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Flat Roof Installation in Toronto. Built Right From the Framing Up.
New builds, additions, townhomes, and laneway suites — we install every flat roof system to Ontario Building Code and manufacturer spec, and we coordinate the details other roofers miss, so your exterior finishes actually fit when they arrive.
Get an Installation Quote Call 416-826-1334Toronto is building flat roofs faster than ever.
The last decade transformed this city's rooflines. Architects brought modern flat roof designs to everything from custom homes to infill projects — sometimes brilliant, sometimes adding real complication that only shows up during construction. We work on these properties every single day, and we know both the designs and their pitfalls:
Modern custom builds with flat and low-slope roofs as the architectural signature — parapets, terraces, and clean rooflines.
Infill town projects where flat roofs are standard — repeated details across units, where one design flaw multiplies.
Toronto's fastest-growing build type — compact flat roofs with tight access, where wheeled-trailer logistics and precise detailing matter most.
The most common project of all — rear and third-storey additions where a new flat roof must tie into an existing structure cleanly.
The roof goes on first. The exterior comes months later.
Here's a construction-sequencing problem we're called to fix on brand-new builds constantly: the flat roof is one of the first things installed after framing — it has to be, to dry the building in. Stucco, siding, or brick arrive months later.
If the roofer didn't calculate the exterior cladding into the edge details — its exact thickness, where it terminates, how it tucks under the drip edge — the cladding doesn't fit under the roof's drip edge when it finally goes up. The result: complex, expensive corrective work on a house that isn't even finished yet. Water management at the most critical edge of the building, improvised after the fact.
We've repaired enough of these to build our installation process around preventing them.
The structure is up — and the roof must go on immediately to protect it.
Roof edges detailed with zero regard for the cladding spec — nobody asked what's going on the walls, or how thick it is.
Stucco, siding, or brick won't tuck under the drip edge. Trades point fingers. The owner pays for corrective roofing on a new home.
Before the first membrane roll opens, we review the exterior specification with your builder or architect — cladding type, thickness, termination heights — and build drip edges and flashings that the exterior will slide under perfectly, months down the road. One conversation at framing stage saves a renovation later.
New builds are code-current. Your roofer has to be too.
One genuinely good thing about the new generation of Toronto builds: they're up to date with the Ontario Building Code — especially the two requirements older roofs chronically fail: insulation values and slope. We engineer both into every installation:
- Insulation assemblies meeting current OBC thermal requirements — no shortcuts that fail inspection
- Positive slope to drains built in per code — tapered insulation or sloped framing, so water never stands
- Drainage sized and placed correctly — drains, scuppers, and overflows engineered, not improvised
- Every detail per manufacturer requirements — mandatory to pass inspection and hold the full warranty
Installed to spec from day one means no corrective overlay in year three — something we fix on other companies' installs far too often.
The systems, ranked by reality — not brochures.
We install every membrane system, so we have no inventory to push. Here's the honest state of the Toronto market, from a company on these roofs daily:
By far the most installed flat roof system in Toronto — a near monopoly on residential builds, and for good reason: proven through freeze-thaw, torch-applied redundancy, easy to detail and repair. IKO and SOPREMA lead the market, alongside other quality manufacturers — and we're certified installers for both.
Steadily gaining share — heat-welded seams, chemical resistance, and clean single-ply aesthetics that suit modern architectural designs. Increasingly specified on higher-end builds.
Still common on commercial decks, but becoming less common on Toronto homes — two-ply and PVC have squeezed it out of most residential specifications.
A drastic reduction in new installs — largely displaced on new construction, though thousands of existing EPDM roofs still need system-correct repairs, which we do daily.
Shingle-to-flat transitions: two roofs, one critical seam.
More and more Toronto designs combine a sloped shingle roof with flat sections — third-storey decks over garages, additions behind gabled fronts, modern rear volumes on traditional homes. It looks great. It also creates the single most failure-prone detail in residential roofing: the transition.
Where shingles end and membrane begins, two different systems with different physics must hand water off perfectly — under-shingle membrane lapping over the flat roof's termination, correct heights, correct sequencing. Get it wrong and the leak appears years later, deep inside the wall below the seam. Most shingle crews can't detail the flat side; most flat roofers won't touch the shingle side.
We specialize in both sides of that seam — designing and installing the transition as one continuous water management system, on the properties where we work every day.
Discuss Your Design
Installation questions
Why does the exterior cladding matter to my roof installation?
Because of sequencing. The roof is installed right after framing; stucco, siding, or brick arrive months later. If the roof's drip edges weren't detailed around the cladding's exact thickness and termination, the exterior won't fit under the drip edge — forcing complex corrective roofing on a brand-new build. We review the exterior specification with your builder before installation so the cladding slides under perfectly when it arrives.
What's the most common flat roof system for Toronto homes?
Two-ply modified bitumen, by a wide margin — it dominates Toronto residential construction, with IKO and SOPREMA the leading manufacturers. PVC is rising on higher-end builds, TPO is becoming less common residentially, and EPDM has seen a steep decline in new installations. We're certified across all of them, so the recommendation fits your building rather than our inventory.
Do you install flat roofs on laneway houses and garden suites?
Constantly — it's Toronto's fastest-growing build type and a perfect fit for how we work: compact flat roofs, tight rear-lane access where bin trucks can't go (our wheeled trailers can), and detailing that has to be right the first time.
Can you tie a new addition's flat roof into my existing roof?
Yes — additions are the most common installation we do. The tie-in to the existing structure, whether flat-to-flat or shingle-to-flat, is engineered as one continuous water management detail with correct laps, heights, and sequencing.
Who handles the shingle-to-flat transition on combined roof designs?
We do — both sides. The transition is the most failure-prone detail in residential roofing, and it fails when a shingle crew improvises the flat side or vice versa. We design and install the handoff as a single system: under-shingle membrane lapped over the flat roof termination at correct heights.
Will my new flat roof meet Ontario Building Code?
Yes — current OBC insulation values and positive slope to drains are engineered into the assembly, with drainage sized and placed per code. Every detail follows manufacturer requirements, which is mandatory to pass inspection and hold the full warranty.
Do you work with builders and architects directly?
Daily. We review drawings, flag flat roof details that will cause trouble before they're built, coordinate sequencing with exterior trades, and deliver the documentation your project needs — from permits to final independent inspection, before which you don't pay.