Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN 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 *
Gill Kevin A
   2. Issuer Name and Ticker or Trading Symbol
Summit Materials, Inc. [SUM] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
See Remarks
(Last)
(First)
(Middle)
C/O SUMMIT MATERIALS, INC., 1550 WYNKOOP STREET, 3RD FLOOR		 3. Date of Earliest Transaction (Month/Day/Year)
03/11/2015
(Street)

DENVER, CO 80202		 4. If Amendment, Date Original Filed(Month/Day/Year)
 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 Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
LP Units of Summit Materials Holdings L.P. (1) 03/11/2015   A   91,175     (1)   (1) Class A Common Stock 91,175 (2) 91,175 D  
Options (right to buy) $ 18 03/11/2015   A   33,471     (3) 03/11/2025 Class A Common Stock 33,471 (2) 33,471 D  
Options (right to buy) $ 18 03/11/2015   A   43,512     (4) 03/11/2025 Class A Common Stock 43,512 (2) 43,512 D  
LP Units of Summit Materials Holdings L.P. (1) 08/11/2015   D(5)     4,052   (1)   (1) Class A Common Stock 4,052 (5) 87,123 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Gill Kevin A
C/O SUMMIT MATERIALS, INC.
1550 WYNKOOP STREET, 3RD FLOOR
DENVER, CO 80202		       See Remarks  

Signatures

 /s/Anne Lee Benedict, as Attorney-in-Fact   08/13/2015
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(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) 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) (the "Registration Statement")) for shares of the issuer's Class A common stock on a one-for-one basis.
(2) These securities were acquired in connection with the reclassification of the interests of Summit Material Holdings L.P. prior to the issuer's initial public offering (as more fully described in the Registration Statement).
(3) The options vest in four equal annual installments beginning on March 11, 2016.
(4) The options vest upon the achievement of certain vesting events more fully described in the Registration Statement.
(5) The Reporting Person sold to the issuer the number of LP Units set forth above at a price per LP Unit of $24.784375, which represents the $25.75 price at which the issuer's Class A common stock was sold in a secondary offering, less the underwriters' discount of $0.965625 per share.
 
Remarks:
Title: EVP & Chief Human Resources Officer

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