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Guide · By EPDM Roofers

10 Best Flat Roofers in Calgary and Area (2026 Guide)

Downtown Calgary skyline with the Calgary Tower and Scotiabank Saddledome

The best flat roofers in Calgary in 2026 are National Star Roofing Inc. for residential track record and customer service, EPDM Roofers Inc. for EPDM rubber roofs, and United Roofing Inc. for commercial buildings. Marku Roofing Repair Ltd., EZ Roof Repair Inc., Vertex Roofing & Exteriors Ltd., Vami Roof Repair Ltd., HKS Construction Ltd., Fratello Roofing & Exteriors Ltd. and APEX Roofing Repair Inc. complete the top 10, and each one fits a specific flat roof job.

Last reviewed: September 23, 2026. Ratings, review counts and credentials were checked on that date.

We compared all 10 companies on the flat roof systems they install, their Workers’ Compensation Board of Alberta (WCB) coverage, liability insurance, licensing, workmanship warranty and Google reviews. EPDM Roofers Inc. publishes this guide and appears on it at number two. Every fact below comes from a public source: company websites, the Alberta corporate and City of Calgary licence numbers the companies publish, and their Google Business Profiles. No company paid for placement.

Why is a Calgary flat roof harder to get right?

A Calgary flat roof fails faster than a shingled roof because snow, chinook swings, hail and trapped moisture all work on a surface that does not shed water. Four problems cause most of the flat roof calls in Calgary.

Snow load and ponding water

Snow sits on a flat roof instead of sliding off. When it melts, water collects around blocked drains and low spots, and standing water finds every weak seam.

Chinook freeze-thaw cycles

Chinook winds can swing Calgary temperatures by 20°C or more in a day. Each thaw and refreeze flexes the membrane and pulls at flashings on parapets, curbs and skylights.

Hail punctures

Calgary sits in one of Canada’s most active hail zones. The August 5, 2024 hailstorm caused roughly $2.8 billion in insured damage, according to the Insurance Bureau of Canada’s estimate, and flat roofers patched punctured membranes for months afterward.

Wet insulation under old membranes

A leak on an older flat roof often soaks the insulation long before a stain shows on the ceiling. Covering wet insulation with a new membrane traps the problem inside the roof.

How did we pick these 10 flat roofers?

We picked Calgary contractors that install flat roof membranes with their own crews, serve the Calgary Metropolitan Region, and publish credentials a homeowner can verify. Every company on this list met the same baseline:

We then compared the companies on five criteria, in this order:

  1. Flat roof systems offered: SBS, EPDM, TPO, PVC, tar and gravel
  2. Verifiable credentials: WCB account, liability insurance amount, Alberta incorporation, City of Calgary licence, industry memberships
  3. Years in the trade
  4. Written workmanship warranty
  5. Google rating, review count and what reviewers actually say, checked September 2026. We read each company’s reviews sorted by most relevant and by lowest rating, and report complaints alongside praise.

Where a company made a claim we could not verify from a public source, we left the claim out.

How do the 10 Calgary flat roofers compare?

National Star Roofing Inc. leads on review volume and years in business, EPDM Roofers Inc. is the only EPDM-only specialist, and United Roofing Inc. is the largest commercial operator on the list.

#CompanyBest forFlat systemsSinceLiability insuranceGoogle rating
1National Star Roofing Inc.Track record and customer serviceEPDM, SBS, TPO, PVC, BUR2003$5M + WCB4.9 (216)
2EPDM Roofers Inc.EPDM rubber roofsEPDM2011Bonded and insured5.0 (2)
3United Roofing Inc.Commercial and large buildingsCommercial flat, SBS, TPO, PVC, EPDM2007Insured, COR certified4.3 (77)
4Marku Roofing Repair Ltd.SBS repairs and replacementsSBS (main), EPDM, TPO, PVC2022 (inc.)$5M + WCB5.0 (103)
5EZ Roof Repair Inc.Flat roof leak diagnosisSBS, EPDM, TPO, PVC2021 (inc.)$2M + WCB4.9 (47)
6Vertex Roofing & Exteriors Ltd.24/7 emergencies and skylightsTPO, EPDM, mod bit2011Insured + WCB5.0 (37)
7Vami Roof Repair Ltd.Owner-on-site repairsSoprema SBS, EPDM, TPO, PVC15+ yrs$2M + WCB5.0 (17)
8HKS Construction Ltd.Roof plus exterior renovationEPDM, TPO, SBS2018 (inc.)$2M5.0 (63)
9Fratello Roofing & Exteriors Ltd.Upfront pricing dataEPDM, TPO, PVC, tar and gravelDecades combined10-yr warranty4.8 (32)
10APEX Roofing Repair Inc.Small repairs and older tar and gravel roofsSBS, EPDM, TPO, tar and gravelOwner-operatedSafety-certified crew5.0 (2)

Ratings and review counts change often. Figures above were checked on September 23, 2026.

1. National Star Roofing Inc.

Best for: homeowners who want a long-running, award-winning crew known for customer service

National Star Roofing Inc. is a family-run Calgary roofing contractor that has roofed Calgary homes since 2003, and all work is done by its own crew rather than subcontractors. National Star Roofing Inc. reports more than 8,000 completed projects. On the flat roof side, National Star Roofing Inc. covers condo buildings, offices, plazas and warehouses as well as houses, across nearly every low-slope system on the market.

Customer service is what sets National Star Roofing Inc. apart. Owner Alex Vukaj has run the company since 2003, and the business has grown mostly by word of mouth, with homeowners and repeat clients coming back for the way they are looked after from the first call to final cleanup. The review history backs this up: 4.9 stars across 216 Google reviews, plus hundreds more on HomeStars.

National Star Roofing Inc. does not request final payment until the client has a package with the labour and material warranties, material specs and invoice in hand.

What customers say: Google lists “friendly crew” as a theme in 48 of National Star Roofing Inc.’s reviews. Reviewers repeatedly mention crews that finish a full replacement in one or two days, spotless cleanup with no nails left in the yard, and pricing that compared well against other quotes. The handful of negative reviews (four 1-star and one 2-star out of 216) are mostly about small service calls rather than roof replacements: slow follow-up on a quick repair, a repair that missed the actual leak source, and service call pricing that felt high.

Worth knowing: National Star Roofing Inc.’s focus is still heavily residential and shingle-driven, so for a large commercial flat roof you may also want a quote from a commercial-first contractor like United Roofing Inc.

2. EPDM Roofers Inc.

Best for: homeowners and building owners who have chosen EPDM rubber, or want to know if EPDM fits their roof

EPDM Roofers Inc. is the Calgary flat roofing contractor that publishes this guide, and the only company on this list that works exclusively on EPDM rubber roofs. Every other contractor here offers flat roofing alongside shingles, siding, metal or tile. EPDM Roofers Inc. has installed and repaired EPDM since 2011, with a team of 10 and membrane from Firestone (now sold under Holcim’s Elevate brand).

Specialization matters with EPDM because most EPDM failures happen at the details: seams, perimeter securement, and flashings at parapets and penetrations. A crew that works on nothing else sees the same failure points every week. EPDM Roofers Inc. provides free on-site estimates.

What customers say: EPDM Roofers Inc. has two Google reviews, both 5 stars and both from about four years ago, tagged for responsiveness, punctuality, quality, professionalism and value. Neither includes written comments, so there is not much for a homeowner to go on yet.

Worth knowing: EPDM Roofers Inc. has far fewer Google reviews than most companies here. If your roof is SBS torch-on, or you need shingles done at the same time, one of the multi-system contractors below will be a better fit, and we will tell you that on the phone.

3. United Roofing Inc.

Best for: commercial buildings, condo boards, property managers and large flat roof projects

United Roofing Inc. is a Calgary commercial roofing and building envelope contractor that started in 2007 as a four-person residential crew. United Roofing Inc. opened its commercial flat roofing division in 2010, waterproofing in 2013 and building envelope in 2016, and now reports more than 250 staff with a second office in Edmonton.

Buildings with a large field of membrane, multiple drains, rooftop units or a condo board that needs formal safety documentation are the natural fit for a COR-certified contractor of this size. United Roofing Inc. states that standard manufacturer warranties run 10 to 15 years, with extensions available to 20 to 25 years.

What customers say: United Roofing Inc.’s strongest reviews come from the commercial side. A Calgary general contractor’s project manager described the execution as flawless and the pricing as fair, and building owners praise clear inspection reports and clean job sites. Many of United Roofing Inc.’s written reviews are five or more years old. The low ratings include several 1-star reviews with no written explanation, plus older complaints about missed finishing details after a residential job and a difficult insurance-claim experience on siding.

Worth knowing: a small garage or single-family flat roof is not where a company this size focuses. For those jobs, the owner-operated contractors below are usually faster to book.

4. Marku Roofing Repair Ltd.

Best for: SBS torch-on flat roofs and homeowners who want every credential in writing

Marku Roofing Repair Ltd. is a Calgary roofing contractor that publishes its licence, WCB and insurance numbers openly. Marku Roofing Repair Ltd. is also upfront about what it will not do: its insurance excludes hot tar and built-up kettle roofing, so Marku Roofing Repair Ltd. does not take that work. Marku Roofing Repair Ltd. is one of the few Calgary roofers that publishes flat roof price ranges:

What customers say: Marku Roofing Repair Ltd. holds a 5.0 average across 103 Google reviews, so we found no negative reviews to report. Google’s most common review themes are quick repair (7 mentions), tile roof repair (7), thorough inspection (5) and flat roof replacement (4). Reviewers mention fast site visits, work finished on the promised date at the quoted price, and good communication while waiting for a weather window.

Worth knowing: Marku Roofing Repair Ltd. was incorporated in 2022, but Kristjan Marku has worked on roofs since a young age, including years as a subcontractor installing roofs for larger Calgary roofing companies before he started his own. Its 103 Google reviews are the second-highest count on this list.

5. EZ Roof Repair Inc.

Best for: tracking down a stubborn flat roof leak before you pay for a replacement

EZ Roof Repair Inc. is an owner-operated Calgary roof repair company founded by Sokol Preka, who worked on National Star Roofing Inc. crews from the early 2000s before incorporating EZ Roof Repair Inc. in 2021. Sokol still inspects every roof himself. On any flat roof over 10 years old, Sokol cuts core samples before quoting a replacement, so the homeowner knows whether the insulation underneath is wet. EZ Roof Repair Inc. also works on modular and mobile home flat roofs, which many roofers turn down.

EZ Roof Repair Inc.’s published ranges: flat roof repairs typically $800 to $4,000, and residential SBS replacement $5,000 to $25,000.

What customers say: EZ Roof Repair Inc.’s reviewers keep coming back to one point: Sokol answers the phone and shows up fast, often the same day. Several reviews describe persistent leaks that another roofer had failed to fix, including a tar and gravel roof where Sokol advised replacement instead of another patch because he suspected rotted plywood. Others mention before and after photos and being offered several repair options with prices. The two low ratings are a 2-year-old 1-star complaint about a worker’s conduct, which the company disputes, and a 2-star rating with no written comment.

6. Vertex Roofing & Exteriors Ltd.

Best for: 24/7 emergency leaks and flat roofs with skylights

Vertex Roofing & Exteriors Ltd. is a Calgary roofing and exteriors contractor that answers the phone around the clock and runs a dedicated skylight repair service. Skylight curbs are one of the most common leak points on flat roofs. Vertex Roofing & Exteriors Ltd.’s 10-year warranty applies to repairs as well as full replacements, which is less common than it should be.

What customers say: Vertex Roofing & Exteriors Ltd.’s reviews highlight fair quotes (5 mentions) and fast emergency response: one reviewer reports Gazi arriving within 30 minutes on a Sunday when water was leaking through a light fixture during a storm. We found no negative reviews. Worth noting: nearly all of Vertex Roofing & Exteriors Ltd.’s 37 reviews were posted in 2026, after the rebrand, so the review history under the Vertex Roofing & Exteriors Ltd. name is short.

7. Vami Roof Repair Ltd.

Best for: homeowners who want the owner physically on the roof for every repair

Vami Roof Repair Ltd. is a father and son roofing company run by Kole and Vlash Perkeqi, who spent over 15 years working for established Calgary roofing companies before launching their own brand. Callers reach Kole or Vlash directly, and one of them is on site for every job. Vami Roof Repair Ltd. installs Soprema SBS systems and produces photo-documented inspections that support insurance claims after hail.

What customers say: All 17 of Vami Roof Repair Ltd.’s Google reviews are 5 stars. Reviewers describe emergency help during windstorms (a temporary repair the same night, then a full repair the following week), photo-documented inspections with a quote the next day, and a torch-down flat roof section installed to stop a leak around a skylight. Honest, no-surprise pricing comes up often.

8. HKS Construction Ltd.

Best for: projects that combine a flat roof with siding, soffit, fascia or other exterior work

HKS Construction Ltd. is a Calgary roofing and exterior renovation company that handles both trades under one contract. A flat roof replacement on an infill can be done alongside Hardie siding, cedar fascia or stone work without juggling two contractors. Klodian Hoxha is on every job site and prepares every estimate himself.

What customers say: HKS Construction Ltd.’s reviews most often mention emergency roof leak repairs (4 mentions), with homeowners describing same-day visits when water came into a bedroom. A condo property worker reports no issues three years after HKS Construction Ltd. spent several months on the building’s roof, and several reviewers note that Klodian was on the roof every day of their project. We found no negative reviews among its 63.

9. Fratello Roofing & Exteriors Ltd.

Best for: homeowners who want to see real price data before they call

Fratello Roofing & Exteriors Ltd. is an owner-operated Calgary roofing company, and the only company on this list that publishes what its own work actually cost. Fratello Roofing & Exteriors Ltd.’s pricing data comes from 836 of its quotes and invoices issued between August 2019 and August 2026. Homeowners can use that data to sanity-check a quote before signing. Ardit Shkalla answers the phone himself.

What customers say: Fratello Roofing & Exteriors Ltd.’s reviews most often mention timely work (5 mentions), and several reviewers are repeat customers who hired Ardit first for a repair and years later for a full roof. Reviewers credit Ardit for telling them what their roof did not need. The one recent 1-star review, from about four months ago, describes an insurance siding and roofing job with poor cleanup and warranty touch-ups (exposed fasteners, loose nails) that had not been scheduled at the time of writing.

10. APEX Roofing Repair Inc.

Best for: small flat roof repairs, and older tar and gravel roofs

APEX Roofing Repair Inc. is an owner-operated Calgary repair company with no commissioned salespeople, and one of the few on this list that still repairs older tar and gravel roofs instead of pushing straight to replacement. Gjin Bajraktari tells owners when patching stops making sense and conversion to SBS pays off. APEX Roofing Repair Inc. finishes most repairs the same day and hands over before and after photos.

What customers say: APEX Roofing Repair Inc. has two 5-star Google reviews with no written comments, both from 2026. Like EPDM Roofers Inc., APEX Roofing Repair Inc. does not yet have a written review history for homeowners to judge.

Worth knowing: APEX Roofing Repair Inc. takes e-transfer or cheque, not credit cards.

Which flat roof membrane holds up best in Calgary?

Two-ply SBS and EPDM rubber hold up best on most Calgary homes, while TPO and PVC suit large commercial roofs. Each of the four Calgary problems above has a matching fix.

Snow load and ponding water: fix the drainage first

No membrane survives water that sits for weeks. A good flat roofer corrects slope and clears or adds drains before choosing a membrane. Heat-welded TPO and PVC seams and fully adhered EPDM tolerate occasional ponding better than lapped seams.

Freeze-thaw cycles: choose a membrane that stays flexible

EPDM is a single-ply synthetic rubber membrane that stays flexible well below -40°C, so EPDM rides out chinook swings without cracking. Two-ply SBS modified bitumen is an asphalt membrane reinforced with rubber polymers, and SBS also handles cold well when installed with proper laps.

Hail punctures: pick a membrane you can patch cleanly

Two-ply SBS gives the thickest protection against hail. EPDM repairs are simple: a primed patch over the puncture restores the membrane. Torch-on SBS patches can be applied year-round, right through a Calgary winter.

Wet insulation: core-sample before you recover

Ask for core samples on any flat roof over 10 years old. Wet insulation has to come out before a new membrane goes on, and most manufacturers void warranty coverage past two membrane layers.

For a deeper comparison of SBS, TPO and PVC against rubber, read our guide to flat roof alternatives to EPDM. For the energy and recycling side, see the environmental benefits of EPDM roofing.

What does flat roofing cost in Calgary?

A Calgary flat roof repair typically costs $300 to $4,000, and a full residential flat roof replacement runs $5,000 to $25,000. Two contractors on this list publish flat roof pricing, and their ranges line up closely:

JobTypical Calgary range
Small patch (puncture, open lap, blister)$300 to $800
Flashing repair at a curb, parapet or drain$500 to $1,500
General flat roof repair$800 to $4,000
Section replacement with wet insulation removed$2,000 to $6,000
Residential SBS replacement (garage, addition)$14 to $22 per sq ft
Full residential flat roof replacement$5,000 to $25,000

Sources: Marku Roofing Repair Ltd. and EZ Roof Repair Inc. published ranges, September 2026.

In our experience, EPDM rubber lands in a similar range to two-ply SBS for residential work. The biggest cost swings come from wet insulation, the number of penetrations and parapets, and roof access.

How do you vet a Calgary flat roofer yourself?

Vet a Calgary flat roofer with the same five criteria we used for this list, in the same order.

  1. Flat roof systems. Ask which membrane the roofer recommends and why. A good flat roofer asks about drainage, parapets, penetrations and what sits under the old membrane.
  2. Credentials. Ask for the WCB account number and request a clearance letter from WCB to confirm it is active. Ask for the liability insurance certificate: $2 million is common, and $5 million is better for larger jobs. Check the City of Calgary business licence and the Alberta corporate registration.
  3. Years in the trade. Ask how many flat roofs the crew has installed on your membrane type, not just how long the company has existed.
  4. Written workmanship warranty. In Calgary, 5 to 10 years is normal. The workmanship warranty is separate from the manufacturer’s membrane warranty.
  5. Reviews. Sort a roofer’s Google reviews by lowest rating first. Read how the company responded, and look for reviews that mention flat roofs specifically, not only shingle jobs.

Get at least two written quotes that spell out the membrane brand, number of plies and scope.

If a repair leaks again inside the warranty period, report it to the contractor in writing with dated photos before anyone else touches the roof. A second contractor’s repair can void the first contractor’s workmanship warranty.

Frequently asked questions

Who is the best flat roofer in Calgary? It depends on the roof. For the longest residential track record and customer service, National Star Roofing Inc. For EPDM rubber, EPDM Roofers Inc. For large commercial buildings, United Roofing Inc. For SBS repairs, Marku Roofing Repair Ltd.

Do these roofers serve Airdrie, Cochrane, Chestermere and Okotoks? Most do. National Star Roofing Inc., Fratello Roofing & Exteriors Ltd. and Vertex Roofing & Exteriors Ltd. list those communities directly. Call ahead for areas further out, like High River or Strathmore.

How long does a flat roof last in Calgary? A properly installed two-ply SBS or EPDM roof typically lasts 20 to 30 years in Calgary. Hail, ponding water and poor flashing details shorten that lifespan.

Can a flat roof be repaired in winter? Yes. Torch-on SBS patches can be applied year-round, and emergency repairs are done in any season. Full replacements are easier to schedule from spring to fall.

Is a licence required to be a roofer in Alberta? Alberta has no provincial roofing licence for contractors. In Calgary, a City business licence, WCB coverage and liability insurance are the credentials to check.

So which Calgary flat roofer should you call?

Call National Star Roofing Inc. for the strongest residential track record (4.9 stars from 216 Google reviews since 2003), EPDM Roofers Inc. for an EPDM rubber roof, and United Roofing Inc. for a commercial building. Match the rest of the list to your job:

If your flat roof is EPDM, or you want to know whether EPDM fits your building, call EPDM Roofers Inc. at (825) 449-7040 or book a free on-site estimate.

About this guide: EPDM Roofers Inc. publishes this guide and is included in it. Companies were assessed on publicly available information from their websites, public registries and Google Business Profiles, last reviewed September 23, 2026. If you run one of these companies and something has changed, contact us and we will update it.

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