Q.: We've heard of the mat test for moisture in concrete. Where can we find out more?
A.: The moisture and surface-bonding characteristics of concrete slabs that are to receive floor coverings of rubber tile, solid vinyl tile, and vinyl sheet may be checked with the mat moisture and bonding test. The test may also be used before placing any resilient flooring on slabs from which paint, oil, adhesive, curing compound, or other coatings have been removed. The test is performed by placing 24-inch (600-mm) square linoleum or vinyl sheet mats on two adhesive bands -- one a water-soluble adhesive, the other a water-resistant latex adhesive. The edges of the mats are taped to the floor. After 72 hours, the mats are removed and the adhesives examined. The presence of too much moisture will partially or completely dissolve the water-soluble adhesive, while the water-resistant adhesive will be stringy with little bond. If after further drying and retesting, moisture in the slab still affects the adhesives, more moisture-resistant alternate flooring materials should be used. An ASTM Standard is being developed.