The room has a concrete floor that is above grade by about a foot or so. We wanted to install conventional hardwood flooring, but that would mean a subfloor be built and that would raise the floor above the sliding doors. So instead we went with an "Engineered Hardwood" floor by Kahrs. This floor is 3/8" Ash hardwood bonded to a lay of plywood. This floor can be nailed down, glued down, or floated over concrete. So we floated it. Even though the concrete is dry as a bone, we installed the vapor barrier to retain the floor warrentee. Floor is a locking tongue and groove install that is hammerd together. Fits tighter than anything I ever saw. Again, I got a lot of help from Jamie.