We are here this week in Strathroy Ontario. We are working on a mobile home with an addition, that has a flat roof system that ties into some shingles that needs replacing. The existing flat roof is a 4ply system. Upon inspecting the system and seeing the condition, our plan is to cover it over with a new 2ply system.
The roof is about 30 x 17 feet, it’s not a huge roof to work on, but there are still some details that require our care. We cleaned the roof system off and let it dry, then we installed recovery boards. These boards provide a new substrate to install our system on, starting with our base sheet.
We had to remove a few rows of shingles to get the new base sheet up and under. Our standard practice is to always bring the membrane underneath the first few rows of shingles, usually one or two feet to ensure a high quality water tight seal.
Once the base sheet is down we do our metal drip edge flashing, and install the cap sheet, which is heat welded at the seams to prevent any water or moisture from getting into the roof.
The thing we love about a 2ply roof system is that it is so much easier to maintain, and remediate any roofing issues, as the roof is so much easier to inspect visually than a 4ply system. It’s also much more cost effective to fix, and even replace many years in the future as the roof can just be roofed over. No more substrate or recovery boards needed.