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Community and Q&A

Seal a new slab for wood floors?

rusty52 | Posted in GBA Pro Help on


I just installed a new slab. Slab is approx 5″ thick, and was set up as follows. We dug trenches and laid drain pipes in gravel, fabric wrapped, etc. On top of that another layer of crushed stone, 2″ insulation and then a fully waterproof layer (Grace Pre-Pruf). On top of that poured the 5″ slab.

Plan is to put down pressure treated sleepers, with t&g plywood on top and then put an engineered wood floor on top of that.

So my question is, should I seal the slab with and type of epoxy or other product. My feeling is that the prepruf product will fully seal the slab at the bottom and the added epoxy could just seal any moisture in.

Slab was poured 2 days ago, but I need to keep the contractor going.


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  1. Expert Member
    Dana Dorsett | | #1

    No sealer is necessary in that stackup- the foam + membrane vapor barrier is enough.

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