No matter how hard, dry and well-cured a concrete slab may appear, it contains moisture. How much moisture depends on many factors, including how the concrete was mixed, humidity, temperature, and cure time. In any case, some level of moisture exists throughout the slab and tends to migrate up to the surface over time. Often, concrete that appearsto be well-cured on the surface contains considerable moisture that will gradually work itself up, resulting in post-installation problems months — or even years — later. When moisture escapes to the surface, problems such as mold and mildew growth, and floor covering failure, often occur.
The suppression of moisture in concrete slabs has always posed problems for general contractors and installers. Now, with tight project timelines combined with climatic and environmental variables, it's an even bigger challenge. Practically all floor coverings require the assurance of low moisture emission levels in concrete before allowing warranted installation. And most liquid moisture barrier systems require surface conditioning, which takes time. Until now, contractors and installers were faced with two equally unattractive alternatives: wait and risk project delays, or install the floor over an unstable, high-moisture slab.
With VersaShield Underlayment, GAF-Elk has taken over 50 years of experience in developing roof moisture control systems and applied that technology to the floor. This patented coated fiberglass reinforced membrane provides superior moisture suppression at a modest cost.
VersaShield Underlayment suppresses moisture in difficult concrete surfaces with moisture emission as extreme as 12 lbs/1000 ft /24 hrs to below 3 lbs (ASTMF1869). Its low moisture perm of .04 (ASTM E96) means it blocks moisture to the floor covering.
