Insulate The Basement Floor

Most people are not aware of the fact that not only can they insulate the basement walls – but they can also insulate the floors. Insulating the floors is not as easy – but it can be done without having to hire someone. By doing this you will help to make it a more comfortable room and that much safer from mold and high energy bills!

Before you begin you need to make sure that the floor does not have any problems with water infiltration. If there are any leaks or if during certain times of the year there is standing water in the floors you should just forget about doing anything at all. The water will ruin whatever you lay down. You will first have to fix the problem.

Seal The Floor

Purchase a heavy duty concrete sealer at your local home department store. Don’t buy the cheap product because you will only have one chance to do this. Before you can seal it you need to wash it down to remove any dust and debris. Once it is dry lay down the sealer. It is easier and less messy if you use a paint roller and apply two coats. Each coat will take twenty-four hours to dry.


Now it is time to frame the floor and raise it up. Lay down pressure treated 2×4 lumber (making sure that the flat side is facing down) around the perimeter of the room and secure them to the floor using 3” masonry screws. Lay more down every 16” on center that extend from wall to wall. They all should be going in the same direction.

When you are done you should have them in a grid pattern. Make sure to toe nail the ends of the center pieces into the rim pieces that you installed before. Blocking should be added every three feet in between the perimeter lumber in the opposite direction that they are going in.


Lay down 1-½” rigid foam insulation into the spaces in between the lumber. This is a tough insulation and is resistant to the natural damp that can occur from concrete floors. Also lay down 15” wide board insulation.

Put in a ¾” tongue and groove plywood and lay it on top of the frame. Secure it using 8” galvanized or stainless steel 2” wood screws. Using regular steel fasteners on the wood will damage it over time.