Fix-It Chick: Waterproof a concrete floor

Drylok Clear Masonry Waterproofer is one of the first non-pigmented products designed specifically for use on bare cement floors and other surfaces. Applying a waterproofing product such as this on basement floors can create a vapor barrier beneath adhesives and new flooring, and it can reduce seepage caused by hydrostatic pressure.

Step 1: The first step to a dry basement and sound foundation is to route as much moisture away from the home as possible. Grade soil so that the ground slopes away from the foundation at a rate of 2 inches per foot or more. Keep shrubs and plants a minimum of 12 inches from the perimeter. Clean and repair gutters, making sure downspouts direct water at least 5 feet away from the home’s foundation.

Step 2: Use hydraulic cement and self leveling polyurethane caulk to seal cracks and crevices in foundation walls and on the floor surface.

Step 3: Spread a bead of caulk around the basement floor perimeter to seal the crevice between the walls and the floors.

Step 4: Install a sump pump and/or French drain to keep excessive water at bay.

Step 5: Thoroughly clean the surface to be sealed and remove any white powdery efflorescence with a mild muriatic acid etching compound.

Step 6: Sprinkle a few drops of water on the floor to test the porosity. If the water is not quickly absorbed into the concrete, further etching of the surface is required before proceeding.

Step 7: Verify the floor is completely dry by taping a 12-inch square piece of plastic to the surface, using duct tape to seal all four sides of the sheeting. Wait 24 hours and remove the plastic. If any moisture is detected on the underside of the plastic, the floor is not sufficiently dry.

Step 8: Use a good-quality stain and decking brush or a 3/8-inch nap roller to apply the first coat of waterproofing sealant. Work the sealant into the pores and natural crevices of the concrete using vertical strokes across the flooring.

Step 9: Allow the first coat to dry for four hours and apply a second coat. Brush or roll the second coat horizontally across the floor to create a uniform appearance.

Step 10: Wait at least 24 hours before allowing heavy foot traffic.

Drylok Clear Masonry Waterproofer can also be used on exterior surfaces such as walkways, patios, chimneys and foundation walls.