Insulation & vapor barrier

[Jeff Dieterle]

I got a good deal on a type of sheet insulation. The sheets are

4'x9'x2"thick', not rigid like Styrofoam board, and not flimsy like polystyrene. Not exactly sure what they are except it's some type of foam, they came in pink and white sheets, to get the varying thicknesses 3/4 or 1 inch sheets are laminated together. They seller had them from 2" all the way up to 4" thick. With a stack of these on a trailer the top couple sheets caught the wind and double over in the middle but didn't tear or suffer any damage. One guy told me he thought that's what's used in semi trailers. Anyway if somebody is familiar with these what's the "R" value and do I need a vapor barrier on top of them. Thanks Jeff

[PeterD]

I'll say this: be very, very careful using something like this as structural insulation. There are all kinds of nasty problems that can arrise (fire releasing deadly fumes, fire ratings, off-gasing of substances, etc.) that can have long reaching, and costly side effects.

Find who made these sheets and then ask them what they are for. Don't just stick them up as insulation in your house (or office, or shop, or whatever) without knowing what they really are and how they are intended to be used!

Case in point: wrong insulation used in the Station Night Club in RI. Fire resulted in 100 deaths.

[George]

If you plan to use this where lives are involved it would really be a good idea to find out what it is made from and if it is suitable for that use. Foam that is intended for dwellings is treated to minimize burning. Flame spread is fast on foam and the gases from burning it are quite deadly.

[Jeff Dieterle]

You can't get this stuff to ignite with a match and have to hold a torch for a little bit to get it going., then it burns extremely slowly. It is not permeable as I tried to blow air though it with my compressor. So how do I go about finding what this stuff is, the seller is no help and I was fishing around here in case my description struck a note with somebody.

[PeterD]

Take a sample to someone who sells/knows insulation and they may be able to help. Also if you really think it is truck insulation, try a truck place (larger one) and see if they've seen anything like it.