Moisture-related flooring and coating problems are one of the most serious and costly of construction-related issues being faced by owners, contractors, design professionals, installers and manufacturers. Each year, hundreds of millions of dollars are being spent to correct such problems and deal with the legal disputes that follow.
Conventional concrete slab mixtures always contain more water than the concrete hydration process actually requires. This “water of convenience” or “free water” is necessary to create a mixture that can be satisfactorily pumped, placed, screeded and finished. Some of this free water leaves the slab during the bleeding process, but further loss of moisture takes place as the slab dries over time. If an adequate vapor retarder/ barrier lies directly beneath a slab on ground, eventually the slab becomes dry enough for safe installation of flooring materials.