Concrete is a mixture of sand, aggregate, Portland cement and moisture, which is poured over compacted clay or soil, crushed rock, and a vapor retardant barrier. It cures slowly and continues to release and absorb moisture throughout its use-life. When contacted by Category 1 water, concrete absorbs moisture over time and releases it slowly. Concrete can resist microbial growth and amplification because it is inorganic, relatively cold and alkaline, although microbials can eventually grow and amplify on soil films.
After removing excess moisture, concrete should be dried using a combination of controlled dry air movement across its surface, combined with ambient temperature control or even direct heat application. Concrete can be dried with porous floor covering materials remaining in place; however, non-porous flooring materials installed over concrete subflooring should be removed to allow efficient drying.
In certain instances, especially concrete slabs with water forced through them, due to hydrostatic pressure, are particularly difficult to dry. Until external hydrostatic pressure is relieved from outside, such as a drainage system, water vapor continues to force its way through the slab. In most cases, if finished flooring is installed over a slab that is wet from subsurface water, the finished wood floor is not salvable.