Three types of moisture conditions may exist which will forewarn of possible moisture problems:

1. Concrete floor moisture - Concrete floors directly in contact with the ground are never completely dry. Also, the moisture content of new concrete is high, regardless of grade levels. Resilient floors may be seriously affected when installed directly over wet concrete which is not sufficiently dry. 2. Wood floor moisture - Wherever a wood floor is constructed over an inadequately ventilated crawl space, resilient floors are not recommended. Crawl spaces must be at least 18 in. (45.72 cm) high and cross-ventilated. Wood floors constructed on sleepers directly over concrete slabs are susceptible to moisture penetration. Such moisture is trapped under the resilient flooring, resulting in deterioration of wood fiber. For this reason, resilient floors are not recommended for installation over this type of subfloor. 3. Surface moisture - Resilient floors may be installed in areas where excessive moisture exists.