0001104659-21-045788.txt : 20210401 0001104659-21-045788.hdr.sgml : 20210401 20210401211726 ACCESSION NUMBER: 0001104659-21-045788 CONFORMED SUBMISSION TYPE: 3 PUBLIC DOCUMENT COUNT: 2 CONFORMED PERIOD OF REPORT: 20210329 FILED AS OF DATE: 20210401 DATE AS OF CHANGE: 20210401 REPORTING-OWNER: OWNER DATA: COMPANY CONFORMED NAME: MacMillan Deon CENTRAL INDEX KEY: 0001854400 FILING VALUES: FORM TYPE: 3 SEC ACT: 1934 Act SEC FILE NUMBER: 001-36873 FILM NUMBER: 21800352 MAIL ADDRESS: STREET 1: C/O SUMMIT MATERIALS, INC. STREET 2: 1550 WYNKOOP STREET, 3RD FLOOR CITY: DENVER STATE: CO ZIP: 08202 ISSUER: COMPANY DATA: COMPANY CONFORMED NAME: Summit Materials, Inc. CENTRAL INDEX KEY: 0001621563 STANDARD INDUSTRIAL CLASSIFICATION: MINING, QUARRYING OF NONMETALLIC MINERALS (NO FUELS) [1400] IRS NUMBER: 471984212 STATE OF INCORPORATION: DE FISCAL YEAR END: 1228 BUSINESS ADDRESS: STREET 1: 1550 WYNKOOP STREET, 3RD FLOOR CITY: DENVER STATE: CO ZIP: 80202 BUSINESS PHONE: 303-893-0012 MAIL ADDRESS: STREET 1: 1550 WYNKOOP STREET, 3RD FLOOR CITY: DENVER STATE: CO ZIP: 80202 3 1 tm2111872-3_3seq1.xml OWNERSHIP DOCUMENT X0206 3 2021-03-29 0 0001621563 Summit Materials, Inc. SUM 0001854400 MacMillan Deon C/O SUMMIT MATERIALS, INC. 1550 WYNKOOP STREET, 3RD F LOOR DENVER CO 80202 0 1 0 0 See Remarks Class A Common Stock 3711 D Restricted Stock Units Class A Common Stock 11215 D Each restricted stock unit represents a contingent right to receive one share of Class A common stock of the Issuer ("Class A Common Stock"). The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee. These restricted stock units vest as follows: (a) 58.33% vest on March 9, 2022, and (b) the remaining vest on March 9, 2023. Title: EVP, Chief People Officer and Head of Corporate Communications Exhibit 24 - Power of Attorney /s/ Christopher B. Gaskill, as Attorney-in-Fact 2021-04-01 EX-24 2 tm2111872d3_ex24.htm EXHIBIT 24

Exhibit 24

POWER OF ATTORNEY

Know all by these presents that the undersigned, does hereby make, constitute and appoint each of Chris Gaskill, Brian Frantz and Kerry Bilewski, or any one of them, as a true and lawful attorney-in-fact of the undersigned with full powers of substitution and revocation, for and in the name, place and stead of the undersigned (in the undersigned's individual capacity), to execute and deliver such forms that the undersigned may be required to file with the U.S. Securities and Exchange Commission as a result of the undersigned's ownership of or transactions in securities of Summit Materials, Inc. (i) pursuant to Section 16(a) of the Securities Exchange Act of 1934, as amended, including without limitation, statements on Form 3, Form 4 and Form 5 (including any amendments thereto) and (ii) in connection with any applications for EDGAR access codes, including without limitation the Form ID. The Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Forms 3, 4 and 5 with regard to his or her ownership of or transactions in securities of Summit Materials, Inc., unless earlier revoked in writing. The undersigned acknowledges that Chris Gaskill, Brian Frantz and Kerry Bilewski are not assuming any of the undersigned’s responsibilities to comply with Section 16 of the Securities Exchange Act of 1934, as amended.

	By:
		/s/ Deon MacMillan
		Name: Deon MacMillan

	Date: March 26, 2021