How to Waterproof a Basement Cement Floor After Water Damage

Clean the floor thoroughly. Sweep up loose dirt and debris with a broom. Fill a bucket with 1 gallon of hot water and ¼ cup chlorine bleach. Scrub the floor with the bleach solution and a stiff scrub brush. Allow the floor to dry completely.

Patch any cracks or holes in the cement floor. Use a putty knife to force a cement patching compound into the cracks and holes. Smooth out the patching compound until it is level with the existing floor. Allow the patching compound to dry completely.

Choose a sodium silicate waterproofing sealer for the cement floor. This water-based type of sealer will prevent water vapors and moisture from entering the floor. You can purchase cement waterproofing sealers at most home improvement centers.

Stir the can of waterproofing sealer thoroughly with a paint stirrer. Pour the sealer into a paint tray with a liner.

Dip a medium-nap paint roller into the tray to absorb a generous amount of sealer. Roll the sealer onto the basement floor in a thin, even coat. Overlap your roller marks to be sure that all of the floor gets covered. Apply the sealer into corners and hard to reach areas using a paintbrush.

Work in 10-foot-by-10-foot sections when applying the sealer. Allow each section to dry for 10 to 20 minutes, then apply a second light coat. For best results, apply a third coat of waterproofing sealer after the second coat has dried for 10 to 20 minutes.

Allow the final coat of waterproofing sealer to dry according to the manufacturer’s instructions. This may take a few days before the floor is suitable for foot traffic.