A basement floor is usually below grade and made of cold, hard concrete. As a result, it's cool. Some homeowners believe that laying carpet directly onto the concrete floor will be fine and in many cases it is. If you want to be sure you have a warm and dry basement floor, though, you should consider installing a subfloor.
Polystyrene Insulation and Plywood
The time-honored way to ensure a warm basement floor is to lay polystyrene sheets directly onto the concrete floor and cover them with plywood. Fasten everything with concrete screws driven into pre-drilled holes right in the basement floor.
With the subfloor, you will have a warm and solid wood base that can support any flooring solution. The downside to polystyrene applications is that they raise the floor by several inches. Since most basement ceilings are less than 8 feet high to start with, that can be a problem, especially for your taller guests.
Alternatively, you can apply new products that are designed specifically for basement subflooring. They use interlocking sections of wafer board that is permanently attached to a dimpled rubber or plastic layer.
The backing is impervious to moisture. The dimpling allows air and or moisture to circulate underneath the flooring. These products have several advantages. They only occupy an inch of space, and they are laid in one step.
Either of these subfloors will provide a great base for whatever type of flooring you install. Carpet, laminate floors, and tiles can all be laid over your subfloor and you'll never have a worry.
Click to continue to Part 4 of the series, which will discuss walls.