How to Repair a Cement Basement

Wear safety goggles when working with loose debris. Chisel out the damaged area with a sledgehammer and cold chisel. Remove any loose pieces and create a smooth surface around the edges of the chip or crack.

Clean out the damaged area with a brush, broom or compressed air. Remove all dust and debris from the area to ensure a strong bond between the cement and the repair patch.

Paint a thin layer of concrete bonding adhesive around the edges of the damaged area. The adhesive will help to ensure a strong bond between the patch and cement surface while the repair work dries; this can be especially important on vertical repairs, such as those in your basement walls.

Mix hydraulic cement or patching compound and additives as recommended by your specific product instructions. Different products will require different additives at different ratios, so follow product instructions carefully.

Fill in your damaged area, using a mason's trowel to apply the cement patch. Cover the edges of the crack or chip in a thin layer of the patch first, then continue to add thin layers until you have filled in the entire damaged area.

Scrape the flat edge of your trowel over the repair work to flatten it against the rest of the surface. Allow the repair work to dry overnight before making any other changes.