How To Fix Water Leaks With Expanding Foam

Water leaks in concrete are common in basements that have begun to age. Using expanding polyurethane foam is one of the best ways to stop water leaks because the foam will expand into the cracks and help prevent future leaks. You don't need chisels or drills as the polyurethane will enter into any existing cracks and seal them. Expanding foam bonds to any type of surface and will quickly and effectively solve your water leak problems.

Step 1

Put on the safety glasses. Scrub the surface of the cracked area with a wire brush. Make sure to eliminate all loose fragments and use the hand broom to completely clean the area and prepare it for the foam. Dry the area with a towel if it is wet, and let any dampened surfaces dry for at least 24 hours before attempting to spray foam into the cracks.

Step 2

Put on the mask and safety glasses before spraying the expanding foam. Shake the can according to the manufacturer's instructions (they will vary depending on the brand) and attach the tube applicator, as indicated on the can's instructions. Insert the other end of the tube into the crack and press the trigger to disperse the foam. Spray into the void until the foam is just short of filling it, then work your way from the bottom up.

Step 3

Spray a light layer of foam on any areas where hairline cracks are beginning to show. Spread the foam quickly over the surface with the putty knife to smooth the foam over the area where cracks are just starting to form. Let both areas dry for at least 24 hours.

Step 4

Cut any excess foam off with a utility knife. Smooth the remaining edges with sandpaper or a rasp until the foam is flush with the face of the wall or other area where you just filled the crack. Finish the surface as your personal preference dictates (such as with paint, wood paneling, tile or wallpaper).