Forum Discussion
RayJayco
May 31, 2017Explorer
Just use structural insulation board, such as this:
FOAMULAR XPS
You really don't need the 600 as the 150 (cheapest) is able to support 15 psi and when you consider the weight is dispersed by the plywood...
Links to the various strengths, compression and otherwise...
It should be available at any big box store.
Actually, any of the rigid foam board would be fine as the compression value is more than you think, however I would up the thickness of the plywood to at least 3/8"...
As a note, most closed cell rigid is a vapor barrier, just read the specs in the links that I provided.
FOAMULAR XPS
You really don't need the 600 as the 150 (cheapest) is able to support 15 psi and when you consider the weight is dispersed by the plywood...
Links to the various strengths, compression and otherwise...
It should be available at any big box store.
Actually, any of the rigid foam board would be fine as the compression value is more than you think, however I would up the thickness of the plywood to at least 3/8"...
As a note, most closed cell rigid is a vapor barrier, just read the specs in the links that I provided.
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