by bobhenry » Tue Dec 18, 2007 7:43 am
Foil faced polyisocyanurate ( probably butchered the spelling)
It's a yellow board with a foil facing on 1 side comes in 4x8 4x9 and 4x10 sheets I have seen it from 1/4" to 3" thick.
The foil acts as a vapor barrier and will reflect the heat back in or out depending on how it is oriented. Placing the foil in and the heat will be returned to the cabin or so they claim. It is tough and durable but has about the same characturistics as the closed cell foam board. Some contains fiberglass strands that can be an skin and eye irritant when cutting and machining so wear gloves and eye protection. A dust mask would be a plus also. There is a companion foil tape to seal any joints and could br taped to the wood support members to eliminate air infiltration.
Growing older but not up !