On Tue, 13 Dec 2005 09:10:33 -0500, "Chas12"
wrote (with possible editing):

Hi, I was wondering if that spray foam insulation that comes in cans is
considered safe. When that kind of insulation first came out I think about
20 years ago, a friend of mine had his whole house done, only to learn that
the product outgassed formaldehyde, and had to take the house down to the
studs. Do the new products now still have that problem? I just want to fill
some holes and cracks to keep out cold air.
Thanks,
Chas


There are two kinds of foam - expanding and non-expanding. The first
is polyurethane with an R value of 6.5 per inch, the second is urea
formaldehyde with an R value of 5.5 per inch. Normally, the foam
which expands is polyurethane, and that is the most common kind you
find in spray cans. Polyurethane is dangerous only if it subjected to
the heat of a fire. The gas produced under those circumstances is
dangerous, even lethal. Urea-Formaldehyde is relatively inert, but
the danger has always been that it outgasses formaldehyde which is
irritating to some (NOT ALL) people. Plywood also outgasses
formaldehyde, although less so. (formaldehyde is used in the glue
which glues plies together)

For your use, I wouldn't worry about either. I used polyurethane foam
around my electrical outlets, being careful not to apply too much. I'm
still here five years later with no ill effects. Main insulation here
is fiberglass with 12" of cellulose over 12" of fiberglass in the
attics.
--

Larry