Q&A: A Forum for Green Building Experts and Beginners

We've had a leak and ceiling damage in a 50 yr old house with a flat roof in zone 4A. Part of the ceiling is gone, damaged, part still intact with its fiberglass.So there are cavities with part fiberglass. There is no ventilation in the cavities. This part of the roof was re-roofed a few years ago and some sort of foam board was added on the exterior (presumably between the old rubber and new TPO) at that time. The is no condensation currently with the cavities open.

I am planning a remodel which will add a cathedral ceiling,and there is already an existing cathedral ceiling in another part of my home. Since much of the roof will already be removed this seems like a good time to correctly insulate and air seal.On this site (thank you Martin et.al.) the outer layer of rigid insulation is taped at the seams. On the BuildingScience site (thank you Joe et.al.) the unvented compact roof shows self-sealing membrane over the structural roof deck for an air barrier. Somewhere else I read the suggestion to use tape on the seams of the structural sheathing.

I live in southern Ontario (think Buffalo) and moved here last year. The house had a 80% efficient furnace that used indoor air for combustion, the house had 17.68 ACH50, with the majority of the air leakage through the crawlspace (under 1/3 of house) and non existent attic hatch (above 1/3 of the house, above the crawlspace house extension ironically). The indoor humidity last winter was 25-30%, i gave up in trying to raise it.

Ever since I got new windows, doors, and a vent put in, it is freezing, there is an awful draft, and even when the fire is lit it is cold. I cannot keep the heat in the house even with the fire and radiators going. There is no heat staying in. I can feel a constant draft blowing all the time.