Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  Harris Brian James
 2. Date of Event Requiring Statement (Month/Day/Year)
03/12/2015		 3. Issuer Name and Ticker or Trading Symbol
Summit Materials, Inc. [SUM]
(Last)
(First)
(Middle)
C/O SUMMIT MATERIALS, INC., 1550 WYNKOOP STREET, 3RD FLOOR		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
EVP & Chief Financial Officer
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

DENVER, CO 80202		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Options (right to buy)   (1) 03/11/2025 Common Stock 101,200 $ 18 D  
Options (right to buy)   (2) 03/11/2025 Common Stock 131,560 $ 18 D  
LP Units of Summit Materials Holdings L.P.   (3)   (3) Common Stock 648,621 $ (3) I See Footnote (4)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Harris Brian James
C/O SUMMIT MATERIALS, INC.
1550 WYNKOOP STREET, 3RD FLOOR
DENVER, CO 80202		       EVP & Chief Financial Officer  

Signatures

/s/ Anne Lee Benedict, as Attorney-in-Fact 03/12/2015
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) The options vest in four equal annual installments beginning on March 11, 2016.
(2) The options vest upon the achievement of certain vesting events more fully described in the Issuer's Registration Statement on Form S-1 (File No. 333-201058).
(3) Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. ("LP Units") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the Issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis.
(4) Reflects securities held by a trust for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee.
 
Remarks:
The Reporting Person disclaims beneficial ownership of the securities reported herein as indirectly beneficially owned, except to the extent of his pecuniary interest therein.

Exhibit 24 - Power of Attorney

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