Exhibit 99.1

Summit Materials, Inc. Reports Third Quarter 2017 Results

-Net Revenue +19.6% Y/Y; Operating Income +28.8% Y/Y; Net Income +76.4% Y/Y

-Generated Y/Y Organic Volume Growth Across Materials Lines of Business

-Completed Four New Acquisitions Since August 2017 For a Combined Purchase Price of $94 million

-Lowering FY17 Adjusted EBITDA Guidance to a Range of $425 million to $435 million due to Hurricanes Harvey & Irma

DENVER, CO. - (October 30, 2017) - Summit Materials, Inc. (NYSE: SUM, “Summit” or the “Company”), a leading vertically integrated construction materials company, today announced results for the third quarter 2017. 

For the three months ended September 30, 2017, the Company reported diluted net income per share of $0.72 on net income of $79.1 million, compared to diluted earnings per share of $0.60 on net income of $44.8 million in the prior year period.  On an adjusted diluted basis, excluding tax-related adjustments, the Company reported adjusted diluted net income per share of $0.73 per share on net income of $82.0 million, compared to adjusted diluted earnings per share of $0.71 on adjusted net income of $73.5 million in the prior year period.  In the third quarter, the Company recorded a significant benefit related to the valuation of its deferred tax assets that was substantially offset by a corresponding Tax Receivable Agreement (“TRA”) expense.  Both of these items are excluded from adjusted net income.  Operating income increased by 28.8% to $113.9 million in the third quarter 2017, versus $88.4 million in the prior year period. 

“We delivered double-digit year-over-year growth in net revenue, operating income and net income during the third quarter, driven by a combination of increased organic sales volumes in our materials businesses, together with contributions from recently completed acquisitions,” stated Tom Hill, CEO of Summit Materials.  “Adjusted EBITDA increased 18.1% year-over-year to $172.7 million, supported by organic growth in our Cement Segment and East Segment.  Organic growth contributed nearly 30% of the year-over-year improvement in third quarter Adjusted EBITDA, as we continue to leverage efficiencies afforded by our vertically integrated, decentralized model.”

“Demand fundamentals remain strong in our core regional markets,” continued Hill.  “Organic sales volumes of cement and aggregates increased 10.0% and 2.6%, respectively, in the third quarter 2017, when compared to the prior year period.  Organic sales volumes of cement in our core northern Mississippi River markets increased significantly on a year-over-year basis in the third quarter, while organic aggregates sales volumes in both the East and West Segments increased versus the prior year period.”

“Our two cement plants located along the Mississippi River corridor are operating at capacity, given continued growth in cement demand throughout the region,” continued Hill. “On a year-to-date basis, cement prices have grown organically by 3.6%, consistent with expectations.  Looking to 2018, we anticipate additional growth in cement prices along the Mississippi River corridor.”

“Organic prices on aggregates declined less than 1% in the third quarter, due mainly to sales mix related factors isolated to the West Segment,” continued Hill.  “Excluding mix, we estimate organic aggregates prices increased nearly 3% in the third quarter, versus the prior year period.”

“We continue to deliver exceptional margin capture in our materials lines of business,” continued Hill.  “During the third quarter, adjusted cash gross profit margin on aggregates increased 130 basis points to a record 73.0% while adjusted cash gross profit margin on cement increased 160 basis points to 50.6%.  Temporary disruptions related to Harvey, a category 4 hurricane, impacted operations in Houston, our single largest ready-mix market by volume, resulting in lower overall margin capture in our products line of business in the third quarter.”

“Since our last update in August 2017, we closed on four additional materials-based acquisitions,” noted Hill.  “Our acquisitions of Georgia Stone/McLanahan provide us with an entry point into the growing Georgia market, while the acquisition of Alan Ritchey Materials provides us an entry point into the Dallas market.  Columbia Silica and Stockman are attractive bolt-on acquisitions that expand our existing footprint in South Carolina and Missouri, respectively.  As before, we remain disciplined acquirors, transacting on quality aggregates reserves with high synergy potential.  For the full-year 2017, we are maintaining our annualized acquired EBITDA target range of $50 million to $70 million.”

“From a regional perspective, we remain bullish on Texas, where we have existing positions in Houston, Midland/Odessa, Austin, North Dallas, together with Utah, Nevada, North/South Carolina, Virginia and Georgia.  Over time, we believe each of these regions stand to benefit from a combination of increased state-level infrastructure investment, stable demand for new single-family homes and the subsequent build-out of low-rise commercial amenities,” noted Hill.

“For the full-year 2017, we expect Adjusted EBITDA to be in a range of $425 million to $435 million, down from the previous range of $440 million to $455 million,” stated Hill.  “In the aftermath of Hurricanes Harvey and Irma, sales volumes in our Texas and southeastern U.S. markets temporarily declined below historical levels in September and, to a lesser degree, in October, the combined impact of which has led us to reduce our full-year Adjusted EBITDA guidance.” 

“We ended the third quarter with significant available liquidity on our balance sheet with which to support a combination of organic and acquisition-related growth,” stated Brian Harris, CFO of Summit Materials.  “As of September 30, 2017, we had $506 million in cash and availability under our revolving credit facility, up from $224 million in the prior year period.” 

“Net leverage was 3.7x exiting the third quarter 2017, versus 4.3x in the prior year period,” continued Harris.  “Looking ahead, we expect net leverage to be at approximately 3.5x by year-end 2017.”

“We are pleased with our year-to-date performance,” continued Hill.  “Although historic volumes of rainfall resulting from the current hurricane season has impacted our full-year outlook, underlying demand conditions remain strong in our private and public end-markets, positioning us for continued profitable growth as we look ahead to 2018.”

Third Quarter 2017 | Financial Performance

Net revenue increased by 19.6% to $574.4 million in the third quarter 2017, versus $480.2 in the prior year period.  The improvement in net revenue was primarily attributable to acquisition-related contributions, increased organic sales volumes of cement, aggregates and asphalt, together with increased organic selling prices on cement, ready-mix concrete and asphalt.  Operating income increased by 28.8% to $113.9 million in the third quarter 2017, when compared to the prior year period.  Adjusted EBITDA increased 18.1% year-over-year to $172.7 million, versus $146.2 million in the prior year period. 

In connection with a normal periodic review of its deferred tax assets, the Company released $513.2 million of the valuation allowance against its deferred tax assets that is largely responsible for a $483.6 million income tax benefit realized in the third quarter 2017. Further, given an increase in the probability that deferred tax assets subject to the TRA would be realized, the Company recorded $489.2 million of TRA expense in the third quarter of 2017. The Company has accrued its full liability related to the TRA, which totaled $548.9 million as of September 30, 2017.  This accrued liability is not classified as debt for the purposes of the Company’s net leverage calculation.

West Segment:  Operating income increased 22.4% to $57.5 million in the third quarter 2017, when compared to the prior year period.  Adjusted EBITDA increased by 20.3% to $76.6 million in the third quarter 2017, when compared to the prior year period.  Adjusted EBITDA margin was 26.1% in the third quarter 2017, versus 27.0% in the prior-year period.  Year-over-year organic improvements in sales volumes of aggregates, ready-mix concrete and asphalt, together with acquisition-related EBITDA contributions, were partially offset by lower organic declines in average selling prices on aggregates.

East Segment:  Operating income increased by 5.2% to $36.9 million in the third quarter 2017, when compared to the prior year period.  Adjusted EBITDA increased by 9.4% to $56.4 million in the third quarter 2017, when compared to the prior year period.  Adjusted EBITDA margin declined to 31.5% in the third quarter 2017, versus 33.3% in the prior year period.  Year-over-year organic improvements in average selling prices on aggregates and ready-mix concrete and asphalt, improved organic sales volumes of aggregates and asphalt, together with acquisition-related EBITDA contributions, were offset by a sales volume decline in ready-mix concrete, due in part to weather-related factors.

Cement Segment:  Operating income increased 7.1% to $35.1 million in the third quarter 2017, when compared to the prior year period.  Adjusted EBITDA increased by 16.4% to $46.9 million in the third quarter 2017, when compared to the prior year period.  Adjusted EBITDA margin increased to 46.3% in the third quarter 2017, versus 45.0% in the prior year period.  A year-over-year increase in average selling prices, organic sales volumes, improved production efficiencies and cost reductions all contributed to improved results.

Third Quarter 2017 | Results by Line of Business

Aggregates Business:   Aggregates net revenues increased by 15.7% to $90.6 million in the third quarter 2017, when compared to the prior year period.  Aggregates adjusted cash gross profit margin increased to 73.0% in the third quarter 2017, versus 71.7% in the prior year period.  Organic aggregates sales volumes increased 2.6% in the third quarter 2017, due mainly to increased demand in north Texas, Utah, Vancouver and additional markets in the southeast.  Organic aggregates average selling prices declined 0.8% in the third quarter, mainly in the West Segment, where hurricane-related weather impacted business conditions.

Cement Business:  Cement segment net revenues increased 13.1% to $101.3 million in the third quarter 2017, when compared to the prior-year period.  Cement adjusted cash gross profit margin was 50.6% in the third quarter 2017, versus 49.0% in the prior-year period.  Organic sales volumes and average selling prices on cement increased 10.0% and 3.2%, respectively, when compared to the prior year period.  Strong regional demand in the Company’s northern markets drove organic volume growth in the third quarter, while continued organic growth in sales prices was attributable to previously announced annual price increase effective January 1, 2017.    

Products Business:  Net revenues increased 23.5% to $280.0 million in the third quarter 2017, when compared to the prior year period.  Products adjusted cash gross profit margin declined to 26.1% in the third quarter 2017, versus 28.4% in the prior year period.  Organic sales volumes of ready-mix concrete declined 3.1%, versus the prior year period, due to Hurricane-related disruptions in the Houston market.  Organic sales volumes of asphalt increased 11.9%, versus the prior year period, given strength in the north Texas, Austin and Utah markets.

Acquisition Program Update

As of October 2017, the Company has completed fourteen acquisitions on a year-to-date basis, including four transactions that have closed since August 2017.  Total investment spend across the fourteen acquisitions completed year-to-date 2017 was approximately $402 million, including approximately $94 million for the four acquisitions completed since August 2017. 

Alan Ritchey Materials (Southern Oklahoma-Northeast Texas).  Alan Ritchey Materials is an aggregates bolt-on acquisition to Summit’s existing business in the northeast Texas market.  This acquisition complements Summit’s existing footprint in the region and provides increased exposure to the fast-growing north Dallas market, Alan Ritchey’s primary shipping destination.  Summit closed on its acquisition of Alan Ritchey in August 2017.

Georgia Stone Products/McLanahan (Northeast Georgia).  Georgia Stone Products is an aggregates bolt-on acquisition comprising two quarries in northeast Georgia.  This transaction represents an expansion westwards into Georgia from Summit’s existing position in the Carolinas.  Summit closed on this acquisition over August/September 2017. 

Columbia Silica (Columbia, South Carolina).  Columbia Silica is an aggregates bolt-on acquisition in central South Carolina.  This acquisition is a strong complementary fit with the recent Glasscock acquisition also in South Carolina (acquired May 2017) and brings additional scale to Summit’s growing footprint in the region.  Summit closed on its acquisition of Columbia Silica in September 2017.

Stockman Quarry (Central Missouri).  Stockman is an aggregates bolt-on acquisition to our existing position in central Missouri.  This transaction brings new market expansion to Summit’s existing Missouri business.  Summit closed on its acquisition of Stockman in October 2017.

Liquidity and Capital Resources

At September 30, 2017, the Company had cash on hand of $287.1 million and borrowing capacity under its revolving credit facility of $218.9 million.  The borrowing capacity on the revolving credit facility is fully available to the Company within the terms and covenant requirements of its credit agreement.  As of September 30, 2017, the Company had $1.8 billion in debt outstanding. 

Financial Guidance and Outlook

Due mainly to the combined effects of Hurricane Harvey, which impacted the Houston market beginning in late August 2017, and Hurricane Irma, which impacted regions of Virginia and South Carolina beginning in early September 2017, the Company is lowering its full-year 2017 Adjusted EBITDA guidance from a range of $440 million to $455 million to a range of $425 million to $435 million.  The downwardly revised Adjusted EBITDA outlook includes the partial-year impact of the four acquisitions completed since August 2017.  No additional potential acquisitions are included within the Company’s full-year 2017 Adjusted EBITDA guidance.

The Company is raising its full-year 2017 capital spending guidance from a range of $140 million to $160 million, to a range of $180 million to $190 million.  The upwardly revised capital spending guidance includes incremental investments related to discretionary organic growth investments, land/reserve acquisitions, together with acquisition-related maintenance expenditures.

Webcast and Conference Call Information

Summit Materials will conduct a conference call today at 11:00 a.m. eastern time (9:00 a.m. mountain time) to review the Company’s third quarter 2017 financial results.  A webcast of the conference call and accompanying presentation materials will be available in the Investors section of Summit’s website at investors.summit-materials.com. To listen to a live broadcast, go to the site at least 15 minutes prior to the scheduled start time in order to register, download, and install any necessary audio software.

To participate in the live teleconference:

To listen to a replay of the teleconference, which will be available through November 30, 2017:

About Summit Materials

Summit Materials is a leading vertically integrated materials-based company that supplies aggregates, cement, ready-mix concrete and asphalt in the United States and British Columbia, Canada. Summit is a geographically diverse, materials-based business of scale that offers customers a single-source provider of construction materials and related downstream products in the public infrastructure, residential and nonresidential, and end markets. Summit has a strong track record of successful acquisitions since its founding and continues to pursue growth opportunities in new and existing markets.  For more information about Summit Materials, please visit www.summit-materials.com.  

Non-GAAP Financial Measures

The Securities and Exchange Commission (“SEC”) regulates the use of “non-GAAP financial measures,” such as Adjusted Net Income, Adjusted EPS, Adjusted EBITDA, Adjusted EBITDA margin, Adjusted Cash Gross Profit, Adjusted Cash Gross Profit Margin, Free Cash Flow and Net Leverage which are derived on the basis of methodologies other than in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”). We have provided these measures because, among other things, we believe that they provide investors with additional information to measure our performance, evaluate our ability to service our debt and evaluate certain flexibility under our restrictive covenants. Our Adjusted Net Income, Adjusted EPS, Adjusted EBITDA, Adjusted EBITDA margin and Adjusted Cash Gross Profit may vary from the use of such terms by others and should not be considered as alternatives to or more important than net income (loss), operating income (loss), revenue or any other performance measures derived in accordance with U.S. GAAP as measures of operating performance or to cash flows as measures of liquidity.

Adjusted EBITDA, Adjusted EBITDA margin and other non-GAAP measures have important limitations as analytical tools, and you should not consider them in isolation or as substitutes for analysis of our results as reported under U.S. GAAP. Some of the limitations of Adjusted EBITDA are that these measures do not reflect: (i) our cash expenditures or future requirements for capital expenditures or contractual commitments; (ii) changes in, or cash requirements for, our working capital needs; (iii) interest expense or cash requirements necessary to service interest and principal payments on our debt; and (iv) income tax payments we are required to make. Because of these limitations, we rely primarily on our U.S. GAAP results and use Adjusted EBITDA, Adjusted EBITDA margin and other non-GAAP measures on a supplemental basis. 

Adjusted EBITDA, Adjusted EBITDA margin, Adjusted Cash Gross Profit, Adjusted Net Income, Adjusted EPS and Free Cash Flow reflect additional ways of viewing aspects of our business that, when viewed with our GAAP results and the accompanying reconciliations to U.S. GAAP financial measures included in the tables attached to this press release, may provide a more complete understanding of factors and trends affecting our business. We strongly encourage investors to review our consolidated financial statements in their entirety and not rely on any single financial measure.  Reconciliations of the non-GAAP measures used in this press release are included in the attached tables.  Because GAAP financial measures on a forward-looking basis are not accessible, and reconciling information is not available without unreasonable effort, we have not provided reconciliations for forward-looking non-GAAP measures. For the same reasons, we are unable to address the probable significance of the unavailable information, which could be material to future results.

Cautionary Statement Regarding Forward-Looking Statements

This report includes “forward-looking statements” within the meaning of the federal securities laws, which involve risks and uncertainties. Forward-looking statements include all statements that do not relate solely to historical or current facts, and you can identify forward-looking statements because they contain words such as “believes,” “expects,” “may,” “will,” “should,” “seeks,” “intends,” “trends,” “plans,” “estimates,” “projects” or “anticipates” or similar expressions that concern our strategy, plans, expectations or intentions. All statements made relating to our estimated and projected earnings, margins, costs, expenditures, cash flows, growth rates and financial results are forward-looking statements. These forward-looking statements are subject to risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from future results, performance or achievements expressed or implied by such forward-looking statements. We derive many of our forward-looking statements from our operating budgets and forecasts, which are based upon many detailed assumptions. While we believe that our assumptions are reasonable, it is very difficult to predict the effect of known factors, and, of course, it is impossible to anticipate all factors that could affect our actual results. In light of the significant uncertainties inherent in the forward-looking statements included herein, the inclusion of such information should not be regarded as a representation by us or any other person that the results or conditions described in such statements or our objectives and plans will be realized. Important factors could affect our results and could cause results to differ materially from those expressed in our forward-looking statements, including but not limited to the factors discussed in the section entitled “Risk Factors” in Summit Inc.’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016 (the “Annual Report”), as filed with the Securities and Exchange Commission (the “SEC”), any factors discussed in the section entitled “Risk Factors” of this report and the following:

All subsequent written and oral forward-looking statements attributable to us, or persons acting on our behalf, are expressly qualified in their entirety by these cautionary statements.

Any forward-looking statement that we make herein speaks only as of the date of this report. We undertake no obligation to publicly update or revise any forward-looking statement as a result of new information, future events or otherwise, except as required by law.

SUMMIT MATERIALS, INC. AND SUBSIDIARIES

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SUMMIT MATERIALS, INC. AND SUBSIDIARIES

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