Measuring Moisture in Slab
Hope everyone is doing well. I want to have some measure of the current moisture levels in my slab to get a better idea of exactly what I’m dealing with before installation of floor. I was thinking about using a calcium chloride test, a 3 pack on amazon is about $40. The flooring manufacturer recommends a maximum of 8lbs per 1000. What will the test results determine? If it’s above 8lbs and I add poly sheet do I retest with the vapor barrier? The flooring manufacturer recommends:
6mil vapor barrier or similar barrier with less than 1 perm rating
A optional 2nd layer of underlayment with a max thickness of 3mm (they make a recommended underlayment)
Then finished vinyl floor with or without attached underlayment
If I build a eps/plywood subfloor I would think I need poly or vapor barrier underneath the foam if the moisture content is very high. However with a dehumidifier controlling condensation and moisture in room, the vapor from concrete would have to travel up through the poly, past the 1.5mm foam underlayment, and through attached underpad of the flooring to cause mold underneath. Riskier than building the eps and wood subfloor but just sounds unlikely to me.
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