Tuff Shed has 2x4 rafters on 24 center. I was going to spray foam 3.5 inches of closed cell foam for r19 value but then read it would defeat the silver lined radiant barrier and that heat would transfer to the foam.
So would it be better to leave a gap at the barrier and install a 1/2 inch rigid foam insulating board 1 inch away from the barrier between the rafters and then spray 2 inches of foam onto the foam board? Which would be more effective? First way would be much easier but is it wrong?
Also there are no vents at all in the shed and it was wrapped with some kind of barrier before the exterior was sheeted. Should I use faced insulation in the walls and the facing towards the interior?. It will be air conditioned in the hot Phoenix summer and slightly heated in the winter. I should add it will be sheet rocked.
Thanks for your response.