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I apologize if this has been asked and answered.  I am in the planning stages of a van for use in Alaska.  It would see three season use during the summer and then travel south for the winter.  In regards to insulation for cold weather has anyone used the Low pressure polyurethane spray foam insulation kits? I have used them in my home which is insulated with the closed cell polyurethane high density spray foam.  It seals all the gaps and sound deadens as well.  It is not cheap but there is a supplier locally that will discount his DYI kits 1/2 price when they reach their expiration date.  The date is typically less than a month in the past.  I have never had problems with a kit.  It is a bit messy but if it is a gut and replace it might work.  Just curious if someone has tried it either with success or a "run away now" advice.  These are a 2 part kit that mixes at the nozzle and is designed to spray between studs and not the 1 part door and window sealer. 

Thanks for the great information on this site.  Ken
We tried all kinds of spray in foam insulation back in the 70's and early 80's in our vans.

The end result is that every one that tried it developed major amounts of squeak in their walls. It got really ugly and loud driving down the highway... Rolleyes

The foam, when under vibration, cracked and then rubbed against itself until it finally fell apart in to something akin to the styrofoam peanuts. When that happened it settled in the cavities and provided no insulation to the upper portion.

No idea if the newer stuff would react differently but personally, I'd be hesitant to use it!
The only issues I've heard are expansion/contraction causing ripples in large flat van sides at high elevation.
I've used closed cell foam in construction- love it for the added strength and support in light weight construction( boats, tiny houses, trailers)

I've always used rigid foam panels in my vans, mainly because it was cheaper and I usually have leftovers around, but would certainly use closed cell spray otherwise.
The 2-part kits do expand *very* forcefully.

And a *huge* problem if you only partially cover the body panels, any condensation trapped in there will very quickly rot the steel from the inside.

Rigid panels cut to fit, small foam infills laterally but allow for some circulation, you'll never get a complete vapor barrier, don't block the drain holes.

And **lots** of ventilation when things get humid.
just don't use "the Right Stuff" foam they sell at hardware stores. it's open cell, holds moisture like a sponge and will rot your sheet metal. highdesertranger
I've seen stuff designed for docks and boats floatation, insulates well and very durable.