MOISTURE AND FLOOR COVERINGS
Moisture related problems are the greatest cause of installation failures of resilient floor coverings.
In order to form a bond between adhesive and concrete, the concrete surface must be dry, or better
stated, Not "water wet". If any part of the surface is water wet, the adhesive will bond to the water instead of
the concrete unless the water is displaced. Areas may be water wet for a variety of reasons.
- Excess of water from hydration within the the slurry.
- Shrinkage cracks opening permeability (capillary)
pathways to the surface.
- Structural cracks/imperfectly sealed joints providing capillary pathways to the surface.
- Condensation
due to temperature inversion between the area below and the area above the concrete
Because the specific composition of the concrete can and will vary, it is difficult to determine what the moisture content
must be for each and every concrete slab.
It is not the amount of moisture contained in the concrete
that causes failures, but rather it is the amount of moisture that is being emitted from the surface that will cause the failure
The moisture tests that will give you a qualitative
and quantitative result is the emission of moisture from the concrete is the calcium chloride test unit and relativity humidity
tests. These test procedures are the mostly recognized by most manufactures.
The emission of moisture vapor from the floor shall not be more than 3- 5.0 pounds per 1,000 square
feet per 24 hours for both linoleum and vinyl products.
It is the responsibility of the flooring contractor to either conduct the moisture test or to have the test results
provided to them prior to beginning the installation. The results should be documented and saved. If the test results exceed
those recommended by the manufacturer, the installation must not proceed until the problem has been corrected.
When moisture tests are conducted, it indicates the conditions only at the time of the test. The flooring contractor
cannot be held responsible if moisture appears in the future, causing a failure.
