Using Rigid Foam for Baffles, vapor barrier on interior?
I'm need to insulate the second floor of my garage that has a cathedral ceiling and live in upstate NY. It has 2x10 joists and I want to get the most bang for my buck. I've looked at closed cell spray foam and its just not in the budget. So my plan is to use 1 inch rigid foam with a 1 inch gap to create my baffles, then use Roxul R30 that should fill the 9.25 cavity perfect to give me a estimated R rating of about 35 and then cover it with OSB. My question is do I need a vapor barrier in between the studs and the interior OSB? Could I put another layer of 1 inch rigid foam on before the OSB to give myself about a R40 plus I think it would help with thermal bridging?