Can you repair my existing flat roof instead of replacing it?

Often, yes. Many leaks come from failed seams, flashing or a single damaged area that can be repaired. We'll only recommend a full replacement when a repair won't give you lasting value — and we'll explain why.

Do you handle commercial and industrial flat roofs?

Yes. Flat and low-slope roofing for commercial and industrial buildings is one of our specialties, alongside residential work. Cairns Roofing has installed and serviced these systems across the GTA since 1974.

How often should a flat roof be inspected?

Twice a year is ideal for flat roofs — in spring and fall — plus after major storms. Regular inspection catches ponding, seam and flashing issues early, which is far less costly than a full replacement.

Commercial flat roof installed by Cairns Roofing

Home/Flat & Low-Slope Roofing

Commercial & industrial specialty

Flat & low-slope roofing built for Ontario buildings.

EPDM, TPO, modified bitumen, tar & gravel and Duradek — installed and repaired across the GTA by crews who have specialized in flat roofs since 1974.

Get a free quote (905) 880-4771

5 flat-roof systemsNew installs & repairsFree inspection

The service

What flat roofing involves — and why the system matters.

Flat and low-slope roofing covers the nearly-level roofs found on commercial buildings, industrial units, additions and modern homes across the GTA. Because water drains slowly, the membrane and its detailing decide how long the roof lasts. Cairns Roofing installs and repairs the five systems best suited to Ontario's freeze-thaw winters and hot summers: EPDM rubber, TPO single-ply, torch-applied modified bitumen, traditional tar & gravel, and Duradek waterproof decking. We start every job with a free inspection, then recommend the system that fits your building, use and budget.

Systems we install & repair

Five flat-roof systems, one experienced crew.

EPDM rubber

A single-ply synthetic rubber membrane prized for its long service life and resistance to Ontario's freeze-thaw cycles. Ideal for commercial and residential flat roofs.

TPO single-ply

Heat-welded, reflective white membrane that helps lower cooling costs in summer. A popular modern choice for commercial buildings — we install new and repair existing TPO.

Modified bitumen

Torch-applied, multi-layer asphalt roofing that stands up to foot traffic and ponding. A dependable workhorse system for low-slope roofs.

Tar & gravel (built-up)

The traditional built-up roof still found on many older buildings. We repair and maintain existing tar & gravel roofs to extend their life.

Duradek waterproof decking

Waterproof vinyl membrane for balconies, decks and walkout areas — turning outdoor surfaces into a sealed, walkable roof.

Not sure which?

Book a free inspection. We'll assess drainage, insulation and the existing roof, then recommend the system that fits your building and budget.

When to call us

Signs your flat roof needs attention.

Flat roofs rarely fail overnight. Catching these early — ideally at a spring or fall inspection — keeps a small repair from becoming a full replacement.

Ponding water

Standing water 48 hours after rain signals poor drainage and stresses the membrane.

Blisters or cracks

Bubbling, splitting or alligatoring in the surface means the membrane is aging or lifting.

Interior leaks & stains

Water marks on ceilings or walls point to a failed seam, flashing or drain.

Loose or lifting flashing

Flashing at walls, curbs and vents is where most flat roofs start to leak.

Higher energy bills

Failing insulation under the membrane can quietly push heating and cooling costs up.

Roof is 15+ years old

Most flat systems near the end of their life benefit from inspection before winter.

Completed roofing project by Cairns Roofing

How the job runs

From inspection to a watertight finish.

Free inspection

We assess drainage, membrane and flashing and document what we find.

Transparent quote

A clear written scope, system recommendation and price — no surprises.

Membrane installation

Tear-off where needed, then a clean, properly detailed install.

Walkthrough & clean-up

We confirm the roof is watertight and leave the site tidy.

Flat roofing questions

What GTA building owners ask about flat roofs.

It depends on your building's use, slope, drainage and budget. EPDM and TPO are common for commercial buildings; modified bitumen suits roofs with foot traffic; Duradek is ideal for balconies and walkouts. Our free inspection lets us recommend the right fit rather than a one-size-fits-all answer.

Get in touch

Ready to quote your flat roof?

Book a free inspection and we'll recommend the right system with a clear written quote — for commercial, industrial and residential flat roofs across the GTA.

Call(905) 880-4771 Email[email protected]

HoursMon–Fri 8am–5pm