I know XPS is generally preferred over EPS, but I live in Arizona. I can only find 1" Foamular(XPS) locally, about $22 per 4x8 sheet. I can also find 2" R-tech(EPS) for a few cents less per 4x8 sheet.
From my understanding, the XPS has a higher compressive strength, but if I used the thicker EPS stuff, I would end up with more tensile strength due to the greater spacing between the canvas skins. Is this correct?
I know I could double up the 1" foam, but I don't want to double the cost. In this situation, which foam wouldn't be considered superior?
For some background information- I am in the planning stages of a camper shell build for my pickup. I haven't drawn up any plans yet or even measured my bed. Not planning on going much taller, if at all, than the cab of the truck. I will have overhangs of 4-6" beyond the width of the bedrails. I want to do this frameless, other than where it sits on the bedrails, and will be doing PMF interior and exterior.