Hardwood floor on slab
I plan on installing hardwood on a concrete slab.
Slab was poured ~1968
Zone 6, Vermont
At some point looks like someone laid 4-6 mill plastic on the original slab then poured ~1″ concrete on top.
Slab seems very dry, there is a clik cork floor on top of thin white foam for floating floors laid right on top of the slab with no plastic, no mold or wet cork.
Also there is some existing wood flooring that i will take up, under it is: paper, 1×3 pine, 6mil plastic the carpet glued directly to slab, smells musty but not wet or moldy.
I would like to create a thermal break with minimum height, here is my plan:
– 1″ polyiso with foil face cut into 12″ strips with a 3/4″ deep by 3″wide lap cut on one long edge This will give 1/4″ foam under the wood strap creating a small thermal break between the strap and the concrete. It adds an overall height of 1/4″ over just installing the straps directly to the concrete, not sure if that is worth it or not. 1/4″ isn’t that much but i have transitions to deal with.
– Will power nail 3/4″ x 3″ plywood strips in the lap joint thru the foam directly to concrete
– Will caulk between each rigid foam piece.
– Will nail the 3/4″ hardwood to the straps
Is there a better way to do this? Cheaper?
Is poly iso the right stuff? or xps? I don’t even think the xtra r-value of the polyiso would make a difference plus it costs more.
Should i use Plastic on the slab? is it cheap insurance, or a waste.
Should I use something between the hardwood and the foam for squeaks, etc?
In the end I don’t think I would gain much, just comfort level of hardwood on foot, do you agree?
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