Repair
Flat Roof Repair in Ottawa
Targeted repairs for leaks, open seams, damaged flashing and drainage problems on flat and low-slope roofs — after the cause is actually found.
The short answer
Flat roof repair fixes a specific, localized failure — a split seam, a lifted flashing, a punctured membrane or a blocked drain — without replacing the whole roof. A good repair starts by tracing where water is really entering, which on a low-slope roof is often some distance from where the drip appears inside.
What this service covers
- Leak investigation and tracing water paths across the roof assembly
- Seam and lap repairs on TPO, EPDM and SBS modified bitumen membranes
- Flashing repairs at parapets, walls, curbs, vents and rooftop equipment
- Drain, scupper and gutter-edge repairs that restore designed drainage
- Patching punctures, splits and blisters where the surrounding membrane is sound
- Temporary protection when a permanent repair has to wait for suitable weather
Signs it's time for an assessment
- Water stains, drips or bubbling paint on top-floor ceilings
- Water that remains on the roof well after rain or melt has stopped
- Visible splits, open seams, blisters or wrinkles in the membrane
- Flashing that has pulled away from a parapet, wall or curb
- Ice build-up around drains or along the roof edge in winter
- Musty smells or damp insulation in the top storey
How the process works
- Step 01
Conversation
We start with what you have noticed: where water appears, when it happens and what has been done before.
- Step 02
Roof assessment
The membrane, seams, flashings, penetrations and drains are inspected to find the likely entry point, not just the visible symptom.
- Step 03
Written scope
You get a clear description of the recommended repair, what it covers and what it does not, so you can compare options.
- Step 04
Repair
Work uses materials compatible with the existing membrane and is scheduled around weather suitable for that system.
- Step 05
Follow-up
We explain what was found and what to watch for, including whether the roof is approaching the point where replacement makes more sense.
What shapes the scope
Every roof is different, so we don't publish flat prices. These factors drive the scope of work — see what affects flat roof cost for more detail.
- Membrane type
- TPO, EPDM and SBS each need compatible repair materials and methods.
- Extent of damage
- A single open seam differs greatly from widespread wet insulation.
- Wet insulation
- Saturated insulation under the membrane may need to be removed and replaced.
- Access
- Roof height, hatch or ladder access and building occupancy affect how work is staged.
- Season
- Cold-weather limits on adhesives and some application methods can change timing.
Ottawa conditions to consider
Ottawa's freeze-thaw cycles are hard on small defects. Water that gets into a seam or crack freezes, expands and widens the gap, so a minor issue in November can be a larger one by March.
Snow and ice also hide problems. Drains can freeze over while meltwater collects behind them, and water may back up under flashings that would shed rain without trouble. Spring and fall are good times to have a roof checked before and after the hardest months.
Please do not climb onto an icy or snow-covered roof to look for a leak. Inside, move valuables, contain drips with a bucket and note where and when the water appears — that information is genuinely useful for the assessment.
Useful references: the City of Ottawa's “Do I need a building permit?” page and the NRC Energy RCI resource on roof insulation.
Frequently asked questions
Can a flat roof leak be repaired in winter?
Often a temporary or permanent repair is possible in winter, but some adhesives and application methods have temperature limits. The assessment will tell you whether a lasting repair can be done now or whether a temporary measure is the right first step.
Why is the leak inside not under the damaged spot?
Water can travel along the deck, insulation or membrane laps before it finds a way down. That is why tracing the path matters more than patching the first visible defect.
Is repair always cheaper than replacement?
In the short term usually, yes. But if a roof has many failures, widespread wet insulation or is near the end of its life, repeated repairs can cost more over time. Our repair-versus-replacement guide explains how to weigh this.
Do I need a permit for a flat roof repair?
Many like-for-like repairs do not, but requirements depend on the scope. The City of Ottawa's building permit page is the authoritative source, and we'll flag anything in the scope that should be checked.
Keep reading
Next step
Talk to us about your roof
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