Geof,
There are pros and cons to every product. Styrofoam will only squeek or wear if it moves, fit it tight and apply PL 300 ,spray foam any gaps and edges, build a truck that has some structural integrity and I feel those issues are covered. The deadly fumes while burning is a concern, I have the same issue with my concrete house if it ever catches on fire. Unlike my hose we do not run any electrical wires through the walls to come in contact with the Styrofoam so I have eliminated that part in the motorhomes.
Johns Mansville foil faced board works very well, an inch has a R value of 6.5. I actually like this product the best but most customers request the Styrofoam. This is the product that I put in my personal truck.
Touch 'n seal is a spray product we have used for years on our Evolution because of the trucks contoured walls having varied thickness. While this is an excellent product because of it's R value, containing no formaldehyde, being flame retardent and adding structual integrity there are also some negatives to the product. On the down side is the fact it has a ton of isocyanates in it, has a very short shelf life and anytime you break the seal you have 24 hours to use the product in its entirity or you throw it away. It hurts to throw a $250 box away after only using a small part of it.
The problem with most manufacturers is they have a wall that is only capable of holding an inch of insulation. This results in the maximum R value of 7 if they used the best insulating product out.
Bead board and fancy looking bubble wrap just seam to fall short of what is needed. When I'm parked in the mountains snowmobiling I need some serious insulation, it gets real cold at 9000'.
Randy
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