Acceptable Moisture Levels In Concrete

How moisture gets into concrete.

Acceptable moisture levels in concrete.

Over time hydrostatic pressure will force that moisture upwards and can cause bubbles in surface treatments and cracks in covering materials that are installed above it. Concrete slabs often have thicknesses measured in feet not inches. Some flooring system manufacturers have products that can handle 95 rh or mor. Acceptable moisture levels in concrete.

Ed wagner answers the questions visit http www rhspec. What are the acceptable moisture levels in concrete. With a typical concrete floor about a quarter to a third of the original water content will evaporate which could be 6 to 9 l m 2 for a 150 thick slab. If excess moisture is present in a concrete slab when an impermeable surface treatment is installed it will become trapped under that covering.

Therefore if the air inside the box measures less than 75 percent it can be assumed that the mois ture content of the concrete is less than 5 percent. Moisture meters can only check the moisture near the surface of a concrete slab which is not sufficient for predicting how the slab will react to having sealant applied or other building materials installed over it. Acceptable moisture levels in concrete according to astm standard when testing via astm f2170 the rh level of a concrete slab needs to be at or below 75 unless the flooring system manufacturer provides alternate guidelines. If the concrete is at 5 percent moisture content it will neither absorb nor desorb moisture if the air above it is 70 f 21 c and 75 percent rh.