Jacob, I had a concrete slab floor, cracked and subsided in one corner (hence the cracks). I could not be sure about Damp Course, so...I dry/slightly damp mixed some sand and cement, levelled things up, let it dry. Laid 10mm sand, followed by a 1200 guage D.P.M., then 50mm Celulite, sorry, Celotex, then glued-at-the-joins 19mm chipboard to form a floating floor. I had to 'edge' it with hardwood at rhe door sill - 8' wide - to protect the chipboard edge.
I have a Wadkin AGS10 sitting on it, along with a heavy bench, planer/thicknesser, floor-mounted drill press, bandsaw, two DX's, a Jet 1221 lathe on its stand and am ust about to drag in a quarter-ton mortiser. No issues whatsoever on settlement, dents, sagging, yada. yada. The construction allows the weight to be distributed over a wide area. The wooden floor is warm and comfortable to the tootsies, edge-friendly to dropped sharp tools.
Sam