Things like this can get pretty complex. The vapor barrier you have is a good idea.
Decking and underlayment would also be wise.
Call me at 1-800-543-8938 ext 201 if you are interested in talking out the details.
Todd Miller
2007-01-05 21:38:17.000000
I have vaulted ceilings with 6x12 rafters on 6ft centers with 2x6 t&g ceiling. The contractor put down a plastic sheet on top of that(moisture barrier?) then built a 2x6framework of bat insulation cells, and then the metal roof. The house is 20 years old. We had dry rot in some of the ceiling boards which led to a carpenter ant problem. Since this is North ID I decided to improve the insulation with 2 layers of foil backed insulation in each cell as I replaced the ceiling boards. A local builder told me to take that sheet of plastic out and to put skip sheathing across the top of the insulation framework before I put down the roof. Now the ceiling is dripping inside one of the upstairs rooms. I'm guessing due to condensation. Should I put down a layer of plywood underneath the metal roofing?
