authorized, validly issued and are fully paid and nonassessable and were not issued in violation of any preemptive or similar rights.

Except with regard to the Transferred Subsidiaries, the Company has the capitalization as set forth in each of the General Disclosure Package and the Final Prospectus under the heading “Capitalization.” Upon completion of the transactions contemplated by the Contribution Agreement, which will occur prior to the Closing, the Company will have the capitalization as set forth in each of the General Disclosure Package and the Final Prospectus under the heading “Capitalization.”

(ix) Offered Securities. The Offered Securities and all other outstanding shares of capital stock of the Company have been duly authorized; the authorized equity capitalization of the Company is as set forth in the General Disclosure Package; all outstanding shares of capital stock of the Company are, and, when the Offered Securities have been delivered and paid for in accordance with this Agreement on each Closing Date, such Offered Securities will have been, validly issued, fully paid and nonassessable, will conform to the information in the General Disclosure Package and to the description of such Offered Securities contained in the Final Prospectus; the stockholders of the Company have no preemptive rights with respect to the Securities; and none of the outstanding shares of capital stock of the Company have been issued in violation of any preemptive or similar rights of any security holder.

(x) No Finder’s Fee. Except as disclosed in the General Disclosure Package, there are no contracts, agreements or understandings between the Company and any person that would give rise to a valid claim against the Company or any Underwriter for a brokerage commission, finder’s fee or other like payment in connection with this offering.

(xi) Registration Rights. Except as disclosed in the General Disclosure Package, there are no contracts, agreements or understandings between the Company and any person granting such person the right to require the Company to file a registration statement under the Act with respect to any securities of the Company owned or to be owned by such person or to require the Company to include such securities in the securities registered pursuant to a Registration Statement or in any securities being registered pursuant to any other registration statement filed by the Company under the Act (collectively, “registration rights”).

(xii) Absence of Further Requirements. No consent, approval, authorization, or order or qualification of, or filing or registration with, any person (including any governmental agency or body or any court) is required to be obtained or made by the Company for the consummation of the transactions contemplated by this Agreement in connection with the sale of the Offered Securities by the Company, except such as have been obtained or made and such as may be required under state securities laws.

(xiii) Title to Property. The Company and its subsidiaries have good and marketable title in fee simple to or have valid leasehold interests in or have valid rights to lease or otherwise use, all real properties and personal properties that are material to the respective businesses of the Company and its subsidiaries, in each case free from liens, encumbrances, claims and defects

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except those that (i) do not materially interfere with the use made and proposed to be made of such property by the Company and its subsidiaries, (ii) would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect, (iii) secure any of the indebtedness incurred under the Existing Credit Agreements, which liens, encumbrances and claims will be released substantially contemporaneously with the issuance of the Offered Securities on the Closing Date, (iv) secure the Senior Credit Agreements or (v) secure the Company’s 7.625% senior secured notes due 2017.

(xiv) Absence of Defaults and Conflicts Resulting from Transaction. The execution, delivery and performance of this Agreement, and the issuance and sale of the Offered Securities, will not result in a breach or violation of any of the terms and provisions of, or constitute a default or a Debt Repayment Triggering Event (as defined below) under, or result in the imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries pursuant to, (A) the charter, by-laws or similar organizational documents of the Company or any of its subsidiaries, (B) any statute, rule, regulation or order of any governmental agency or body or any court, domestic or foreign, having jurisdiction over the Company or any of its subsidiaries or any of their properties, or (C) any agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the properties of the Company or any of its subsidiaries is subject except, in the case of clauses (B) and (C) above, any breach, violation, default, lien, charge or encumbrance that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect; a “Debt Repayment Triggering Event” means any event or condition that gives, or with the giving of notice or lapse of time would give, the holder of any note, debenture, or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any of its subsidiaries.

(xv) Absence of Existing Defaults and Conflicts. Neither the Company nor any of its subsidiaries is (x) in violation of its respective charter, by-laws or other similar organizational documents, (y) in default (or with the giving of notice or lapse of time would be in default) under any covenant or condition contained in any indenture, loan agreement, mortgage or other agreement or instrument to which any of them is a party or by which any of them is bound or to which any of the properties of any of them is subject or (z) in violation of any law or statute or any judgment, order, rule or regulation of any court or arbitrator or governmental or regulatory authority, except in the case of clauses (y) and (z) above, such defaults or violations that would not reasonably be expected to result, individually or in the aggregate, in a Material Adverse Effect.

(xvi) Authorization of Agreement. This Agreement has been duly authorized, executed and delivered by the Company.

(xvii) Possession of Licenses and Permits. The Company and its subsidiaries possess all adequate certificates, authorizations, franchises, licenses and permits (“Licenses”) necessary to the conduct of the business now conducted as described in the General Disclosure Package except where the failure to have such Licenses would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect, and have not received any notice of proceedings relating to the revocation or modification of any Licenses that, if determined adversely to the Company or any of its subsidiaries, would individually or in the aggregate reasonably be expected to have a Material Adverse Effect.

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(xviii) Absence of Labor Dispute. No labor dispute with the employees of the Company or any of its subsidiaries exists or, to the knowledge of the Company, is imminent or threatened that would, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect. None of the Company or its subsidiaries has received any notice of cancellation or termination with respect to any collective bargaining agreement to which it is a party.

(xix) Possession of Intellectual Property. The Company and its subsidiaries own, possess or have the right to employ all trademarks, trade names, inventions, know-how, patents, copyrights, confidential information and other intellectual property (collectively, “intellectual property”) necessary to conduct the business now operated by them except where the failure to own or possess such intellectual property would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect. The use of the intellectual property in connection with the business and operations of the Company and its subsidiaries does not infringe on the rights of any person, except such infringements as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(xx) Environmental Laws. Neither the Company nor any of its subsidiaries (i) is party to any proceedings that are pending, or to the knowledge of the Company or any of its subsidiaries, threatened, under any foreign, federal, state or local law, rule, regulation, requirement, decision or order relating to the protection of human health or safety, the environment, natural resources, hazardous or toxic substances or wastes, pollutants or contaminants (collectively, “environmental laws”) in which a governmental authority is also a party, other than such proceedings that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect, (ii) has failed to comply with any environmental law or to obtain, maintain or comply with any permits, licenses, certificates or other authorizations or approvals required under applicable environmental laws to conduct its respective business other than such failure to comply or failure to obtain, maintain and comply with required permits, licenses, certificates or other authorizations or approvals that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect and (iii) is aware of any other proceedings, claims or any other issues regarding compliance with, or liabilities or obligations under, environmental laws, or concerning hazardous or toxic substances or wastes, pollutants or contaminants, other than such proceedings, claims or issues that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(xxi) Absence of Manipulation. The Company has not taken, directly or indirectly, any action that is designed to or that could reasonably be expected to cause or result in the stabilization or manipulation of the price of the Offered Securities.

(xxii) Statistical and Market-Related Data. Any statistical, industry and market-related data included in a Registration Statement, a Statutory Prospectus or the General Disclosure Package are based on or derived from management estimates and third-party sources and the Company believes such estimates and sources are reasonable, reliable and accurate in all material respects.

(xxiii) Internal Controls and Compliance with the Sarbanes-Oxley Act – Builders FirstSource, Inc. and its Subsidiaries. To the extent applicable, there is and has been no failure on the part of the Company or any of its directors or officers, in their capacities as such, to comply with Sarbanes-Oxley, including Section 402 related to loans and Sections 302 and 906 related to certifications. The Company maintains a system of internal controls over financial reporting (as defined in Rule 13a-15(f) of the Exchange Act) that comply with the requirements of the Exchange Act and are sufficient to provide reasonable assurances that (i) transactions are executed in accordance with management’s general or specific authorizations, (ii) transactions are recorded as

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necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain accountability for assets, (iii) access to assets is permitted only in accordance with management’s general or specific authorization, and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences. There are no material weaknesses or significant deficiencies in the Company’s or its subsidiaries’ (excluding ProBuild and its subsidiaries) internal controls. The Internal Controls are, or upon consummation of the offering of the Offered Securities will be, overseen by the Audit Committee (the “Audit Committee”) of the Board in accordance with Exchange Rules.

(xxiv) Internal Controls – ProBuild and its Subsidiaries. ProBuild and its subsidiaries maintain systems of internal control over financial reporting that have been designed by, or under the supervision of, their respective principal executive and principal financial officers, or persons performing similar functions, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements in accordance with generally accepted accounting principles. ProBuild and its subsidiaries maintain internal accounting controls sufficient to provide reasonable assurance that: (i) transactions are executed in accordance with management’s general or specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences. In connection with the audit of its December 31, 2014 financial statements, ProBuild’s independent auditors did not identify any deficiencies in internal control over financial reporting that would be considered a material weakness or significant deficiency.

(xxv) Disclosure Controls. The Company and its subsidiaries (excluding ProBuild and its subsidiaries) maintain an effective system of “disclosure controls and procedures” (as defined in Rule 13a-15(e) of the Exchange Act) that is designed to ensure that information required to be disclosed by the Company in reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the Commission’s rules and forms, including controls and procedures designed to ensure that such information is accumulated and communicated to the Company’s management as appropriate to allow timely decisions regarding required disclosure. The Company and its subsidiaries have carried out evaluations of the effectiveness of their disclosure controls and procedures as required by Rule 13a-15 of the Exchange Act.

(xxvi) Litigation. There are no pending legal, governmental or regulatory investigations, actions, suits or proceedings against the Company, any of its subsidiaries or any of their respective properties that, if determined adversely to the Company or any of its subsidiaries, would individually or in the aggregate reasonably be expected to have a Material Adverse Effect; and no such actions, suits or proceedings are, to the Company’s knowledge, threatened or contemplated.

(xxvii) Financial Statements. The financial statements and the related notes thereto of (i) the Company and its subsidiaries and (ii) ProBuild and its subsidiaries, in each case included in each Registration Statement and the General Disclosure Package present fairly in all material respects the financial position of the Company and its subsidiaries or ProBuild and its subsidiaries, as the case may be, as of the dates indicated and the results of their operations and the changes in their cash flows for the periods specified; such financial statements have been prepared in conformity with generally accepted accounting principles applied on a consistent basis throughout the periods covered thereby; the other financial information included in each Registration Statement

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and the General Disclosure Package has been derived from the accounting records of the Company and its subsidiaries or ProBuild and its subsidiaries, as the case may be, and presents fairly in all material respects the information shown thereby; and the pro forma financial information of the Company and the related notes thereto included in each Registration Statement and the General Disclosure Package has been prepared in accordance with the Commission’s rules and guidance with respect to pro forma financial information in all material respects, and the assumptions underlying such pro forma financial information are reasonable and are set forth in each Registration Statement and the General Disclosure Package.

(xxviii) No Material Adverse Change in Business. Since the date of the most recent financial statements of the Company included in the General Disclosure Package, there has not been any Material Adverse Effect or any change or development that is reasonably likely to result in any Material Adverse Effect, the Company has not incurred or become subject to any material liabilities that have not been disclosed in the General Disclosure Package and no dividend or distribution of any kind has been declared, paid or made by the Company or its subsidiaries on any class of stock.

(xxix) Investment Company Act. The Company is not and, at Closing after giving effect to the offering and sale of the Offered Securities and the application of the proceeds thereof as described in the General Disclosure Package, will not be an “investment company” as defined in the Investment Company Act of 1940 (the “Investment Company Act”).

(xxx) Acquisition Agreement. The Company expects that the Acquisition will be consummated in all material respects on the terms and by the date and as contemplated by the Acquisition Agreement.

(xxxi) Compliance with ERISA. (i) Each employee benefit plan, within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), for which the Company has any liability, direct or indirect, contingent or otherwise, including any liability on account of any member of their respective “Controlled Group” (defined as any organization which is a member of a controlled group of corporations within the meaning of Section 414 of the Internal Revenue Code of 1986, as amended (the “Code”)) (each, a “Plan”) has been maintained in compliance with its terms and the requirements of any applicable statutes, orders, rules and regulations, including but not limited to ERISA and the Code; (ii) no prohibited transaction, within the meaning of Section 406 of ERISA or Section 4975 of the Code, has occurred with respect to any Plan excluding transactions effected pursuant to a statutory or administrative exemption; (iii) for each Plan that is subject to the funding rules of Section 412 of the Code or Section 302 of ERISA, no Plan has failed (whether or not waived), or is reasonably expected to fail, to satisfy the minimum funding standards (within the meaning of Section 302 of ERISA or Section 412 of the Code) applicable to such Plan; (iv) no Plan is, or is reasonably expected to be, in “at risk status” (within the meaning of Section 303(i) of ERISA) or “endangered status” or “critical status” (within the meaning of Section 305 of ERISA); (v) except as otherwise disclosed in the Registration Statement and the General Disclosure Package, the fair market value of the assets of each Plan exceeds the present value of all benefits accrued under such Plan (determined based on those assumptions used to fund such Plan); (vi) no “reportable event” (within the meaning of Section 4043(c) of ERISA) has occurred or is reasonably expected to occur; (vii) each Plan that is intended to be qualified under Section 401(a) of the Code is so qualified and, to the knowledge of the Company, nothing has occurred, whether by action or by failure to act, which would reasonably be expected to cause the loss of such qualification; and (viii) none of the Company or any member of its Controlled Group has incurred, nor reasonably expects to incur, any liability under Title IV of ERISA (other than contributions to the Plan or premiums to the Pension Benefit Guaranty

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Corporation, in the ordinary course and without default) in respect of a Plan (including a “multiemployer plan,” within the meaning of Section 4001(a)(3) of ERISA), except, in each case with respect to the events or conditions set forth in (i) through (viii) hereof, as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(xxxii) Independent Accountants. PricewaterhouseCoopers LLP, who have certified certain financial statements of the Company and its subsidiaries and of ProBuild Holdings LLC and its subsidiaries, are independent public accountants with respect to the Company and its subsidiaries and ProBuild Holdings LLC and its subsidiaries, within the applicable rules and regulations adopted by the Commission and the Public Company Accounting Oversight Board (United States) and as required by the Securities Act.

(xxxiii) Taxes. All federal, state and foreign income and franchise tax returns required to be filed by the Company or its subsidiaries in all jurisdictions have been so filed through the date hereof, subject to permitted exceptions, except where the failure to make such filings would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect. All taxes, including withholding taxes, penalties and interest, assessments, fees and other charges due or claimed to be due from such entities or that are due and payable have been paid, other than those being contested in good faith or those currently payable without penalty or interest and except where the failure to make such required filings or payments would not, individually or in the aggregate, reasonably be expected to result in a Material Adverse Effect.

(xxxiv) Insurance. The Company and its subsidiaries have insurance covering their respective properties, operations, personnel and businesses, insuring against such losses and risks as are consistent with industry practice, except where the failure to maintain such insurance would not reasonably be expected to have a Material Adverse Effect.

(xxxv) No Unlawful Payments. None of the Company or any of its subsidiaries or, to the knowledge of the Company, any director, officer, agent, affiliate or other person acting on behalf of the Company or any of its subsidiaries has: (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (ii) made or taken an act in furtherance of an offer, promise or authorization of any direct or indirect unlawful payment or benefit to any foreign or domestic government official or employee (including any government-owned or controlled entity or of a public international organization) or any person acting in an official capacity for or on behalf of any of the foregoing, or any political party or party official or candidate for political office; (iii) violated or is in violation of any provision of the Foreign Corrupt Practices Act of 1977, as amended ( “FCPA”), or any other applicable anti-bribery or anti-corruption law; or (iv) made, offered, agreed, requested or taken an act in furtherance of any unlawful bribe or other unlawful benefit, including, without limitation, any rebate, payoff, influence payment, kickback or other unlawful payment or benefit. The Company and its subsidiaries have instituted, maintain and enforce policies and procedures designed to promote and ensure compliance with all applicable anti-bribery and anti-corruption laws. No part of the proceeds of the offering will be used, directly or indirectly, in violation of the FCPA or similar law of any other relevant jurisdiction, or the rules or regulations thereunder.

(xxxvi) Compliance with Money Laundering Laws. The operations of the Company and its subsidiaries are and have been conducted in compliance with applicable financial recordkeeping and reporting requirements, including those of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the applicable money laundering statutes of all jurisdictions where the Company or any of its subsidiaries conducts business, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any applicable

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governmental agency (collectively, the “Anti-Money Laundering Laws”), and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Anti-Money Laundering Laws is pending or, to the knowledge of the Company, threatened.

(xxxvii) Compliance with Sanctions Laws. None of the Company or any of its subsidiaries, nor, to the knowledge of the Company, any director, officer, employee, agent, affiliate or other person acting on behalf of the Company or any of its subsidiaries is currently the subject or the target of, or is controlled or 50% or more owned by or is acting on behalf of an individual or entity that is currently the subject of, any sanctions administered or enforced by the U.S. government (including, without limitation, the Office of Foreign Assets Control of the U.S. Department of the Treasury (“OFAC”) or the U.S. Department of State and including, without limitation, the designation as a “specially designated national” or “blocked person”), or other relevant sanctions authority (collectively, “Sanctions”), nor is the Company or any of its subsidiaries located, organized or resident in a country or territory that is the subject or target of Sanctions, including, without limitation, Cuba, Iran, North Korea, Sudan, Syria and Crimea (each, a “Sanctioned Country”); and the Company will not use, directly or indirectly, the proceeds of the offering of the Offered Securities hereunder, or lend, contribute or otherwise make available, directly or indirectly, such proceeds to any subsidiary, joint venture partner or other person or entity (i) to fund or facilitate any activities of or conduct business with any person that, at the time of such funding or facilitation is the subject of Sanctions, (ii) to fund, facilitate, or conduct any activities of or business in any Sanctioned Country or (iii) in any other manner that will result in a violation by any person (including any person participating in the transaction, whether as initial purchaser, advisor, investor or otherwise) of Sanctions. For the past five years, the Company and its subsidiaries have not knowingly engaged in and are not now knowingly engaged in any dealings or transactions with any person that at the time of the dealing or transaction is or was the subject or the target of Sanctions or with any Sanctioned Country.

(xxxviii) Margin Rules. Neither the issuance, sale and delivery of the Offered Securities nor the application of the proceeds thereof by the Company as described in each of the General Disclosure Package and the Registration Statement will violate Regulation T, U or X of the Board of Governors of the Federal Reserve System or any other regulation of such Board of Governors.

(xxxix) Forward-looking Statements. No forward-looking statement (within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act) included in any of the General Disclosure Package or the Registration Statement has been made or reaffirmed without a reasonable basis or has been disclosed other than in good faith.

(b) Representations and Warranties of the Selling Stockholder. The Selling Stockholder represents and warrants to, and agrees with, the Underwriters that:

(i) Title to Securities. The Selling Stockholder has and on each Closing Date hereinafter mentioned will have valid and unencumbered title to the Offered Securities to be delivered by the Selling Stockholder on such Closing Date and full right, power and authority to enter into this Agreement and to sell, assign, transfer and deliver the Offered Securities to be delivered by the Selling Stockholder on such Closing Date hereunder; and upon the delivery of and payment for the Offered Securities on each Closing Date hereunder the Underwriters will acquire valid and unencumbered title to the Offered Securities to be delivered by the Selling Stockholder on such Closing Date.

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(ii) Absence of Further Requirements. No consent, approval, authorization, or order or qualification of, or filing or registration with, any person (including any governmental agency or body or any court) is required to be obtained or made by the Selling Stockholder for the consummation of the transactions contemplated by this Agreement in connection with the sale of the Offered Securities by the Selling Stockholder, except such as have been obtained or made and such as may be required under state securities laws.

(iii) Absence of Defaults and Conflicts Resulting from Transaction. The execution, delivery and performance of this Agreement and the consummation of the sale of the Offered Securities will not result in a breach or violation of any of the terms and provisions of, or constitute a default under, or result in the imposition of any lien, charge or encumbrance upon any property or assets of the Selling Stockholder pursuant to, (A) any statute, any rule, regulation or order of any governmental agency or body or any court having jurisdiction over the Selling Stockholder or any of its properties, (B) any agreement or instrument to which the Selling Stockholder is a party or by which the Selling Stockholder is bound or to which any of the properties of the Selling Stockholder is subject or (C) the charter, by-laws, partnership agreement or any other constituent document, as applicable, of the Selling Stockholder, except, in the case of clauses (A) and (B) above, any breach, violation, default, lien, charge or encumbrance that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(iv) Compliance with Securities Act Requirements. (i) (A) At the time each Registration Statement initially became effective, (B) at the time of each amendment thereto for the purposes of complying with Section 10(a)(3) of the Act (whether by post-effective amendment, incorporated report or form of prospectus), (C) at the Effective Time relating to the Offered Securities and (D) on the Closing Date, each Registration Statement, solely with respect to any information pertaining to the Selling Stockholder, did not and will not include any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein not misleading and (ii) (A) on its date, (B) at the time of filing pursuant to Rule 424(b) and (C) on the Closing Date, each Final Prospectus, solely with respect to any information pertaining to the Selling Stockholder, will not include any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein not misleading. The preceding sentence shall only apply to statements in or omissions from any such document based upon written information furnished to the Company by the Selling Stockholder specifically for use therein, it being understood and agreed that the only such information pertaining to the Selling Stockholder consists of the following information in each Final Prospectus furnished on behalf of the Selling Stockholder: the beneficial ownership table under the caption “The Selling Stockholder.”

(v) Authorization of Agreement. This Agreement has been duly authorized, executed and delivered by the Selling Stockholder.

(vi) No Finder’s Fee. Except as disclosed in the General Disclosure Package, there are no contracts, agreements or understandings between the Selling Stockholder and any person that would give rise to a valid claim against the Selling Stockholder or any Underwriter for a brokerage commission, finder’s fee or other like payment in connection with this offering.

(vii) Absence of Manipulation. The Selling Stockholder has not taken, directly or indirectly, any action that is designed to or that has constituted or that would reasonably be expected to cause or result in the stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Offered Securities.

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3. Purchase, Sale and Delivery of Offered Securities. On the basis of the representations, warranties and agreements and subject to the terms and conditions set forth herein, the Company and the Selling Stockholder agree, severally and not jointly, to sell to each Underwriter, and each Underwriter agrees, severally and not jointly, to purchase from the Company and the Selling Stockholder, at a purchase price of $12.224 per share, that number of Firm Securities (rounded up or down, as determined by the Representative in their discretion, in order to avoid fractions) obtained by multiplying 8,000,000 shares of Firm Securities, in the case of the Company, and 4,000,000 shares of Firm Securities, in the case of a Selling Stockholder, in each case by a fraction the numerator of which is the number of Firm Securities set forth opposite the name of such Underwriter in Schedule A hereto and the denominator of which is the total number of Firm Securities.

The Company and the Selling Stockholder will deliver the Firm Securities to or as instructed by the Representatives for the accounts of the Underwriters in a form reasonably acceptable to the Representatives, against payment of the purchase price by the Underwriters in Federal (same day) funds as instructed in writing by the Company and the Selling Stockholder, respectively, and satisfactory to the Underwriters, on July 31, 2015, or at such other time not later than seven full business days thereafter as the Representatives and the Company determine, such time being herein referred to as the “First Closing Date”. For purposes of Rule 15c6-1 under the Exchange Act, the First Closing Date (if later than the otherwise applicable settlement date) shall be the settlement date for payment of funds and delivery of securities for all the Offered Securities sold pursuant to the offering. The Firm Securities so to be delivered or evidence of their issuance will be made available for checking at the above office of Skadden, Arps, Slate, Meagher & Flom LLP at least 24 hours prior to the First Closing Date.

In addition, upon written notice from the Representatives given to the Company and the Selling Stockholder from time to time not more than 30 days subsequent to the date of the Final Prospectus, the Underwriters may purchase all or less than all of the Optional Securities, up to 1,200,000 shares from the Company and up to 600,000 shares from the Selling Stockholder, at the purchase price per Security to be paid for the Firm Securities. The Company and the Selling Stockholder agree, severally and not jointly, to sell to the Underwriters the number of shares of Optional Securities specified in such notice and the Underwriters agree, severally and not jointly, to purchase such Optional Securities. Such Optional Securities shall be purchased for the account of each Underwriter in the same proportion as the number of shares of Firm Securities set forth opposite such Underwriter’s name bears to the total number of Firm Securities (subject to adjustment by the Representatives to eliminate fractions) and may be purchased by the Underwriters only for the purpose of covering over-allotments made in connection with the sale of the Firm Securities. No Optional Securities shall be sold or delivered unless the Firm Securities previously have been, or simultaneously are, sold and delivered. The right to purchase the Optional Securities or any portion thereof may be exercised from time to time and to the extent not previously exercised may be surrendered and terminated at any time upon notice by the Representatives to the Company and the Selling Stockholder.

Each time for the delivery of and payment for the Optional Securities, being herein referred to as an “Optional Closing Date”, which may be the First Closing Date (the First Closing Date and each Optional Closing Date, if any, being sometimes referred to as a “Closing Date”), shall be determined by the Representatives but shall be not later than five full business days after written notice of election to purchase Optional Securities is given. The Company and the Selling Stockholder will deliver the Optional Securities being purchased on each Optional Closing Date to or as instructed by the Representatives for the accounts of the Underwriters, in a form reasonably acceptable to the Representatives against payment of the purchase price therefore in Federal (same day) funds as instructed in writing by the Company and the Selling Stockholder, respectively, and satisfactory to the Underwriters. The Optional Securities being purchased on each Optional Closing Date or evidence of their issuance will be made available for checking at the above office of Skadden, Arps, Slate, Meagher & Flom LLP at least 24 hours prior to such Optional Closing Date.

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4. Offering by Underwriters. It is understood that the Underwriters propose to offer the Offered Securities for sale to the public as set forth in the Final Prospectus.

5. Certain Agreements of the Company and the Selling Stockholder. The Company agrees with the Underwriters and the Selling Stockholder that:

(a) Filing of Prospectuses. The Company has filed or will file each Statutory Prospectus (including each Final Prospectus) pursuant to and in accordance with Rule 424(b)(2) (or, if applicable and consented to by the Representatives, subparagraph (5)) not later than the second business day following the earlier of the date it is first used or the execution and delivery of this Agreement. The Company has complied and will comply with Rule 433.

(b) Filing of Amendments; Response to Commission Requests. The Company will promptly advise the Representatives of any proposal to amend or supplement any Registration Statement or any Statutory Prospectus at any time and will offer the Representatives a reasonable opportunity to comment on any such amendment or supplement; and the Company will also advise the Representatives promptly of (i) the filing of any such amendment or supplement, (ii) any request by the Commission or its staff for any amendment to any Registration Statement, for any supplement to any Statutory Prospectus or for any additional information, (iii) the institution by the Commission of any stop order proceedings in respect of a Registration Statement or the threatening of any proceeding for that purpose, and (iv) the receipt by the Company of any notification with respect to the suspension of the qualification of the Offered Securities in any jurisdiction or the institution or threatening of any proceedings for such purpose. The Company will use its best efforts to prevent the issuance of any such stop order or the suspension of any such qualification and, if issued, to obtain as soon as possible the withdrawal thereof.

(c) Continued Compliance with Securities Laws. If, at any time when a prospectus relating to the Offered Securities is (or but for the exemption in Rule 172 would be) required to be delivered under the Act by any Underwriter or dealer, any event occurs as a result of which a Final Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, or if it is necessary at any time to amend a Registration Statement or supplement a Final Prospectus to comply with the Act, the Company will promptly notify the Representatives of such event and will promptly prepare and file with the Commission and furnish, at its own expense, to the Underwriters and the dealers and any other dealers upon request of the Representatives, an amendment or supplement which will correct such statement or omission or an amendment which will effect such compliance. Neither the Representatives’ consent to, nor the Underwriters’ delivery of, any such amendment or supplement shall constitute a waiver of any of the conditions set forth in Section 7 hereof.

(d) Rule 158. As soon as practicable, but not later than 16 months, after the date of this Agreement, the Company will make generally available to its securityholders an earnings statement covering a period of at least 12 months beginning after the date of this Agreement and satisfying the provisions of Section 11(a) of the Act and Rule 158 under the Act.

(e) Furnishing of Prospectuses. The Company will furnish to the Representatives copies of each Registration Statement, including all exhibits, any Statutory Prospectus, each Final Prospectus and all amendments and supplements to such documents, in each case as soon as

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available and in such quantities as the Representatives reasonably request. The Company and the Selling Stockholder will pay the expenses of printing and distributing to the Underwriters all such documents.

(f) Blue Sky Qualifications. The Company will arrange for the qualification of the Offered Securities for sale under the laws of such jurisdictions as the Representatives designate and will continue such qualifications in effect so long as required for the distribution; provided that the Company shall not be required to (i) qualify as a foreign corporation or other entity or as a dealer in securities in any such jurisdiction where it would not otherwise be required to so qualify, (ii) file any general consent to service of process in any such jurisdiction or (iii) subject itself to taxation in any such jurisdiction if it is not otherwise so subject.

(g) Reporting Requirements. During the period of five years hereafter, the Company will furnish to the Representatives and, upon request, to each of the other Underwriters, as soon as practicable after the end of each fiscal year, a copy of its annual report to stockholders for such year; and the Company will furnish to the Representatives (i) as soon as available, a copy of each report and any definitive proxy statement of the Company filed with the Commission under the Exchange Act or mailed to stockholders, and (ii) from time to time, such other information concerning the Company as the Representatives may reasonably request. However, so long as the Company is subject to the reporting requirements of either Section 13 or Section 15(d) of the Exchange Act and is timely filing reports with the Commission on its Electronic Data Gathering, Analysis and Retrieval system (“EDGAR”), it is not required to furnish such reports or statements to the Underwriters.

(h) Payment of Expenses. The Company and the Selling Stockholder agree with the Underwriters that the Company and the Selling Stockholder will pay all expenses incident to the performance of the obligations of the Company and the Selling Stockholder, as the case may be, under this Agreement, including but not limited to any filing fees and other expenses incurred in connection with qualification of the Offered Securities for sale under the laws of such jurisdictions as the Representatives designate and the preparation and printing of memoranda relating thereto, costs and expenses related to the review by the Financial Industry Regulatory Authority, Inc. of the Offered Securities, 50% of the costs and expenses relating to investor presentations or any “road show” in connection with the offering and sale of the Offered Securities including, without limitation, any travel expenses of the Company’s officers and employees and any other expenses of the Company, fees and expenses incident to listing the Offered Securities on the NASDAQ Stock Market and fees and expenses in connection with the Registration of the Offered Securities under the Exchange Act and expenses incurred in distributing preliminary prospectuses and each Final Prospectus (including any amendments and supplements thereto) to the Underwriters and for expenses incurred for preparing, printing and distributing any Issuer Free Writing Prospectuses to investors or prospective investors. Such amount may be deducted from the purchase price for the Offered Securities set forth in Section 3 hereof. The fees and expenses of counsel to the Underwriters shall be the exclusive responsibility of the Underwriters.

(i) Use of Proceeds. The Company will use the net proceeds received by it in connection with this offering in the manner described in the “Use of Proceeds” section of the General Disclosure Package and, except as disclosed in the General Disclosure Package, the Company does not intend to use any of the proceeds from the sale of the Offered Securities hereunder to repay any outstanding debt owed to any affiliate of any Underwriter.

(j) Absence of Manipulation. The Company and the Selling Stockholder will not take, directly or indirectly, any action designed to or that would constitute or that would reasonably be expected to cause or result in, stabilization or manipulation of the price of any securities of the Company to facilitate the sale or resale of the Offered Securities.

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(k) Restriction on Sale of Securities by Company. For the period specified below (the “Lock-Up Period”), the Company will not, directly or indirectly, take any of the following actions with respect to its Securities or any securities convertible into or exchangeable or exercisable for any of its Securities (“Lock-Up Securities”): (i) offer, sell, issue, contract to sell, pledge or otherwise dispose of Lock-Up Securities, (ii) offer, sell, issue, contract to sell, contract to purchase or grant any option, right or warrant to purchase Lock-Up Securities, (iii) enter into any swap, hedge or any other agreement that transfers, in whole or in part, the economic consequences of ownership of Lock-Up Securities, (iv) establish or increase a put equivalent position or liquidate or decrease a call equivalent position in Lock-Up Securities within the meaning of Section 16 of the Exchange Act or (v) file with the Commission a registration statement under the Act relating to Lock-Up Securities, or publicly disclose the intention to take any such action, without the prior written consent of the Representatives, other than the Shares to be sold hereunder, grants of employee stock options, restricted stock units, restricted stock or other equity-based awards pursuant to the terms of an employee benefit plan or similar arrangement described in the Registration Statement, the General Disclosure Package and the Final Prospectus, any shares of Stock of the Company issued upon the exercise or vesting of options, restricted stock units, warrants or equity awards or vesting of previously issued awards under the stock-based compensation plans of the Company and its subsidiaries described in the Registration Statement, the General Disclosure Package and the Final Prospectus (the “Company Stock Plans”) and the filing of any registration statement on Form S-8 designed to register or replace an employee benefit or similar arrangement described in the Registration Statement, the General Disclosure Package and the Final Prospectus. The initial Lock-Up Period will commence on the date hereof and continue for 60 days after the date hereof or such earlier date that the Representatives consent to in writing; provided, however, that if (1) during the last 17 days of the initial Lock-Up Period, the Company releases earnings results or material news or a material event relating to the Company occurs or (2) prior to the expiration of the initial Lock-Up Period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the initial Lock-Up Period, then in each case the Lock-Up Period will be extended until the expiration of the 18-day period beginning on the date of release of the earnings results or the occurrence of the materials news or material event, as applicable, unless the Representatives waive, in writing, such extension. The Company will provide the Representatives with notice of any announcement described in clause (2) of the preceding sentence that gives rise to an extension of the Lock-Up Period.

(l) Listing. The Company will list the Offered Securities on the NASDAQ Stock Market.

6. Free Writing Prospectuses.

(a) Issuer Free Writing Prospectuses. The Company and the Selling Stockholder represent and agree that, unless they obtain the prior consent of the Representatives, and each Underwriter represents and agrees that, unless it obtains the prior consent of the Company and the Representatives, it has not made and will not make any offer relating to the Offered Securities that would constitute an Issuer Free Writing Prospectus, or that would otherwise constitute a “free writing prospectus,” as defined in Rule 405, required to be filed with the Commission. Any such free writing prospectus consented to by the Company and the Representatives are hereinafter referred to as a “Permitted Free Writing Prospectus.” The Company represents that it has treated and agrees that it will treat each Permitted Free Writing Prospectus as an “issuer free writing prospectus,” as defined in Rule 433, and has complied and will comply with the requirements of Rules 164 and 433 applicable to any Permitted Free Writing Prospectus, including timely Commission filing where required, legending and record keeping.

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7. Conditions of the Obligations of the Underwriters. The obligations of the Underwriters to purchase and pay for the Firm Securities on the First Closing Date and the Optional Securities to be purchased on each Optional Closing Date will be subject to the accuracy of the representations and warranties of the Company and the Selling Stockholder herein (as though made on such Closing Date), to the accuracy of the statements of Company officers made pursuant to the provisions hereof, to the performance by the Company and the Selling Stockholder of their obligations hereunder and to the following additional conditions precedent:

(a) Accountants’ Comfort Letter. The Representatives shall have received letters, dated, respectively, the date hereof and each Closing Date, of (i) PricewaterhouseCoopers LLP covering the financial information in the General Disclosure Package in respect of the Company, and (ii) PricewaterhouseCoopers LLP, covering the financial information in the General Disclosure Package in respect of ProBuild, in each case confirming that they are a registered public accounting firm and independent public accountants within the meaning of the Securities Laws and substantially in form and substance satisfactory to the counsel for the Representatives (except that, in any letter dated on the Applicable time or a Closing Date, the procedures shall be brought down to a date no more than three days prior to such Closing Date).

(b) Filing of Prospectus. Each Final Prospectus shall have been filed with the Commission in accordance with the Rules and Regulations and Section 5(a) hereof. No stop order suspending the effectiveness of the Registration Statement or of any part thereof shall have been issued and no proceedings for that purpose shall have been instituted or, to the knowledge of the Company, the Selling Stockholder or any Underwriter, shall be contemplated by the Commission.

(c) No Material Adverse Change. (i) No event or condition described in Section 2(xxviii) hereof shall have occurred or shall exist, which event or condition is not described in each General Disclosure Package (excluding any amendment or supplement thereto) and each Final Prospectus (excluding any amendment or supplement thereto) the effect of which in the judgment of the Representatives make it impracticable or inadvisable to proceed with the offering, sale or delivery of the Offered Securities on the terms and in the manner contemplated by this Agreement, each General Disclosure Package and each Final Prospectus.; (ii) any suspension or material limitation of trading in securities generally on the New York Stock Exchange or the NASDAQ Stock Market, or any setting of minimum or maximum prices for trading on such exchange; (iii) or any suspension of trading of any securities of the Company on any exchange or in the over-the-counter market; (iv) any banking moratorium declared by any U.S. federal or New York authorities; or (v) any attack on, outbreak or escalation of hostilities or act of terrorism involving the United States, any declaration of war by Congress or any other national or international calamity or emergency if, in the judgment of the Representatives, the effect of any such attack, outbreak, escalation, act, declaration, calamity or emergency is such as to make it impractical or inadvisable to market the Offered Securities or to enforce contracts for the sale of the Offered Securities.

(d) Opinion of Counsel for the Company. The Representatives shall have received an opinion and negative assurance letter, dated such Closing Date and addressed to the Underwriters, of Skadden, Arps, Slate, Meagher & Flom LLP, counsel for the Company, substantially in form and substance as set forth in Exhibit A.

(e) Opinion of Counsel for Underwriters. The Representatives shall have received from Cahill Gordon & Reindel LLP, counsel for the Underwriters, such opinion or opinions, dated

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such Closing Date, with respect to such matters as the Representatives may require, and the Company and the Selling Stockholder shall have furnished to such counsel such documents as they request for the purpose of enabling them to pass upon such matters.

(f) Opinion of General Counsel for the Company. The Representatives shall have received from Donald McAleenan, Senior Vice President and General Counsel of the Company, an opinion, dated such Closing Date and addressed to the Underwriters, in form and substance reasonably satisfactory to the Underwriters and their counsel.

(g) Officer’s Certificate –Company. The Representatives shall have received a certificate, dated such Closing Date, of an executive officer of the Company in which such officer shall state that: the representations and warranties of the Company in this Agreement are true and correct; the Company has complied with all agreements and satisfied all conditions on its part to be performed or satisfied hereunder at or prior to such Closing Date; no stop order suspending the effectiveness of any Registration Statement has been issued and no proceedings for that purpose have been instituted or, to the best of their knowledge and after reasonable investigation, are contemplated by the Commission; subsequent to the respective dates of the most recent financial statements in the General Disclosure Package, there has been no material adverse change, nor any development or event involving a prospective material adverse change, in the condition (financial or otherwise), results of operations, business, properties or prospects of the Company and its subsidiaries taken as a whole except as set forth in the General Disclosure Package or as described in such certificate; and the condition in clause (k) below shall have been satisfied.

(h) Lock-Up Agreements. On or prior to the date hereof, the Representatives shall have received lockup letters from each of the executive officers and directors of the Company named in Schedule C hereto, Warburg Pincus LLC and JLL Partners, Inc.

(i) CFO Certificates. On the date hereof and on each Closing Date, the Representatives shall have received a certificate of the Company, dated the date hereof and such Closing Date and addressed to the Underwriters, signed on behalf of the Company by its Chief Financial Officer, regarding certain information in the General Disclosure Package and in form and substance reasonably satisfactory to the Underwriters and their counsel.

(j) Opinion of Counsel for the Selling Stockholder. The Representatives shall have received an opinion, dated such Closing Date and addressed to the Underwriters, of Brett Shawn, Assistant General Counsel of Warburg Pincus LLC (the manager of the Selling Stockholder), substantially in form and substance reasonably acceptable to the Underwriters and their counsel.

(k) No Downgrade. Subsequent to the earlier of (A) the Applicable Time and (B) the execution and delivery of this Agreement, (i) no downgrading shall have occurred in the rating accorded the Securities or any other debt securities or preferred stock issued or guaranteed by the Issuer or any of its subsidiaries by any “nationally recognized statistical rating organization,” as such term is defined under Section 3(a)(62) under the Exchange Act, and (ii) no such organization shall have publicly announced that it has under surveillance or review, or has changed its outlook with respect to, its rating of the Offered Securities or of any debt securities or preferred stock issued or guaranteed by the Issuer or any of its subsidiaries (other than an announcement with positive implications of a possible upgrading).

(l) Officer’s Certificate – Selling Stockholder. The Representatives shall have received a certificate, dated such Closing Date, of an authorized signatory of the Selling Stockholder in which such authorized signatory shall state that: the representations and warranties

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of the Selling Stockholder in this Agreement are true and correct; and the Selling Stockholder has complied with all agreements and satisfied all conditions on its part to be performed or satisfied hereunder at or prior to such Closing Date.

The Company and the Selling Stockholder will furnish the Representatives with such conformed copies of such opinions, certificates, letters and documents as the Representatives reasonably request. The Representatives may in their sole discretion waive on behalf of the Underwriters compliance with any conditions to the obligations of the Underwriters hereunder, whether in respect of an Optional Closing Date or otherwise.

8. Indemnification and Contribution.

(a) Indemnification of Underwriters by Company. The Company will indemnify and hold harmless each Underwriter, its affiliates, directors, officers and employees and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Act or Section 20 of the Exchange Act (each an “Indemnified Party”), from and against any and all losses, claims, damages and liabilities (including, without limitation, reasonable legal fees and other expenses incurred in connection with investigating, preparing for or defending against any loss, damage, liability, litigation, investigation, suit, action or proceeding or any claim asserted (whether or not such Indemnified Party is a party thereto), whether threatened or commenced, and in connection with the enforcement of this provision with respect to any of the above, as such fees and expenses are incurred) joint or several, that arise out of, or are based upon, any untrue statement or alleged untrue statement of any material fact contained in the General Disclosure Package (or any amendment or supplement thereto) or any omission or alleged omission to state therein a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, in each case except insofar as such losses, claims, damages or liabilities arise out of or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use therein, it being understood and agreed that the only such information consists of the information described as such in subsection (b) below.

(b) Indemnification of Company and the Selling Stockholder. Each Underwriter will severally and not jointly indemnify and hold harmless the Company, each of its directors and each of its officers who signs a Registration Statement and each person, if any, who controls the Company within the meaning of Section 15 of the Act or Section 20 of the Exchange Act, and the Selling Stockholder, to the same extent as the indemnity set forth in paragraph (a) above (each, an “Underwriter Indemnified Party”), but only with respect to any losses, claims, damages or liabilities to which such Underwriter Indemnified Party may become subject, under the Act, the Exchange Act, or other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of any material fact contained in any Registration Statement at any time, any Statutory Prospectus at any time, each Final Prospectus or any Issuer Free Writing Prospectus or arise out of or are based upon the omission or the alleged omission of a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in reliance upon and in conformity with written information furnished to the Company by such Underwriter through the Representatives specifically for use therein, and will reimburse any legal or other expenses reasonably incurred by such Underwriter Indemnified Party in connection with investigating, preparing or defending against any such loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such Underwriter Indemnified Party is a party thereto), whether threatened or commenced, based upon any such untrue statement or omission, or any such alleged untrue

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statement or omission as such expenses are incurred, it being understood and agreed that the only such information furnished by any Underwriter consists of the following information in each Final Prospectus furnished on behalf of each Underwriter: the concession and reallowance figures, if any, appearing under the caption “Underwriting”.

(c) Actions against Parties; Notification. Promptly after receipt by an indemnified party under this Section of notice of the commencement of any action, such indemnified party (the “Indemnified Person”) will, if a claim in respect thereof is to be made against the indemnifying party (the “Indemnifying Person”) under subsection (a) or (b) above or subsection (g) below, notify the Indemnifying Person of the commencement thereof; but the failure to notify the Indemnifying Person shall not relieve it from any liability that it may have under subsection (a) or (b) above or subsection (g) below except to the extent that it has been materially prejudiced (through the forfeiture of substantive rights or defenses) by such failure; and provided further that the failure to notify the indemnifying party shall not relieve it from any liability that it may have to an Indemnified Person otherwise than under subsection (a) or (b) above or subsection (g) below. In any such proceeding, any Indemnified Person shall have the right to retain its own counsel, but the fees and expenses of such counsel shall be at the expense of such Indemnified Person unless: (i) the Indemnifying Person and the Indemnified Person shall have mutually agreed to the contrary; (ii) the Indemnifying Person has failed within a reasonable time to retain counsel reasonably satisfactory to the Indemnified Person; (iii) the Indemnified Person shall have reasonably concluded, based on the advice of counsel, that there may be legal defenses available to it that are materially different from or in addition to those available to the Indemnifying Person; or (iv) the named parties in any such proceeding (including any impleaded parties) include both the Indemnifying Person and the Indemnified Person and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them. It is understood and agreed that the Indemnifying Person shall not, in connection with any proceeding or related proceeding in the same jurisdiction, be liable for the reasonable fees and expenses of more than one separate firm (in addition to any local counsel) for all Indemnified Persons, and that all such reasonable fees and expenses shall be reimbursed as they are incurred. Any such separate firm for any Underwriter, its affiliates, directors and officers and any control persons of such Underwriter shall be designated in writing by the Representatives and any such separate firm for the Company and its respective directors and officers and any control persons of the Company shall be designated in writing by the Company. The Indemnifying Person shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, the Indemnifying Person agrees to indemnify each Indemnified Person from and against any loss or liability by reason of such settlement or judgment. Notwithstanding the foregoing sentence, if at any time an Indemnified Person shall have requested that an Indemnifying Person reimburse the Indemnified Person for fees and expenses of counsel as contemplated by this paragraph, the Indemnifying Person agrees that it shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into more than 45 days after receipt by such Indemnifying Person of the aforesaid request; (ii) such Indemnifying Person shall have received notice of the terms of such settlement at least 30 days prior to such settlement being entered into and (iii) such Indemnifying Person shall not have reimbursed the Indemnified Person in accordance with such request prior to the date of such settlement. No Indemnifying Person shall, without the prior written consent of the Indemnified Person, which consent, in respect of clause (i) below, will not be unreasonably withheld, effect any settlement of any pending or threatened action in respect of which any Indemnified Person is or could have been a party and indemnification could have been sought hereunder by such Indemnified Person unless such settlement (i) includes an unconditional release of such Indemnified Person in form and substance reasonably satisfactory to such Indemnified Person, from all liability on any claims that are the subject matter of such action and (ii) does not include a statement as to, or an admission of, fault, culpability or a failure to act by or on behalf of an Indemnified Person.

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(d) Contribution. If the indemnification provided for in paragraph (a) or (b) above is unavailable to an Indemnified Person or insufficient in respect of any losses, claims, damages or liabilities referred to therein, then each Indemnifying Person under such paragraph, in lieu of indemnifying such Indemnified Person thereunder, shall contribute to the amount paid or payable by such Indemnified Person as a result of such losses, claims, damages or liabilities (i) in such proportion as is appropriate to reflect the relative benefits received by the Company and the Selling Stockholder on the one hand and the Underwriters on the other from the offering of the Securities or (ii) if the allocation provided by clause (i) is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) but also the relative fault of the Company and the Selling Stockholder on the one hand and the Underwriters on the other in connection with the statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company and the Selling Stockholder on the one hand and the Underwriters on the other shall be deemed to be in the same respective proportions as the net proceeds (before deducting expenses) received by the Issuer from the sale of the Securities and the total discounts and commissions received by the Underwriters in connection therewith, as provided in this Agreement, bear to the aggregate offering price of the Securities. The relative fault of the Company and the Selling Stockholder on the one hand and the Underwriters on the other shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company, the Selling Stockholder or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

(e) Limitation on Liability. The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 8 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in paragraph (d) above. The amount paid or payable by an Indemnified Person as a result of the losses, claims, damages and liabilities referred to in paragraph (d) above shall be deemed to include, subject to the limitations set forth above, any legal or other expenses reasonably incurred by such Indemnified Person in connection with any such action or claim. Notwithstanding the provisions of this Section 8, in no event shall an Underwriter be required to contribute any amount in excess of the amount by which the total discounts and commissions received by such Underwriter with respect to the offering of the Offered Securities exceeds the amount of any damages that such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations to contribute pursuant to this Section 8 are several in proportion to their respective purchase obligations hereunder and not joint.

(f) Non-Exclusive Remedies. The remedies provided for in this Section 8 are not exclusive and shall not limit any rights or remedies that may otherwise be available to any Indemnified Person at law or in equity.

(g) Indemnification of Underwriters by Selling Stockholder. The Selling Stockholder will indemnify and hold harmless each Underwriter, its affiliates, directors, officers and employees and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Act or Section 20 of the Exchange Act (each, a “Indemnified Party”), from and against any and all losses, claims, damages and liabilities (including, without limitation, reasonable legal fees and other expenses incurred in connection with investigating, preparing for or defending against any loss, damage, liability, litigation, investigation, suit, action or proceeding or any claim asserted (whether or not such Indemnified Party is a party thereto), whether threatened or commenced, and in connection with the enforcement of this provision with respect to

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any of the above, as such fees and expenses are incurred) joint or several, that arise out of, or are based upon, any untrue statement or alleged untrue statement of any material fact contained in the General Disclosure Package (or any amendment or supplement thereto) or any omission or alleged omission to state therein a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, in each case except insofar as such losses, claims, damages or liabilities arise out of or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use therein, it being understood and agreed that the only such information consists of the information described as such in subsection (b) above; provided, however, that the Selling Stockholder will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement in or omission or alleged omission from any of such documents in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in subsection (b) above.

9. Default of Underwriters. If any Underwriter or Underwriters default in their obligations to purchase Offered Securities hereunder on either the First or any Optional Closing Date and the aggregate number of shares of Offered Securities that such defaulting Underwriter or Underwriters agreed but failed to purchase does not exceed 10% of the total number of shares of Offered Securities that the Underwriters are obligated to purchase on such Closing Date, the Representatives may make arrangements satisfactory to the Company and the Selling Stockholder for the purchase of such Offered Securities by other persons, including any of the Underwriters, but if no such arrangements are made by such Closing Date, the non-defaulting Underwriters shall be obligated severally, in proportion to their respective commitments hereunder, to purchase the Offered Securities that such defaulting Underwriters agreed but failed to purchase on such Closing Date. If any Underwriter or Underwriters so default and the aggregate number of shares of Offered Securities with respect to which such default or defaults occur exceeds 10% of the total number of shares of Offered Securities that the Underwriters are obligated to purchase on such Closing Date and arrangements satisfactory to the Representatives, the Company and the Selling Stockholder for the purchase of such Offered Securities by other persons are not made within 36 hours after such default, this Agreement will terminate without liability on the part of any non-defaulting Underwriter or the Company or the Selling Stockholder, except as provided in Section 10 (provided that if such default occurs with respect to Optional Securities after the First Closing Date, this Agreement will not terminate as to the Firm Securities or any Optional Securities purchased prior to such termination). As used in this Agreement, the term “Underwriter” includes any person substituted for an Underwriter under this Section. Nothing herein will relieve a defaulting Underwriter from liability for its default.

10. Survival of Certain Representations and Obligations. The respective indemnities, agreements, representations, warranties and other statements of the Company, the Selling Stockholder or its officers and of the Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation, or statement as to the results thereof, made by or on behalf of any Underwriter, the Company, the Selling Stockholder or any of their respective representatives, officers or directors or any controlling person, and will survive delivery of and payment for any Offered Securities. If the purchase of the Offered Securities by the Underwriters is not consummated for any reason other than solely because of the termination of this Agreement pursuant to Section 9 hereof, the Company and the Selling Stockholder will reimburse the Underwriters for all out-of-pocket expenses (including fees and disbursements of counsel) reasonably incurred by them in connection with the offering of the Offered Securities, and the respective obligations of the Company, the Selling Stockholder and the Underwriters pursuant to Section 8 hereof shall remain in effect shall remain in effect.

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11. Notices. All communications hereunder will be in writing and, if sent to the Underwriters, will be mailed, delivered or telegraphed and confirmed to the Representatives, c/o Credit Suisse Securities (USA) LLC, Eleven Madison Avenue, New York, New York 10010; Attention: LCD-IBD; c/o Deutsche Bank Securities Inc., 60 Wall Street, 2^nd Floor, New York, New York 10005; Attention: Equity Capital Markets – Syndicate Desk, with a copy to Deutsche Bank Securities, Inc., 60 Wall Street, 36^th Floor, New York, New York 10005; Attention: General Counsel; Fax: (212) 797-4561; and c/o Citigroup Global Markets Inc., c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, New York 11717; Phone: (800) 831-9146; or, if sent to the Company, will be mailed, delivered or telegraphed and confirmed to it at Builders FirstSource, Inc., 2001 Bryan Street, Suite 1600, Dallas, Texas 75201, Attention: Donald F. McAleenan, Esq., Phone: (214) 880-3500, Fax: (214) 231-6201, Email: Don.McAleenan@buildersfirstsource.com with a copy to Skadden, Arps, Slate, Meagher & Flom LLP Four Times Square, New York, New York 10036, Phone: (212) 735-2439; Fax: (917) 777-2439, Attention: Laura Kaufmann Belkayat; or, if sent to the Selling Stockholder, Warburg Pincus Private Equity IX, L.P., 450 Lexington Avenue, New York, New York 10017; Attention: Lora Giampetruzzi; provided, however, that any notice to an Underwriter pursuant to Section 8 will be mailed, delivered or telegraphed and confirmed to such Underwriter.

12. Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers and directors and controlling persons referred to in Section 7, and no other person will have any right or obligation hereunder.

13. Representation. The Representatives will act for the Underwriters in connection with the transactions contemplated by this Agreement, and any action under this Agreement taken by the Representatives jointly will be binding upon all the Underwriters.

14. Counterparts. This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts shall together constitute one and the same Agreement.

15. Absence of Fiduciary Relationship. The Company and the Selling Stockholder acknowledge and agree that:

(a) No Other Relationship. The Representatives have been retained solely to act as underwriters in connection with the sale of the Offered Securities and that no fiduciary, advisory or agency relationship between the Company, on the one hand, and the Representatives, on the other, has been created in respect of any of the transactions contemplated by this Agreement or the Final Prospectus, irrespective of whether the Representatives have advised or is advising the Company on other matters;

(b) Arms’ Length Negotiations. The price of the Offered Securities set forth in this Agreement was established by Company and the Selling Stockholder following discussions and arms-length negotiations with the Representatives and the Company and the Selling Stockholder are capable of evaluating and understanding and understand and accept the terms, risks and conditions of the transactions contemplated by this Agreement;

(c) Absence of Obligation to Disclose. The Company and the Selling Stockholder have been advised that the Representatives and their affiliates are engaged in a broad range of transactions which may involve interests that differ from those of the Company or the Selling

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Stockholder and that the Representatives have no obligation to disclose such interests and transactions to the Company or the Selling Stockholders by virtue of any fiduciary, advisory or agency relationship; and

(d) Waiver. The Company and the Selling Stockholder waive, to the fullest extent permitted by law, any claims they may have against the Representatives for breach of fiduciary duty or alleged breach of fiduciary duty and agree that the Representatives shall have no liability (whether direct or indirect) to the Company or the Selling Stockholder in respect of such a fiduciary duty claim or to any person asserting a fiduciary duty claim on behalf of or in right of the Company, including stockholders, employees or creditors of the Company.

16. Applicable Law. This Agreement shall be governed by, and construed in accordance with, the laws of the State of New York.

17. Compliance with USA Patriot Act. In accordance with the requirements of the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)), the Underwriters are required to obtain, verify and record information that identifies their respective clients, including the Company, which information may include the name and address of their respective clients, as well as other information that will allow the Underwriters to properly identify their respective clients.

The Company hereby submits to the non-exclusive jurisdiction of the Federal and state courts in the Borough of Manhattan in The City of New York in any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. The Company irrevocably and unconditionally waives any objection to the laying of venue of any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated hereby in Federal and state courts in the Borough of Manhattan in the City of New York and irrevocably and unconditionally waives and agrees not to plead or claim in any such court that any such suit or proceeding in any such court has been brought in an inconvenient forum.

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If the foregoing is in accordance with the Representatives’ understanding of our agreement, kindly sign and return to the Company one of the counterparts hereof, whereupon it will become a binding agreement among the Company and the Underwriters in accordance with its terms.

[Signature Page to Underwriting Agreement]

[Signature Page to Underwriting Agreement]

SCHEDULE A

SCHEDULE B

The following information is also included in the General Disclosure Package:

SCHEDULE C

Lock-up Signatories

Floyd F. Sherman

M. Chad Crow

Morris E. Tolly

Donald F. McAleenan

Michael Graff

Robert C. Griffin

Brett N. Milgrim

Daniel Agroskin

Kevin J. Kruse

Paul S. Levy

David A. Barr

Cleveland A. Christophe

Craig A. Steinke

JLL Partners, Inc.

Warburg Pincus LLC

EXHIBIT A

Form of Opinion of Skadden, Arps, Slate, Meagher & Flom LLP

[Provided under separate cover]

Exhibit C

EXECUTION VERSION

July 29, 2015

Builders FirstSource, Inc.

2001 Bryan Street, Suite 1600

Dallas, Texas 75201

and

Credit Suisse Securities (USA) LLC

Eleven Madison Avenue

New York, New York 10010

Deutsche Bank Securities Inc.

60 Wall Street

New York, New York 10005

and

Citigroup Global Markets Inc.

390 Greenwich Street

New York, New York 10013

each as a Representative

Dear Sirs:

As an inducement to the Representatives to execute the Underwriting Agreement (the “Underwriting Agreement”), providing for a public offering of the common stock (the “Securities”) of Builders FirstSource, Inc., and any successor (by merger or otherwise) thereto, (the “Company”), the undersigned hereby agrees that during the period specified in the following paragraph (the “Lock-Up Period”), the undersigned will not offer, sell, contract to sell, pledge or otherwise dispose of, directly or indirectly, any Securities or securities convertible into or exchangeable or exercisable for any Securities, enter into a transaction which would have the same effect, or enter into any swap, hedge or other arrangement that transfers, in whole or in part, any of the economic consequences of ownership of the Securities, whether any such aforementioned transaction is to be settled by delivery of the Securities or such other securities, in cash or otherwise, or publicly disclose the intention to make any such offer, sale, pledge or disposition, or to enter into any such transaction, swap, hedge or other arrangement, without, in each case, the prior written consent of Credit Suisse Securities (USA) LLC, Deutsche Bank Securities Inc. and Citigroup Global Markets Inc., as representatives for the several underwriters named in Schedule A to the Underwriting Agreement (collectively, the “Representatives”), in each case other than (A) transfers of Securities as a bona fide gift or gifts, (B) distributions of Securities to limited partners, members or stockholders of the undersigned, (C) transfers of Securities by will or intestacy, (D) transfers of Securities to any trust, partnership, limited liability company or other entity for the direct or indirect benefit of the undersigned or the immediate family of the undersigned (for purposes of this Lock-Up Agreement, “immediate family” shall mean any relationship by blood, current or former marriage or adoption, not more remote than first cousin), (E) transfers of Securities to any immediate family member or other dependent, (F) transfers of Securities to the undersigned’s affiliates or to any investment fund or other entity controlled or managed by the undersigned; provided that the undersigned notify the Representatives of such transfer, (G) transfers of Securities to a nominee or custodian of a person or entity to whom a disposition or transfer would be permissible under clauses (A) through (F) above, (H) transfers of Securities pursuant to an order of a court or regulatory agency, (I) transfers of Securities from an executive officer to the Company upon death, disability or termination of employment, in each case, of such executive officer, (J) transfers of Securities acquired in open market or in an issuer directed share program, if any, (K) the pledge, hypothecation or other granting of a security interest in Securities to one or more banks or financial institutions as collateral or security for any loan, advance or extension of credit and any transfer upon foreclosure upon such Securities, provided that the undersigned or the Company, as the case may be, shall provide the Representatives prior written notice informing them of any public filing, report or

announcement made by or on behalf of the Company or the undersigned with respect thereto, and (L) Securities to be sold by Warburg Pincus Private Equity IX, L.P. pursuant to the Underwriting Agreement; provided that (i) in the case of any transfer or distribution pursuant to clauses (A), (B), (D), (E), (F), (G), (I) and (K) above, each donee or distributee shall execute and deliver to the Representatives a lock-up letter in the form of this paragraph and (ii) in the case of any transfer or distribution pursuant to clauses (A) through (E), and (I) above, such transfer or distribution shall not be for value; and provided, further, that in the case of any transfer or distribution pursuant to clauses (A), (B), (D), (E), (F) and (G), during the period ending 60 days after the Public Offering Date (as defined below) no public reports or filings (including filings under Section 16(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) reporting a reduction in beneficial ownership of Securities shall be required or voluntarily made . In addition, the undersigned agrees that, without the prior written consent of the Representatives, it will not, during the Lock-Up Period, make any demand for or exercise any right with respect to, the registration of any Securities or any security convertible into or exercisable or exchangeable for the Securities.

The initial Lock-Up Period will commence on the date of this Lock-Up Agreement and continue and include the date 60 days after the public offering date set forth on the final prospectus used to sell the Securities (the “Public Offering Date”) pursuant to the Underwriting Agreement, to which you are or expect to become parties; provided, however, that if (1) during the last 17 days of the initial Lock-Up Period, the Company releases earnings results or material news or a material event relating to the Company occurs or (2) prior to the expiration of the initial Lock-Up Period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the initial Lock-Up Period, then in each case the Lock-Up Period will be extended until the expiration of the 18-day period beginning on the date of release of the earnings results or the occurrence of the material news or material event, as applicable, unless each Representative waives, in writing, such extension.

Any Securities received upon exercise of options granted to the undersigned will also be subject to this Lock-Up Agreement.

Notwithstanding anything herein to the contrary, the undersigned may enter into a written trading plan established pursuant to Rule 10b5-1 of the Exchange Act during the Lock-Up Period, and the Company may announce the establishment of such a plan, provided that no direct or indirect offers, pledges, sales, contracts to sell, sales of any option or contract to purchase, purchases of any option or contract to sell, grants of any option, right or warrant to purchase, loans, or other transfers or disposals of any Securities or any securities convertible into or exercisable or exchangeable for Securities may be effected pursuant to such plan during the Lock-Up Period.

In furtherance of the foregoing, the Company and its transfer agent and registrar are hereby authorized to decline to make any transfer of Securities if such transfer would constitute a violation or breach of this Lock-Up Agreement.

If the undersigned is an officer or director of the Company, the undersigned further agrees that the foregoing restrictions in this Lock-Up Agreement shall be equally applicable to any issuer-directed Securities the undersigned may purchase in the above-referenced offering.

This Lock-Up Agreement shall be binding on the undersigned and the successors, heirs, personal representatives and assigns of the undersigned. This Lock-Up Agreement shall lapse and become null and void if the Public Offering Date shall not have occurred on or before August 31, 2015. This agreement shall be governed by, and construed in accordance with, the laws of the State of New York.