Where flat roofing actually shows up here
Very few full roofs on the North Shore are genuinely flat, but a lot of homes have a flat or low slope section somewhere: an addition off the back of a rancher, a laneway home, a covered deck roof, or the tie in where a lower roofline meets a taller part of the house. Those sections take the same rainfall as the rest of the roof but without a steep pitch to help shed it, which makes the membrane and the drainage detail more important than on any pitched section.
Why torch on membrane over other options
Torch on modified bitumen membrane is heated and fused into a single continuous surface rather than relying on overlapping pieces the way shingles do, which makes it suited to a roof that will see standing water rather than fast runoff. We install it over a clean, prepared substrate with the seams properly lapped and the edges terminated in metal that ties cleanly into the roofing or siding above and below it.
Where an existing flat section has been holding water rather than draining, we look at whether tapered insulation or a reframe is needed underneath the new membrane, since a membrane installed over a roof that already ponds will simply pond again, whatever it is covered with.
Tie ins with the rest of the roof
The point where a flat section meets a pitched roof or a wall is where flat roofs most often fail, not the field of the membrane itself. We build proper step flashing and counterflashing at every wall intersection, and where a flat roof ties under a pitched section above it, we make sure the upper roofing laps over the membrane rather than the other way around, so water is always directed away from the joint rather than into it.
Laneway homes and additions
Laneway homes and rear additions have become common across North Vancouver as lots get built out further, and a lot of them include at least one flat or low slope roof section by design, whether over a garage conversion or a single story addition. We build those roofs as part of the original construction where we are brought in early, and we retrofit or repair them where an existing flat section was built without proper drainage or membrane detailing in the first place.