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Flat Roof Repair in Toronto. Diagnosed Right. Repaired Once.
Very few companies can properly diagnose a flat roof leak — and a wrong diagnosis is how homeowners end up buying roofs they never needed. We repair every system — EPDM, TPO, two-ply SBS, and more — after a 50+ point inspection finds the real problem.
Book a Repair Assessment Emergency? Call NowMost "roof leaks" are misdiagnosed before anyone climbs a ladder.
Here's what the industry doesn't say out loud: very few companies that advertise flat roof repair can actually diagnose a flat roof leak. Roof salesmen are paid to sell roofs. General shingle companies think in slopes and shingles — flat roofs are a different discipline with different physics, materials, and failure points. When either one looks at your ceiling stain, the answer is suspiciously often the most expensive one: "you need a new roof."
Proper diagnosis alone can save you thousands — because most homeowners who end up with new roofs didn't need them. And when the inspection concludes wrong, the story gets worse: the roof gets replaced, and the same problem comes back with the next rain or the next February, because the real cause was never touched.
A repair is only as good as the diagnosis behind it. That's why ours starts with instruments, not opinions.
Flat roof repair demands deep specialization in every flat roof system — how EPDM ages differently from TPO, why two-ply SBS fails at laps, where PVC gets brittle. That's all we do, and it's why other roofers refer us their unsolvable leaks.
Every February, the same story.
Almost every year, late winter brings the same wave of panicked calls: water inside, stains spreading, and a roofer already in the driveway quoting a replacement. And almost every year, the real culprits are the same two — and neither needs a new roof:
Ice dams and roof overflow. Freeze-thaw builds ice at drains and scuppers; meltwater backs up over flashing heights and finds its way inside. It looks exactly like a failed membrane. The fix is often as simple as correcting the scuppers and drainage details — a few hundred dollars, not tens of thousands.
Condensation, not a leak. Interior humidity condensing in a cold roof assembly stains ceilings with no rain in sight. No membrane repair on earth fixes condensation — ventilation and insulation do. Our instrumented diagnostics settle leak-vs-condensation definitively before a dollar is spent.
Melt backs up over the flashing line and enters — mimicking membrane failure perfectly. Corrected by fixing scuppers and drainage, not replacing the roof.
Stains with no rainfall, worst in cold snaps. It's interior humidity, not water intrusion — and a new membrane won't change a thing.
Roof replaced, problem back next season — because the inspection concluded wrong. The diagnosis, not the membrane, was the failure.
The repairs Toronto flat roofs really need
After a thousand-plus roofs, the pattern is clear — most flat roof leaks come down to details, not membranes. These are the fixes we make week after week:
The most common finding of all: caulking at membrane terminations dried out and no longer working. A precise re-termination stops the leak — for a tiny fraction of what a "new roof" quote demands.
Curb flashing that was never installed right lets water in around the skylight, not through the roof. We rebuild it to manufacturer detail — dome, curb, and membrane tie-in.
Clogged, undersized, or badly detailed drainage backs water up until it finds a way inside. Corrected scuppers and drain details are the cheapest leak fix in roofing.
Membrane no longer sticking at the drip edge peels back in wind and lets water run behind the fascia. Re-adhered and mechanically secured to spec.
Trades traffic, dropped tools, and UV aging — locally cut out, patched, and sealed with system-matched materials, then water-tested.
When instruments prove it's condensation, we say so — and recommend the ventilation fix instead of selling you roofing work you don't need.
Every membrane repaired the way its manufacturer demands
A TPO repair done with EPDM logic fails. A torch detail on the wrong system starts fires. Each membrane has its own chemistry, primers, and approved methods — and repairs that ignore manufacturer requirements don't just fail early, they void warranties and can't pass inspection.
Toronto's most common system. Torch-applied patches, lap repairs, and cap sheet work with matched membranes.
Primered and taped repairs, seam restoration, and termination work — cold-applied, the way EPDM requires.
Hot-air welded patches and seam repairs with compatible membrane — never glued shortcuts that peel by spring.
Tar-and-gravel, liquid-applied, and hybrid assemblies — repaired with system-correct materials and details.
Every roof gets a 50+ point inspection.
State, age, and repairability — determined by evidence across five zones, with instruments where the roof is complex: infrared thermal imaging, smoke testing, and controlled water tests.
Surface condition, laps, blisters, alligatoring, punctures, granule loss, membrane age indicators.
Terminations, caulking, drip edges, parapet caps, skylight curbs, AC curbs, penetrations, pitch pans.
Drains, scuppers, gutters, slope adequacy, ponding evidence, overflow paths, winter ice-dam risk points.
Deflection, soft spots, rot indicators, layer count, moisture readings through the assembly.
Stain patterns, timing versus weather, humidity sources, ventilation — the clues that separate leaks from condensation.
Then you get a verdict, not a pitch: exactly what's wrong, whether repair is the smart money, and what it costs — in writing. In most cases, a flat roof can be repaired, and a targeted repair extends its life by 5–10 years.
When repair is smart — and when it's a waste of your money
Repair is the right call when…
- The failure is a detail: termination, flashing, drain, scupper, drip edge, seam
- The membrane has life left and the assembly tests dry
- The problem is drainage or ice-dam overflow — corrected at the scuppers
- It's condensation — solved with ventilation, not roofing at all
- A targeted repair buys 5–10 more years for a fraction of replacement cost
We'll tell you not to waste money when…
- The deck shows serious rot — patches over rot just postpone a bigger bill
- The membrane is beyond its life expectancy and failing everywhere at once
- Multiple old layers are stacked — repairs can't reach the real problem
- The system was never installed to manufacturer requirements and fails systemically
- Honest math favours restoration or replacement — we'll show you the evidence
Flat roof repair questions
Why does my flat roof only leak in winter, especially February?
Two Toronto classics. Ice dams block drains and scuppers, so meltwater backs up over flashing heights and enters — looking exactly like membrane failure, but often fixed by correcting the scuppers. Or it's condensation: interior humidity condensing in the cold roof assembly, which stains ceilings with no rain at all and can't be fixed by any roof repair. Instruments tell the two apart definitively.
Do I need a new roof, or just a repair?
In most cases, a flat roof can be repaired — the majority of leaks trace to details: terminations with failed caulking, skylight flashing, drains and scuppers, drip edges no longer adhered. Replacement is warranted only when the membrane is beyond life expectancy, the deck has serious rot, multiple layers are stacked, or the system was never installed to manufacturer requirements. Our 50+ point inspection gives you that verdict with evidence.
Why did my last repair fail — or my new roof still leak?
Because the diagnosis was wrong, so the work fixed a symptom. If the true cause was a scupper, a parapet, a skylight, or condensation, patching the membrane — or even replacing the entire roof — changes nothing. This is the single most common story we hear from new clients, and it's why diagnosis comes before any repair we do.
How much life does a targeted repair add?
Done right, on a roof that qualifies, a targeted repair typically extends service life by 5–10 years — at a small fraction of replacement cost. That's the best return on investment in roofing, which is exactly why the industry undersells it.
Can you repair EPDM, TPO, and two-ply SBS roofs?
Yes — every flat roof system, each with its manufacturer-approved method: torch-applied work on two-ply SBS, primered tape repairs on EPDM, hot-air welding on TPO and PVC, plus built-up and liquid systems. System-correct repairs are the difference between a fix that lasts and one that peels off by spring.
When is a repair a waste of money?
When the deck has too much rot, the membrane is past its life expectancy, or multiple old layers are stacked — then repairs only postpone and inflate the inevitable. In those cases we'll say so plainly and show you the evidence, with restoration or replacement quoted honestly instead.
Do you use thermal imaging and testing on complex roofs?
Yes — infrared thermal imaging, smoke testing, and controlled water tests whenever a leak path isn't obvious or the roof is complex. Finding the exact entry point is what makes a one-visit permanent repair possible.
What does a flat roof repair cost in Toronto, and when do I pay?
Most repairs land in the hundreds to low thousands, depending on the detail and system — quoted in writing after inspection. And as with everything we do, you pay only after the repair is water-tested and passes independent inspection.