Plywood floor on-grade
Can anyone give me advice on an on-grade plywood floor? This would be used in a cold climate, and would be built in lieu of a concrete slab on grade, in conjunction with a shallow frost-protected foundation. As I understand it, this is the material sequence, from the top down:
plastic vapor barrier
4″ XPS foam
(another vapor barrier?)
coarse gravel for leveling and radon collection
This assembly would be floating inside of the concrete SFPF. Would any special detail need to be used to support a non-load-bearing wall. What details would be needed for an interior load-bearing wall? Would the plywood need to be pressure-treated, or would standard exterior grade plywood be satisfactory?
If this system really works, I see it as being faster and cheaper than a concrete slab over foam, and much warmer underfoot.
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