Spray foam is best but takes prep and equipment. It adds super strength but don't spray it onto the aluminum from inside. You would never be able to remove skins again! LOL You would have to take skins off and spray from outside, let set up, trim. then reinstall skins.
I use foam boards all over. I learned doing custom vans in the 70's that fiberglass holds moisture.
Foil bubble wrap (Automat) is great in areas with bends. Used in vintage autos all the time now.
Thanks everybody for the quick response(s)! This site seems like it has endless answers and everyone has been very helpful.Our local hardware store does carry 3/4 rigid. What is the best way to install/attach to the framing? Taped in? Dare I say caulked in(although I think I might know the answer to that already. Caulking seems like it's the newest four letter word on the site!)? A little insight on what I'm working on: Shasta 1400 ...not sure of the year, but I think it's early 70's. The # on the tongue said S32956 PA 4247 N. All help is greatly appreciated! Make it a great day-mattyshorts
I wouldn't use spray foam. I'm currently repairing a Loliner and having to pick and chop to do the work... very bad. Please don't use spray foam.
On the rigid foam, I cut to fit tight. It will normally stay in place by itself. You can also caulk it; it's certainly not going to show! Personally, I've never had to use glue. The Reflectix bubble wrap can be stapled in between rafters and cross boards, the silver tape is great for joints, really sticks.
I used the rigid shown in the picture. Where it was needed I used construction adhesive to hold it in place. As the first picture indicates, I cut some small blocks and screwed them to the cross members to hold it in place where necessary. That worked great. I can't take credit for this idea as it came from someone on this forum. Where I needed to bend it around a radius, I simply scribed it with a knife and then clamped it in place. Once the construction adhesive dried, it never moved. As with Vikx, I cut it to fit tight and none of the side panels required an adhesive.
I used rigid foam too. Tuff-R (Polyisocyanurate) has the highest R-value I could find (6.5/inch, I've got three inches in the center 2' of the roof), and is silver coated so it acts as a radiant/moisture/air barrier as well. I used aluminum tape over all the inside seams, covering the inside of the frame too, so that no condensation could ever get farther than behind the paneling. Kept me toasty at 14 degrees last Christmas Eve!
I cut to fit tight like the other folks here, and used Great Stuff spray foam behind outlets, in small gaps and in the gaps where the thick 110v wiring goes through the wall, around the water fillers and drains and such. The only place I needed any adhesive was in the floor, because when I did the floor I hadn't yet found any 1.5" sheets, so I used a combo of half inch and one inch, and I didn't want any of the pieces to fall out where the belly pan isn't tight against the floor. I used dabs of caulk between the layers (the caulk was what I had handy, I'd probably use panel adhesive if I did it again).
'76 Shasta 2250 kept in a perpetual state of restoration. That way I don't have to buy any more campers
When you installed your rigid foam did you leave an air gap between the insulation and skin
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vschwartz, I used 3/4" rigid foam and it fit rather snugly in between the 1 x 2 frame pieces of my trailer. There is not really "gap" between the skin and aluminum. The breaks in the skin, the lines in the aluminum, allow the skin room to expand and contract and keep it from being tight against the frame. Hope this makes sense.