See here what "Frank" did when he built his brothers camper. He did an outstanding job on it...
Here he is doing the floor insulation
http://www.sunlineclub.com/forums/f6...html#post85938
And here are the walls. See the post after it too as he sealed the gaps
http://www.sunlineclub.com/forums/f6...html#post90459
Your looking for close cell foam, not the normal little round balls of Styrofoam board.
The R value will help guide you
Good luck and curious to see how yours comes out.
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Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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