I'm insulating a shed and have gotten mixed input on how to insulate the floor. The shed is built on piers, so the "crawlspace" is actually open to the world, not enclosed by foundation. Advice I've gotten is fiberglass batts w/ vapor barrier towards the interior, then something to protect/enclose the batts. I could use foam insulating board for this, I suppose. THis all seems ad hoc to me, though. Does anyone know how one does such a job properly? thanks.