Insulating subfloor in small studio (shed) with XPS
I’m finishing the inside of a small prefab shed to turn it into a little backyard studio/office (thanks covid) and I’m wondering about my options for insulating the floor. I plan to eventually do hardwood flooring inside.
Currently the floor is 3/4″ OSB and there is no crawlspace – the joists (steel) are resting directly on a slab and there’s no access to the underside of the subfloor without ripping out the subfloor (which I’m not interested in doing).
I was considering using Dricore R+ panels – which seem to be basically 1/2″ 25psi (I guess, based on their rating of ~3k pounds/sq foot) XPS foam and 1/2″ OSB. The downside is R+ panels aren’t stocked anywhere locally.
It seems like it’d be easier/cheaper for me to just lay down regular type IV XPS (25psi) foam (lowes kingspan or foamular 250) and a layer of 3/4″ underlayment on that (either plywood or OSB) and screw that sandwich down onto the existing subfloor.
Any problems with that plan? Anything about this that’s going to turn out to be a real bad idea? I really don’t think the floor needs to be insulated (the shed is tiny and I could just put a rug down) but it’d be nicer if it were insulated somewhat.
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