Flat roofing contractor in Longueuil

One problem comes up a lot with South Shore flat roofs: drips from an addition's ceiling in the middle of January, when it hasn't rained in weeks. Another involves building owners who want a new roof without making life hard for their tenants. Les Toitures Garcia, holder of RBQ licence 5705-4066-01, handles those two situations very differently, and here's how.

Leak or condensation under an addition's roof?

Plenty of bungalows in Saint-Hubert and Greenfield Park picked up a rear addition or an enclosed sunroom with a flat roof somewhere along the way. Between the ceiling and the membrane there's often just a thin cavity with no venting at all. Warm, humid air from the house rises into it, meets cold wood and turns to frost. At the first mild spell that frost melts and drips, and it looks exactly like a leak.

So before replacing anything, we track down the real source: we examine the membrane, open a small section if needed and look at the insulation and vapour barrier. If it's condensation, a new roof covering wouldn't fix a thing. The answer is better insulation, often added on top of the deck during the re-roof, plus a continuous vapour barrier on the warm side.

Corners and edges facing the river wind

Near the St. Lawrence, wind hits flat roofs side-on and creates stronger suction at the corners and along the edges. On an aging tar and gravel roof, it pushes the gravel toward the middle and leaves the bitumen bare near the edges, where the sun dries it out until it cracks. On a membrane roof, it's the corner lap that lifts first.

When we redo an exposed roof, we beef up those zones instead of treating the whole surface the same way.

• Stronger membrane adhesion at the corners and around the perimeter
• Heavier edge flashing, anchored solidly into the wood
• Gravel put back or bare spots repaired after a storm
• Corner laps checked at every inspection

Re-roofing an apartment building without upsetting the tenants

In the plexes and apartment buildings of Vieux-Longueuil, roof work happens above people who work, sleep and have guests over. We agree with the owner on a clear schedule, an access route that doesn't block the stairs, protection for the balconies and doorways below the work area, and a roof that's closed up every evening so no overnight rain catches anyone off guard. A notice prepared ahead of time for the tenants saves a lot of phone calls.