Remove foil from one side?
I'm installing some Tuff-R polyisocyanurate sheets in the 2x3 exterior stud bays of the bathroom in my motor home.
It's foil faced both sides. There is a 1/2 inch air gap between it and the aluminum outer siding - no sheathing. The aluminum is unfinished on the inside and therefore should function as a poor man's radiant barrier.
I'm thinking I should remove the foil facing on the outside, to prevent moisture trapping within and around the insulation, and to allow the radiant barrier function - heat radiating from the insulation must reflect off the aluminum and then be reabsorbed by the insulation, which won't happen with the foil present.
The inside surface will retain the foil, and there will be foil tape over the studs to create the class 1 vapor barrier.