08-23-2010, 05:54 AM
Well...no "sand" below the slab. We cored the slab at a couple of locations a week after the probes were installed to check the slab thickness and to see if there was a vapor barrier. Slab thickness was 5 7/8 inches and beneath the vapor barrier was "virgin soil" consisting of a silty sand. All of the probes are placed well within the interior of the slab, 50 to 75 feet from the perimeter.