Flat & Commercial Roofing in Ontario
Flat and low-slope roofing covers a different set of problems than a house with shingles. Think TPO, EPDM rubber, modified bitumen, and built-up asphalt systems on top of strip malls, warehouses, apartment blocks, and office buildings. This category also includes larger commercial jobs on sloped metal or membrane roofs where drainage, insulation, and rooftop equipment (HVAC units, exhaust fans, drains) all have to be worked around. We've listed 416 businesses across Ontario that handle this kind of work, from small crews doing repairs and coating to larger firms that manage full tear-offs and re-roofs on multi-unit properties.
What to look for before you hire
Ask for proof of WSIB coverage and liability insurance specific to commercial work, since flat roofing crews are working at height with torches, kettles, or adhesives. Get a written scope that names the membrane system (TPO, EPDM, or SBS-modified bitumen), the number of layers or plies, insulation R-value, and how drains, flashings, and parapet walls will be handled. A property with a leak history or ponding water needs someone who will actually diagnose the cause, not just patch the surface. Manufacturer certification (from suppliers like Soprema, GAF, or Firestone/Elevate) matters too, since it usually determines whether you get a real material warranty.
How we rank contractors
Our scoring pulls together verified licensing and insurance status, review volume and consistency over time, how long a company has operated in Ontario, and how responsive they are to commercial clients with tight timelines. See the full breakdown in our methodology, or jump straight to the ranked guide to roofing contractors to compare the top-rated names before you request quotes.
Get quotes from suitable flat & commercial roofing
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All flat & commercial roofing, ranked by score and relevance
694 businesses. The order weighs each business's overall score by how much of its reviewed work is flat & commercial roofing, so a lower-scored specialist can rank above a higher-scored generalist. Filter and sort below, or open the full map view.
Enquiries you submit through our forms may be shared with partner providers who can carry out the work, and we may receive a referral fee. Our rankings and scores are based only on our published methodology and are not influenced by referral fees.
Common questions about flat & commercial roofing
- How much does flat or commercial roof replacement cost in Ontario?
- Most jobs are priced per square foot, and costs vary a lot by membrane type and building height. A TPO or EPDM replacement often lands somewhere between $8 and $18 per square foot installed, while built-up or modified bitumen systems can run higher due to labor and equipment. Get at least three itemized quotes since access, insulation upgrades, and rooftop obstructions change the price quickly.
- How often does a flat or commercial roof need to be replaced?
- A well-installed TPO or EPDM membrane typically lasts 20 to 25 years, and modified bitumen or built-up systems can go 15 to 20 years with regular maintenance. Actual lifespan depends heavily on drainage, foot traffic from mechanical servicing, and how quickly small punctures or seam failures get repaired.
- What should a commercial roof inspection actually cover?
- A proper inspection checks membrane seams, flashing around parapets and penetrations, drain condition, insulation moisture (often with a moisture scan or core sample), and any ponding areas after rain. Ask the contractor to document findings with photos and a written report, not just a verbal summary.
- How can I judge the quality of a flat roofing contractor before hiring?
- Check whether they carry manufacturer certification for the membrane system they're proposing, since that usually affects warranty eligibility. Ask for references from similar commercial or multi-unit properties, confirm WSIB and liability insurance are current, and make sure the quote specifies materials and layers rather than a vague lump sum.
Guides to choosing flat & commercial roofing
- Signs your flat or commercial roof needs repair before it fails
The visible and less obvious warning signs that a flat or low-slope roof needs attention, before a small issue turns into a costly leak.