Before putting a protective coating or flooring materials to a concrete slab, verify the moisture level has fallen to appropriate levels—typically ≤75% Relative Humidity (RH), 3 lbs/1000 sq. ft./24 hours MVER, or less than 5% moisture content (MC). If not, moisture may accumulate beneath the coating or flooring, resulting in discolouration, cupping, buckling, blistering, adhesive failure, and/or mold growth. There are several methods for measuring concrete moisture. The two most prevalent approaches use non-destructive electronic impedance meters (ASTM F2659) or in situ relative humidity probes (ASTM F2170).