Exhibit 99.1

Summit Materials Announces First Quarter 2016 Results

Denver, Colorado (May 4, 2016) — Summit Materials, Inc. (NYSE: SUM, “Summit” or the “Company”), a leading vertically integrated construction materials company, today announced results for the first quarter 2016. The Company has posted supplementary materials to its investor relations website.

Highlights – First Quarter 2016 Compared to First Quarter 2015:

Tom Hill, CEO of Summit, stated, “We had a strong start to 2016 with price moving higher in all lines of business. We are especially pleased with our aggregates pricing momentum up 9.4% organically throughout key markets. In cement we more than doubled our volume for the second straight quarter with the continued integration of our Davenport cement plant progressing according to plan. Favorable industry dynamics in the upper Midwest and Mississippi river regions continue to support an attractive outlook for our growth initiatives, with cement price up 6.7% during the quarter. Through our products and services businesses we continue to gain exceptional advantages from our vertically integrated approach driving sustained margin improvement at each stage of the vertical chain. Gross profit increased 44.2% to $51.5 million, representing a gross margin expansion of 440 basis points, led by 85.8% incremental gross margins in aggregates. The overall result from all these favorable developments was a 480 basis point improvement in our Adjusted EBITDA margin during the first quarter. This collective improvement demonstrates the strength of our materials based-strategy, which focuses on securing attractively positioned reserves in well-structured markets, with selective downstream exposure.”

Mr. Hill continued, “Since the beginning of 2016 we have completed three aggregates-based acquisitions consistent with our strategy to source, acquire and integrate businesses. Boxley Materials Company (“Boxley”) and American Materials Company (“AMC”), which were added in the first quarter, provide a strategic path to deepen our Mid-Atlantic presence with a combined materials-focused platform of scale. In April, we entered the growing Las Vegas market with the addition of Sierra Ready Mix, LLC (“Sierra”), which fits nicely into our existing West segment operations. We expect these transactions to be accretive to our 2016 results as we integrate and optimize performance of these assets.

Furthermore, with these three completed acquisitions we have already exceeded our target of $30 million of annualized acquired Adjusted EBITDA.

Beyond acquisitions, our public and private construction markets continue to exhibit positive fundamentals positioning us to capture incremental volume and price improvements while actively managing costs to accomplish our objectives for 2016.”

Brian Harris, CFO of Summit, stated, “We continue to produce stronger margins and focus on cash flow to generate attractive returns from our rapidly expanding operations. Our balance sheet strength and access to capital resources were key factors in our ability to acquire Boxley and AMC and to move swiftly on our acquisition of Sierra. We successfully completed a bond offering in February to fund these acquisitions while maintaining our credit metrics and cost of capital within our targeted levels. We ended the quarter with ample flexibility to continue investing in our announced aggregates facility enhancement initiatives. We are accomplishing this while remaining poised to further execute our strategic growth initiatives in a disciplined manner. However, we remain committed to reducing our leverage ratios by year end while growing Adjusted EBITDA to generate additional cash flow.”

First Quarter 2016 Operating Results

In the first quarter of 2016, net revenue increased 18.8% to $208.0 million, compared to $175.1 million in the prior year quarter. The improvement in net revenue was primarily attributable to an increase in volumes and price in aggregates, cement and ready-mixed concrete. Net revenue growth from acquisitions in the West and East segments was $8.5 million compared to the prior year quarter.

Adjusted EBITDA grew to $8.4 million, compared to ($1.4) million in the prior year quarter, with growth in all operating segments. As a percentage of net revenue, Adjusted EBITDA improved to 4.0%, up 480 basis points from the prior year quarter. Adjusted EBITDA by segment in the first quarter of 2016 compared to the prior year quarter was as follows:

Gross profit increased 44.2% to $51.5 million, compared to $35.7 million in the prior year quarter. As a percentage of net revenue, gross margin improved to 24.8%, compared to 20.4% in the prior year quarter, primarily attributable to improved profitability in materials and products, a higher percentage of revenue from materials and lower energy costs.

Adjusted net loss in the first quarter 2016 was ($42.5) million and Adjusted EPS was ($0.42) per diluted share of Class A common stock. Before adjustments, net loss attributable to Summit Materials, Inc. was ($21.1) million, and EPS was ($0.42) per diluted share of Class A common stock. The shares of Class A common stock are issued by Summit Materials, Inc., and as such the earnings and equity interests of noncontrolling interests, including LP Units, are not included in basic or diluted earnings per share. Summit believes adjusted net income and Adjusted EPS are representative of earnings performance, because these measures exclude the non-operating impact to earnings per share of any potential conversions of LP units to Class A common stock in any given quarter. 

Acquisitions

In February 2016, Summit acquired AMC, an aggregates company, which expanded Summit’s geographic reach into the high-growth coastal North and South Carolina markets. In March 2016, Summit acquired Boxley, a vertically integrated construction materials business in Virginia. Together, Boxley and AMC comprise 11 aggregates locations with 0.5 billion tons of reserves, along with four asphalt plants, four ready-mix concrete plants and one architectural products manufacturing facility. These acquisitions, along with Summit’s existing two aggregates operations in South Carolina, establish a strong aggregates-based position in the Mid-Atlantic region.

In April 2016, Summit acquired Sierra, a vertically integrated aggregates and ready-mixed concrete business located in Las Vegas, Nevada.  Sierra is a well-established aggregates and ready mix concrete supplier in the Las Vegas market with an excellent reputation for quality and service. It operates a sand & gravel pit and two ready-mixed concrete facilities, and has well-balanced exposure across all end-use segments. The acquisition provides Summit with premier, well-located assets in an expanding market.

Liquidity and Capital Resources

In connection with the acquisition of Boxley and AMC, in February 2016, the Company issued $250.0 million aggregate principal amount of 8.500% Senior Notes due 2022, at par. The Company used the proceeds from the offering primarily to fund the acquisition of Boxley and replenish cash used for the acquisition of AMC.

At April 2, 2016, the Company had cash of $92.2 million and total outstanding debt of $1,540.4 million. As of April 2, 2016, the Company’s borrowing capacity was $210.6 million under its $235.0 million revolving credit facility, net of $24.4 million outstanding letters of credit.

Full Year 2016 Outlook

For the full year 2016, based on current market conditions Summit expects to generate Adjusted EBITDA in the range of $350.0 million to $370.0 million, compared to Adjusted EBITDA of $287.5 million in 2015. The Adjusted EBITDA outlook assumes organic improvement, along with the successor period for acquisitions completed through today’s date, including the acquisition of Sierra.

Summit continues to target approximately $30.0 million of annualized Adjusted EBITDA per year from acquisitions. The upwardly revised full year 2016 Adjusted EBITDA outlook range of $350.0 million to $370.0 million excludes the potential upside from any future acquisitions due to the unspecified closing dates of any future acquisitions, the timing of which will impact the magnitude of acquired Adjusted EBITDA realized in 2016.

Webcast and Conference Call Information

Summit will conduct a conference call at 11:00 a.m. Eastern Time (9:00 a.m. Mountain Time) on Wednesday, May 4, 2016 to review first quarter 2016 results, discuss recent events, and conduct a question-and-answer period. A webcast of the conference call and presentation slides to be referred to on the call 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 telephone conference call:

To listen to a replay of the telephone conference call:

About Summit Materials

Summit Materials is a leading vertically integrated materials-based company that supplies aggregates, cement, ready-mixed 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 rules of the SEC regulate the use in filings with the SEC of “non-GAAP financial measures,” such as adjusted net income, Adjusted EPS, Adjusted EBITDA, gross profit and free cash flow, 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, gross profit and free cash flow, may vary from the use of such terms by others and should not be considered as alternatives to 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 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; (iv) income tax payments we are required to make; and (v) any cash requirements for the replacement cost of assets being

depreciated or amortized. Because of these limitations, we rely primarily on our U.S. GAAP results and use Adjusted EBITDA only supplementally.

Adjusted EBITDA, gross profit, adjusted net income, Adjusted EPS and free cash flow reflect an additional way 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. However, non-GAAP financial measures should not be construed as being more important than other comparable U.S. GAAP financial measures and should be considered in conjunction with the U.S. GAAP measures. In addition, non-GAAP financial measures are not standardized; therefore, it may not be possible to compare such financial measures with other companies’ non-GAAP financial measures having the same or similar names. 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 tables attached to this press release, to the extent available without unreasonable effort. 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.

Cautionary Statement Regarding Forward-Looking Statements

This press release contains “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. Any and all statements made relating to the macroeconomic outlook for our markets, potential acquisition activity, our estimated and projected earnings, margins, costs, expenditures, cash flows, sales volumes and financial results are forward-looking statements. These forward-looking statements are subject to risks and uncertainties that may change at any time, and, therefore, our actual results may differ materially from those expected. 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 impact 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 achieved. 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 our Annual Report on Form 10-K for the fiscal year ended January 2, 2016. Such factors may be updated from time to time in our periodic filings with the SEC, which are accessible on the SEC’s website at www.sec.gov.

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 otherwise required by law.

SUMMIT MATERIALS, INC. AND SUBSIDIARIES

Unaudited Consolidated Statements of Operations

($ in thousands, except share and per share amounts)

SUMMIT MATERIALS, INC. AND SUBSIDIARIES

Consolidated Balance Sheets

($ in thousands, except share and per share amounts)

SUMMIT MATERIALS, INC. AND SUBSIDIARIES

Unaudited Consolidated Statements of Cash Flows

($ in thousands)

SUMMIT MATERIALS, INC. AND SUBSIDIARIES

Unaudited Revenue Data by Segment and Line of Business

($ in thousands)

SUMMIT MATERIALS, INC. AND SUBSIDIARIES

Unaudited Volume and Price Statistics

(Units in thousands)

*     The Davenport Assets were immediately integrated with our existing cement operations such that it is impracticable to bifurcate the growth attributable to the Davenport Assets from organic growth. 

SUMMIT MATERIALS, INC. AND SUBSIDIARIES

Unaudited Reconciliations of Gross Revenue to Net Revenue by Line of Business

($ and Units in thousands)

SUMMIT MATERIALS, INC. AND SUBSIDIARIES

Unaudited Reconciliations of Non-GAAP Financial Measures

($ in thousands, except share and per share amounts)

The tables below reconcile our net loss to Adjusted EBITDA and present Adjusted EBITDA by segment for the three months ended April 2, 2016 and March 28, 2015.

The table below reconciles our net loss per share attributable to Summit Materials, Inc. to adjusted loss per share for the three months ended April 2, 2016 and March 28, 2015.

The following table reconciles operating loss to gross profit for the three months ended April 2, 2016 and March 28, 2015.

The following table reconciles net cash used for operating activities to free cash outflow for the three months ended April 2, 2016 and March 28, 2015.