1.5in is about the most I am comfortable doing. I have a 80ft wide lot with 10ft on each side required to be left alone, and I have about 6in margin for error. They are anal here about where the finished siding winds up, not concrete. So I don't want to get close to the limit. Yea I know a 1/2in doesn't sound like much but I don't want a problem. The villages here are extremely anal. For the wall, I will likely spend some time on air sealing, then 5in of ocSPF with the smart vapor retarder. For the cathedral 14in TJI roof, I think I will do this: put tyvek on TOP of the rafters before the roof sheathing goes on, then blow 11" of ocSPF to that, and use the smart vapor retarder on the underside at the rooms and drywall over that. I'm being told by people around here this is more than sufficient. The Tyvek will prevent the sheathing from sticking and ruining the foam should anything weird happen. |