If the concrete slab is at a temperature that is not at least 10 degrees F (5 degrees C) above the dew point of the room, condensation will form on the concrete, that cannot be seen by the naked eye, creating all sorts of issues with your coating or floor covering.
This video, presented by David from Tramex Meters, talks about the features of the digital Concrete Moisture Encounter, the CMEX5.
Ambient Dew Point, Surface Temperature, %MC of the top 3/4", %MC In-Site, and %RH In-situ.
In this video, we learn how to turn the Beeper on and off on the Tramex Moisture Encounter 5 (ME5).
When using a Tramex Concrete Moisture Meter on clean new concrete 4.5% MC is considered "dry" in most conditions. In drier conditions, 4% MC is considered "dry". In Desert conditions generally, 3.5% is considered "dry". These numbers are %MC numbers on our Concrete Moisture Meters that are Calibrated specifically for concrete based on Gravimetric testing.