A Day On Wikipedia

Concrete moisture meters are designed to detect moisture to a depth of 1’ of a [[concrete slab]] in order to avoid the [[rebar]] reinforcement below the surface.<ref>Why are We Still Having Problems with Moisture? http://www.concreteconstruction.net/industry-news.asp?sectionID=718&articleID=616752
ASTM F 2170</ref> They are designed to be used as a relative test. The meters are used to ‘‘Spot check’ the top surface at one particular location on the slab.’ <ref>’Concrete Moisture Meters and Calcium Chloride Tests: There Are Better Ways to Test Concrete for Moisture FCI’ http://www.fcimag.com/Articles/Feature_Article/BNP_GUID_9-5-2006_A_10000000000000187293 </ref> The results can determine where the best place to put a concrete [[relative humidity]] test.

To determine if an area has high surface moisture, a known dry area should be first tested and then compared to a reading from the area in question.

==Why concrete moisture meter should not be used as a final reading.==

There is no [[ASTM]] standard for using a concrete moisture meter to determine a final moisture content reading.

Concrete moisture meters, either non-pin or pin meters are affected by what it sees in the concrete. This can be anything from the [[density]] of the concrete and [[construction|aggregate]] size to the chemical properties in the slab.<ref>Accurate Relative Humidity Testing Vs. Testing With ‘Moisture’ Meters: KNOW THE FACTS http://www.wwwagner.com/news.php?a=detail&id=33 </ref>

Uncovered concrete dries from the top down. Concrete moisture meters measure only the top inch at most and this area is drier than the concrete further down. Once a [[floor covering]] has been installed the moisture in the slab [[equilibration|equilibrates]].<ref>How Confident Are You In Moisture Testing? http://www.ntlfloortrends.com/Articles/Column/BNP_GUID_9-5-2006_A_10000000000000217849</ref> In order to ensure the equilibrated moisture will be a safe level for a floor covering, a relative humidity sensor must be drilled and placed at 40% of the depth of the slab.<ref>ASTM F 2170, ’Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes,’ ASTM International.</ref> This depth has been proven to be the relative humidity percentage that the slab will equilibrate once the top has been covered by a floor covering.

== References ==

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