If you have made the decision to refinish your basement, the renovations probably include the installation of a new carpet. In order to prevent moisture and mildew from penetrating the carpeting, it is important to prepare your concrete basement floor prior to the installation. This includes giving the concrete floor a thorough cleaning, which will ensure that there is no debris trapped between the concrete floor and the carpet padding, and adding a sealer that will keep your carpet dry.
Remove all dirt and debris from the concrete floor. Sweep the concrete floor with a stiff broom, or vacuum the concrete with an attachment specially designed for hard floors.
Mop the concrete floor using a bleach solution. Pour approximately a gallon of water into a large bucket; add a few squirts of dish soap and a capful of bleach. Apply the bleach solution with a mop. The bleach will kill any bacterial growth that is on the concrete floor before the carpet is laid down.
Rinse the floor with clear, hot water. This can be done by using a second, clean mop. It is important to remove as much of the excess bleach and soap as you can.
Allow the concrete floor to dry thoroughly. You can use floor fans to help speed up the drying process. It may be necessary to move the fans around to help the floor dry evenly.
Seal the concrete floor using a commercial sealing product. Sealers are usually applied with a paint roller and are effective in preventing moisture from entering your carpeting and padding. Allow the sealer to dry according to the manufacturer's recommendations before beginning the installation of your new carpet.
A shop vacuum also works well for the initial concrete floor cleaning. Shop vacuums have strong suction and are able to pick up larger pieces of debris than a traditional household vacuum.
Never install carpeting on a floor that has just been washed. The floor will need at least a few days to dry thoroughly. If you carpet the concrete before it is dry, it will be prone to mould and mildew. Make sure that the basement windows are open to ensure proper ventilation when you are cleaning with the bleach solution.