Does anyone know if there is a problem having hardwood flooring in a home built on a cement slab (no basement), that has a high water table and is located close to the ocean? No moisture has ever come up through the slab, but someone at a home center told us we might have a problem with warping because of the high humidity. Any advice would be appreciated. Thanks! Rico |
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Here are several tests that you can do to tell if the moisture content of the slab is an issue. I got these from http://www.nofma.org/
TESTING CONCRETE FOR EXCESSIVE MOISTURE.
1. The Rubber Mat Test. Lay a smooth, non-corrugated rubber mat on the slab, place a weight on top to prevent moisture from escaping, and allow the mat to remain 24 hours. If the covered area shows water marks when the mat is removed too much moisture is present. This test is worthless if the slab surface is other than light in color originally.
2. The Polyethylene Film Test. Tape a one-foot square of 6 mil clear polyethylene film to the slab, sealing all edges with plastic moisture resistant tape. If, after 24 hours, there is no "clouding" or drops of moisture on the underside of the film, the slab can be considered dry enough to install wood floors.
3. The Calcium Chloride Test. Place a quarter teaspoonful of dry (anhydrous) Calcium Chloride crystals inside a 3-inch diameter putty ring on the slab. Cover with a glass so the crystals are totally sealed off from the air. If the crystals dissolve within 12 hours the slab is too wet.
4. The Phenolphthalein Test. Put several drops of a 3% Phenolphthalein solution in grain alcohol at various spots on the slab. If a red color develops in a few minutes, too much moisture is present.
The only thing I know about it is if you do glue it, do not use a latex based adhesive. Any moisture in the slab (and concrete always has some) will weaken the adhesive. You can also do some type of sleeper system, if height is not an issue. That will at least keep it off the slab.