Lignomat offers in-situ RH test kits, pinless and pin meters  to measure concrete moisture.

Pin and pinless meters give instant results and can detect areas of low and high moisture levels. However, the readings are not reliable enough to determine whether or not resilient floor coverings or coatings can be installed. The in-situ RH test method is recommended before installing floor coverings.

Comparison:  RH in-situ – Pinless- Pin – Calcium Choride

Why drilling holes for in-situ probes is necessary?

Concrete slabs are an integral part of a building. Excess moisture in the slab will over time be released and can affect the entire structure — from walls, to floor coverings, to interior decorations. Not to mention serious health problems caused by mold.

Moisture tests of concrete slabs are usually conducted to determine whether or not floor coverings or sealers can be applied or to find out why a problem occurred. To give reliable results, the test needs to show, that the middle of the slab is dry. It is not enough to show the surface has dried out.

A slab freshly poured or centuries old is dry if:
– all free water is bound within the concrete
– an equilibrium with the surrounding air has been reached
– no other moisture source (e.g. ground water) is available.
– concrete is a hygroscopic material, which will absorb any water spill —like a sponge.

Graph 1:  If a slab is not entirely dry and the surface is not covered or sealed, the moisture distribution within the slab is uneven. The slab is loosing moisture through the surface, but the core still has a higher moisture level.
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Graph 2:  Once the surface is covered or sealed, moisture inside the slab is trapped and over time distributes itself evenly throughout the slab. The increase in surface concrete moisture can damage resilient floor coverings. Floor installers need to make sure, that no extra moisture is hiding in the core of the slab.
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Graph 3:  RH probes measure the evaporation from the concrete at the depth of the hole. No other test measures moisture at the mid section of a slab. Many floor covering manufacturers recommend the RH test for its accuracy and great reliability. Limits for RH values are now given for most floor covering materials, sealers and glues. ASTM standard F2170 regulates the test procedure. Lignomat’s RH BluePeg system is in compliance with ASTM F2170.
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Graph 4:  The Calcium Chloride test cannot detect core concrete moisture, it only takes into consideration the top section of the slab. In addition, the evaporation measured by the test depends on the ambient condition around the slab.
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Graph 5:  Handheld pin and pinless meters should only be used for quantitative measurements to show high or low moisture areas and not to determine whether or not resilient floor coverings should be installed.

Choose the Ligno-VersaTec, if you are looking for a do-it-all combination meter: RH – pin – pinless.

Questions? Call Customer Service at 800-227-2105