Floor covering manufacturers whether producers of tile wood carpet or high performance floor coatings publish the maximum allowable moisture content of the concrete over which their flooring products can be installed based on results of various astm.
Flooring damaged by vapor drive and calcium.
Standard test method for measuring moisture vapor emission rate of concrete subfloor using anhydrous calcium chloride.
How to remove calcium chloride residue from flooring.
The majority of commercial and industrial buildings are constructed with a concrete substrate laid over prepared soil called slab on grade.
In extreme cases when you started with wet concrete or when the ground beneath the slab is very wet the floor can actually be damp and slick and moisture will condense beneath objects placed on the slab.
Delamination or raised fluid filled blisters are often seen as the direct result of moisture or vapor drive issues.
The calcium chloride vapor emission test was developed in 1950 to measure the volume of water vapor radiating from a concrete slab surface over time.
Grout or cementitious bonds.
Extrapolated test data is reported as pounds of moisture vapor being emitted from the concrete subfloor over a 1 000 square foot area during a 24 hour period.
Water vapor from the floor can make rooms more humid which can be a concern with new tighter home construction.
Water or more importantly water vapor will migrate to the surface when there is a higher vapor pressure in the concrete than in the air above the surface 4 in many cases testing for moisture vapor transmission on new buildings is done prior to enclosing the building to allow the flooring contractor to proceed.
Moisture vapor pressure in a floor slab is generally very low relative to a well adhered floor covering moisture vapor emission rates can be assessed qualitatively astm d4263 plastic sheet method and quantitatively astm f1869 anhydrous calcium chloride method moisture vapor can condense to water in a slab.
Through concrete the calcium chloride test procedure appears to be the most reliable test available.
Calcium chloride is a salt like rock salt or sodium chloride and it can come into your house on your shoes through pores in a concrete.
The difficulty of course is that if the moisture barrier is compromised in any way moisture from the slab beneath can still damage the flooring or finish.
For floating floors manufacturers often recommend installing a moisture barrier between the subfloor and the floating floor to prevent moisture intrusion.
