Signs a Concrete Floor Has Moisture Issues
The majority of commercial and industrial buildings are constructed with a concrete substrate laid over prepared soil, called slab-on-grade. Floor covering manufacturers publish the maximum allowable moisture content of the concrete over which their flooring products can be installed, based on results of various ASTM test methods. Floor moisture and moisture vapor can be cause for concern, whether the slab is newly poured or many decades old, and regardless of location. Moisture issues in concrete floors tend to arise from either the concrete mix itself — in the event the slab is insufficiently cured or is otherwise holding moisture — or the soil under a slab-on-grade is making its way through an improperly functioning vapor barrier. A concrete surface can easily give a false impression of being dry enough despite containing moisture well above the allowable limits because it is never completely free of moisture and it is pourous. The earlier any problems are noticed, the sooner you can act and help mitigate adverse outcomes. Concrete slabs should be subject to a moisture test, a calcium chloride test, and a relative humidity test, and to do these properly, floor coverings should be removed, as well as any mortars, grouts or adhesives.