I just built a simple wood frame platform for my air mattress out of 2x4s and the top surface was going to be a layer of well supported cheap luan covered by canvas for puncture resistance, but I was wondering if instead of luan a layer of polyiso with foil side up would work to insulate as well as reflect body heat so as to warm the air in the mattress. Or will the skin of the air mattress where it contacts the foil defeat the purpose.....however due to the ridges in the mattress structure running length wise there will be some required air space every six inches or so provided I keep the mattress pumped up firm. Anyone tried this? I'm thinking at least it would provide some insulation from the cold floor in my CT.