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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1. Name and Address of Reporting Person * Murphy Damian John   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) EVP & East Division President (Last) (First) (Middle) C/O SUMMIT MATERIALS, INC., 1550 WYNKOOP STREET, 3RD FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 12/11/2017 (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 Class A Common Stock 12/11/2017   M   62,042 A $ 18 66,440 D   Class A Common Stock 12/11/2017   M   48,622 A $ 18 115,062 D   Class A Common Stock 12/11/2017   M   4,454 A $ 17.07 119,516 D   Class A Common Stock 12/11/2017   S   115,118 D $ 31.75 (1) 4,398 D   Class A Common Stock               1,848 I By child

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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

Options (right to buy)

$ 18

12/11/2017

M

62,042

(2)

03/11/2025

Class A Common Stock

62,042

$ 0

62,042

D

Options (right to buy)

$ 18

12/11/2017

M

48,622

(3)

03/11/2025

Class A Common Stock

48,622

$ 0

80,655

D

Options (right to buy)

$ 17.07

12/11/2017

M

4,454

(4)

02/24/2026

Class A Common Stock

4,454

$ 0

8,906

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Murphy Damian John C/O SUMMIT MATERIALS, INC. 1550 WYNKOOP STREET, 3RD FLOOR DENVER, CO 80202			EVP & East Division President

Signatures

/s/ Anne Lee Benedict, as Attorney-in-Fact		12/13/2017
**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)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $31.505 to $32.05, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above.
(2)	Reflects a grant of 124,084 options that vests in four equal annual installments beginning on March 11, 2016.
(3)	Reflects a grant of 161,310 options that vests in four equal annual installments beginning on March 11, 2016.
(4)	Reflects a grant of 13,360 options that vests in three equal annual installments beginning on February 24, 2017.
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.

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