I've been doing a little research on insulating crawlspaces and want to get your opinions. I have an unvented crawlspace about 3.5' high. It has plastic on the floors, and two 1" pieces of rigid foam insulation along the perimeter walls, which looks to have a lot of gaps and poor seals. I don't seem to have any moisture problems, but there is always a faint musty smell. There are water pipes running through it, and the one to the outside hose cracked last year. The room above it is always colder than the rest of the house. I was thinking about putting fiberglass insulation along the walls to keep the heat in better. Would it be ok to put the fiberglass right against the rigid foam? Or would it be best to remove the rigid foam and then apply the fiberglass insulation?
I think fibreglass insulation is not allowed by code in crawlspaces (where I am). They only allow closed cell blue or pink fibreglass board and nowadays it has to be coated or the type that does not give off fumes in a fire. Fibreglass will always absorb moisture and get soaked and useless. All it takes is one small hole in a vapor barrier or board joint to let moisture in to it. The best type is probably that Icynene sprayed on type as it seals all openings 100%. Best to get a pro to spray it on as it can be incredibly messy if you get it on yourself.