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Wingnut Moisture Test

dfvellone | Posted in General Questions on

Will taping a piece of clear poly to a concrete slab offer a good idea of moisture content?

Is there a minimum size required for an acceptable test result?

Will room temp and concrete temp affect results?

Thank you, Daniel

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  1. darrin_k | | #1

    Funny, I was researching this very thing today. There are very affordable and simple Vapor Emission Test Kits available that follow the ASTM F1869 standard. A pack of 3 from Humboldt Construction Materials Testing Equipment is $36. Seems easy to use.

  2. Expert Member


    Yes, although it's worth remembering it only give you a snapshot in time. A slab without a functioning vapour barrier may be dry for part of the year and not others. The poly test is better at telling if you have a problem, than telling if you don't.

    1. dfvellone | | #3

      I believe that the foundation is well protected from the intrusion of moisture and hoping that testing it might offer a general idea of the year-round moisture content: I poured the concrete over a 20" base of crushed stone on a site that slopes away on all sides and is well-draining. I used vaporblock 15 along with the xps insulation beneath the concrete, and I have deep overhangs and perimeter drainage.

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