Camper gets cozy: spray foam insulation

Spray foam day!  Over a year after initially inquiring about the qualities of this soy-based spray-on insulation typically used for sealing basement walls, I finally had the guy over to spray my camper.

The contractor came with a big self-contained work trailer with his compressor/engine/miles of hose and drums of product.  He fired it up- it was very noisy, sounded diesel, and took some time to prepare.  I was too tired to get nosy but I gathered that there was compressed air, then the liquid product that must be pumped or pressurized somehow, delivered in two hoses and mixed at the gun as it’s sprayed on the walls.

The very beginning

A third hose is supplied air to his breathing apparatus.  He suited up and got into his breathing mask, dragged all the hoses from the trailer to the camper, and began.  He knelt on the floor and did systematic side to side passes with the gun, occasionally doing a depth check by stabbing it with a screwdriver.  He sprayed over the walls and wheel wells and ceiling until it was all one puffy peach coloured surface.  It didn’t take very long.  It had no smell, inert as soon as it dried (almost instantly). 

I liked the colour a lot.  Light peach, and the texture was nubbly in places and more rounded in others.  Very much like a cave.    I planned to leave the surface as is, cavelike and peaceful peach, but he suggested shaving it down wherever necessary and painting it.

It sealed the styrofoam on the floor in perfectly, and he gave all the seams a shot too, slicing off the excess with a wood saw as soon as it dried.

One unforeseen side effect of the foam was the rigidity of it after installation. It dries very quickly (seconds – not at all like expanding foam in the can), hard and dense, more rigid than rigid styrofoam.  The effect was to solidify the whole flexible bubble of the fiberglass shell, exactly as it was, like paralysis.

Note to egg renovators: this is an amazing side effect of the spray foam!  You can prop up your ceiling without resorting to steel supports, you can pressure the floppy fiberglass egg any direction you want to improve it, and the moment that spray foam hardens, it is solid in that position, forever.

I really wish I’d known or understood this side effect in advance.  It first revealed itself when we tried to set the windows back in their slots and the wall of the camper seemed to be sloping away from the window.  The insulation had rigidified it in the relaxed concave shape it was in without the support of the window in place.

20-20 Hindsight

Clearly the right thing to do (note to egg renovators) is to install the windows beforehand, mask them out, spray the foam, and then carve the insulation out to find the window frame again.  Also prop up the egg from the inside as high as possible (eggs without their structure inside are pretty floppy and squish, and then the doors fit so well either), foam around the props, and then right at the end knock the props out and fill the holes. It sure would have been nice to have known that and done that, but we had no precedent to follow.  I’d never heard of anyone spray foaming their camper, it just seemed like a good idea.   We managed.

It was a world of hurt getting the windows back in.  The windows install by screwing from the outside through the fiberglass into the wood frame floating on the inside, essentially sandwiching a bit of the fiberglass shell between the flange of the window and the interior wooden trim with a perimeter of screws.  It was nearly impossible to do alone, as the shell in its new shape needed some serious force applied to bend out a little bit to meet the window.  Insert more despair, frustration, and rainfall for good measure.

fiberglassrv.com for all fiberglass egg resources

7 thoughts on “Camper gets cozy: spray foam insulation”

  1. Hello! Thank you for your informative post. Good to know about the instant rigidity thing(!) I have a 1960 Siesta canned ham that I’m planning to gut and renovate into a little back yard guesthouse, and I’ve considered doing the interior with this spray insulation (leaving it uncovered, but probably painted cream). I like the look of it, the cozy foamy lumps and bumps. Can I ask how much this cost?

    1. Hmmm. I thought I said. Hard to remember now. A “few” hundred dollars? All I can say for sure right now is ≤$800. More than $300.

    1. At bottom of this post or on the right sidebar (click on Camper reno) there’s a link to the whole group of camper renovation posts.

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