I am building a log home in the Black Hills SD. I am using tongue & groove over the exposed rafters, then vapor barrier (30 lb felt), then 6" rigid foam insulation, then sheathing, felt and shingles. Roof pitch is 12/12. This is a non vented roof system. Couple of questions: I'm new to this, so do you see any problems with this system? Someone suggested two vapor barriers might be a problem. Second question: How do I keep the roof dry while building...will the felt be enough or do I need to use tarps..ect...Thanks for your help.