March 2020

Investor Overview

2

Safe Harbor and Basis of Presentation

Forward-Looking Statement 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,” “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 the economy generally, statements about strategic growth priorities, and statements

about growth potential across the Company’s business and the ability to deliver growth and value creation and cash generation contained in this presentation are forward-

looking statements. The Company has based these 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, economic,

competitive, governmental and technological factors outside of the Company’s control, that may cause its business, strategy or actual results to differ materially from the

forward-looking statements. These risks and uncertainties may include, among other things: changes in the prices, supply, and/or demand for products which GMS

distributes; general economic and business conditions in the United States and Canada; the activities of competitors; changes in significant operating expenses; changes

in the availability of capital and interest rates; adverse weather patterns or conditions; cybersecurity breaches and other disruptions to our IT systems; our recently

announced executive management transitions; variations in the performance of the financial markets, including the credit markets; the risk that acquisitions will not be

integrated successfully; the risk of customer attrition; our ability to efficiently manage and control our costs; and other factors 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. 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.

Use of Non-GAAP and 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.

3

GMS at a Glance

• Leading North American specialty distributor

of interior construction products:

- Wallboard, Ceilings, Steel Framing and Other Products

• More than 250 branches across US & Canada

• One-stop-shop for the interior contractor with broad product

offering

• Critical link between suppliers and a highly fragmented

customer base

• North American scale combined with local expertise

• Diversified and balanced end-market exposure

• Over 5,800 employees embracing strong entrepreneurial

culture

• Multiple levers to drive growth

• NYSE: GMS (IPO in 2016)

• Market Cap: $1.2 billion

• Enterprise Value: $2.2 billion

• Founded in 1971

• Headquartered in Atlanta, GA

$1,570

$1,858

$2,319$2,511

$3,116

6.7%

7.4%

8.1% 7.9%

9.5%

FY-15 FY-16 FY-17 FY-18 FY-19

Net Sales Adj. EBTIDA Margin*

$ millions

* Adj. EBITDA Margin is a non-GAAP financial measure. For a reconciliation of Adj. EBITDA to Net Income (loss), the most directly comparable GAAP

measure, see Appendix.

4

A One-Stop-Shop for the Interior Contractor

GMS provides a complementary

and complete product offering

with value-added service delivery

to the interior contractor who

installs wallboard, ceilings, steel

framing and ancillary products

needed to complete the job.

Other28%

Ceilings 15%

Steel Framing 16%

Wallboard 41%

Net Sales Breakdown (FY2019)

5

Product Offering

• Used to finish the interior walls and ceilings in residential, commercial and institutional construction projects

• Exterior wallboard

Wallboard Ceilings Steel Framing Other Products

• Suspended ceiling systems primarily comprised of mineral fiber, ceiling tile and grid

• Architectural specialty ceilings systems

• Steel framing products for interior walls

• Sold into commercial applications, typically as part of a package with wallboard, ceilings and other products

• Primarily consists of complementary interior construction products, including joint compound, tools and fasteners, safety products and EIFS (exterior insulation and finishing system)

• Various types of wallboard including: 1/2” standard (residential), 5/8” fire rated (commercial), foil backed, lead lined, moisture resistant, mold resistant and vinyl covered

• Acoustical ceiling tiles (standard and architectural specialty)

• Clips and hangers

• Covered fiberglass

• Ceiling tile grid

• Drywall steel

• Flat stock

• Plastering steel

• Structural framing

• Studs and track

• Adhesives

• EIFS

• Insulation

• Joint compound and plaster

• Safety equipment

• Tools

• Fasteners

Description

Products

Core Offering Complementary

6

GMS Serves as a Critical Link Between Suppliers and a

Highly Fragmented Customer Base

Wallboard

Ceilings

Residential / commercial

contractors

• Mostly independent operators

• Highly diversified; values support

and relationship with distributors

Large National Home Builders

Commercial contractors

• Value extensive product expertise

and complete product offering

Key Manufacturers Specialty Distributor Customers

• Specialty distributors lead the wallboard and ceiling distribution channels

- Neither big boxes nor lumberyards want to make the investment in required capital-intensive specialized equipment, which limits

their addressable market

- Ceilings manufacturers rely on the technical expertise of specialty distributors’ salesforces

• Suppliers have limited desire to serve customers directly, which puts distributors in a very strong position in the value chain

7

North American Platform With Local Presence

• GMS combines the benefits of North American scale with a local “go-to-market” strategy

• GMS has an integrated North American platform, but operates through over 50 local brands that are highly regarded in their markets

• GMS’s model provides for significant economies of scale, while maintaining the high service levels, entrepreneurial culture, andthe customer intimacy of a local business

8

Differentiated Service Model Drives Market Leadership

Breadth of Product Line Differentiates GMS from Smaller

Competitors

• Ensures product availability

• Access to latest product innovations; significant customer for its top suppliers

• Leading ceilings lines with exclusivity in certain markets

Professional Salesforce Helps Customers Succeed in the Market Place

• Deep technical expertise and knowledge of local markets

• Key intermediary for suppliers in reaching the end customer

• Provides business development, bid support, expertise and sourcing

Differentiated

Service Model

Logistics Execution is Critical GivenWeight and Delivery Requirements

• Reputation for best-in-class delivery execution

• Strong processes, sequenced loading, coordinated delivery and leading technology and equipment

• Customized delivery plan and unique degree of quality control

• Network of Regional Safety Managers

• Strict and consistent safety procedures

• Safety protocol critical to larger commercial contractor customers

Superior Safety Track Record isHighly Valued by Customers

GMS believes it sets the industry standard in product availability, customer support, delivery execution and safety; this

differentiated service model has driven attractive gross profit margins and is a competitive advantage vs. smaller

competitors

9

Diversified and Balanced End Market Exposure

Residential ~45%

Commercial ~55%

Net Sales Breakdown (FY2019) • GMS’s business is diversified across the spectrum of construction end markets:

• Residential

• Single-Family New

• Multi-Family New

• Repair & Remodel

• Commercial

• New Construction

• Repair & Remodel

10

Entrepreneurial Culture and Vision, Mission & Values Drive Execution

GMS’ unique culture combines a results-driven environment with a

highly entrepreneurial, self starter attitude, guided by a strong Vision,

Mission & Core Values.

VISION

We will be the premier distributor in every market we serve through embracing

our unique culture and professional humility.

MISSION

We create opportunities, build significant relationships and deliver solutions.

CORE VALUES

AT GMS –

• Our people have the independence and authority to make a difference.

• We invest in relationships and every person is important.

• Our highest priority is serving others.

• We passionately pursue a safe work environment along with a relentless focus

on operational excellence.

• We believe you can never go wrong doing the right thing.

11

Proven Track Record of Growth

$87$106

$138

$188

$199

$296

6.4% 6.7%7.4%

8.1% 7.9%

9.5%

0%

5%

10%

15%

20%

$0

$40

$80

$120

$160

$200

$240

$280

FY-14 FY-15 FY-16 FY-17 FY 18 FY 19

Adj. EBITDA % Margin

$1,353$1,570

$1,858

$2,319$2,511

$3,116

16.4% 16.0%18.3%

24.8%

8.3%

24.1%

0%

10%

20%

30%

40%

50%

$0

$500

$1,000

$1,500

$2,000

$2,500

$3,000

$3,500

FY-14 FY-15 FY-16 FY-17 FY-18 FY-19

Revenue % Growth vs. Prior Yr

Net Sales ($ mm) Growth (% )

FY Net Sales

Adj. EBITDA ($ mm) Adj. EBITDA Margin (%)

FY Adjusted EBITDA *

* Adj. EBITDA is a non-GAAP financial measure. For a reconciliation of Adj. EBITDA to Net Income (loss), the most directly comparable GAAP

measure, see Appendix.

Significant growth achieved over the past 5 years through a combination of acquisitions,

greenfield openings and market share gains, coupled with margin expansion through

synergy realization and increased operational effectiveness and efficiencies

12

$34 $40$57

$68

$140

$35

32.1%29.0% 30.3%

34.2% 47.3%

0%

10%

20%

30%

40%

50%

60%

70%

$0

$40

$80

$120

$160

$200

FY-15 FY-16 FY-17 FY 18 FY 19

Free Cash Flow FCF as % of AEBITDA

Free Cash Flow ($ mm) FCF as % of Adj. EBITDA* (%)

Free Cash Flow*

Strong Free Cash Flow* Generation

* Free Cash Flow and Adj. EBITDA are non-GAAP financial measures. For a reconciliation of Free Cash Flow to Cash from Operating Activity and Adj.

EBITDA to Net Income (loss), the most directly comparable GAAP measures, see Appendix.

• Target Free Cash Flow* as % of Adj. EBITDA* is 40 – 45% in FY 2020 (FY 2019 included ~$35 million increase in

accounts payable not expected to recur)

• Priorities for Free Cash Flow* include debt repayment and selective acquisitions

Non-Recurring

13

Multiple Levers to Drive Growth

(5)

• Well Diversified End Markets with

Significant Room for Continued

Expansion

Market

Growth

• Operating leverage

• Operational excellence

Margin

Expansion

Organic

Growth

Strategic

Acquisitions

• Strategic Acquisition Opportunities in

Highly Fragmented Market

• Expanding in New and Existing Markets

to Enhance Strategic Capabilities

• Market Share Gains

• Greenfield Branch Openings

• Capitalize on “Other Products”

Growth Opportunities

* Adj. EBITDA is a non-GAAP financial measure. For a reconciliation of Adj. EBITDA to Net Income (loss), the most directly comparable GAAP

measure, see Appendix.

5 Year CAGR through FY 2019:

Net Sales - 18.2%

Adj. EBITDA* - 27.7%

South Central

Texas

Central Midwest

Gulf Coast

14

GMS has a significant opportunity to expand its geographic footprint in under-served and under-penetrated markets

through accretive greenfields and acquisitions

• Current footprint

comprises 259

locations covering 43

U.S. States and 5

Canadian Provinces

• At least some level of

market presence in

69 of the Top 100

U.S. Metropolitan

Statistical Areas

(“MSA’s”) and 13 of

the Top 25 Canadian

Metropolitan Areas

(“CMA’s)

• Significant

whitespace and

underpenetrated

markets remaining

in both the U.S. and

Canada

• Opportunities to

develop “Other

Products” in

markets where GMS

already has an

established

presence to drive

further share gains

Opportunity to Further Expand

Map Legend

- GMS Location as of Dec-19

- Targeted Expansion Area

15

Expansion Strategy

GMS continues to focus on expansion of the platform via accretive acquisitions and greenfields

Acquisition & Greenfield Strategy Case Study: New England Gypsum Supply

Evaluating Targeted Markets

◼ Focus on large metro areas where GMS has limited and/or

underpenetrated footprint

◼ Leverage GMS platform to extend operations into large suburban

areas with proximity to metro hubs

◼ Evaluate opportunities to gain further scale and market penetration in

areas where GMS already has an established presence

Acquisition Strategy:

◼ Dedicated M&A team

◼ Leading capabilities in targeted markets

◼ Fit GMS culture and platform

◼ Attractive purchase price multiples with realization of scale benefits

and identified cost synergies

Greenfield Strategy:

◼ Organic expansion in targeted markets with favorable dynamics for

further GMS presence and high strategic value

◼ Emphasis on incremental revenue generation; ability to leverage

existing cost base for profitable expansion

◼ Have been able to expand market coverage of New England through

a combination of both acquisition and greenfield activity

◼ Original acquisition of Robert N. Karpp company in Feb-16

established initial GMS position in New England with a significant

presence in the Boston metro area

◼ Subsequent greenfields aid in penetration of the metro area as well as

expansion of the platform to additional surrounding markets

leveraging scale of the platform in Boston

Feb-16: Original Acquisition Robert N. Karpp Company

1

Jun-17: Greenfield Expansion in Wilmington, MA

2

Feb-18: Greenfield Expansion in Hartford, CT

3

May-19: Greenfield Expansion in Portland, ME

4

July-19: Greenfield Expansion in Manchester, NH

5

16

Track Record of Successful Expansion

GMS has a long history of successful platform expansion including the completion of over 60+ acquisitions and

greenfields since May 1, 2014

◼ Since May 1, 2014,

GMS has acquired 31

companies

representing a total of

96 locations

◼ Opened additional

30+ organic

greenfield locations

over the same period,

complementing

acquisition strategy

◼ All U.S. locations

fully-integrated into

GMS platform;

dedicated integration

supporting platform

expansion

◼ Continue to evaluate

strong pipeline of

strategic acquisition

and greenfield

opportunities

Select Recent GMS Expansion

Date

Expansion

Type Acquisition/Greenfield Locations Strategic Rationale

Nov-19 Acquisition ▪ Kingston, ON

▪ Expands Titan’s footprint further into the Eastern Ontario market with a

strategic location in Kingston, ON, where Titan does not currently have

a facility within 85 km

▪ Joins existing Watson Building Supplies platform (6 locations in

Southern Ontario)

Nov-19 Greenfield Cambridge, ON ▪ Cambridge, ON

▪ Additional market density in Cambridge / Kitchener / Guelph, ON metro

area

▪ Highly complementary footprint relative to existing platform, adds much

needed market coverage in Cambridge / Kitchener / Guelph where

majority of business was serviced via Burlington, ON located ~50KM to

southwest

Apr-19 Greenfield Wilsonville, OR ▪ Wilsonville, OR

▪ Additional market density in Portland-Vancouver-Hillsboro, OR-WA

metro area

▪ Highly complementary footprint relative to existing platform, adds much

needed market coverage in southern Portland

Jun-19 Acquisition▪ San Antonio, TX (2)

▪ La Feria, TX

▪ Consolidates position in San Antonio and the Rio Grande Valley; adds

location serving Brownsville & McAllen metro areas

▪ Armstrong ceilings line in all three locations

▪ Joins existing Lone Star Materials platform (3 locations in South Texas)

Mar-19 Greenfield Carrollton, TX ▪ Carrollton, TX

▪ Additional market density in Dallas/Fort-Worth metro area

▪ Highly complementary footprint relative to existing platform, adds much

needed market coverage in northern Dallas

Mar-19 Acquisition▪ LaPlace, LA

▪ Baton Rouge, LA

▪ Expands Gulf Coast presence with first locations in New Orleans and

Baton Rouge markets

▪ Joins established Capitol Materials, Inc. platform (19 locations in

Georgia, Alabama and Florida Panhandle)

17

US Non-Residential Spending ($MM)US Housing Starts

CAN Non-Residential Spending ($MM)Canada Housing Starts

~15% of

GMS

Sales

~85% of

GMS

Sales

Source: U.S. Census Bureau, Bloomberg and CIBC World Markets Inc. US Housing starts 2019E and 2020E estimates are taken from

average projections of Fannie Mae, Fannie Mac, Mortgage Bankers Association and NAHB.

Construction End Markets Outlook

18

Operating Leverage Opportunity

◼ North American scale, local market leadership, differentiated operating platform and value-added services drive

industry-leading margins

◼ Positioned to benefit from operating leverage and operational excellence initiatives

◼ Some near-term headwinds from lower selling prices and inflationary cost pressures

◼ Making additional investments in business initiatives to drive growth and productivity

$2,511

$2,647

$2,833

$2,972

$3,116

$3,185$3,213

$3,251

24.8%

24.3%

23.5%

23.1%23.0% 23.0%

23.2%

23.5%

22%

23%

23%

24%

24%

25%

25%

$2,000

$2,200

$2,400

$2,600

$2,800

$3,000

$3,200

$3,400

LTM Q4 18 LTM Q1 19 LTM Q2 19 LTM Q3 19 LTM Q4 19 LTM Q1 20 LTM Q2 20 LTM Q3 20

Revenue Adjusted SG&A*

* Adjusted SG&A is a non-GAAP financial measure. For a reconciliation of Adjusted SG&A to SG&A, the most directly comparable GAAP measure,

see Appendix

$ MM

19

Attractive Capital Structure

Net Debt / LTM PF Adjusted EBITDA*

4.3x

2.9x 2.8x

4.2x

3.8x 3.8x3.6x 3.7x

3.5x3.3x

3.0x

2016 2017 2018 Q1 19 Q2 19 Q3 19 Q4 19 Q1 20 Q2 20 Q3 20 Near-TermObjective

$11$48 $45 $39 $30

$908

2020 2021 2022 2023 2024 Thereafter

Debt** Maturity Schedule as of Q3 2020

($ mm)

*See appendix for a reconciliation of LTM PF Adjusted EBITDA **Debt includes First Lien Term Loan, ABL Facility, Capital Leases & Installment Notes

• Substantial liquidity, with $41 million of cash on hand and an additional $425 million available under

our ABL Facilities as of 1/31/2020

• First Lien Term Loan (~85% of total long term debt) does not mature until 2025

• Moody’s and Standard & Poors current ratings of B1 and BB- respectively

20

Expand Share in Core

Products

Grow Other Products

Platform Expansion

Capitalize on existing fixed investment in

locations and equipment where we’re

underpenetrated or below expected share

Grow select “Other Product” opportunities

outside of core products to diversify and

profitably expand our product offering

Expand the platform through accretive

acquisition and greenfield opportunities,

balanced with debt reduction priorities

Strategic Growth Priorities

ProfitabilityLeverage our scale and employ

technology and best practices to deliver

further margin expansion

21

Investment Rationale

• A North American market leader in specialty distribution of interior construction products

• Significant scale combined with local expertise

• Differentiated service model drives market leadership

• Multiple levers to drive above-market growth

• Capitalizing on large, diverse end markets poised for continued long-term growth

• Entrepreneurial culture with dedicated employees and experienced leadership driving

superior execution

• Proven track record of growth and cash generation

• Attractive capital structure and balanced approach to capital allocation

Appendix

23

Net Income (Loss) to Adjusted EBITDA

( $ in 000s) 2019 2018 2017 2016 2015 2014

(Unaudited)

Net Income (loss) 56,002$ 62,971$ 48,886$ $ 12,564 $ (11,697) $ (219,814)

Add: Interest Expense 73,677 31,395 29,360 37,418 36,396 7,180

Add: Write off of debt discount and deferred financing fees - 74 7,103 - - -

Less: Interest Income (66) (177) (152) (928) (1,010) (922)

Add: Income Tax Expense 14,039 20,883 22,654 12,584 (6,626) (240)

Add: Change in fair value of mandatorily redeemable shares - - - - - 200,004

Add: Depreciation Expense 46,456 24,075 25,565 26,667 32,208 16,042

Add: Amortization Expense 71,003 41,455 43,675 37,548 31,957 2,556

EBITDA 261,111$ 180,676$ 177,091$ $ 125,853 $ 81,228 $ 4,806

Adjustments

Executive Compensation (A) - - - - - 2,447

Stock appreciation rights expense (B) 2,730 2,318 148 1,988 2,268 1,368

Redeemable noncontrolling interests (C) 1,188 1,868 3,536 880 1,859 3,028

Equity-based compensation (D) 3,906 1,695 2,534 2,699 6,455 28

AEA transaction related costs (E) - - - - 837 67,964

Severance and other permitted costs (F) 8,152 581 (157) 379 413 -

Transaction costs (acquisition and other) (G) 7,858 3,370 2,249 3,751 1,891 -

Gain on disposal of assets (525) (509) (338) (645) 1,089 (864)

AEA management fee (H) - - 188 2,250 2,250 188

Effects of fair value adjustments to inventory (I) 4,176 324 946 1,009 5,012 8,289

Change in fair value of financial instruments (J) 6,395 6,125 382 - - (192)

Secondary public offerings (K) - 1,525 1,385 19 2,494 -

Debt transaction costs (L) 678 1,285 265 - - -

Total Add-Backs 34,558$ 18,582$ 11,138$ 12,330$ 24,568$ 82,256$

Adjusted EBITDA 295,669$ 199,258$ 188,229$ 138,183$ 105,796$ 87,062$

LTM Sales 3,116,033 2,511,469 2,319,046 1,858,177 1,570,085 1,353,340

EBITDA margin 9.5% 7.9% 8.1% 7.4% 6.7% 6.4%

Reconciliation Commentary

A. Represents non-cash expense related to

stock appreciation rights agreements

B. Represents non-cash compensation

expense related to changes in the values of

noncontrolling interests

C. Represents non-cash equity-based

compensation expense related to the

issuance of share-based awards

D. Represents severance expenses and other

costs permitted in calculations under the

ABL Facility and the First Lien Facility

E. Represents one-time costs related to our

initial public offering and acquisitions paid to

third party advisors as well as costs related

to the retirement of corporate stock

appreciation rights

F. Represents management fees paid to AEA,

which were discontinued after the IPO

G. Represents the non-cash cost of sales

impact of purchase accounting adjustments

to increase inventory to its estimated fair

value

H. Represents mark-to-market adjustments for

derivative financial instruments

I. Represents one-time costs related to our

secondary offerings paid to third party

advisors

J. Represents expenses paid to third party

advisors related to debt refinancing activities

K. Pro forma impact of earnings from

acquisitions from the beginning of the LTM

period to the date of acquisition, including

synergies

24

Historical Cash Flows

($ in millions)

(Unaudited) FY15 FY16 FY17 FY18 FY19

Net income $ (11.7) $ 12.6 $ 48.9 $ 63.0 $ 56.0

Non-cash changes & other changes 79.6 62.2 62.5 63.4 119.3

Changes in primary working capital components:

Trade accounts and notes receivable (11.6) (27.3) (20.4) (11.8) (13.7)

Inventories (4.6) (0.7) (19.3) (34.8) 5.2

Accounts payable (3.7) 1.1 (3.8) 11.4 26.8

Cash provided by (used in) operating activities 48.0 47.7 67.9 91.2 193.6

Purchases of property and equipment (13.9) (7.7) (11.1) (23.7) (18.8)

Proceeds from sale of assets 3.8 9.8 4.0 2.9 1.2

Purchase of financial instruments (4.6) - - - -

Acquisitions of businesses, net of cash acquired (67.7) (120.2) (150.4) (28.3) (583.1)

Cash (used in) investing activities (82.5) (118.0) (157.5) (49.2) (600.7)

Cash provided by (used in) financing activities 14.1 77.1 85.1 (20.2) 419.0

Effect of exchange rates - (1.0)

Increase in cash and cash equivalents (20.4) 6.8 (4.5) 21.8 10.9

Balance, beginning of period 32.7 12.3 19.1 14.6 36.4

Balance, end of period $ 12.3 $ 19.1 $ 14.6 $ 36.4 $ 47.3

Supplemental cash flow disclosures:

Cash paid for income taxes $ 16.1 $ 26.1 $ 49.2 $ 39.0 $ 19.4

Cash paid for interest $ 31.7 $ 34.6 $ 26.4 $ 28.6 $ 66.4

Cash provided by (used in) operating activities $ 48.0 $ 47.7 $ 67.9 $ 91.2 $ 193.6

Purchases of property and equipment (13.9) (7.7) (11.1) (23.7) (18.8)

Free cash flow (1)

34.1 40.1 56.8 67.4 174.8

25

Reported SG&A to Adjusted SG&A

Reconciliation Commentary

A. Represents non-cash expense related to

stock appreciation rights agreements

B. Represents non-cash compensation

expense related to changes in the values

of noncontrolling interests

C. Represents non-cash equity-based

compensation expense related to the

issuance of share-based awards

D. Represents severance expenses and

other costs permitted in calculations under

the ABL Facility and the First Lien Facility

E. Represents one-time costs related to

acquisitions paid to third parties.

F. Represents costs paid to third-party

advisors related to the secondary public

offering of our common stock

G. Represents expenses paid to third-party

advisors related to debt refinancing

activities

H. Represents SG&A incurred by any

branches that were acquired in the current

fiscal year, prior fiscal year and three

months prior to the start of the prior fiscal

year

(Unaudited) LTM 4Q18 LTM 1Q19 LTM 2Q19 LTM 3Q19 LTM 4Q19 LTM 1Q20 LTM 2Q20 LTM 3Q20

($ in millions)

LTM Reported SG&A 633.9$ 663.2$ 688.6$ 710.5$ 739.5$ 748.7$ 763.8$ 779.0$

LTM Adjustments

Stock appreciation rights (expense) benefit (A) (2.3) (2.1) (2.1) (1.9) (2.7) (2.5) (3.1) (2.3)

Redeemable noncontrolling interests (B) (1.9) (1.5) (1.7) (1.3) (1.2) (1.3) (1.0) (0.7)

Equity-based compensation (C) (1.7) (1.6) (2.3) (3.1) (3.9) (4.9) (6.1) (6.4)

Severance and other permitted costs (D) (0.6) (5.2) (6.0) (6.2) (8.2) (3.9) (4.4) (4.6)

Transaction costs (acquisition and other) (E) (3.4) (8.0) (8.7) (9.7) (7.9) (4.1) (3.6) (2.9)

Gain (loss) on disposal of assets 0.5 0.2 0.2 0.3 0.5 0.6 1.0 1.0

Secondary Public Offering (F) (1.5) (0.9) (0.9) - - - (0.4) (0.4)

Debt Related Costs (G) (1.3) (1.2) (1.2) (1.2) (0.7) (0.1) - -

LTM Adjusted SG&A 621.7$ 643.0$ 666.0$ 687.5$ 715.5$ 732.5$ 746.3$ 762.7$

LTM Revenue 2,511.5$ 2,647.4$ 2,833.3$ 2,971.7$ 3,116.1$ 3,185.2$ 3,213.3$ 3,250.7$

LTM Adjusted SG&A as % of LTM Sales 24.8% 24.3% 23.5% 23.1% 23.0% 23.0% 23.2% 23.5%

26

Net Income (Loss) to Pro Forma Adjusted EBITDA

Reconciliation Commentary

A. Represents non-cash compensation expenses

related to stock appreciation rights agreements

B. Represents non-cash compensation expense

related to changes in the fair values of

noncontrolling interests

C. Represents non-cash equity-based compensation

expense related to the issuance of share-based

awards

D. Represents non-recurring expenses related

specifically to the AEA acquisition of GMS

E. Represents severance and other costs permitted in

calculations under the ABL Facility and the First

Lien Facility

F. Represents one-time costs related to our initial

public offering and acquisitions (including the

Acquisition) paid to third party advisors, including

fees to financial advisors, accountants, attorneys

and other professionals as well as costs related to

the retirement of corporate stock appreciation rights.

G. Represents management fees paid to AEA, which

were discontinued after the IPO

H. Represents the non-cash cost of sales impact of

purchase accounting adjustments to increase

inventory to its estimated fair value

I. Represents mark-to-market adjustments for certain

financial instruments

J. Represents costs paid to third party advisors related

to the secondary public offerings of our common

stock

K. Represents costs paid to third party advisors related

to debt refinancing activities

L. Pro forma impact of earnings from acquisitions from

the beginning of the LTM period to the date of

acquisition, including synergies

M. Represents the favorable impact to Adjusted

EBITDA related to the amendment of existing GMS

equipment operating leases to capital leases

LTM LTM LTM LTM LTM LTM LTM LTM

( $ in 000s) 4/30/2019 1/31/2019 10/31/2018 7/31/2018 4/30/2018 4/30/2017 4/30/2016 4/30/2015

(Unaudited)

Net Income (loss) 56,002$ 49,296$ 63,167$ 56,278$ 62,971$ 48,886$ $ 12,564 $ (11,697)

Add: Interest Expense 73,677 63,003 51,348 40,083 31,395 29,360 37,418 36,396

Add: Write off of debt discount and deferred financing fees - - - - 74 7,103 - -

Less: Interest Income (66) (127) (161) (390) (177) (152) (928) (1,010)

Add: Income Tax Expense 14,039 17,665 11,735 13,659 20,883 22,654 12,584 (6,626)

Add: Depreciation Expense 46,456 40,121 34,211 28,696 24,075 25,565 26,667 32,208

Add: Amortization Expense 71,003 63,190 55,370 46,811 41,455 43,675 37,548 31,957

EBITDA 261,111$ 233,148$ 215,670$ 185,137$ 180,676$ 177,091$ $ 125,853 $ 81,228

Adjustments

Stock appreciation rights expense (A) 2,730 1,880 2,069 2,062 2,318 148 1,988 2,268

Redeemable noncontrolling interests (B) 1,188 1,276 1,651 1,533 1,868 3,536 880 1,859

Equity-based compensation (C) 3,906 3,056 2,345 1,626 1,695 2,534 2,699 6,455

AEA transaction related costs (D) - - - - - - - 837

Severance and other permitted costs (E) 8,152 6,203 5,981 5,212 581 (157) 379 413

Transaction costs (acquisition and other) (F) 7,858 9,709 8,718 7,964 3,370 2,249 3,751 1,891

Gain (loss) on disposal of assets (525) (273) (206) (240) (509) (338) (645) 1,089

AEA management fee (G) - - - - - 188 2,250 2,250

Effects of fair value adjustments to inventory (H) 4,176 4,177 4,266 4,453 324 946 1,009 5,012

Change in fair value of financial instruments (I) 6,395 11,810 12,086 11,948 6,125 382 - 2,494

Secondary public offerings (J) - - 894 894 1,525 1,385 19 -

Debt transaction costs (K) 678 1,205 1,205 1,189 1,285 265 - -

Total Add-Backs 34,558$ 39,043$ 39,009$ 36,642$ 18,582$ 11,138$ 12,330$ 24,568$

Adjusted EBITDA 295,669$ 272,191$ 254,679$ 221,779$ 199,258$ 188,229$ 138,183$ 105,796$

Contributions from acquisitions (L) 6,717 26,990 42,827 64,321 1,280 9,500 12,093 8,064

Pro Forma Adjusted EBITDA with Acquisitions 302,386$ 299,181$ 297,506$ 286,100$ 200,538$ 197,729$ 150,276$ 113,860$

Conversion of GMS Operating Leases (M) - 6,151 12,039 17,926 - - - -

Pro Forma Adjusted EBITDA 302,386$ 305,332$ 309,545$ 304,026$ 200,538$ 197,729$ 150,276$ 113,860$

27

Net Income to Pro Forma Adjusted EBITDA

Reconciliation Commentary

A. Represents non-cash expense related to

stock appreciation rights agreements

B. Represents non-cash compensation

expense related to changes in the values of

noncontrolling interests

C. Represents non-cash equity-based

compensation expense related to the

issuance of share-based awards

D. Represents severance expenses and other

costs permitted in calculations under the

ABL Facility and the First Lien Facility

E. Represents one-time costs related to our

initial public offering and acquisitions paid to

third party advisors as well as costs related

to the retirement of corporate stock

appreciation rights

F. Represents management fees paid to AEA,

which were discontinued after the IPO

G. Represents the non-cash cost of sales

impact of purchase accounting adjustments

to increase inventory to its estimated fair

value

H. Represents mark-to-market adjustments for

derivative financial instruments

I. Represents one-time costs related to our

secondary offerings paid to third party

advisors

J. Represents expenses paid to third party

advisors related to debt refinancing activities

K. Pro forma impact of earnings from

acquisitions from the beginning of the LTM

period to the date of acquisition, including

synergies

( $ in 000s) 3Q20 LTM 2Q20 LTM 1Q20 LTM 2019 2018 2017 2016

(Unaudited)

Net Income 81,462$ 76,398$ 72,172$ 56,002$ 62,971$ 48,886$ $ 12,564

Add: Interest Expense 71,091 74,143 75,766 73,677 31,395 29,360 37,418

Add: Write off of debt discount and deferred financing fees 707 707 - - 74 7,103 -

Less: Interest Income (49) (51) 158 (66) (177) (152) (928)

Add: Income Tax Expense 20,035 18,661 18,793 14,039 20,883 22,654 12,584

Add: Depreciation Expense 50,333 49,322 48,268 46,456 24,075 25,565 26,667

Add: Amortization Expense 68,012 69,821 72,144 71,003 41,455 43,675 37,548

EBITDA 291,591$ 289,001$ 287,301$ 261,111$ 180,676$ 177,091$ $ 125,853

Adjustments

Stock appreciation rights expense (A) 2,285 3,074 2,456 2,730 2,318 148 1,988

Redeemable noncontrolling interests (B) 736 1,019 1,319 1,188 1,868 3,536 880

Equity-based compensation (C) 6,443 6,118 4,897 3,906 1,695 2,534 2,699

Severance and other permitted costs (D) 5,853 4,382 3,870 8,152 581 (157) 379

Transaction costs (acquisition and other) (E) 2,931 3,563 4,077 7,858 3,370 2,249 3,751

Gain on disposal of assets (985) (973) (560) (525) (509) (338) (645)

AEA management fee (F) - - - - - 188 2,250

Effects of fair value adjustments to inventory (G) 508 198 198 4,176 324 946 1,009

Change in fair value of financial instruments (H) - - 376 6,395 6,125 382 -

Secondary public offerings (I) 363 363 - - 1,525 1,385 19

Debt transaction costs (J) - - 51 678 1,285 265 -

Total Add-Backs 18,134$ 17,744$ 16,684$ 34,558$ 18,582$ 11,138$ 12,330$

Adjusted EBITDA (as reported) 309,725$ 306,745$ 303,985$ 295,669$ 199,258$ 188,229$ 138,183$

Contributions from acquisitions (K) 1,635 905 1,293 6,717 1,280 9,500 12,093

Pro Forma Adjusted EBITDA 311,360$ 307,650$ 305,278$ 302,386$ 200,538$ 197,729$ 150,276$

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