GMS : March 2024 Investor Overview

Investor Overview

March 2024

Safe Harbor and Basis of Presentation

Forward-LookingStatement Safe Harbor - This presentation includes "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. You can generally identify forward-looking statements by the Company's use of forward-looking terminology such as "anticipate," "believe," "confident," "continue," "could," "estimate," "expect," "intend," "may," "might," "plan," "potential," "predict," "seek," or "should," or the negative thereof or other variations thereon or comparable terminology. In particular, statements about the markets in which GMS operates and our products, including potential or expected growth in those markets and products, the economy generally, our ability to continue successfully navigating the evolving operating environment and executing our business, strategic initiatives and priorities and growth potential, closing of acquisitions and integration of such acquisitions, future M&A and greenfields, inflation, capital structure, pricing (including but not limited to, fluctuations in commodity pricing), volumes, net sales, organic sales, gross margins, net income, incremental EBITDA, Adjusted EBITDA, Adjusted EBITDA margin, interest expense, capital expenditures, free cash flow, tax rates, future financial performance and liquidity, and the ability of the Company to grow stronger contained in this presentation may be considered forward-looking statements. Statements about our expectations, beliefs, plans, strategies, objectives, prospects, assumptions or future events or performance may be considered forward-looking statements. The Company has based forward-looking statements on its current expectations, assumptions, estimates and projections. While the Company believes these expectations, assumptions, estimates and projections are reasonable, such forward- looking statements are only predictions and involve known and unknown risks and uncertainties, many of which are beyond its control. Forward-looking statements involve risks and uncertainties, including, but not limited to, those described in the "Risk Factors" section in the Company's most recent Annual Report on Form 10-K, and in its other periodic reports filed with the SEC. In addition, the statements in this release are made as of March 4, 2024. The Company undertakes no obligation to update any of the forward-looking statements made herein, whether as a result of new information, future events, changes in expectation or otherwise. These forward-looking statements should not be relied upon as representing the

Company's views as of any date subsequent to March 4,2024.

Use of Non-GAAPand Adjusted Financial Information - To supplement GAAP financial information, we use adjusted measures of operating results which are non-GAAP measures. This non-GAAP adjusted financial information is provided as additional information for investors. These adjusted results exclude certain costs, expenses, gains and losses, and we believe their exclusion can enhance an overall understanding of our past financial performance and also our prospects for the future. These adjustments to our GAAP results are made with the intent of providing both management and investors a more complete understanding of our operating performance by excluding non-recurring, infrequent or other non-cash charges that are not believed to be material to the ongoing performance of our business. The presentation of this additional information is not meant to be considered in isolation or as a substitute for GAAP measures of net income, diluted earnings per share or net cash provided by (used in) operating activities prepared in accordance with generally accepted accounting principles in the United States. Please see the Appendix to this presentation for a further discussion on these non-GAAP measures and a reconciliation of these non-GAAP measures to the most directly comparable GAAP measures.

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GMS at a Glance

(LTM Q3 FY24)

53yrs

Founded in

1971

300+

Distribution yards

& 100+

Tool Sales, Rentals & Service Centers

$5.4B

LTM Q3 FY24

Net Sales

60+

Leading Brands

$295M

LTM Q3 FY24

Net Income

7,000+

GMS Team Members

$623M

LTM Q3 FY24 Adj. EBITDA1

GMS

NYSE Ticker

Symbol

1. For a reconciliation of Adjusted EBITDA to the most directly comparable GAAP metrics, see Appendix. LTM Q3 FY24 refers to the 12 months ended January 31, 2024.

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Diversified and Balanced End Market Exposure

Diversified exposure across commercial and residential new and repair and remodel construction markets continues to be an advantage

~45%	~55%
Residential	Commercial
•	Single-Family New	•	New Construction
•	Multi-Family New	•	Repair & Remodel
•	Repair & Remodel

While these percentages fluctuate from time to time as market conditions change, the numbers shown reflect the Company's "through the cycle" expectations.

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Providing Value to Contractors and Builders

GMS provides a complementary and complete product offering with value-added service delivery to the contractors who install wallboard, ceilings, steel framing and ancillary products needed to complete the job

Complementary
Products	Wallboard
30%
41%

LTM

Q3 FY24

Steel

Framing

17%Ceilings

12%

1

A leading North American specialty distributor of construction products

GMS provides the products and value-added services to contractors who install wallboard, ceilings, steel framing and other complementary building products

• Expertise across local markets, leveraging scaled North
  American footprint​
• One-stop-shopfor contractors with a broad product offering​
• Critical link between suppliers and a highly fragmented customer base​

Note: LTM Q3 FY24 refers to the twelve months ended January 31, 2024.	5
1Complementary products consists of Tools & Fasteners, Insulation, Joint Treatment, Lumber, EIFS/Stucco and Other

Local Go-To-Market Strategy with Scale Benefits

GMS distribution locations

USA and Canada

GMS's model provides for the intimacy of a local business, exceptional customized service and an entrepreneurial culture while leveraging North American economy of scale

• Combines the benefits of a local "go-to-market" strategy with economics of scale

• Integrated North American platform operated through over 60 highly-respected local brands

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Strategic Growth Priorities - Q3 FY24 Update

Expand Share in

Core Products

Capitalize on existing fixed investments in locations & equipment where we are underpenetrated or below expected share

• The Gypsum Association, Steel Framing Industry Association and ceilings manufacturers all indicate that GMS continues to gain share

Grow Complementary

Products

Grow Complementary Product

opportunities to diversify and profitably

expand our product offerings

• Q324 was the 15th consecutive quarter of year-over-year growth for our Complementary Products
• Focus areas Tools & Fasteners, EIFS/Stucco and Insulation continue to outperform the broader category

Platform Expansion

Expand the platform through accretive acquisition and greenfield opportunities, balanced with debt reduction priorities

• Opened three greenfield locations
• Announced our agreement to purchase Kamco Supply Corporation during Q3 FY24. This transaction closed on March 1, 2024.
• Solid pipeline of M&A opportunities in both our core and complementary product lines

Drive Improved

Productivity & Profitability

Leverage our scale and employ

technology and best practices to deliver

1. best-in-classcustomer experience with an aim to further profit improvement

• Equipping yard operators with the right tools and technologies continues to improve the efficiency of their operations.
• Consolidation of legacy legal entities is reducing organizational and process complexity, along with costs, while also leveraging the standardization of product, vendor, customer and other operational data across the business

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Continuing to Diversify and Profitably Expand Offerings

Successfully Growing Complementary Products

Net Sales by Product Category

Complementary Products

*

Core Products:

• Wallboard: Used to finish the interior walls and ceilings in residential, commercial and institutional construction projects
• Ceilings: Suspended ceiling systems comprised primarily of acoustical solutions for commercial spaces including mineral fiber tiles and grid as well as architectural specialties such as wood, steel and other unique finishes
• Steel Framing: Steel framing products sold into commercial applications, typically as part of a package with wallboard, ceilings and other products

Up from 20% to 30% of sales

from FY2014 to LTM Q3 FY24

45%					41%
					20%
	NET SALES BREAKDOWN				NET SALES BREAKDOWN
	(FISCAL 2014)							(FISCAL 2023)
	2014 Net Sales:				LTM Q324 Net Sales:	30%
			$1.4B							$5.4B
					17%
16%
19%	12%
			Complementary Products		Ceilings		Steel Framing		Wallboard

LTM Q3 FY24 refers to the 12 months ended January 31, 2024

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Opportunities for Further Platform Expansion

• Opportunity to expand our geographic footprint in under-served and under-penetrated markets through accretive greenfield locations and acquisitions
• Current footprint comprises over 300 distribution yard locations covering 47 U.S. States and 6 Canadian Provinces; Plus more than 100 AMES store locations
• At least some level of presence in 78 of the Top 100 U.S. Metropolitan Statistical Areas
  ("MSA's") and 8 of the Top 10 Canadian Metropolitan Areas ("CMA's")
• Significant whitespace and underpenetrated markets remaining in both the U.S. and Canada
• Opportunities to develop "Complementary Products" in markets where GMS already has an established presence to drive further share gains

Western

Canada

Mountain

West

California

Central

Midwest

South	Gulf
Central	Coast
Texas

Map Legend

GMS Distribution

Location

AMES Location

Targeted Expansion

Area

Eastern

Canada

New

England

South

Florida

As of Jan 2024	9

GMS + Kamco NY

A Highly Strategic Transaction

Expands share in core product categories

Adds notable cross-selling opportunities and broader suite of top- tier product offerings

Creates significant entry into underpenetrated NYC metro area

Represents strong cultural alignment

to GMS' core values

Generates significant revenues (~$235 million for the 12 months ended 12-31-23)

Enhances go-forward customer serviceability and value proposition

On March 1, 2024, GMS successfully completed the acquisition of Kamco Supply Corporation, a leading supplier of ceilings,

wallboard, steel, lumber and other complementary products in the New York City metropolitan area.

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