Flat Roof Leaking Next to Exterior Wall of London Ontario Home

We were out in the North end of London Ontario this week. We were contacted by a homeowner who reported that water was coming into their garage, and they think its because of their flat roof section of their home.

Upon our flat roof inspection at the home, we saw that the 15’ x 15’ roof was situated in a section where the shingled roof peaked to a flat roof, and at the detail where the flat roof meets the exterior wall, the roof membrane had opened up a little, letting water into the home and into the garage. There were quite a few openings by the wall, and we could see that the flat roof was older and really needed replacing.

We tore off the old roof system, cleaned the whole area up, and checked every part of the roof to make sure the substrate was dry and sturdy.

We installed a new peel and stick adhesive base sheet membrane, then we put down a metal detail around the edge of the float roof where it meets the shingles.

This is a little different than our regular metal flashing, which we normally install to control water on a flat roof so it heads to a sloped section where a drain would be located to get water off the roof.

This is just a detail flashing, meaning we don’t want to control or keep the water on the flat roof, it is supposed to let water run off all sections of the roof down the shingles to the eavestroughs while protecting the seam where the shingles and flat roof are as well.

With the metal down we use a roll on adhesive primer, we let the adhesive set for a bit to make sure it is going to adhere the cap sheet, then we use a peel and stick 2ply modified bitumen cap sheet. Once we have that neatly measured out and applied to the roof, we weld the asphalt seams of that cap sheet with a heat gun to provide a water tight seal between the cap sheet seams.

Once that was complete we put a new metal flashing on the wall detail that stops any driving rain or harsh elements from even getting near the membrane seam on the wall, protecting the home and garage from any type of water.

The client is going to have a trouble free flat roof system for many years to come!