flooring choices for finished basement with concrete-free floor
We are about to do floors on our new Maine home: climate zone 6; sloped lot, super-insulated (including concrete basement walls), concrete-free basement slab. My contractor is concerned with my choice of using wood (pine) flooring below grade.
Incorporating helpful advice from GBA, the slab consists of 6″ layer of 2″ crushed rock, then geotextile, then 2″ layer 1/4″ crushed gravel , then 2 layers of 3″ thick EPS foam, then heavyweight plastic sheeting taped continuously to same layer on basement walls, then 2 layers Advantech. Exterior of basement coated with thick black coating. Perimeter drains to grade. We had an extraordinarily wet late fall and winter with about 3 very large rain falls and no evidence of leakage.
I think the construction makes it unlikely we will have issues with condensing moisture in basement. Obviously, we could have a flood from plumbing mishap or unexpected water intrusion. We have no interest in vinyl or ceramic tile; Marmoleum nice but pricey.
Your thoughts?
Many thanks, Dorothy
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Your floor system sounds robust. Do you know what was used to backfill the foundation walls? Where do the footing drains lead to?
The black coating is likely asphalt emulsion damp-proofing, and footing drains can clog over time, so there is some risk of flooding, but probably minimal.
thanks michael, footings lead to downhill grade on opposite sides of the house. confirmed asphalt emulsion. backfilled with sand.
I prefer to have one more layer of protection on the exterior, usually either an elastomeric membrane instead of damp-proofing, or damp-proofing with a dimple mat, but a basement with sand backfill and gravity drainage is almost as good. I think there is little chance your basement will flood, but it's always a possibility. I have only had floods on upper levels on my projects, never in a new basement, for whatever that's worth.
maine_dorothy_2,
With a concrete-free slab I'm not sure the type of finished flooring matters as much. Your basement floor structure is already susceptible to water damage, so it's not like choosing a flooring that is more moisture resistant than the pine will eliminate the risk the way it might over concrete.
old trick is to use might 4x4x 3/4" MDF [or strawboard] with 3/4x 1-3/4" [for instance] hardwood contrasting perimeter boards. adhered/pin nailed/screwed and plugged without puncturing your vapor barrier below.
then spring for marmoleum or other when you can justify the expense.