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I'm planning on insulating my van with foam board. I have seen where people say to get the blue or pink boards. Only thing I can find locally is the white R-Max (?) board that looks like a heavy Styrofoam. Does anyone have a proper name for the blue/pink boards so I can order some from Lowe’s or HD? Or is the white board just as good? IIRC I read somewhere that it's not.

How should I attach the foam boards? Spray adhesive to the side of the van? If so what type? Attach wood strips to glue it to so there’s a small gap between van and board for moisture to excape? I can see advantages for both and can’t decide which one is best.

I’m sure most of these questions have been answered before as I think I’ve read it, but I can’t seem to find them now.
Fiberglass insulation is basically designed to preserve an air space in a house. It is that air space that is actually providing much of the insulation properties. This insulation is typically vented to the outside to prevent moisture build up.

In a vehicle, it is very difficult to ventilate the skin, floor, and roof to the outside. This means that they must be vented to the interior. To prevent rust and mold issues, the interior skin must be vented to have positive air flow to compensate for the condensation which you can not prevent.

So you need an air gap between any insulation and the outer skin, at least an inch. Then that gap needs to be vented through to the interior both top and bottom, and it doesn't hurt to have it vented all the way around. It is imperative that you keep the inner skin and the entire space between your interior paneling, and the inner skin well ventilated to prevent moisture build up.
what you want is polysiro(sp). foam board is not fiber glass and they don't let the insulation of a house vent to the outside. in fact today they try to seal the whole house with tyvek or a similar product. that link that OP posted is the stuff you want. highdesertranger
The pink or blue is better than the white, but the white is just fine. Polyiso is best of all, much better R-value.

I've never sweated venting the insulation. You can spray glue it direct to the walls or you can use 2x3 runners and screw it to them. The advantage of the 2x3 runners is you can attach the sheets whole with much less time spent cutting. However you will waste more space inside.
One has to consider the application as well;

Make sure any adhesive you use is compatible with foam board. Don't use Liquid Nails as it will melt the foam when applied. Tape any seams as well.
(07-14-2015, 11:52 AM)climbing coastie Wrote: [ -> ]#1: Does anyone have a proper name for the blue/pink boards so I can order some from Lowe’s or HD? Or is the white board just as good? IIRC I read somewhere that it's not.

#2: How should I attach the foam boards?
#1: The BLUE Rigid Foam Sheathing is made by the DOW company. The PINK is made by Owens-Corning (Think Pink!). They have slightly better insulation value per inch than the white polystyrene. I ended up with R-Max with a heat barrier film. Face the foil to the inside of your living quarters.

#2: Use an adhesive made for foam insulation (it will say FOAMBOARD on the tube and it is in the paint dept at Home Depot... I don't know where Lowes keeps it). Regular construction adhesive will eat the foam sheathings. An alternative and more expensive method to "glue" the foam sheathing to metal is to squirt Great Foam onto the metal and then stick the foam sheathing to the space and brace it until dry (overnight).

Even more important than the insulation is to understand what a thermal break is and to incorporate it into your insulation. Do an internet search for "thermal break" and "thermal bridge".

Warning: Foamboard is the thickness it says it is. Like 1" is really 1". Furring strips and lumber is nominal sized. Meaning a 1X2 inch furring strip is really 3/4 X 1-1/2 inches (after milling). You will need to shim out or have a gap. Your choice. We shimmed. And no it doesn't squeek.

When you tape your seams, use the "metal" tape. It's like heavy aluminum foil with a really sticky back. You should find it with the duct work. DO NOT USE DUCT TAPE. It's just not what it used to be. The metal stuff is much more durable, useful and expensive.
Thanks for the help! Looks like I found what I need:
Foam Board
I just couldn't decipher all the different foams they had on their site. Funny that Lowe’s doesn’t carry it locally.
(07-15-2015, 09:57 AM)climbing coastie Wrote: [ -> ]Funny that Lowe’s doesn’t carry it locally.

My guess the local lack is that it has something to do with local buiilding codes. I have noticed that some forum recommended insulation products are not available in NJ HD stores, but are available in next door PA HD stores.

O/T derail - like 30 round magazines. Don't reply to this here. /sarc

So I started installing my Rmax boards in my van yesterday. It wasn't until I got about 1/2 of it done that I noticed I wasn't getting it to sit flush with the van skin. I didn't realize that the edges of the cutouts stuck up from the skin so much, now there is a small (1/8"-1/4") gap between the skin and my foam board.

I can't decide if this is a good thing or bad. Is it best to have the foam board directly in contact with the skin or to leave a small gap?
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