Homes with basements are becoming a hot button as buyers try to stretch their housing dollars by finishing off below-grade space into usable living areas. An insulated floating floor system not only warms the basement floor slab but also enables a wider variety of flooring finishes.
Make sure the slab is flat and even. Use a self-leveling slurry to make sure or mitigate any low/high spots and cracks. Set a 1/4- to 1/2- inch drainage mat directly on the slab, topped with a sheet of polyethylene, to protect the floor finish from incidental moisture. Tape all seams and joints/overlapping edges.
To add insulating value, place 2-inch-thick, R-10 foam insulation panels over the drainage mat/visqueen layer and use recommended joint tape at all panel edges and along the perimeter to seal it against air leaks.
Install a tongue-and-groove wood subfloor (also taped/sealed) on which you can install a glueless engineered-wood plank system, laminate flooring, carpet, resilient surface, or ceramic or stone tiles.