Using the Wagner Rapid RH 4.0 to Measure Moisture in Concrete

Hi, this is Joe Glavin with Philadelphia Floor. Today we’re going to discuss the Wagner Rapid RH 4.0 Meter. Testing the relative humidity of a concrete slab. To test the relative humidity of the slab to make sure that the adhesive we’re going to use will keep the floor in contact with the cement slab. It gives you an understanding of what’s happening inside the slab down a certain percentage in depth so that when that slab is covered and normal airflow across the slab has stopped, you’ve now capped it, there’s going to be a buildup underneath there of the moisture that used to migrate through. So once it’s capped, you want to know what it’s going to be and the only way we can measure that is in the slab, approximately 40 percent depending on how the slab itself is drying. If you’re doing an install of floor covering, period––carpet, tile, vinyl, or hardwood–– you want to know what is in the slab as far as moisture. This is a 5-inch slab. We’re going to do 40 percent of that since it’s really just drying in one direction, which is the top. That’s going to put us at two inches. So I just put a piece of tape down two inches from the bit tip. And this bit comes with the kit, as well as a vacuum nozzle, an insertion nozzle, an insertion tool, four sensors, and a reader. So we’re going to drill down. You’ve got to keep this 90 degrees, perpendicular to the floor, and go down two inches. After drilling the hole, use a vacuum to clean up the debris, then clean out the hole with the supplied steel wire brush. Attach the vacuum nozzle to the hose cup and clean the hole. This is the Rapid RH 4.0 sensor. This is the bottom of the sensor. The reader is placed inside on the brass contacts and measures temperature and relative humidity of the slab. And we’re just going to drive this in by hand. It should just insert straight in. This is the reading mechanism. So that unit is going to read the bottom of the sensor, and this is going to tell us what it says. 68 degrees and 73 percent relative humidity. The Rapid RH sensors from Wagner, when they’re installed in the hole, those sensors can remain in there indefinitely. If there’s ever an issue with glue failure, or the floor’s buckling, or something’s happened, you can pop the board out if you’ve mapped out where you put them. You can pop those boards out or remove that floor covering. You can then re-insert the reader and find out what the moisture of that slab is at that current time. Here are the key points for the use of the Rapid RH 4.0 from Wagner. If you’d like to purchase the Wagner Rapid RH 4.0 Meter or extra sensors, go to

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