Correct board for raising camper?
Is this the correct insulating board for raising older camper in modern truck?
Forum Discussion
Part of the compression problem seen is how people size/orient the extruded polystyrene foam (XPS). Sized to just fit under the TC doesn't give a lot of support to the foam edges (my version 1). Placing the sheet(s) across the bed width provides more support.
If you have a light camper, the 15 psi compressive strength of the XPS shown by the original poster will work to raise the TC with little compression. If you have a heavier TC both Owens Corning and Dow make XPS foam in higher compressive strengths of: 25, 30, 40, and 60 psi. The 30-60 psi XPS is used under concrete slabs.
If you need more height than a single sheet of XPS foam provides, they can readily be glued together with a water based contact cementwater based contact cement. I glued 1.5" and 2" sheets of Owens Corning Formular 250 together to get the height I needed.
If you want to prevent movement you can glue together pieces of foam to make a block to prevent the TC from moving side to side or too far forward (permanent or added after loading the TC).
You can also make the foam nonskid by mixing up some epoxy resin (local marine supply store or online), applying it to the foam (where the TC touches) and then lightly broadcast dry, fine, sand onto the wet epoxy (similar to a nonskid surface on a boat). I've successfully used epoxy resin on XPS foam. I don't know whether the cheaper polyester based resins will melt the XPS foam or not.
If you still have issues with crushing the foam, you can always epoxy in a layer of 6" wide fiberglass to the foam in that area to further spread the load. Much lighter than a wood frame.
If you have a light camper, the 15 psi compressive strength of the XPS shown by the original poster will work to raise the TC with little compression. If you have a heavier TC both Owens Corning and Dow make XPS foam in higher compressive strengths of: 25, 30, 40, and 60 psi. The 30-60 psi XPS is used under concrete slabs.
If you need more height than a single sheet of XPS foam provides, they can readily be glued together with a water based contact cementwater based contact cement. I glued 1.5" and 2" sheets of Owens Corning Formular 250 together to get the height I needed.
If you want to prevent movement you can glue together pieces of foam to make a block to prevent the TC from moving side to side or too far forward (permanent or added after loading the TC).
You can also make the foam nonskid by mixing up some epoxy resin (local marine supply store or online), applying it to the foam (where the TC touches) and then lightly broadcast dry, fine, sand onto the wet epoxy (similar to a nonskid surface on a boat). I've successfully used epoxy resin on XPS foam. I don't know whether the cheaper polyester based resins will melt the XPS foam or not.
If you still have issues with crushing the foam, you can always epoxy in a layer of 6" wide fiberglass to the foam in that area to further spread the load. Much lighter than a wood frame.
