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Originally Posted by packdad52
While researching insulation for my attic I ran across a company that sells closed cell polyurethane spray foam in cans that look like gas grill bottles. The material is measured in board feet 12"x12"x1" and cost about a dollar a board foot. Has anyone ever used this on an airstream and if so with what results. I was just curious.
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There has been some discussion here on the forums from time to time about using spray in place foam insulation. You can probably find the postings if you search for "foam". I remember reading that some people have used it under the floor. I don't recall anyone having used in their walls but someone may have.
Generally the sentiment seems to be that it is not the best thing to use. Some people have said that it will eventually disintegrate because of road vibration. I am not sure that would be a big problem if the insulation is contained and does not lose its R value if it is in pieces. The other problem is that it would fully encapsulate wiring and other things making it very hard to fix something if you had to later. It would be pretty expensive too. The wall cavities are about 1-1/2" to 1-3/4" deep which means that you would need at least 1.5 board feet per square feet of wall. On my 31' Airstream I have somewhere in the range of 400 to 500 square feet of walls. That means that the spray in place foam could run up to about $700 or $800 dollars for the walls. I also have about 200 square feet of floor so that would add even more. The reflecive foil insulation sells at Home Depot and Lowes for less than 50 cents per square foot. I belive it is available other places for even less if you shop around the Internet. That means that the foam approach would be more than three times the cost of foil.
On the other hand I do know that new high-end trailers of other brands are using square aluminum tubing and fiberglass foam-core wall construction. Sine the fome in that type of insulation is part of the structure they must have picked a type of foam that will not disitegrate with road vibration.
Malcolm