Nearly every home in Seminole County and Orange County, FL sits on a concrete slab. That’s just how Central Florida was built. And concrete slabs — especially older ones — don’t just sit there. They wick moisture upward from the ground, continuously, and that moisture has nowhere to go except into your flooring. Homes built in the 1970s, 1980s, and early 1990s — a huge portion of the housing stock in communities like Longwood, Casselberry, Altamonte Springs, Maitland, and Winter Park — were constructed before modern vapor barrier requirements existed. That means the slab beneath your floors may have been moving moisture upward for decades, and no one has ever tested it. A surface moisture meter only reads the top layer of the slab. It won’t catch what’s happening deeper inside, where moisture migrates up from the soil. That’s why we use in-situ relative humidity probe testing — the method required by ASTM F-2170 — which takes a minimum of 24 hours to complete and gives us an accurate picture of what’s actually happening inside your slab. Most hardwood manufacturers require the slab to read 75% relative humidity or lower, measured at 40% slab depth, before installation can begin. If we’re above that threshold, we address it with the right vapor barrier or moisture mitigation system before anything else happens. You can’t rush this step, and we don’t try to.