UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Amendment No. 6)*

Under the Securities Exchange Act of 1934

GCP APPLIED TECHNOLOGIES INC.

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

36164Y101

(CUSIP Number)

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

COPIES TO:

Robert W. Downes, Esq.

Sullivan & Cromwell LLP

125 Broad Street

New York, NY 10004

(212) 558-4000

April 28, 2020

(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 §240.13d-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).

AMENDMENT NO. 6 TO SCHEDULE 13D

This Amendment No. 6 supplements the information set forth in the Schedule 13D filed by 40 North Management LLC, a Delaware limited liability company, 40 North Latitude Fund LP, a Delaware limited partnership, 40 North GP III LLC, a Delaware limited liability company, 40 North Latitude Master Fund Ltd., a Cayman Islands exempted company incorporated with limited liability, 40 North Latitude SPV-D LLC, a Delaware limited liability company, Dalbergia Investments LLC, a Delaware limited liability company, Standard Industries Inc., a Delaware corporation, Standard Industries Holdings Inc., a Delaware corporation, G-I Holdings Inc., a Delaware corporation, G Holdings LLC, a Delaware limited liability company, G Holdings Inc., a Delaware corporation, David S. Winter, an American citizen, David J. Millstone, an American citizen, and Ronnie F. Heyman, an American citizen, with the United States Securities and Exchange Commission (the “SEC”) on March 13, 2017, as heretofore amended (the “Schedule 13D”), relating to Common Stock, par value $0.01 per share (the “Shares”), of GCP Applied Technologies Inc., a Delaware corporation, (the “Issuer”). All capitalized terms contained herein but not otherwise defined shall have the meanings ascribed to such terms in the Schedule 13D.

The information set forth in response to each separate Item below shall be deemed to be a response to all Items where such information is relevant. The Schedule 13D is hereby supplementally amended as follows:

This statement on Schedule 13D is filed on behalf of 40 North Management LLC, a Delaware limited liability company (“40 North Management”), 40 North Latitude Fund LP, a Delaware limited partnership (“40 North Latitude Feeder”), 40 North GP III LLC, a Delaware limited liability company (“40 North GP III”), 40 North Latitude Master Fund Ltd., a Cayman Islands exempted company incorporated with limited liability (“40 North Latitude Master”), 40 North Latitude SPV-D LLC, a Delaware limited liability company (“40 North Latitude SPV”), Dalbergia Investments LLC, a Delaware limited liability company (“Dalbergia”), Standard Industries Inc., a Delaware corporation (“Standard Industries”), Standard Industries Holdings Inc., a Delaware corporation (“Standard Holdings”), G-I Holdings Inc., a Delaware corporation (“G-I Holdings”), G Holdings LLC, a Delaware limited liability company (“G Holdings LLC”), G Holdings Inc., a Delaware corporation (“G Holdings Inc.”), David S. Winter, an American citizen, David J. Millstone, an American citizen, and Ronnie F. Heyman, an American citizen (all of the foregoing, collectively, the “Reporting Persons”).

This statement relates to Shares held by (i) 40 North Latitude SPV, a wholly owned subsidiary of 40 North Latitude Master, the “master” fund in a “master-feeder” structure in which 40 North Latitude Feeder is a “feeder” fund, (ii) 40 North Latitude Master and (iii) Dalbergia.

The principal business of each of 40 North Latitude Feeder, 40 North Latitude Master, 40 North Latitude SPV and Dalbergia is the making of investments in securities and other assets.  The principal business of 40 North GP III is to serve as general partner of 40 North Latitude Feeder. 40 North Management serves as principal investment manager to 40 North Latitude Feeder and 40 North Latitude Master. As such, 40 North Management has been granted investment discretion over portfolio investments, including the Shares held by 40 North Latitude SPV and 40 North Latitude Master. Standard Industries, the sole owner of Dalbergia, is a global diversified holding company whose businesses are engaged in the manufacture and sale of commercial and residential roofing and waterproofing products, insulation products, aggregates, and other specialty construction products. Standard Holdings, G-I Holdings, G Holdings LLC and G Holdings Inc. are direct or indirect parent companies of Standard Industries. David S. Winter and David J. Millstone serve as: the sole members and principals of each of 40 North Management and 40 North GP III; as the principals of 40 North Latitude SPV; as the sole directors of 40 North Latitude Master; as Co-Executive Chairmen, Chief Executive Officers and Presidents of Dalbergia; as directors, Co-Executive Chairmen, and Chief Executive Officers of Standard Industries; as the sole directors, Co-Executive Chairmen, Chief Executive Officers and Presidents of each of Standard Holdings and G-I Holdings; and as Co-Executive Vice Chairmen of each of G Holdings LLC and G Holdings Inc. Ronnie F. Heyman is the Chairman, Chief Executive Officer, and President of each of G Holdings LLC and G Holdings Inc. and the sole member of the Board of Directors of G Holdings Inc. The principal business address of Dalbergia, Standard Industries, G-I Holdings, G Holdings LLC and G Holdings Inc. is 1 Campus Drive, Parsippany, New Jersey 07054. The principal business address of Standard Holdings is 1011 Centre Road, Suite 315, Wilmington, Delaware 19805. The principal business address of all of the other Reporting Persons is 9 West 57th Street, 47th Floor, New York, New York 10019. A joint filing agreement of the Reporting Persons is attached hereto as Exhibit 1.

During the last five years, none of the Reporting Persons has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors) or has been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

The responses to Items 4, 5 and 6 of this Schedule 13D are incorporated herein by reference.

On February 3, 2016, 3,360,428 of the Shares reported herein were acquired by 40 North Latitude Master, 40 North Latitude SPV, and Dalbergia in connection with a one-for-one spinoff of the Issuer from W.R. Grace & Co. Of such Shares, 60,017 Shares were acquired by 40 North Latitude Master, 2,423,580 Shares were acquired by 40 North Latitude SPV, and 876,831 Shares were acquired by Dalbergia.

62,000 of the Shares reported herein were purchased by Dalbergia as a result of the exercise of certain put-call combination contracts with respect to the Shares. 11,725,717 of the Shares reported herein were purchased by Dalbergia using its working capital, 2,682,108 of the Shares reported herein were purchased by 40 North Latitude Master using its working capital (including 355,840 Shares purchased by 40 North Latitude Master and transferred to Dalbergia for cash), and 303,939 of the Shares reported herein were purchased by 40 North Latitude SPV using its working capital and on margin.

The total purchase price for the Shares reported herein was $478,690,289.  The margin transactions are with 40 North Latitude SPV’s usual brokers, on such brokers’ usual terms and conditions. All or part of the Shares owned by the Reporting Persons may from time to time be pledged with one or more banking institutions or brokerage firms as collateral for loans made by such bank(s) or brokerage firm(s) to the Reporting Persons. Such indebtedness may be refinanced with other banks or broker-dealers.

The response to Item 4 of this Schedule 13D is hereby amended and supplemented by adding the following paragraph at the end of Item 4:

On April 28, 2020, Messrs. Winter and Millstone issued a statement of how such persons intend to vote at the 2020 Annual Meeting of the Issuer, as well as the reasons therefor, in the form of an open letter to the Board of Directors of the Issuer. Such open letter is filed herewith as Exhibit 2 and incorporated into this Item 4 by reference.

(a) – (b)  40 North Latitude SPV may be deemed the beneficial owner of 2,727,519 of the Shares reported herein, which represent approximately 3.7% of the Issuer’s outstanding Shares. Each of 40 North Management, 40 North Latitude Master, 40 North Latitude Feeder and 40 North GP III may be deemed the beneficial owner of 5,113,804 of the Shares reported herein, which represent approximately 7.0% of the Issuer’s outstanding Shares. Each of Dalbergia, Standard Industries, Standard Holdings, G-I Holdings, G Holdings LLC, G Holdings Inc. and Ms. Heyman may be deemed the beneficial owner of 12,664,548 of the Shares reported herein, which represent approximately 17.4% of the Issuer’s outstanding Shares. Each of Messrs. Winter and Millstone may be deemed to be the beneficial owner of all of the 17,778,352 Shares reported herein, which represent approximately 24.4% of the Issuer’s outstanding Shares.

All of the Reporting Persons may be deemed to have shared power to vote and shared power to dispose of such Shares as they may be deemed to have beneficial ownership of.

The percentages in the immediately foregoing paragraphs are calculated based on a total of 72,901,420 Shares outstanding as of April 10, 2020 (based on the Issuer’s Proxy Statement for its 2020 Annual Meeting of Stockholders filed with the SEC on Schedule 14A on April 15, 2020).

(c) There have been no transactions with respect to the Shares during the sixty days prior to the date hereof by any of the Reporting Persons.

(d) In addition to the Reporting Persons, the limited partners of (or investors in) 40 North Latitude Feeder or its subsidiaries or affiliated entities and the shareholders of G Holdings Inc. have the right to participate in the receipt of dividends from, or proceeds from the sale of, the Shares in accordance with their respective limited partnership interests (or investment percentages) or shareholdings.

(e) Not applicable.

Exhibit 1 – Agreement by and among 40 North Management LLC, 40 North GP III LLC, 40 North Latitude Fund LP, 40 North Latitude Master Fund Ltd., 40 North Latitude SPV-D LLC, Dalbergia Investments LLC, Standard Industries Inc., Standard Industries Holdings Inc., G-I Holdings Inc., G Holdings LLC, G Holdings Inc., David S. Winter, David J. Millstone and Ronnie F. Heyman, to file this Schedule 13D and any amendments thereto jointly on behalf of each of them.

Exhibit 2 – Open Letter from Messrs. Winter and Millstone to the Board of Directors of the Issuer, dated April 28, 2020.

SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief, the undersigned certifies that the information set forth in this statement is true, complete and correct.

Exhibit 1

AGREEMENT

JOINT FILING OF SCHEDULE 13D

The undersigned hereby agree to jointly prepare and file with regulatory authorities this Schedule 13D and any future amendments thereto reporting each of the undersigned’s ownership of securities of GCP Applied Technologies Inc., and hereby affirm that such Schedule 13D is being filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning the other, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

Exhibit 2

April 28, 2020

Board of Directors

GCP Applied Technologies Inc.

62 Whittemore Avenue

Cambridge, Massachusetts 02140

Dear Members of the Board:

As you know, 40 North Management LLC and Standard Industries Inc. have been shareholders of GCP Applied Technologies Inc. (“GCP” or the “Company”) for over four years and today collectively we are the single largest shareholder, holding 17.8 million shares, or approximately 24.4% of the outstanding common stock. As long-term shareholders, we have patiently supported the Company since its spin-off from W.R. Grace and Co. in 2016. Despite that patient support, GCP’s Board of Directors has proven itself incapable of making sound strategic and tactical decisions in the best interests of the Company and its stakeholders. It is, therefore, after serious consideration that we write to you to let you know that we are left with no other tenable course of action but to support Starboard Value’s call for an almost complete replacement of GCP’s Board.

Our decision was not taken lightly and is based upon numerous factors that have impaired the business and fundamentally undermined our confidence in GCP’s Board.

Even in strong economic times, GCP’s business and stock performance have been lackluster. Prior to the COVID-19 crisis, despite leading positions in many of its product lines and a buoyant macroeconomic backdrop, GCP’s business failed to grow.

In addition, in every year since the spin-off, management has revised down its annual guidance highlighting a troubling lack of control over the business. This repeated pattern has undermined the credibility of GCP’s management as well as that of its Board.

GCP lacks a coherent strategy. GCP is broadly perceived to be falling behind its competition in terms of product innovation and sales force reach. Further, the GCP Board has not been held accountable for the failure of its 2019 strategic review process and, at this point, the Board appears to have no strategy at all. It is not surprising, then, that the public markets place little faith in the ability of this Board to rectify the situation and put GCP on a course to create value.

Inadequate corporate stewardship. While failing in its duty to oversee management and architect a coherent and effective strategy for the business, the Board has adopted a host of measures to entrench its position and reward failure.

We believe that, with proper leadership at the Board level, GCP has the opportunity to become a premier global construction products company, providing outstanding service to its customers, growth and opportunities to its employees and returns to its shareholders. As GCP’s largest shareholder, and one that has been with the Company since its inception in 2016, we are focused on helping the Company realize this unfulfilled potential. As a result, we have chosen to support Starboard Value’s call for new Board leadership at the Company.

Regards,