Disclaimer - investors.siteone.com

1 Fourth Quarter and Full Year 2021 Earnings2 DisclaimerForward-Looking StatementsThis presentation contains forward-looking statements within the meaning of the Federal Private Securities Litigation Reform Act of 1995. Forward-looking statements may include, but are not limited to, statements relating to our 2022 Adjusted EBITDA outlook. Some of the forward-looking statementscan be identified by the use of terms such as may, intend, might, will, should, could, would, expect, believe, estimate, anticipate, predict, project, potential, or the negative of these terms, and similar expressions. You should be aware that these forward-looking statements are subject to risks and uncertainties that are beyond our control. Further, any forward-looking statement speaks only as of the date on which it is made, and we undertake no obligation to update any forward-looking statement to reflect events or circumstances after the date on which it is made or to reflect the occurrence of anticipated or unanticipated events or circumstances.

2 New factors emerge from time totime that may cause our business not to develop as we expect, and it is not possible for us to predict all of them. Factors that may cause actual results to differ materially fromthose expressed or implied by the forward-looking statements include, but are not limited to, the following: the potential negative impact of the COVID-19 pandemic (which, among other things, may exacerbate each of the risk listed below); economic downturn or recession; cyclicality in residential and commercial construction markets; general economic and financial conditions; weather conditions, seasonality and availability of water to end-users; public perceptions that our products and services are not environmentally friendly; competitive industry pressures; product shortages and the loss of key suppliers; product price fluctuations; ability to pass along product cost increases; inventory management risks; ability to implement our business strategies and achieve our growth objectives; acquisition and integration risks; increased operating costs.

3 Risks associated with our large labor force(including work stoppages due to COVID-19); retention of key personnel; construction defect and product liability claims; impairment of goodwill; adverse credit and financial markets events and conditions; credit sale risks; performance of individual branches; environmental, health and safety laws and regulations; hazardous materials and related materials; laws and government regulations applicable to our business that could negatively impact demand for our products; computer data processing systems; cybersecurity incidents (including the July 2020 ransomware attack); security of personal information about our customers; intellectual property and other proprietary rights; the possibility of securities litigation; unanticipated changes in our tax provisions; our substantial indebtedness and our ability to obtain financing in the future; increases in interest rates; risks related to our common stock; terrorism or the threat of terrorism; and other risks, as described in Item 1A, Risk Factors, and elsewhere in our Annual Report on Form 10-K for the fiscal year ended January 3, 2021, as updated by our subsequent filings under the Securities Exchange Act of 1934, as amended, including Forms 10-K and 8-K.

4 Non-GAAP Financial InformationThis release includes certain financial information, not prepared in accordance with GAAP. Because not all companies calculate non-GAAP financial information identically (or at all), the presentations herein may not be comparable to other similarly titled measures used by other companies. Further, these measures should not be considered substitutes for the information contained in the historical financial information of the Company prepared in accordance with GAAP that is set forth present Adjusted EBITDA in order to evaluate the operating performance and efficiency of our business. Adjusted EBITDA represents EBITDA as further adjusted for items permitted under the covenants of our credit facilities. EBITDA represents our Net income (loss) plus the sum of income tax (benefit) expense, interest expense, net of interest income, and depreciation and amortization. Adjusted EBITDA is further adjusted for stock-based compensation expense, (gain) losson sale of assets and termination of finance leases not in the ordinary course of business, other non-cash items, financing fees, other fees, and expenses related to acquisitions and other non-recurring (income) loss.

5 Adjusted EBITDA excludes any earnings or loss of acquisitions prior to their respective acquisition dates for all periods presented. Adjusted EBITDA is not a measure of our liquidity or financial performance under GAAP and should not be considered as an alternative to Net income, operating income or any other performance measures derived in accordance with GAAP, or as an alternative to cash flow from operating activities as a measure of our liquidity. The use of Adjusted EBITDA instead of Net income has limitations as an analytical tool. Because not all companies use identical calculations, our presentation of Adjusted EBITDA may not be comparable to other similarly titled measures of other companies, limiting its usefulness as a comparative measure. Net debt is defined as long-term debt (net of issuance costs and discounts) plus finance leases, net of cash and cash-equivalents on our balance sheet. Leverage Ratio is defined as Net debt to trailing twelve months Adjusted EBITDA.

6 We define Organic Daily Sales as Organic Sales divided by the number of Selling Days in the relevant reporting period. We define Organic Sales as Net sales, including Net sales from newly-opened greenfield branches, but excluding Net sales from acquired branches until they have been under our ownership for at least four full fiscal quarters at the startofthe fiscal year. Selling Days are the number of business days, excluding Saturdays, Sundays and holidays, that SiteOne branches are open during the relevant reporting call agendaIntroductionJohn Guthrie, CFOB usiness UpdateDoug Black, Chairman and CEOF inancial UpdateJohn Guthrie, CFOD evelopment UpdateScott Salmon, EVP Strategy & DevelopmentClosing & OutlookDoug Black, Chairman and CEOQ&A4 Company and industry overview Largestand only national wholesale distributor of landscape supplies $23 billion highly fragmented market(1) More than five times the size of next competitor and only ~15%market share(1) Serving residentialand commerciallandscape professionals Complementary value-added services and product support Approximately 135,000 SKUs Over 590 branches and fourdistribution centers covering states and sixCanadian provinces(2)Balanced end markets (FY21)(1)As ofyear end2021.

7 Source: Management estimates, Company data, independent3rdparty support(2)Branch count as ofQ4 21; fourth distribution center established in Q4 21 Maintenance37%New Construction36%Repair & Upgrade27%Distribution CenterBranch5 SiteOne is poised for continued growth and margin enhancementCurrent strategy Leverage strengths of both large and local company Fully exploit our scale, resources and capabilities Execute local market growth strategies Deliver superior value to our customers and suppliers Close and integrate high value-added acquisitions Entrepreneurial local area teams supported by world-class functional support Drive commercial and operational performance Category management Supply chain Salesforce performance Operational excellence Marketing and DigitalValue creation levers1)Organicgrowth2)Margin expansion3)Acquisition growth6 Lucky Landscape Arizona Stone & Solstice Timberwall Melrose Irrigation Supply Rock & Block Green Brothers Semco Stone Seffner Rock & Gravel1341571762011,6481,8622,1122,3582, 705 Track record of performance and growth McGinnis Farms ( 01) Century RainAid( 01) UGM ( 05) LESCO ( 07) Eljay( 14) Diamond Head ( 14) Stockyard ( 14) BISCO ( 14) Shemin( 15) AMC ( 15) Green Resource ( 15) Tieco( 15) Hydro-Scape Blue Max Bissett Glen Allen Loma Vista East Haven Aspen Valley Stone Forest Angelo's AB Supply Evergreen Partners South Coast Supply Marshall Stone Harmony GardensBuilding the Foundation Pete Rose Atlantic Irrigation Village Nurseries Terrazzo & Stone Landscaper s Choice Auto-Rain All American Stone Landscape Express Kirkwood Stone Center CentralPro C&C Sand and Stone All AroundSource: Company data2015201620172018 Initial Public Offering SalesGross Margin %Adj.

8 EBITDAAdj. EBITDA Margin %Sales $+111%GM % +360 bpsPerformance & GrowthBrand(in Millions)Net SalesAdjusted EBITDA 16- 21 Cutting Edge All Pro Horticulture Landscape Depot Fisher s Depot Stone & Soil Depot Voss Materials Trendset Concrete Design Outdoor Dirt Doctors Daniel Stone2019 Acquisitions2020 Wittkopf Empire Supplies The Garden Dept Big Rock Alliance Stone Modern Builders BURNCO Landscape HedbergSupply Alpine Materials Dirt and Rock Stone Center of 2018 Adj. EBITDA $+209%Adj. EBITDA % +380 bps(in Millions) 16- 21 2019FY , 2021FY 2016FY 2017FY 2018FY 2019FY 2020FY 2021FY 20162607# ofmarkets(1)FullProduct Line OfferingMissingeitherHardscapes or NurseryMissing bothHardscapes and NurseryNo PresenceSignificant room to grow across product linesSource: Management estimates; Census Bureau~75~50~60~55 SiteOne offers all product lines in only ~21% of our target markets (1)Target markets as of Q4 2021 are represented by metropolitan statistical areas ( MSAs ) where either SiteOne currently has a presence or MSAs with a population above ~200k, which cover ~80% of the total population.

9 8 Fiscal Year 2021 highlights Net sales increased 29% to $ billion Organic Daily Sales increased by 22% Gross profit increased 35% to $ billion; gross margin increased 160 basis points to SG&A as a percentage of Net sales decreased by 100 basis points to Net income increased 97% to $ million Adjusted EBITDA increased 60% to $ million Adjusted EBITDA margin increased 230 basis points to Net leverage ratio improved from to Completed 8 acquisitions with approximately $155 million in TTM net sales(1) Launched fourth distribution center near Dallas, Texas Issued 2021 Environmental, Social, and Governance (ESG) Report Source: Company data(1) Trailing twelve months (TTM) revenues in the year acquiredFiscal Year 2021 highlights (compared to Fiscal Year 2020) salesGross profit & marginNet incomeAdjusted EBITDAR eview of Fourth Quarter 2021 financial resultsSummary financialsFinancial highlights($ in millions) 20Q4 21Q4 Net sales increased 19% YoY to $ million Four fewer selling days compared to the prior year period Organic Daily Sales increased by 21% driven by solid demand and elevated cost inflation Acquired sales growth was $ million, contributing 7% to the overall growth rate Gross profit increased 27% to $ million Gross margin increased 220 basis points to Driven by supply chain initiatives, price realization and supplier incentives Net income increased 139% to $ million Driven by higher Net sales and gross margin improvement Adjusted EBITDA increased 41% to $ million Adjusted EBITDA margin increased 120 basis points to 20Q4 21Q4 20Q4 21+19%+27%+139%+41%Source: Company salesGross profit & marginNet incomeAdjusted EBITDAR eview of Fiscal Year 2021 financial resultsSource.

10 Company filingsSummary financialsFinancial highlights (compared to prior year period)($ in millions)2, , , Net sales increased 29% to $ billion Organic Daily Sales increased by 22% Acquired sales growth was $ million, contributing 9% to the overall growth rate Gross profit increased 35% to $ billion Gross margin increased 160 basis points to Reflects supply chain initiatives and price realization Net income increased 97% to $ million Driven by higher Net sales and improved margins Adjusted EBITDA increased 60% to $ million Adjusted EBITDA margin increased 230 basis points to , driven by gross margin and SG&A leverageFY20FY21FY20FY21+97%+60% +35%+29%11 Balance sheet & cash flow highlightsWorking capital$ by operating activities $ expenditures $ the year ended January 2, 2022 Balance sheet & cash flow highlights (compared to prior-year period)($ in millions)1 Net debt is calculated as long-term debt plus finance leases, net of cash and cash equivalents2 Leverage ratio definedasnet debt (including finance leases) to trailing twelve months Adjusted EBITDAS ource.