Wood Flooring Over Concrete Slab

Q: I am looking to have a hardwood floor installed. My house is on a concrete slab and I do not have water seepage problems. Is it better to have the floor glued down or layered over an underlay of plywood?

A: For best results with laying a hardwood floor over concrete, I would suggest a floating floor system where the floor is not glued to the concrete. One example is Harris-Tarkett longstrip, which is installed over an underlay consisting of a moisture barrier and foam. The wood is glued to itself by tongue and grooves.

I have seen a floor like this installed over a concrete slab, which does have a little moisture emission problem. After 8 years, it still looks great.

Wood flooring is a major investment, so always have the concrete checked for moisture prior to installation. Remember, carpet is porous and vapor emissions that wouldn't usually show up with soft goods can cause problems in harder floors, including wood and vinyl.

John Fuchs, Carpet Warehouse, Rancho Cordova, CA