It didn’t strike me as reasonable to use a floating substrate underneath ceramic tiles when I first heard about it either, so I checked into it. As it turns out, the Tile Council of North America completed official testing of tiles on Tyroc using a heavy, rotating device called the Robinson-type floor tester. It applies hundreds of pounds of pressure to tile installations, and depending on how the tiles and grout survive, various application designations are proclaimed. Tiles on Tyroc meets the requirements for residential applications in kitchens, bathrooms and foyers. I know from experience installing this product that you should let it sit for a few days before tiling so it conforms to undulations in the concrete underneath. You’ll need gap-free contact between the Tyroc and the underlying floor for reliable tile performance, regardless what designation has be earned.