Flat Roof Repair for Homes and Additions

Flat roofs aren’t really flat. They’re low-slope, and when water doesn’t drain the way it should, small problems grow quickly. We connect you with a local roofer who works on flat roofs, and the inspection is free.

Call 1 (833) 435-4261 Book a free roof inspection

Flat roof types on Ontario homes

Type	What it is	Where you’ll see it
EPDM	A rubber membrane, usually black, glued or ballasted	Additions, garages, dormers
TPO	A single-ply membrane, usually white, with heat-welded seams	Newer additions, some whole-house flat roofs
Modified bitumen	Asphalt-based rolls, torch-applied or self-adhered, often in layers	Very common on residential flat roofs
Tar and gravel (built-up)	Layers of felt and tar under a gravel surface	Older homes and mid-century additions

Knowing which one you have matters, because each is repaired differently. If you’re not sure, the roofer will tell you at the inspection.

Signs your flat roof needs attention

Ponding: water still sitting a couple of days after rain.
Blisters or bubbles in the membrane.
Open or lifting seams, especially at laps and corners.
Cracks and alligatoring on older bitumen or tar surfaces.
Failing flashing where the roof meets a wall, parapet or skylight. This is one of the most common leak points.
Bald spots in the gravel on a built-up roof.
Stains on the ceiling below, sometimes well away from the actual problem.

Winter on a flat roof

Flat roofs hold snow. As it melts and refreezes, standing water can freeze inside open seams and widen them. In Ontario that cycle repeats dozens of times a winter: from about 55 freeze-thaw days a year in downtown Toronto to more than 90 around Kitchener-Waterloo and Barrie. Spring is when many flat-roof leaks finally show up.

Repair, recover or replace?

Repair fixes a seam, blister, puncture or flashing detail.
Recover adds a new membrane over a sound existing roof, where the roof and local rules allow it.
Replace strips the roof back to the deck. It’s the right call when the insulation or deck is wet, or the membrane has failed widely.

Flat-roof work can become structural. Hamilton, for example, requires a building permit to repair roof sheathing, and Mississauga requires one to change a roof’s slope, which applies if you’re converting a flat roof to a pitched one. Your roofer should confirm permit needs with your city. For full replacement, see roof replacement.

What the free inspection covers

The roofer checks the membrane, seams, drains and scuppers, and the flashing at walls and edges. They look for ponding and soft spots, and check inside for stains. You get a clear explanation of repair vs recover vs replace, and a quote if you want one.

Stop the ponding before it becomes a leak. Call 1 (833) 435-4261 or book a free roof inspection.