How to Repair Cinder Blocks With Water Leaks

Remove the soil from the outside of the cinder block wall. Break up the soil with a pick axe and shovel it into a nearby pile. Clean the cinder blocks with muriatic acid and an acid brush. Mix water and acid to a ratio of 4 to 1 in a 5-gallon bucket. In other words, mix 1 gallon of acid to 4 gallons of water to make an acid cleaning mix.

Scrub the cinder block vigorously with an acid brush and wash off the wall with a garden hose. Let the blocks dry completely.

Apply tar to the exterior of the cinder blocks using a tar brush. Begin at the bottom of the cinder blocks where they meet the footer, saturating the blocks and joints. Allow the tar to dry for two to four hours.

Place gravel and perforated pipe at the base of the cinder blocks to channel away excess water and prevent water infiltration. Place 6-inch perforated pipe at the base of the wall with the holes facing up.

Extend the pipe out beyond the wall for 4 feet. Cover the pipe with 6 inches of gravel. Replace the soil against the wall directly over the gravel and smooth it out.

Clean the interior of the cinder blocks with a stiff brush and TSP (trisodium phosphate). Add one box of TSP powder to 2 gallons of hot water. Scrub the wall and wipe it down with a wet sponge. Allow the wall to dry.

Apply Dryloc paint to the wall to prevent leakage from the cinder blocks. Roll on the paint, beginning at the bottom and working up. Paint in the corners and block joints with a paint brush. Apply three coats, allowing one hour drying time between coats.