Spray foam insulating ceiling under flat roof

Jed Lukewater

Our small, two story, two bedroom row house in Toronto's east end was built in 1921. It is of common design for the time and area, steep-sloped roof at the front, with a large 2nd floor dormer window and flat roof at the back of the house.

We would like to insulate the ceiling under the flat roof, but we're finding very little information about the best approach for this style house.

Should we use spray foam insulation? If so, is open or closed cell, polyurethane, or soya-based foam preferred? Would traditional bat insulation, or rigid insulation be better? Do we need to install a vapour barrier and roof vents?

Any one got any suggestions or recommendations?

Thanks in advance

Bob Mariani

icynene spray foam is give you the best job and does not need any venting. Searche the web you can order DIY kits. Can spray foam is no good.