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Flat Roof Flashing in Toronto. Where the Membrane Ends, the Real Roofing Begins.
Flashing and terminations are behind a huge share of the roof leaks in this city — and when flashing fails, it fails heavy, because past the flashing there is nothing left to stop the water. We fabricate, repair, and replace every type of flat roof flashing, custom, to spec.
Book a Flashing Assessment Call 416-826-1334Past the flashing, there's nothing.
Flashing is the metal and membrane work that seals every place your roof meets something else — walls, parapets, chimneys, edges. It's the roof's last line of defense: the membrane sheds water, but the flashing decides where the roof's protection ends.
That's why flashing leaks aren't drips — expect a heavy leak. Directly under a termination there's usually nothing but plywood, so water goes straight through onto the drywall below. And through a parapet wall, water drops through multiple floors inside the wall cavity — very often ending in the basement as flooding.
The flashing failures behind Toronto's leaks
The champion of hidden leaks: caps, membrane returns, and terminations on parapet walls fail out of sight, and water travels floors before surfacing. It's the same territory as our scupper repair specialty — the parapet is where Toronto's mystery leaks live.
Where the roof meets rising walls — base flashing heights, membrane terminations, and seals that were never done to the system's requirements. A chronic failure point on additions and commercial wall terminations alike.
The metal layer that covers and protects the base flashing — cut into masonry reglets and lapped correctly, or it channels water behind the very flashing it's supposed to protect. The most commonly botched detail in the set.
Masonry, movement, and four corners of complexity — chimney flashing on flat roofs demands custom-fit metal and proper membrane tie-ins, not the tar smears we routinely find and replace.
Every flashing, custom-made to fit your roof.
Stock profiles rarely fit real Toronto buildings — old masonry, uneven parapets, custom additions. So we do all types of roof flashing as custom fabrication: repairs where the flashing can be saved, full replacements where it can't, and new metal bent to your building's exact geometry:
- Parapet caps, base flashing & membrane terminations
- Counterflashing cut into masonry reglets, lapped correctly
- Chimney flashing — custom metal with proper membrane tie-ins
- Drip edges and edge metal, coordinated with cladding (our installation specialty)
- Copper where adhesion matters most — like our scuppers and drain details
- Membrane tie-ins per manufacturer requirements — IKO, SOPREMA, and every system we install
Traced, fabricated, sealed, proven.
Water testing and inspection isolate which flashing failed — because the stain downstairs rarely sits under the actual failure. Same instruments as our leak detection.
The detail opened, plywood and framing behind it checked for rot, damage documented with photos — including for insurance.
Custom metal bent to the building, membrane tied in with system-matched materials per manufacturer requirements — no tar smears, no improvising.
The rebuilt detail flooded on the spot, then independent inspection — and you pay only after it passes.
Flashing questions
Why is my flashing leak so much worse than a normal roof leak?
Because past the flashing there's nothing left to stop water. Under a termination is usually bare plywood, so water goes straight through onto the drywall below — and through a parapet wall it drops floor after floor inside the cavity, often ending as basement flooding. Membrane leaks seep; flashing leaks pour.
What are the most common flashing failures on Toronto flat roofs?
Four dominate: parapet wall flashing (the most common and best hidden), wall flashing where the roof meets rising walls, counterflashing that channels water behind the base flashing it should protect, and chimney flashing improvised with tar instead of custom metal. Our assessment checks all four.
Can flashing be repaired, or does it need full replacement?
Both happen — honestly decided after we open the detail. Sound flashing with a failed seal gets repaired; corroded, mis-fabricated, or improvised flashing gets replaced with custom metal bent to your building's geometry and tied into the membrane per manufacturer requirements.
Why does flashing need to be custom-made?
Because real buildings aren't stock-sized — old masonry, uneven parapets, settled walls, custom additions. Off-the-shelf profiles leave gaps that caulking is then asked to fill, and caulking always loses eventually. Custom fabrication fits the metal to the building, not the building to the metal.
My basement flooded but my roof "looks fine" — can it still be flashing?
Very possibly. Parapet flashing failures send water down inside wall cavities through multiple floors, surfacing far from the entry — including in basements. The roof surface can look perfect while the parapet detail pours. A targeted water test at the flashing settles it.
What does flashing repair cost, and when do I pay?
A fraction of the interior damage it prevents — quoted in writing after the source is confirmed. Payment only after the rebuilt flashing passes a water test and independent inspection, like everything we do.