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<title>Document</title></head><body><div id="id2e246166ec9496db90c1ca236867621_1"></div><div style="min-height:72pt;width:100%"><div><font><br></font></div></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">As filed with the Securities and Exchange Commission on August 5, 2021.</font></div><div style="margin-bottom:12pt;text-align:right"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Registration No.&#160;333-</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="margin-bottom:6pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:18pt;font-weight:700;line-height:120%">UNITED STATES<br>SECURITIES AND EXCHANGE COMMISSION<br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">Washington, D.C. 20549</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="margin-bottom:6pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:18pt;font-weight:700;line-height:120%">FORM S-8<br>REGISTRATION STATEMENT<br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-style:italic;font-weight:700;line-height:120%">UNDER</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-style:italic;font-weight:700;line-height:120%">THE SECURITIES ACT OF 1933</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="margin-bottom:3pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:24pt;font-weight:700;line-height:120%">Summit Materials, Inc.<br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(Exact name of registrant as specified in its charter)</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:48.900%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:48.900%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Delaware</font></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">47-1984212</font></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">(State or other jurisdiction of<br>incorporation or organization)</font></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">(I.R.S. Employer<br>Identification No.)</font></td></tr></table></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="margin-bottom:6pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">1550 Wynkoop Street, 3rd Floor<br>Denver, Colorado 80202<br><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">(Address of Principal Executive Offices)</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="margin-bottom:6pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Summit Materials, Inc. Amended and Restated 2015 Omnibus Incentive Plan<br>Summit Materials, Inc. 2021 Employee Stock Purchase Plan<br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">(Full title of the plan)</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Christopher B. Gaskill, Esq.<br>Executive Vice President,  Chief Legal Officer and Secretary<br>Summit Materials, Inc.<br>1550 Wynkoop Street, 3rd Floor<br>Denver, Colorado 80202<br>Telephone&#58; (303) 893-0012<br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">(Name and address and telephone number, including area code, of agent for service)</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:9pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div><font><br></font></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div><font><br></font></div></div></div><hr style="page-break-after:always"><div style="min-height:72pt;width:100%"><div><font><br></font></div></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="margin-bottom:12pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Copies to&#58;</font></div><div style="margin-bottom:6pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Edgar J. Lewandowski<br>Bradley P. Goldberg<br>Simpson Thacher&#160;&#38; Bartlett LLP<br>425 Lexington Avenue<br>New York, New York 10017<br>(212) 455-2000</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="margin-bottom:12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of &#8220;large accelerated filer,&#8221; &#8220;accelerated filer,&#8221; &#8220;smaller reporting company&#8221; and &#8220;emerging growth company&#8221; in Rule 12b-2 of the Exchange Act.</font></div><div style="margin-bottom:6pt;padding-left:4.97pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:97.916%"><tr><td style="width:1.0%"></td><td style="width:21.485%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:46.035%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:25.413%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:2.667%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:middle"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Large&#160;accelerated&#160;filer</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:middle"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:400;line-height:120%">&#9746;</font></td><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:middle"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Accelerated filer</font></td><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:middle"><font style="color:#000000;font-family:'MS Gothic',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#9744;</font></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:middle"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Non-accelerated filer</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:middle"><div style="margin-bottom:12pt;padding-right:3.1pt"><font style="color:#000000;font-family:'MS Gothic',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#9744;</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> (Do not check if a smaller reporting company)</font></div></td><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:middle"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Smaller reporting company</font></td><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:middle"><font style="color:#000000;font-family:'MS Gothic',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#9744;</font></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:middle"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Emerging Growth Company</font></td><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:middle"><font style="color:#000000;font-family:'MS Gothic',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#9744;</font></td></tr></table></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act  </font><font style="color:#000000;font-family:'MS Gothic',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#9744;</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:11pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="margin-bottom:6pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">CALCULATION OF REGISTRATION FEE</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:43.932%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.400%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:14.605%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.843%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">Title of securities<br>to be registered</font></td><td colspan="3" style="border-left:0.25pt solid #000;border-top:0.25pt solid #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:3.1pt;padding-right:3.1pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">Amount</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">to be</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">registered</font></div></td><td colspan="3" style="border-left:0.25pt solid #000;border-top:0.25pt solid #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:3.1pt;padding-right:3.1pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">Proposed</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">maximum</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">offering price</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">per share(4)</font></div></td><td colspan="3" style="border-left:0.25pt solid #000;border-top:0.25pt solid #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:3.1pt;padding-right:3.1pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">Proposed</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">maximum</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">aggregate</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">offering price(4)</font></div></td><td colspan="3" style="border-left:0.25pt solid #000;border-right:0.25pt solid #000;border-top:0.25pt solid #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:3.1pt;padding-right:3.1pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">Amount of</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:120%">registration fee(4)</font></div></td></tr><tr><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:left;vertical-align:top"><div style="padding-left:15.1pt;padding-right:3.1pt;text-indent:-12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Class A Common Stock, par value $0.01 per share(1)(3)</font></div></td><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">4,000,000</font></td><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">$33.21</font></td><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">$132,840,000.00</font></td><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">$14,493.00</font></td></tr><tr><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:left;vertical-align:top"><div style="padding-left:15.1pt;padding-right:3.1pt;text-indent:-12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Class A Common Stock, par value $0.01 per share(2)(3)</font></div></td><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">5,500,000</font></td><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">$33.21</font></td><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">$182,655,000.00</font></td><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">$19,928.00</font></td></tr></table></div><div><font><br></font></div><div style="padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(1)&#160;&#160;&#160;&#160;Covers shares of Class&#160;A common stock (the &#8220;Class A Common Stock&#8221;) of Summit Materials, Inc. (the &#8220;Registrant&#8221;), par value $0.01 per share, issuable under the Summit Materials, Inc. Amended and Restated 2015 Omnibus Incentive Plan (the &#8220;Plan&#8221;).</font></div><div style="padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(2)&#160;&#160;&#160;&#160;Covers Class A Common Stock issuable under the Summit Materials, Inc. 2021 Employee Stock Purchase Plan (the &#8220;ESPP&#8221;)</font></div><div style="padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(3)&#160;&#160;&#160;&#160;Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the &#8220;Securities Act&#8221;), this Registration Statement also covers an indeterminate number of additional shares of Class&#160;A common stock that may be offered and issued under the Plan and the ESPP to prevent dilution resulting from stock splits, stock distributions or similar transactions.</font></div><div style="margin-bottom:9pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(4)&#160;&#160;&#160;&#160;Pursuant to Rule 457(c) and Rule 457(h) under the Securities Act, the proposed maximum offering price per share, the proposed maximum aggregate offering price and the amount of the registration fee have been computed on the basis of the average high and low prices per share of the Registrant&#8217;s Class A Common Stock reported on the New York Stock Exchange on August 3, 2021.</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-bottom:0.25pt solid #000;padding:0 1pt"></td></tr></table></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div><font><br></font></div></div></div><div id="id2e246166ec9496db90c1ca236867621_4"></div><hr style="page-break-after:always"><div style="min-height:72pt;width:100%"><div><font><br></font></div></div><div style="-sec-extract:summary;margin-bottom:12pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">EXPLANATORY NOTE</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On May 19, 2021, at the annual meeting of stockholders (the &#8220;Annual Meeting&#8221;) of the Registrant, the Registrant&#8217;s stockholders approved the Plan (which, among other things, increased the number of shares of the Registrant&#8217;s Class A common stock (the &#8220;Class A Common Stock&#8221;), par value $0.01 per share (the &#8220;Shares&#8221;), that may be issued under the Plan by 4,000,000 Shares from the 13,500,000 Shares which were previously authorized for issuance and registered on a registration statement on Form S-8 filed with the Securities and Exchange Commission (the &#8220;Commission&#8221;) on March 11, 2015. As a result, the total number of Shares authorized for issuance under the Plan is 17,500,000. Stockholders at the Annual Meeting also approved the ESPP which authorizes 5,500,000 Shares for issuance under the ESPP. This Registration Statement on Form S-8 (the &#8220;Registration Statement&#8221;) relates to the additional 4,000,000 Shares authorized for issuance under the Plan and the 5,500,000 Shares authorized for issuance under the ESPP.</font></div><div style="margin-bottom:12pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">PART I<br><br>INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The information specified in Item&#160;1 and Item&#160;2 of Part I of Form S-8 is omitted from this Registration Statement in accordance with the provisions of Rule 428 under the Securities Act of 1933, as amended (the &#8220;Securities Act&#8221;), and the introductory note to Part I of Form S-8. The documents containing the information specified in Part I of Form S-8 will be delivered to the participants in the Plan and the ESPP covered by this Registration Statement as specified by Rule 428(b)(1) under the Securities Act. Such documents are not required to be, and are not, filed with the Commission either as part of this Registration Statement or as a prospectus or prospectus supplement pursuant to Rule 424 under the Securities Act.</font></div><div style="margin-bottom:12pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">PART II<br><br>INFORMATION REQUIRED IN THE REGISTRATION STATEMENT</font></div><div style="margin-bottom:12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;3. Incorporation of Documents by Reference.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following documents filed with the Commission by the Registrant pursuant to the Securities Act and the Securities Exchange Act of 1934, as amended (the &#8220;Exchange Act&#8221;), are hereby incorporated by reference in this Registration Statement&#58;</font></div><div style="margin-bottom:12pt;padding-left:54pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">a)&#160;&#160;&#160;&#160;the Registrant&#8217;s Annual Report on Form 10-K for the fiscal year ended </font><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/ix?doc=/Archives/edgar/data/1571371/000162828021003021/sum-20210102.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">January 2, 2021</a></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#59;</font></div><div style="margin-bottom:12pt;padding-left:54pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">b)&#160;&#160;&#160;&#160;the Registrant&#8217;s Quarterly Reports on Form 10-Q for the quarterly periods ended </font><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/ix?doc=/Archives/edgar/data/1571371/000162828021009779/sum-20210403.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">April 3, 2021</a></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> and </font><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/ix?doc=/Archives/edgar/data/1571371/000162828021015769/sum-20210703.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">July 3</a><a href="http://www.sec.gov/ix?doc=/Archives/edgar/data/1571371/000162828021015769/sum-20210703.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">, 2021</a></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#59;</font></div><div style="margin-bottom:12pt;padding-left:54pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">c)&#160;&#160;&#160;&#160;the Registrant&#8217;s Current Reports on Form 8-K, filed with the Commission on </font><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/ix?doc=/Archives/edgar/data/1621563/000110465921037984/tm2110132d1_8k.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">March 18, 2021</a></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, </font><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/ix?doc=/Archives/edgar/data/1621563/000110465921043999/tm2111264d1_8k.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">March 30, 2021</a></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, and </font><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/ix?doc=/Archives/edgar/data/1621563/000162828021010695/sum-20210519.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">May 19, 2021</a></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> (except for any portions of such Current Reports on Form 8-K furnished pursuant to Item 2.02 and&#47;or Item 7.01 thereof and any corresponding exhibits thereto not filed with the Commission)&#59; and</font></div><div style="margin-bottom:12pt;padding-left:54pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">d)&#160;&#160;&#160;&#160;the description of the Class A Common Stock contained in the Registrant&#8217;s description of securities, filed with the Commission as </font><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/Archives/edgar/data/1571371/000162828020001083/ex4110k2019.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Exhibit 4.1</a></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> to the Registrant&#8217;s Annual Report on Form 10-K for the fiscal year ended December 28, 2019, including any amendment or reports filed for the purpose of updating such descriptions.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">All documents that the Registrant subsequently files pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act after the date of this Registration Statement (except for any portions of the Registrant&#8217;s Current Reports on Form 8-K furnished pursuant to Item&#160;2.02 or Item&#160;7.01 thereof and any corresponding exhibits thereto not filed with the Commission) and prior to the filing of a post-effective amendment to this Registration Statement </font></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div><font><br></font></div></div></div><hr style="page-break-after:always"><div style="min-height:72pt;width:100%"><div><font><br></font></div></div><div style="margin-bottom:12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">indicating that all securities offered have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference into this Registration Statement and to be a part hereof from the date of filing of such documents.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.</font></div><div style="margin-bottom:12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;4. Description of Securities.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Not applicable.</font></div><div style="margin-bottom:12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;5. Interests of Named Experts and Counsel.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Not applicable.</font></div><div style="margin-bottom:12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;6. Indemnification of Directors and Officers.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Section&#160;102(b)(7) of the General Corporation Law of the State of Delaware (the &#8220;DGCL&#8221;), allows a corporation to provide in its certificate of incorporation that a director of the corporation will not be personally liable to the corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except where the director breached the duty of loyalty, failed to act in good faith, engaged in intentional misconduct or knowingly violated a law, authorized the payment of a dividend or approved a stock repurchase or redemption in violation of Delaware corporate law or obtained an improper personal benefit. The Registrant&#8217;s restated certificate of incorporation provides for this limitation of liability.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Section&#160;145 of the DGCL (&#8220;Section 145&#8221;) provides, among other things, that a Delaware corporation may indemnify any person who was, is or is threatened to be made, party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of such corporation), by reason of the fact that such person is or was an officer, director, employee or agent of such corporation or is or was serving at the request of such corporation as a director, officer, employee or agent of another corporation or enterprise against expenses (including attorneys&#8217; fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by such person in connection with such action, suit or proceeding, provided such person acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the corporation&#8217;s best interests and, with respect to any criminal action or proceeding, had no reasonable cause to believe that his or her conduct was unlawful. A Delaware corporation may indemnify any persons who were or are a party to any threatened, pending or completed action or suit by or in the right of the corporation by reason of the fact that such person is or was a director, officer, employee or agent of another corporation or enterprise against expenses (including attorneys&#8217; fees) actually and reasonably incurred by such person in connection with the defense or settlement of such action or suit, provided such person acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the corporation&#8217;s best interests, provided further that no indemnification is permitted without judicial approval if the officer, director, employee or agent is adjudged to be liable to the corporation. Where an officer or director is successful on the merits or otherwise in the defense of any action referred to above, the corporation must indemnify him or her against the expenses (including attorney&#8217;s fees) which such officer or director has actually and reasonably incurred.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Section 145 also provides that the expenses incurred by a director, officer, employee or agent of the corporation or a person serving at the request of the corporation as a director, officer, employee or agent of another corporation or enterprise in defending any action, suit or proceeding may be paid in advance of the final disposition of the action, suit or proceeding, subject, in the case of current officers and directors, to the corporation&#8217;s receipt of an undertaking by or on behalf of such officer or director to repay the amount so advanced if it shall be ultimately determined that such person is not entitled to be indemnified.</font></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="-sec-extract:summary;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">2</font></div></div></div><hr style="page-break-after:always"><div style="min-height:72pt;width:100%"><div><font><br></font></div></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Section&#160;145 further authorizes a corporation to purchase and maintain insurance on behalf of any person who is or was a director, officer, employee or agent of the corporation or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation or enterprise, against any liability asserted against such person and incurred by such person in any such capacity, or arising out of his or her status as such, whether or not the corporation would otherwise have the power to indemnify him or her under Section&#160;145.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Registrant&#8217;s second amended and restated bylaws provide that the Registrant must indemnify its directors and officers to the fullest extent authorized by the DGCL and must also pay expenses incurred in defending any such proceeding in advance of its final disposition upon delivery of an undertaking, by or on behalf of an indemnified person, to repay all amounts so advanced if it should be determined ultimately that such person is not entitled to be indemnified under the Registrant&#8217;s second amended and restated bylaws or otherwise.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The indemnification rights set forth above shall not be exclusive of any other right which an indemnified person may have or hereafter acquire under any statute, provision of the Registrant&#8217;s restated certificate of incorporation, the Registrant&#8217;s second amended and restated bylaws, agreement, vote of stockholders or disinterested directors or otherwise.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Registrant maintains standard policies of insurance that provide coverage (1)&#160;to its directors and officers against loss arising from claims made by reason of breach of duty or other wrongful act and (2)&#160;to the Registrant with respect to indemnification payments that it may make to such directors and officers.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Registrant is currently party to indemnification agreements with its directors and executive officers. These agreements require the Registrant to indemnify these individuals to the fullest extent permitted under Delaware law against liabilities that may arise by reason of their service to the Registrant, and to advance expenses incurred as a result of any proceeding against them as to which they could be indemnified. Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors or executive officers, the Registrant has been informed that, in the opinion of the Commission, such indemnification is against public policy and is therefore unenforceable.</font></div><div style="margin-bottom:12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;7. Exemption from Registration Claimed.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Not applicable.</font></div><div style="margin-bottom:12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;8. Exhibits.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following exhibits are filed as part of this Registration Statement&#58;</font></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="-sec-extract:summary;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">3</font></div></div></div><hr style="page-break-after:always"><div style="min-height:72pt;width:100%"><div><font><br></font></div></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:8.980%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:88.820%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="margin-bottom:12pt;padding-left:3.1pt;padding-right:3.1pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Exhibit</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"><br></font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Number</font></div></td><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Description of Document</font></td></tr><tr><td colspan="3" style="border-top:0.25pt solid #000000;padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">4.1</font></td><td colspan="3" style="border-top:0.25pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:top"><div style="padding-left:3.12pt"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/Archives/edgar/data/1621563/000162828021010695/ex31-restatedcertificateof.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Restated Certificate of Incorporation of Summit Materials, Inc. (incorporated by reference to Exhibit 3.1 to the Registrant&#8217;s Current Report on Form 8-K filed with the Commission on May 19, 2021).</a></font></div></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">4.2</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><div style="padding-left:3.12pt"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/Archives/edgar/data/1621563/000162828021010695/ex33-amendedandrestatedbyx.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Second Amended and Restated Bylaws of Summit Materials, Inc. (incorporated by reference to Exhibit 3.3 to the Registrant&#8217;s Current Report on Form 8-K filed with the Commission on May 19, 2021).</a></font></div></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">4.3</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><div style="padding-left:3.12pt"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/Archives/edgar/data/1621563/000162828021010695/ex101-summitmaterialsincam.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Summit Materials, Inc. Amended and Restated 2015 Omnibus Incentive Plan (incorporated by reference to Exhibit 10.1 to the Registrant&#8217;s Current Report on Form 8-K filed with the Commission on May 19, 2021).</a></font></div></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">4.4</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><div style="padding-left:3.12pt"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="http://www.sec.gov/Archives/edgar/data/1621563/000162828021010695/ex102-summitmaterialsinc20.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Summit Materials, Inc. 2021 Employee Stock Purchase Plan (incorporated by reference to Exhibit 10.2 to the Registrant&#8217;s Current Report on Form 8-K filed with the Commission on May 19, 2021).</a></font></div></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">5.1</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><div style="padding-left:3.12pt"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="a8521s-8exhibit51.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Opinion of Simpson Thacher &#38; Bartlett LLP.</a></font></div></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">23.1</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><div style="padding-left:3.12pt"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="a8521s-8exhibit231.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Consent of KPMG LLP.</a></font></div></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">23.4</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><div style="padding-left:3.12pt"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="a8521s-8exhibit51.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Consent of Simpson Thacher &#38; Bartlett LLP (included as part of Exhibit 5.1).</a></font></div></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 4.12pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">24.1</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><div style="padding-left:3.12pt"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a href="#id2e246166ec9496db90c1ca236867621_10" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Powers of Attorney (included in the signature pages to this Registration Statement).</a></font></div></td></tr></table></div><div><font><br></font></div><div style="margin-bottom:12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;9. Undertakings.</font></div><div style="margin-bottom:12pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(a)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:6.91pt">The undersigned registrant hereby undertakes&#58;</font></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(1)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:6.34pt">To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement&#58;</font></div><div style="margin-bottom:12pt;padding-left:54pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(i)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:8.57pt">To include any prospectus required by Section&#160;10(a)(3) of the Securities Act&#59;</font></div><div style="margin-bottom:12pt;padding-left:54pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(ii)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:5.8pt">To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement&#59; and</font></div><div style="margin-bottom:12pt;padding-left:54pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(iii)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:3.03pt">To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement&#59;</font></div><div style="margin-bottom:12pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">provided, however</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, that paragraphs (a)(1)(i) and (a)(1)(ii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference in this Registration Statement.</font></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(2)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:6.34pt">That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">bona fide</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> offering thereof.</font></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(3)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:6.34pt">To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.</font></div><div style="margin-bottom:12pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(b)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:6.34pt">The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the registrant&#8217;s annual report pursuant to Section&#160;13(a) or Section&#160;15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan&#8217;s annual report pursuant to Section&#160;15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">bona fide</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> offering thereof.</font></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="-sec-extract:summary;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">4</font></div></div></div><hr style="page-break-after:always"><div style="min-height:72pt;width:100%"><div><font><br></font></div></div><div style="margin-bottom:12pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(c)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:6.91pt">Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question of whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.</font></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="-sec-extract:summary;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">5</font></div></div></div><div id="id2e246166ec9496db90c1ca236867621_7"></div><hr style="page-break-after:always"><div style="min-height:72pt;width:100%"><div><font><br></font></div></div><div style="margin-bottom:12pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">SIGNATURES</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Denver, Colorado, on the 5th day of August, 2021.</font></div><div style="margin-bottom:24pt;padding-left:216pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">SUMMIT MATERIALS, INC.</font></div><div style="padding-left:243pt;text-indent:-27pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">By&#58;&#160;&#160;&#160;&#160;</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">&#47;s&#47; Anne P. Noonan&#160;&#160;&#160;&#160;</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"><br>Name&#58;  Anne P. Noonan<br>Title&#58;    Chief Executive Officer</font></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div><font><br></font></div></div></div><div id="id2e246166ec9496db90c1ca236867621_10"></div><hr style="page-break-after:always"><div style="min-height:72pt;width:100%"><div><font><br></font></div></div><div style="margin-bottom:12pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">POWER OF ATTORNEY</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">KNOW ALL PERSONS BY THESE PRESENTS, that the undersigned directors and officers of the Registrant, which is filing a Registration Statement on Form S-8 with the Securities and Exchange Commission, Washington, D.C. 20549 under the provisions of the Securities Act of 1933 hereby constitute and appoint Anne P. Noonan, Brian J. Harris and Christopher B. Gaskill, and each of them, any of whom may act without joinder of the other, the individual&#8217;s true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for the person and in his or her name, place and stead, in any and all capacities, to sign this Registration Statement and any or all amendments or supplements to this Registration Statement, including post-effective amendments, and to file the same, with all exhibits thereto, and other documents in connection therewith with the Securities and Exchange Commission, and does hereby grant unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof.</font></div><div style="margin-bottom:12pt;text-indent:36pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Pursuant to the requirements of the Securities Act of 1933, this Registration Statement and powers of attorney have been signed by the following persons in the capacities indicated on the 5th day of August, 2021.</font></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:48.419%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.761%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:48.420%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Signature</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Title</font></td></tr><tr><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47; &#160;&#160;&#160;&#160;Anne P. Noonan</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">President and Chief Executive Officer<br>(Principal Executive Officer)&#59;</font></td></tr><tr><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Anne P. Noonan</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Director</font></td></tr><tr style="height:13pt"><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47; &#160;&#160;&#160;&#160;Brian J. Harris</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Chief Financial Officer<br>(Principal Financial and Accounting Officer)</font></td></tr><tr style="height:13pt"><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Brian J. Harris</font></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:13pt"><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47; &#160;&#160;&#160;&#160;&#160;Joseph S. Cantie</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Director</font></td></tr><tr style="height:13pt"><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Joseph S. Cantie</font></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:13pt"><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47;&#160;&#160;&#160;&#160;&#160; Anne M. Cooney</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Director</font></td></tr><tr style="height:13pt"><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Anne M. Cooney</font></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:13pt"><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47;&#160;&#160;&#160;&#160;&#160; Susan A. Ellerbusch</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Director</font></td></tr><tr style="height:13pt"><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Susan A. Ellerbusch</font></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:13pt"><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47; &#160;&#160;&#160;&#160;Howard L. Lance</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Director</font></td></tr><tr style="height:13pt"><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Howard L. Lance</font></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:13pt"><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47; &#160;&#160;&#160;&#160;Tamla Oates-Forney</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Director</font></td></tr><tr style="height:13pt"><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Tamla Oates-Forney</font></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:13pt"><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47; &#160;&#160;&#160;&#160;John R. Murphy</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Director</font></td></tr><tr style="height:13pt"><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">John R. Murphy</font></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:13pt"><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47; &#160;&#160;&#160;&#160;Anne K. Wade</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Director</font></td></tr><tr style="height:13pt"><td colspan="3" style="border-top:0.25pt solid #000;padding:2px 1pt;text-align:center;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Anne K. Wade</font></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:13pt"><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47; &#160;&#160;&#160;&#160;Steven H. 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Document
As filed with the Securities and Exchange Commission on August 5, 2021.
Registration No. 333-
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM S-8
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933
Summit Materials, Inc.
(Exact name of registrant as specified in its charter)
Delaware
47-1984212
(State or other jurisdiction of
incorporation or organization)
(I.R.S. Employer
Identification No.)
1550 Wynkoop Street, 3rd Floor
Denver, Colorado 80202
(Address of Principal Executive Offices)
Summit Materials, Inc. Amended and Restated 2015 Omnibus Incentive Plan
Summit Materials, Inc. 2021 Employee Stock Purchase Plan
(Full title of the plan)
Christopher B. Gaskill, Esq.
Executive Vice President,  Chief Legal Officer and Secretary
Summit Materials, Inc.
1550 Wynkoop Street, 3rd Floor
Denver, Colorado 80202
Telephone: (303) 893-0012
(Name and address and telephone number, including area code, of agent for service)
Copies to:
Edgar J. Lewandowski
Bradley P. Goldberg
Simpson Thacher & Bartlett LLP
425 Lexington Avenue
New York, New York 10017
(212) 455-2000
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company" and "emerging growth company" in Rule 12b-2 of the Exchange Act.
Large accelerated filer
☒
Accelerated filer
☐
Non-accelerated filer
☐
(Do not check if a smaller reporting company)
Smaller reporting company
☐
Emerging Growth Company
☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act
☐
CALCULATION OF REGISTRATION FEE
Title of securities
to be registered
Amount
to be
registered
Proposed
maximum
offering price
per share(4)
Proposed
maximum
aggregate
offering price(4)
Amount of
registration fee(4)
Class A Common Stock, par value $0.01 per share(1)(3)
4,000,000
$33.21
$132,840,000.00
$14,493.00
Class A Common Stock, par value $0.01 per share(2)(3)
5,500,000
$33.21
$182,655,000.00
$19,928.00
(1)    Covers shares of Class A common stock (the "Class A Common Stock") of Summit Materials, Inc. (the "Registrant"), par value $0.01 per share, issuable under the Summit Materials, Inc. Amended and Restated 2015 Omnibus Incentive Plan (the "Plan").
(2)    Covers Class A Common Stock issuable under the Summit Materials, Inc. 2021 Employee Stock Purchase Plan (the "ESPP")
(3)    Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "Securities Act"), this Registration Statement also covers an indeterminate number of additional shares of Class A common stock that may be offered and issued under the Plan and the ESPP to prevent dilution resulting from stock splits, stock distributions or similar transactions.
(4)    Pursuant to Rule 457(c) and Rule 457(h) under the Securities Act, the proposed maximum offering price per share, the proposed maximum aggregate offering price and the amount of the registration fee have been computed on the basis of the average high and low prices per share of the Registrant's Class A Common Stock reported on the New York Stock Exchange on August 3, 2021.
EXPLANATORY NOTE
On May 19, 2021, at the annual meeting of stockholders (the "Annual Meeting") of the Registrant, the Registrant's stockholders approved the Plan (which, among other things, increased the number of shares of the Registrant's Class A common stock (the "Class A Common Stock"), par value $0.01 per share (the "Shares"), that may be issued under the Plan by 4,000,000 Shares from the 13,500,000 Shares which were previously authorized for issuance and registered on a registration statement on Form S-8 filed with the Securities and Exchange Commission (the "Commission") on March 11, 2015. As a result, the total number of Shares authorized for issuance under the Plan is 17,500,000. Stockholders at the Annual Meeting also approved the ESPP which authorizes 5,500,000 Shares for issuance under the ESPP. This Registration Statement on Form S-8 (the "Registration Statement") relates to the additional 4,000,000 Shares authorized for issuance under the Plan and the 5,500,000 Shares authorized for issuance under the ESPP.
PART I
INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS
The information specified in Item 1 and Item 2 of Part I of Form S-8 is omitted from this Registration Statement in accordance with the provisions of Rule 428 under the Securities Act of 1933, as amended (the "Securities Act"), and the introductory note to Part I of Form S-8. The documents containing the information specified in Part I of Form S-8 will be delivered to the participants in the Plan and the ESPP covered by this Registration Statement as specified by Rule 428(b)(1) under the Securities Act. Such documents are not required to be, and are not, filed with the Commission either as part of this Registration Statement or as a prospectus or prospectus supplement pursuant to Rule 424 under the Securities Act.
PART II
INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
Item 3. Incorporation of Documents by Reference.
The following documents filed with the Commission by the Registrant pursuant to the Securities Act and the Securities Exchange Act of 1934, as amended (the "Exchange Act"), are hereby incorporated by reference in this Registration Statement:
a)    the Registrant's Annual Report on Form 10-K for the fiscal year ended
January 2, 2021
;
b)    the Registrant's Quarterly Reports on Form 10-Q for the quarterly periods ended
April 3, 2021
and
July 3
, 2021
;
c)    the Registrant's Current Reports on Form 8-K, filed with the Commission on
March 18, 2021
,
March 30, 2021
, and
May 19, 2021
(except for any portions of such Current Reports on Form 8-K furnished pursuant to Item 2.02 and/or Item 7.01 thereof and any corresponding exhibits thereto not filed with the Commission); and
d)    the description of the Class A Common Stock contained in the Registrant's description of securities, filed with the Commission as
Exhibit 4.1
to the Registrant's Annual Report on Form 10-K for the fiscal year ended December 28, 2019, including any amendment or reports filed for the purpose of updating such descriptions.
All documents that the Registrant subsequently files pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act after the date of this Registration Statement (except for any portions of the Registrant's Current Reports on Form 8-K furnished pursuant to Item 2.02 or Item 7.01 thereof and any corresponding exhibits thereto not filed with the Commission) and prior to the filing of a post-effective amendment to this Registration Statement
indicating that all securities offered have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference into this Registration Statement and to be a part hereof from the date of filing of such documents.
Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.
Item 4. Description of Securities.
Not applicable.
Item 5. Interests of Named Experts and Counsel.
Not applicable.
Item 6. Indemnification of Directors and Officers.
Section 102(b)(7) of the General Corporation Law of the State of Delaware (the "DGCL"), allows a corporation to provide in its certificate of incorporation that a director of the corporation will not be personally liable to the corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except where the director breached the duty of loyalty, failed to act in good faith, engaged in intentional misconduct or knowingly violated a law, authorized the payment of a dividend or approved a stock repurchase or redemption in violation of Delaware corporate law or obtained an improper personal benefit. The Registrant's restated certificate of incorporation provides for this limitation of liability.
Section 145 of the DGCL ("Section 145") provides, among other things, that a Delaware corporation may indemnify any person who was, is or is threatened to be made, party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of such corporation), by reason of the fact that such person is or was an officer, director, employee or agent of such corporation or is or was serving at the request of such corporation as a director, officer, employee or agent of another corporation or enterprise against expenses (including attorneys' fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by such person in connection with such action, suit or proceeding, provided such person acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the corporation's best interests and, with respect to any criminal action or proceeding, had no reasonable cause to believe that his or her conduct was unlawful. A Delaware corporation may indemnify any persons who were or are a party to any threatened, pending or completed action or suit by or in the right of the corporation by reason of the fact that such person is or was a director, officer, employee or agent of another corporation or enterprise against expenses (including attorneys' fees) actually and reasonably incurred by such person in connection with the defense or settlement of such action or suit, provided such person acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the corporation's best interests, provided further that no indemnification is permitted without judicial approval if the officer, director, employee or agent is adjudged to be liable to the corporation. Where an officer or director is successful on the merits or otherwise in the defense of any action referred to above, the corporation must indemnify him or her against the expenses (including attorney's fees) which such officer or director has actually and reasonably incurred.
Section 145 also provides that the expenses incurred by a director, officer, employee or agent of the corporation or a person serving at the request of the corporation as a director, officer, employee or agent of another corporation or enterprise in defending any action, suit or proceeding may be paid in advance of the final disposition of the action, suit or proceeding, subject, in the case of current officers and directors, to the corporation's receipt of an undertaking by or on behalf of such officer or director to repay the amount so advanced if it shall be ultimately determined that such person is not entitled to be indemnified.
2
Section 145 further authorizes a corporation to purchase and maintain insurance on behalf of any person who is or was a director, officer, employee or agent of the corporation or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation or enterprise, against any liability asserted against such person and incurred by such person in any such capacity, or arising out of his or her status as such, whether or not the corporation would otherwise have the power to indemnify him or her under Section 145.
The Registrant's second amended and restated bylaws provide that the Registrant must indemnify its directors and officers to the fullest extent authorized by the DGCL and must also pay expenses incurred in defending any such proceeding in advance of its final disposition upon delivery of an undertaking, by or on behalf of an indemnified person, to repay all amounts so advanced if it should be determined ultimately that such person is not entitled to be indemnified under the Registrant's second amended and restated bylaws or otherwise.
The indemnification rights set forth above shall not be exclusive of any other right which an indemnified person may have or hereafter acquire under any statute, provision of the Registrant's restated certificate of incorporation, the Registrant's second amended and restated bylaws, agreement, vote of stockholders or disinterested directors or otherwise.
The Registrant maintains standard policies of insurance that provide coverage (1) to its directors and officers against loss arising from claims made by reason of breach of duty or other wrongful act and (2) to the Registrant with respect to indemnification payments that it may make to such directors and officers.
The Registrant is currently party to indemnification agreements with its directors and executive officers. These agreements require the Registrant to indemnify these individuals to the fullest extent permitted under Delaware law against liabilities that may arise by reason of their service to the Registrant, and to advance expenses incurred as a result of any proceeding against them as to which they could be indemnified. Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors or executive officers, the Registrant has been informed that, in the opinion of the Commission, such indemnification is against public policy and is therefore unenforceable.
Item 7. Exemption from Registration Claimed.
Not applicable.
Item 8. Exhibits.
The following exhibits are filed as part of this Registration Statement:
3
Exhibit
Number
Description of Document
4.1
Restated Certificate of Incorporation of Summit Materials, Inc. (incorporated by reference to Exhibit 3.1 to the Registrant's Current Report on Form 8-K filed with the Commission on May 19, 2021).
4.2
Second Amended and Restated Bylaws of Summit Materials, Inc. (incorporated by reference to Exhibit 3.3 to the Registrant's Current Report on Form 8-K filed with the Commission on May 19, 2021).
4.3
Summit Materials, Inc. Amended and Restated 2015 Omnibus Incentive Plan (incorporated by reference to Exhibit 10.1 to the Registrant's Current Report on Form 8-K filed with the Commission on May 19, 2021).
4.4
Summit Materials, Inc. 2021 Employee Stock Purchase Plan (incorporated by reference to Exhibit 10.2 to the Registrant's Current Report on Form 8-K filed with the Commission on May 19, 2021).
5.1
Opinion of Simpson Thacher & Bartlett LLP.
23.1
Consent of KPMG LLP.
23.4
Consent of Simpson Thacher & Bartlett LLP (included as part of Exhibit 5.1).
24.1
Powers of Attorney (included in the signature pages to this Registration Statement).
Item 9. Undertakings.
(a)
The undersigned registrant hereby undertakes:
(1)
To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:
(i)
To include any prospectus required by Section 10(a)(3) of the Securities Act;
(ii)
To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement; and
(iii)
To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;
provided, however
, that paragraphs (a)(1)(i) and (a)(1)(ii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference in this Registration Statement.
(2)
That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial
bona fide
offering thereof.
(3)
To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.
(b)
The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the registrant's annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial
bona fide
offering thereof.
4
(c)
Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question of whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.
5
SIGNATURES
Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Denver, Colorado, on the 5th day of August, 2021.
SUMMIT MATERIALS, INC.
By:
/s/ Anne P. Noonan
Name:  Anne P. Noonan
Title:    Chief Executive Officer
POWER OF ATTORNEY
KNOW ALL PERSONS BY THESE PRESENTS, that the undersigned directors and officers of the Registrant, which is filing a Registration Statement on Form S-8 with the Securities and Exchange Commission, Washington, D.C. 20549 under the provisions of the Securities Act of 1933 hereby constitute and appoint Anne P. Noonan, Brian J. Harris and Christopher B. Gaskill, and each of them, any of whom may act without joinder of the other, the individual's true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for the person and in his or her name, place and stead, in any and all capacities, to sign this Registration Statement and any or all amendments or supplements to this Registration Statement, including post-effective amendments, and to file the same, with all exhibits thereto, and other documents in connection therewith with the Securities and Exchange Commission, and does hereby grant unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof.
Pursuant to the requirements of the Securities Act of 1933, this Registration Statement and powers of attorney have been signed by the following persons in the capacities indicated on the 5th day of August, 2021.
Signature
Title
/s/     Anne P. Noonan
President and Chief Executive Officer
(Principal Executive Officer);
Anne P. Noonan
Director
/s/     Brian J. Harris
Chief Financial Officer
(Principal Financial and Accounting Officer)
Brian J. Harris
/s/      Joseph S. Cantie
Director
Joseph S. Cantie
/s/      Anne M. Cooney
Director
Anne M. Cooney
/s/      Susan A. Ellerbusch
Director
Susan A. Ellerbusch
/s/     Howard L. Lance
Director
Howard L. Lance
/s/     Tamla Oates-Forney
Director
Tamla Oates-Forney
/s/     John R. Murphy
Director
John R. Murphy
/s/     Anne K. Wade
Director
Anne K. Wade
/s/     Steven H. Wunning
Director
Steven H. Wunning