Expert roof leak detection and repair for all roof types across Greater Montreal. We trace leaks to their source and fix them permanently, not just where the stain appears.
A roof leak is often more complex than it appears from inside the building. Water that shows up as a stain on a bedroom ceiling may have entered the roof system several feet away, traveling along rafters, sheathing, and insulation before gravity finally pulls it through to a visible spot. This is why patching the area directly above the stain frequently fails to solve the problem. Effective leak repair requires tracing the water back to its actual point of entry and addressing the root cause.
In Montreal, the most common sources of roof leaks include failed flashing around chimneys, vents, and skylights; deteriorated valley linings where two roof planes meet; cracked or missing shingles on sloped roofs; blistered, split, or punctured membrane on flat roofs; ice dam water infiltration at eaves; and blocked or damaged drainage systems on flat roofs. Each failure type requires a different repair approach, and correctly identifying the source is the most critical step.
Our leak investigation process is methodical. We start by examining the interior damage to understand the water path and approximate entry zone. We then inspect the roof exterior in that zone, checking every potential failure point: flashings, seams, penetrations, transitions between materials, and the condition of the roofing material itself. On flat roofs, we also check drain function, scupper condition, and membrane adhesion. When the entry point is not visually obvious, we may use controlled water testing to isolate the source.
Once we identify the source, we perform a targeted repair using materials compatible with the existing roof system. For flashing failures, we remove the old flashing, prepare the substrate, and install new flashing with proper overlap and sealant. For membrane damage on flat roofs, we cut out the damaged area, prepare the surface, and apply a reinforced patch that extends well beyond the damage perimeter. For shingle damage, we replace the affected shingles and verify the underlayment condition. We also address any secondary damage caused by the leak, such as wet insulation, stained sheathing, or small areas of rot that need to be replaced before the repair is closed up.
Why this service
Expert leak tracing to find the actual source
Permanent repairs using compatible materials
All roof types: shingles, flat membrane, metal, slate
Flashing and penetration detail repairs
Secondary damage addressed (wet insulation, rot)
Controlled water testing for difficult-to-find leaks
FAQ for this service
This is common and usually indicates a wind-driven rain issue. If the leak only appears during heavy rain with wind from a specific direction, the entry point is likely a flashing, seam, or transition that is intact under normal conditions but lets water in when wind pushes rain at a particular angle. We test for this during our investigation.
Yes. Most leaks can be traced and repaired with targeted investigation and minimal disturbance to the surrounding roof. We use our experience with common failure patterns, visual inspection, and when needed, controlled water testing to isolate the source. Full tear-off is rarely needed for leak repair.
Water often enters at one location and travels along framing members, sheathing, or insulation before dripping onto the ceiling at a different spot. The entry point may be several feet from the stain. It is also possible that the leak has sealed itself temporarily but will reopen in the next rain event.
An active leak during rain is urgent and should be addressed quickly to prevent interior damage, mold growth, and structural deterioration. A dried stain from a past event is less urgent but should still be investigated promptly because the underlying problem will cause another leak the next time conditions are right.
Yes. Even a small, slow leak can cause significant damage over time. Persistent moisture leads to wood rot in sheathing and framing, mold growth that affects air quality, insulation damage that increases energy costs, and staining that is expensive to repair on interior finishes. Early repair prevents escalation.