"George" george@least wrote in message
...
Heatable space within the unheatable sounds good. I think I'd avoid the
temptation to use expanded foam for my igloo, though. Flame can do some
nasty things quick.

Expanded polystyrene foam insulation is modified so as not to burn if the
source of ignition is removed. It will just put itself out. It is less
flammable that many forms of paneling or other wall coverings. When it
burns, the products of combustion are soot, water, and carbon dioxide, same
as a wood fire.

Building codes do call for it to have a layer of sheetrock though.