Summit Materials Third Quarter 2020 Earnings Call Presentation...other forms of work stoppage or other union activities. All subsequent written and oral forward-looking statements

1

Legal Disclaimer

Forward-Looking Statements

This presentation 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,” “outlook,” “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 Materials, Inc.’s (“Summit Inc.”) Annual Report on Form 10-K for the fiscal year ended December 28, 2019

and Quarterly Report on Form 10-Q for the quarterly period ended March 28, 2020, each as filed with the SEC, and any factors discussed in the section entitled “Risk Factors” in any of our subsequently filed SEC filings as

filed with the Securities and Exchange Commission (the “SEC”), and the following: the impact of the coronavirus (“COVID-19”) pandemic on our business, or any similar crisis; our dependence on the construction industry and

the strength of the local economies in which we operate; the cyclical nature of our business; risks related to weather and seasonality; risks associated with our capital-intensive business; competition within our local markets;

our ability to execute on our acquisition strategy, successfully integrate acquisitions with our existing operations and retain key employees of acquired businesses; our dependence on securing and permitting aggregate

reserves in strategically located areas; declines in public infrastructure construction and delays or reductions in governmental funding, including the funding by transportation authorities and other state agencies particularly if

such are not augmented by federal funding or if the federal government fails to act on a highway infrastructure bill; our reliance on private investment in infrastructure, which may be adversely affected by periods of economic

stagnation and recession; environmental, health, safety and climate change laws or governmental requirements or policies concerning zoning and land use; costs associated with pending and future litigation; rising prices for

commodities, labor and other production and delivery inputs as a result of inflation or otherwise; conditions in the credit markets; our ability to accurately estimate the overall risks, requirements or costs when we bid on or

negotiate contracts that are ultimately awarded to us; material costs and losses as a result of claims that our products do not meet regulatory requirements or contractual specifications; cancellation of a significant number of

contracts or our disqualification from bidding for new contracts; special hazards related to our operations that may cause personal injury or property damage not covered by insurance; unexpected factors affecting self-

insurance claims and reserve estimates; our substantial current level of indebtedness, including our exposure to variable interest rate risk; our dependence on senior management and other key personnel, and our ability to

retain and attract qualified personnel; supply constraints or significant price fluctuations in the electricity and petroleum-based resources that we use, including diesel and liquid asphalt; climate change and climate change

legislation or other regulations; unexpected operational difficulties; interruptions in our information technology systems and infrastructure, including cybersecurity and data leakage risks; and potential labor disputes, strikes,

other forms of work stoppage or other union activities. 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 presentation. 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.

Non-GAAP Financial Measures

Included in this presentation are certain non-GAAP financial measures, such as Adjusted EBITDA, Adjusted EBITDA Margin, Further Adjusted EBITDA, Adjusted Net Income (Loss), Adjusted Diluted Net Income (Loss),

Adjusted (Diluted) Earnings Per Share, Adjusted Cash Gross Profit, Adjusted Cash Gross Profit Margin, Net Debt, Net Leverage, Free Cash Flow, designed to complement the financial information presented in accordance

with U.S. GAAP because management believes such measures are useful to investors. These non-GAAP financial measures should be considered only as supplemental to, and not superior to, financial measures provided in

accordance with GAAP. Please refer to the appendix of this presentation for a reconciliation of the historical non-GAAP financial measures included in this presentation to the most directly comparable financial measures

prepared in accordance with GAAP.

Reconciliations of the non-GAAP measures used in this presentation are included or described in the tables attached to the appendix. 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.

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Conference Call Agenda

Safe Harbor Disclosure

Karli Anderson, VP Investor Relations

Business Update

Anne Noonan, CEO

Financial Update

Brian Harris, CFO

Management Outlook

Anne Noonan, CEO

Q&A

Cement Segment

Net Revenue of $84.9MM

Adj EBITDA of $35.1MM

❖ June 1, 2020 price increase

❖ Northern markets stable, southern

markets recovering slowly

❖ Green America Recycling downtime

-$4.3MM 3Q Adj EBITDA impact

3

3Q HeadlinesRecord West Segment Results, East Segment and Cement Segment Mixed

West Segment

Record Net Revenue of $351.5MM

Record Adj EBITDA of $95.5MM

❖ Residential drove higher

aggregates and ready mix

❖ Acquisitions of Multisources

(Houston) & Valley Gravel (BC)

East Segment

Net Revenue of $208.9MM

Adj EBITDA of $56.9 MM

❖ Aggregates volume stronger

in Kansas and Virginia;

Missouri at normal run rates,

less public work in Kentucky

Mainland, West Region Continental Cement, Hannibal, MOBoxley, East Region

✓ Residential demand in our markets is strong, particularly in TX, UT, central US

✓ Non-residential activity fueled by windfarms and distribution centers; airport and retail delayed

✓ Public activity resilient in TX, KS, UT, VA; challenging in KY, Carolinas, BC

4

3Q Results & Early 4Q IndicatorsResilient Performance Despite Tough Aggregates Comp to Prior Year

3Q20 Results compared to 3Q19:

Early 4Q indicators:

✓ Net Revenue of $645MM, down 3.1%;

✓ Net Income Attributable to Summit Inc. of $90.7MM, up 63% ($32.9MM unrecog. tax benefit reversal)

✓ Adjusted Diluted Net Income of $63.9MM ($0.55/share), up 10%

✓ Adjusted EBITDA of $177.7 million, down 8%

✓ Cash from Operations of $156.3MM, up 6%

✓ Free Cash Flow of $124.3MM, up 5% on working capital improvements; leverage steady at 3.5x

✓ Net Revenue of $1.56B, up 2.5%

✓ Net Income Attributable to Summit Inc. of $103MM

✓ Adjusted Cash Gross Profit Margin of 34.7%(2,3), up 120bps

✓ Adjusted EBITDA of $354MM, up 4%

✓ Mix-adjusted aggregates pricing is up 2.1%

✓ Ready-mix pricing is up 5.2%

✓ Products Adjusted Cash Gross Profit Margin expanded 240bps to 23.8%

✓ Services Adjusted Cash Gross Profit Margin expanded 510bps to 29.2%

Additional capex for reserve replacement and

5

YTD ResultsYTD 2020 Performance in Line with 2019 Despite Uncertain Economic Conditions

YTD 2020 Results compared to YTD 2019(1):

(1) References to “YTD” in this presentation are to the nine month periods ended September 26, 2020 or September 28, 2019, as app licable, unless the context indicates otherwise.

(2) See reconciliations of Adjusted Cash Gross Profit Margin in the appendix.

(3) Adjusted Cash Gross Profit Margin is defined as Adjusted Cash Gross Profit divided by Net Revenue. In this presentation of the data, Adjusted Cash Gross Profit is calculated by line of

business, less net cost of revenue by line of business

Kilgore, West Region

PublicPrivate

6

% of Total ’19 Revenue(1)

Private vs. Public (%)(1)

Current Public Activity

(October 2020)

Texas Missouri

(1) For the fiscal year 2019.

Current Private Activity

(October 2020)

Residential/Non-Residential

Top 5 States by Revenue – Private/Public End Market StatusStrength and Stability in top 4, Kentucky Improving Slowly

Top 5 State Markets = 64% of Total Company Revenue and 40% of Total Company Public Infrastructure Work in FY ’19

Kansas Utah

23%13% 12% 8%

40%60% 46%54%

32%

68%

Kentucky

70%

30%

22% 10% 7%

25%

75%

TXDOT awarding jobs

and backlog has not

been interrupted. Expect

to receive full Prop 7

allocation in FY21

Houston Single Family

permits +13.9% August

y/y; strong in-migration

market; non res resilient

Res & non res bidding

slower in Permian and

Panhandle

July-Sept tax collections

5.1% higher than

expected (+$108MM);

KDOT has several 2021

projects planned.

Non-res projects are

typically let and

completed in the

same calendar year.

Res activity steady.

Lettings activity is normal;

2nd lowest unemployment

in the US (4.7%)

DOT steady for now,

less flood repair work

than 2019.

Non-res windfarm and

warehouse work

continues. Most non

res let and completed

in same calendar

year; residential

steady

Road fund impacts less severe

than originally estimated, but

department of transportation

still proceeding cautiously and

lettings have not rebounded

Stable res and non res

activity, a small proportion of

KY business

Salt Lake City Single

Family permits +10%

in August y/y; strong

in-migration market;

7

Outlook by End-MarketResidential Resilient, Non-Residential Limited Visibility, Public Budgets Steady

▪ NAHB reports that the supply of single family homes for sale is the lowest in 3 decades(1)

▪ Homebuilder sentiment at all time high and mortgage rates near all-time lows(2)

▪ Buyer traffic and pricing strong in many of our markets

▪ Official unemployment rate of 7.9%(3) ; much better than 11-14% range forecasted earlier this year(4)

▪ We focus on low-rise commercial that follows residential avoiding more volatile high-rise construction

▪ September architectural billings flat relative to June/July but are still significantly lower than a year ago(5)

▪ Windfarms, distribution centers active throughout the Midwest

▪ Several airport expansion projects have been delayed or deferred

▪ Funding sources and tax revenue impacts vary by state but holding up better than expected

▪ Both House and Senate plans would increase federal funding for infrastructure

▪ FAST Act funded through 2021 under continuing resolution

(1) National Association of Home Builders, October 16, 2020.

(2) NAHB/Wells Fargo Housing Market Index, October 19, 2020.

(3) US Bureau of Labor Statistics, October 2, 2020.

(4) Wall Street Journal Economic Survey May 2020 of 75 economists.

(5) AIA Architectural Billings Index September 23, 2020.

Residential

Non-

Residential

Public

8

Aggregates GreenfieldsAn Important Component of our Organic Growth Strategy

Projects

▪ 5 Aggregates Greenfields completed

❖ Utah, Texas (3 projects), Georgia

❖ 5 Aggregates Greenfields under development

❖ Georgia (2), Carolinas(2), Missouri

▪ Estimated future Greenfields spending:

❖ ~$50-60MM in each of 2020 and 2021

▪ ~450 million tons of reservesRecently acquired Aggregates property in Missouri

0

10

20

30

40

50

$0

$50

$100

$150

$200

$250

2014-2018 2019 2020 2021 2022 2023 2024

Greenfields Estimated CapEx(1) and Illustrative Adjusted EBITDA ($MM)

Estimated Incremental Capex Illustrative Incremental Adjusted EBITDA

~$45MM Adjusted

EBITDA per year,

run rate by 2024

Cap

Ex

($M

M)

Adjusted E

BIT

DA

($MM

)

Recently commissioned crushing plant, Georgia, October 2019

(1) Does not include deferred consideration.

9

Financial Update

Brian Harris, CFO

Capital Structure Overview

10

(2)

(2)

(2)

(2)▪ Ended 3Q with enhanced flexibility

❖ Redeemed all of the outstanding $650

million 6.125% notes due 2023 with

proceeds from $700 million of 5.250%

notes due 2029

❖ Ending cash of $289MM, up over

$100MM from a year ago

❖ Leverage ratio 3.5x at quarter end 3Q20

from 4.2x at 3Q19% notes due

❖ $617MM available liquidity 3Q end

Refinanced Nearest Term Maturity in 3Q

11

Cap Ex UpdatePrudent Investments to Maintain Fixed Asset Base, Aggregates Greenfields & Higher Growth Markets

2020 Cap Ex Guidance Range $175-$185MM includes $50-60MM for Greenfields

Greenfields: Deferred ~$10MM to 2021; not expected to change estimated 2024 EBITDA contribution

Maintenance: Deferred ~$20-$35MM of maintenance and discretionary projects

Other considerations: $131.2MM spent net of asset sales YTD; ~$40-$50MM to spend in 4Q

2020 Cap Ex Review Considerations

$US

D M

illio

ns

Original

Low End

of Capex

Guidance

Greenfields - LowGreenfields - High

Reserve

Investment

Equipment for

High Growth

Markets

High End of

New Guidance

$140

$185

12

Net Revenue Bridge

Net Revenue by Reporting Segment – Q3 2019 vs. Q3 2020 ($MM)

$665.8

$645.2

$10.6

$9.4

$0.5

$27.0

$14.1

Q3 2019 West - Organic West - Acquisition East - Organic East - Acquisition Cement - Organic Q3 2020

13

Adjusted EBITDA Bridge

Adjusted EBITDA by Reporting Segment - Q3 2019 vs Q3 2020 Adjusted EBITDA ($MM)

$193.3

$3.0 $4.0

$177.7

$11.3

$2.3

$19.8

$0.1

$7.6

$1.6

Q3 2019 West - Organic West - Acquisition East - Organic East - Acquisition Cement - Organic Corp - Organic Q3 2020

14

Key Performance IndicatorsGAAP Financial Metrics

Net Revenue ($MM) Operating Income ($MM)

Net Income - Summit Inc. ($MM) Basic Earnings Per Share(1)

(1) Diluted share count includes all outstanding Class A common stock and LP Units not held by Summit Inc.

$665.8 $645.2

$1,524.4 $1,562.9

3Q19 3Q20 YTD 3Q19 YTD 3Q20

$130.9

$100.6

$153.6 $159.0

3Q19 3Q20 YTD 3Q19 YTD 3Q20

$55.8

$90.7

$23.4

$102.8

3Q19 3Q20 YTD 3Q19 YTD 3Q20

$0.50

$0.79

3Q19 3Q20

15

Key Performance IndicatorsNon-GAAP Financial Metrics

Adj. Cash Gross Profit ($MM)

& Margin (%)(1,2)

Adj. Diluted Earnings Per Share (1,4)

Adj. EBITDA ($MM)

& Margin (%)(1,3)

(1) See appendix for reconciliation of these non-GAAP metrics to the most comparable GAAP metrics

(2) Adjusted Cash Gross Profit Margin is defined as Adjusted Cash Gross Profit divided by Net Revenue

(3) Adjusted EBITDA Margin is defined as Adjusted EBITDA divided by Net Revenue

(4) Adjusted diluted share count includes all outstanding Class A common stock and LP Units not held by Summit Inc.

Adj. Diluted Net Income ($MM)(1)

$249.1 $240.6

$510.1 $542.5

3Q19 3Q20 YTD 3Q19 YTD 3Q20

$193.3 $177.7

$340.4 $354.4

3Q19 3Q20 YTD 3Q19 YTD 3Q20

$58.2 $63.9

$37.3

$66.6

3Q19 3Q20 YTD 3Q19 YTD 3Q20

29.0%

$0.50

$0.55

3Q19 3Q20

37.4% 37.3%

33.5%34.7%

27.5%

22.3%22.7%

16

Aggregates Average Selling Price

(year-over-year % change)

Organic Cement Sales Volume and Price


Sales Volume, Excluding Acquisitions


Sales Volume, Including Acquisitions


Excluding

AcquisitionsIncluding

Acquisitions

Aggregates Ready-Mix

ConcreteAsphalt Aggregates Ready-Mix

ConcreteAsphalt

YTD 3Q19 YTD 3Q20

Volume Price

Price and Volume Analysis

7.3% 7.9%

0.6%

-0.5%

7.7%

-3.7%

2.0%1.3%

4.5%

0.0%

2.9%1.4%

-7.4%

1.1%

12.6%

-3.1%

2.6%4.5% 4.5%

0.0%

17

Adjusted Cash Gross Margin ScorecardMargins expanding in Aggregates, Products and Services, Holding in Cement

Aggregates Business

Adjusted Cash Gross Profit Margin (%)(1,2)

Cement Segment


Products Business


Services Business


(1) See reconciliations of Adjusted Cash Gross Profit Margin in the appendix

(2) Adjusted Cash Gross Profit Margin is defined as Adjusted Cash Gross Profit divided by Net Revenue. In this presentation of the data, Adjusted Cash Gross Profit is

calculated by line of business, less net cost of revenue by line of business

68.6%64.2%

59.7% 59.7%

3Q19 3Q20 YTD 3Q19 YTD 3Q20

24.4% 25.4%

21.4%23.8%

3Q19 3Q20 YTD 3Q19 YTD 3Q20

26.9%

31.7%

24.1%

29.2%

3Q19 3Q20 YTD 3Q19 YTD 3Q20

46.0% 45.1%

38.7% 36.7%

3Q19 3Q20 YTD 3Q19 YTD 3Q20

18

Management Outlook

Anne Noonan, CEO

19

Migration trends towards rural and exurban US markets

Management OutlookMigration Trends Favor Summit Materials Chosen Geographies & End-Markets

Source: JBREC, 10-16-20 Source: JBREC, 10-16-20

SUM Markets

Residential strength today, and non-residential construction

typically follows residential by 12-24 monthsHouston, TX

Salt Lake City

▪ Summit is well positioned for its next phase of growth and value creation:

✓ Growing markets, strengthening financial position with focus on FCF conversion

✓ Aligning business to maximize Returns on Invested Capital (ROIC)

✓ Conducting a comprehensive, strategic review of the business

✓ Consistent, organic growth; greenfields & markets a foundation for M&A & deleveraging

Summit Operating Location

20

APPENDIX

21

Aggregates Pricing Has Proven to be Resilient Throughout Periods of Demand CyclicalityConsumption and Consumption per Capita Remain Below Long-Term Trendlines and Price has Increased 70 of last 75 Years (1)

EXHIBIT 1Historical Industry Dynamics—Consumption & Price

Cement Outlook Supported by Below Trendline Consumption, High Cost of Entry and Demand Nearing CapacityConsumption and Consumption per Capita Remain Below Long-Term Trendlines(1)

(1) Source: USGS and PCA.

-

2.0

4.0

6.0

8.0

10.0

12.0

-

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

1903

1906

1909

1912

1915

1918

1921

1924

1927

1930

1933

1936

1939

1942

1945

1948

1951

1954

1957

1960

1963

1966

1969

1972

1975

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

2011

2014

2017

Consumption 116 Yr. Consumption Trendline Consumption per Capita 116 Yr. Consumption per Capita Trendline

-

0.10

0.20

0.30

0.40

0.50

0.60

-

25,000

50,000

75,000

100,000

125,000

150,000

1900

1903

1906

1909

1912

1915

1918

1921

1924

1927

1930

1933

1936

1939

1942

1945

1948

1951

1954

1957

1960

1963

1966

1969

1972

1975

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

2011

2014

2017

Consumption 118 Yr. Consumption Trendline Consumption per Capita 118 Yr. per Capita Trendline

22

EXHIBIT 2Residential Housing Inventory

• Mortgage rates are at all-time lows

• Permits, starts and sales remain below historical averages on a national level

• Home ownership remains below the historical average

Fundamentals Are In Place for Extended, Steady Growth Once Economic Conditions Stabilize(1)

Estimated Months of Supply In SUM Metro Markets1

Every SUM market had below-average inventory through September 2020

(1) Source: JBREC, October 26 2020; US National Reflects August 2020, all others reflect September 2020

0

1

2

3

4

5

6

7

Dallas, TX Fort Worth, TX Houston, TX Kansas City, MO-KS

Las Vegas, NV Lexington, KY Minneapolis, MN-WI

Salt Lake City,UT

US National (May2020)

Wilmington, NC

Sep-20 Average

Mon

ths

of in

vent

ory

23

EXHIBIT 3Positive Outlook For Infrastructure Funding

(1) Source: FHWA, ARBTA, Bloomberg.

(2) ARTBA - 2020 Transportation Construction Market Forecast, January 2020

Federal Highway Program Could See a ~5% CAGR, 2017-2022

($B) FAST Act Authorization and Additional Appropriations(1)

U.S. Construction Spending Forecast On Highway, Street, Bridge & Tunnel Related Work

Spending Rebounded in 2019 with Stable Growth Forecasted through 2023(2)

$43.3 $48.3 $49.4 $49.6

$54.4 $55.5

FY '17 Enacted FY'18 Enacted FY '19 FAST Act + AdditionalAppropriations

FY' 20 FAST Act + AdditionalAppropriations

FY '21 Projected (ARTBA) FY '22 Projected(ARTBA)

$89.4 $96.9 $98.9 $94.5 $92.3 $101.7 $106.9 $110.0 $113.3 $115.8

$52.3 $57.4 $61.6 $65.2 $67.5

$69.1 $71.8 $73.8 $75.4 $77.0

2014 2015 2016 2017 2018E 2019F 2020F 2021F 2022F 2023F

Public Highway, Steet, Bridge & Tunnel Private Highway, Street & Bridge

$141.7

$154.3

+8.9%

$160.5

+4.0%

$156.7

-.05%

$159.8

+.1%

$170.8

+6.9%

$178.7

+4.6%

$183.8

+2.9%

$188.7

+2.7%

$192.8

+2.2%

EXHIBIT 4Reconciliation of Operating Income to Adjusted Cash Gross Profit

24

(1) Adjusted Cash Gross Profit Margin defined as Adjusted Cash Gross Profit divided by Net Revenue

September 26, September 28, September 26, September 28,

Reconciliation of Operating Income to Adjusted Cash Gross Profit 2020 2019 2020 2019

($ in thousands)

Operating income $ 100,617 $ 130,881 $ 158,957 $ 153,632

General and administrative expenses 81,499 62,344 218,267 190,915

Depreciation, depletion, amortization and accretion 58,054 55,127 163,760 164,140

Transaction costs 445 751 1,517 1,449

Adjusted Cash Gross Profit (exclusive of items shown separately) $ 240,615 $ 249,103 $ 542,501 $ 510,136

Adjusted Cash Gross Profit Margin (exclusive of items shown separately) (1) 37.3% 37.4% 34.7% 33.5%

Three months ended Nine months ended

25

EXHIBIT 5Reconciliation of Gross Revenue to Net Revenue by LOB

Volumes

Aggregates 16,383 $ 10.89 $ 178,377 $ (41,981) $ 136,396

Cement 733 116.17 85,108 (2,410) 82,698

Materials $ 263,485 $ (44,391) $ 219,094

Ready-mix concrete 1,531 117.12 179,261 (137) 179,124

Asphalt 2,118 60.40 127,919 (406) 127,513

Other Products 107,745 (92,572) 15,173

Products $ 414,925 $ (93,115) $ 321,810

Three months ended September 26, 2020

Gross Revenue Intercompany Net

Elimination/Delivery Revenue Pricing by Product

Volumes

Aggregates 42,476 $ 10.96 $ 465,498 $ (102,952) $ 362,546

Cement 1,686 116.22 195,972 (7,118) 188,854

Materials $ 661,470 $ (110,070) $ 551,400

Ready-mix concrete 4,217 115.97 489,034 (324) 488,710

Asphalt 4,281 59.69 255,535 (634) 254,901

Other Products 275,566 (236,106) 39,460

Products $ 1,020,135 $ (237,064) $ 783,071

Nine months ended September 26, 2020

Gross Revenue Intercompany Net

Elimination/Delivery RevenuePricing by Product

EXHIBIT 6Reconciliation of Net Income to Further Adjusted EBITDA

26

(1) Last twelve month (“LTM”) information corresponding to fiscal years (i.e., the periods ended December 28, 2019, December 29, 2018, and December 30, 2017, and reflects our audited historical results for such fiscal years presented in accordance with U.S. GAAP. Information presented for other LTM periods (i.e., September 26, 2020, June 27, 2020, March 28, 2020, September 28, 2019, June 29, 2019, March 30, 2019, September 29, 2018, June 30, 2018, and March 31, 2018) reflect unaudited trailing four quarter financial information calculated by starting with the results from the most recent audited fiscal year included in such LTM period and then (x) adding quarterly information for subsequent fiscal quarters and (y) subtracting quarterly information for the corresponding prior year period. For example, LTM September 26, 2020 has been calculated by starting with the data from the twelve months ended December 28, 2019 and then adding data for the nine months ended September 26, 2020, followed by subtracting data for the nine months ended September 28, 2019. This presentation is not in accordance with U.S. GAAP. However, we believe this information is useful to investors as we use it to evaluate our financial performance for ongoing planning purposes, including a continuous assessment of our financial performance in comparison to budgets and internal projections. We also use such LTM financial data to test compliance with covenants under our senior secured credit facilities. This presentation has limitations as an analytical tool, and you should not consider it in isolation or as a substitute for analysis of our results as reported under U.S. GAAP. Please see our Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q for the relevant periods for the historical amounts used to calculate the LTM information presented.

(2) EBITDA for certain completed acquisitions, net of dispositions, is pro forma for all acquisitions completed as of the date listed. (3) Further Adjusted EBITDA is calculated using trailing four quarter financial data to test compliance with covenants under our senior secured credit facilities.(4) Adjusted EBITDA Margin defined as Adjusted EBITDA as a percentage of net revenue(5) Net Leverage defined as net debt divided by Further Adjusted EBITDA

($ in millions) September 26, September 28, September 26, September 28, September 26, June 27, March 28, December 28, September 28, June 29, March 30, December 29, September 29, June 30, March 31, December 30,

2020 2019 2020 2019 2020 2020 2020 2019 2019 2019 2019 2018 2018 2018 2018 2017

Net income (loss) 93$ 58$ 105$ 25$ 141$ 107$ 86$ 61$ 6$ 22$ 21$ 36$ 99$ 110$ 125$ 126

Interest expense 25 29 78 88 106 110 114 117 118 118 118 117 115 115 112 109

Income tax (benefit) expense (20) 46 (25) 34 (42) 23 22 17 78 53 48 60 229 (290) (299) (284)

Depreciation, depletion, amortization, and accretion expense 58 55 164 164 216 214 213 217 218 217 214 205 197 192 187 180

Loss on debt financings 4 - 4 15 4 - - 15 15 15 15 - 5 5 5 5

Gain on sale of business - - - - - - - - - (12) (12) (12) (12) - - -

Tax receivable agreement expense - - - - 16 16 16 16 (23) (23) (23) (23) (232) 269 271 271

Acquisition transaction expenses 1 1 2 2 2 3 3 2 2 2 3 4 5 6 8 8

Non-cash compensation 13 5 23 15 28 20 19 20 21 22 23 25 27 26 25 21

Other 4 (1) 3 (3) 4 (2) (2) (4) (1) (2) - (6) (6) (5) (6) -

Adjusted EBITDA 178$ 193$ 354$ 340$ 475$ 491$ 471$ 461$ 434$ 412$ 407$ 406$ 427$ 428$ 428$ 436$

EBITDA for certain completed acquisitions (2) 15 - - - - - 1 2 6 11 22 17

Further Adjusted EBITDA (3) 490$ 491$ 471$ 461$ 434$ 412$ 408$ 408$ 433$ 439$ 450$ 453$

Net Revenue 645$ 666$ 1,563$ 1,524$ 2,069$ 2,090$ 2,067$ 2,031$ 1,969$ 1,929$ 1,925$ 1,909$ 1,905$ 1,854$ 1,783$ 1,752$

Adjusted EBITDA Margin (4) 27.5% 29.0% 22.7% 22.3% 23.0% 23.5% 22.8% 22.7% 22.0% 21.4% 21.2% 21.3% 22.4% 23.1% 24.0% 24.9%

Net Debt 1,732$ 1,717$ 1,774$ 1,667$ 1,820$ 1,938$ 1,940$ 1,828$ 1,845$ 1,866$ 1,760$ 1,551$

Total Net Leverage (5) 3.5x 3.5x 3.8x 3.6x 4.2x 4.7x 4.8x 4.5x 4.3x 4.3x 3.9x 3.4x

Three months ended Nine months ended Last Twelve Months Ended (1)

EXHIBIT 7Non-GAAP Reconciliation of Long-Term Debt to Net Debt

27

Reconciliation of Long-term Debt to Net Debt

($ in millions) Q3'20 Q2'20 Q1'20 Q4'19 Q3'19 Q2'19 Q1'19 Q4'18 Q3'18 Q2'18 Q1'18 Q4'17

Long-term debt, including current portion 1,919$ 1,871$ 1,873$ 1,874$ 1,876$ 1,876$ 1,877$ 1,831$ 1,831$ 1,832$ 1,834$ 1,835$

Acquisition related liabilities 42 42 42 48 71 71 72 77 37 38 60 64

Finance leases and other 60 57 58 56 56 59 56 49 42 46 44 36

Less: Cash and cash equivalents (289) (253) (199) (311) (183) (68) (65) (129) (65) (50) (178) (384)

Net debt 1,732$ 1,717$ 1,774$ 1,667$ 1,820$ 1,938$ 1,940$ 1,828$ 1,845$ 1,866$ 1,760$ 1,551$

EXHIBIT 8Non-GAAP Reconciliation of Net Income (Loss) to Adj. EBITDA

28(1) Adjusted EBITDA Margin is defined as Adjusted EBITDA as a percentage of net revenue

Reconciliation of Net Income (Loss) to Adjusted

EBITDA by Segment

($ in thousands)

Net income (loss) $ 72,871 $ 31,013 $ 27,324 $ (38,439) $ 92,769

Interest expense (income) (1,192) (649) (3,393) 29,857 24,623

Income tax expense (benefit) 937 (193) — (20,357) (19,613)

Depreciation, depletion and amortization 22,973 22,346 11,066 979 57,364

EBITDA $ 95,589 $ 52,517 $ 34,997 $ (27,960) $ 155,143

Accretion 144 457 89 — 690

Loss on debt financings — — — 4,064 4,064

Transaction costs — — — 445 445

Non-cash compensation — — — 13,322 13,322

Other (263) 3,969 — 377 4,083

Adjusted EBITDA $ 95,470 $ 56,943 $ 35,086 $ (9,752) $ 177,747

Adjusted EBITDA Margin (1) 27.2% 27.3% 41.3% 27.5%


East Cement Corporate ConsolidatedWest


EBITDA by Segment

($ in thousands)

Net income (loss) $ 56,829 $ 56,640 $ 34,303 $ (89,535) $ 58,237

Interest expense 411 182 (2,731) 31,055 28,917

Income tax expense 1,144 26 — 44,432 45,602

Depreciation, depletion and amortization 23,171 19,406 10,957 1,041 54,575

EBITDA $ 81,555 $ 76,254 $ 42,529 $ (13,007) $ 187,331

Accretion 136 262 154 — 552

Loss on debt financings — — — — —

Transaction costs 1 — — 750 751


Other 244 309 — (689) (136)

Adjusted EBITDA $ 81,936 $ 76,825 $ 42,683 $ (8,127) $ 193,317



Corporate ConsolidatedWest East Cement

EXHIBIT 9Non-GAAP Reconciliation of Net Income (Loss) to Adj. EBITDA by Segment

29(1) Adjusted EBITDA Margin is defined as Adjusted EBITDA as a percentage of net revenue


EBITDA by Segment

($ in thousands)

Net income (loss) $ 130,409 $ 52,152 $ 44,432 $ (122,063) $ 104,930

Interest expense (income) (2,479) (1,651) (9,685) 91,864 78,049

Income tax expense (benefit) 1,524 (358) — (26,499) (25,333)


EBITDA $ 196,161 $ 114,223 $ 62,912 $ (53,738) $ 319,558

Accretion 375 1,213 260 — 1,848


Transaction costs — — — 1,517 1,517


Other 345 4,464 — (522) 4,287

Adjusted EBITDA $ 196,881 $ 119,900 $ 63,172 $ (25,560) $ 354,393



West East Cement Corporate Consolidated


EBITDA by Segment

($ in thousands)

Net income (loss) $ 78,016 $ 73,448 $ 51,652 $ (178,390) $ 24,726

Interest expense (income) 1,905 2,237 (7,395) 91,676 88,423

Income tax expense 1,478 144 — 32,650 34,272


EBITDA $ 151,150 $ 134,680 $ 75,087 $ (51,079) $ 309,838

Accretion 405 868 450 — 1,723


Transaction costs 12 — — 1,437 1,449


Other (513) (1,069) — (1,046) (2,628)

Adjusted EBITDA $ 151,054 $ 134,479 $ 75,537 $ (20,699) $ 340,371



West East Cement Corporate Consolidated

EXHIBIT 10Non-GAAP Reconciliation of Net Income to Adj. Diluted Net Income

30

(In thousands, except share and per share amounts)

Net income attributable to Summit Materials, Inc. $ 90,730 $ 0.77 $ 55,757 $ 0.48 $ 102,815 $ 0.88 $ 23,395 $ 0.20

Adjustments:

Net income attributable to noncontrolling interest 2,039 0.02 2,480 0.02 2,115 0.02 1,331 0.01

Adjustment to acquisition deferred liability — — — — — — (2,000) (0.02)

Loss on debt financings 4,064 0.04 — — 4,064 0.03 14,565 0.13

Adjusted diluted net income before tax related adjustments 96,833 0.83 58,237 0.50 108,994 0.93 37,291 0.32

Changes in unrecognized tax benefits (32,885) (0.28) — — (42,422) (0.36) — —

Adjusted diluted net income $ 63,948 $ 0.55 $ 58,237 $ 0.50 $ 66,572 $ 0.57 $ 37,291 $ 0.32

Weighted-average shares:

Basic Class A common stock 114,116,564 112,179,137 113,943,292 112,020,275

LP Units outstanding 3,053,115 3,368,058 3,086,820 3,404,231

Total equity units 117,169,679 115,547,195 117,030,112 115,424,506

Three months ended Nine months endedReconciliation of Net Income Per Share to

Adjusted Diluted EPS September 28, 2019 September 26, 2020 September 28, 2019September 26, 2020

Per Equity Unit Net Income Per Equity UnitNet Income Per Equity Unit Net Income Per Equity Unit Net Income

EXHIBIT 11Non-GAAP Reconciliation of Adj. Cash Gross Profit by LOB

31

(1) Net revenue for the cement line of business excludes revenue associated with hazardous and non-hazardous waste, which is processed into fuel and used in the cement plants and is included in services net revenue. Additionally, net revenue from cement swaps and other cement-related products are included in products net revenue.

(2) Adjusted cash gross profit calculated as net revenue by line of business less net cost of revenue by line of business. Adjusted cash gross profit margin is defined as adjusted cash gross profit divided by net revenue.(3) The cement adjusted cash gross profit includes the earnings from the waste processing operations, cement swaps and other products. Cement line of business adjusted cash gross profit margin defined as cement adjusted

cash gross profit divided by cement segment net revenue.

($ in thousands)

Segment Net Revenue:

West $ 351,510 $ 331,501 $ 835,026 $ 773,036

East 208,862 235,355 529,405 530,508

Cement 84,874 98,991 198,461 220,844

Net Revenue $ 645,246 $ 665,847 $ 1,562,892 $ 1,524,388

Line of Business - Net Revenue:

Materials

Aggregates $ 136,396 $ 137,528 $ 362,546 $ 354,050

Cement (1) 82,698 92,482 188,854 202,780

Products 321,810 324,711 783,071 737,169

Total Materials and Products 540,904 554,721 1,334,471 1,293,999

Serv ices 104,342 111,126 228,421 230,389

Net Revenue $ 645,246 $ 665,847 $ 1,562,892 $ 1,524,388

Line of Business - Net Cost of Revenue:

Materials

Aggregates $ 48,829 $ 43,156 $ 146,015 $ 142,698

Cement 44,445 46,960 115,987 117,423

Products 240,084 245,396 596,672 579,286

Total Materials and Products 333,358 335,512 858,674 839,407

Serv ices 71,273 81,232 161,717 174,845

Net Cost of Revenue $ 404,631 $ 416,744 $ 1,020,391 $ 1,014,252

Line of Business - Adjusted Cash Gross Profit (2):

Materials

Aggregates $ 87,567 $ 94,372 $ 216,531 $ 211,352

Cement (3) 38,253 45,522 72,867 85,357

Products 81,726 79,315 186,399 157,883

Serv ices 33,069 29,894 66,704 55,544

Adjusted Cash Gross Profit $ 240,615 $ 249,103 $ 542,501 $ 510,136

Adjusted Cash Gross Profit Margin (2)

Materials

Aggregates 64.2% 68.6% 59.7% 59.7%

Cement (3) 45.1% 46.0% 36.7% 38.7%

Products 25.4% 24.4% 23.8% 21.4%

Serv ices 31.7% 26.9% 29.2% 24.1%

Total Adjusted Cash Gross Profit Margin 37.3% 37.4% 34.7% 33.5%

September 28,

Nine months ended

2020 2019

September 26,

Three months ended

September 26, September 28,

2020 2019

EXHIBIT 12Free Cash Flow

32

($ in thousands)

Net income $ 92,769 $ 58,237 $ 104,930 $ 24,726

Non-cash items 47,613 100,538 157,626 208,368

Net income adjusted for non-cash items 140,382 158,775 262,556 233,094

Change in working capital accounts 15,956 (10,880) (44,517) (69,251)

Net cash provided by operating activities 156,338 147,895 218,039 163,843

Capital expenditures, net of asset sales (32,041) (29,163) (131,158) (126,727)

Free cash flow $ 124,297 $ 118,732 $ 86,881 $ 37,116

Nine months endedThree months ended


2020 2019 2020 2019


33

EXHIBIT 13Capital Structure

Documents

Summit Materials Third Quarter 2020 Earnings Call Presentation...other forms of work stoppage or other union activities. All subsequent written and oral forward-looking statements