How to Stop a Basement Wall Leak

cracked concrete
  • 3-6 hours
  • Intermediate
  • $20-80
What You'll Need
Small Brush
Hydraulic cement
Compressed air
Protective gloves and goggles
Mortar trowel

Whether you use your basement as an extra room or just for storage, a basement wall leak is bad news. Not only will the dampness damage your possessions, but it can also cause a health hazard. Fixing the leak as soon as possible makes the job easier and less expensive in the long run. Follow the steps below to fix a basement leak.

Step 1 - Locate the Leak

The source of a leak is not necessarily in the same place that you found water. Trace the water to its source on the wall. Be thorough, as there may be more than a single entry point.

Step 2 - Inspect Crack

Use the hammer and chisel to carefully open cracks and voids. Inspect them for extensive damage or holes. Remember that the cracks which are visible on your wall are not the total extent of the damage. If you simply cover it, the water will find another place to go and you'll have more work to do in the future.

Step 3 - Clear Debris

Use a small brush to remove loose debris in the crack. Once you've got rid of as much as possible, use the can of compressed air for a final tidy-up.

Step 4 - Apply Hydraulic Cement

Wear protective gear. Mix hydraulic cement per the instructions on the packet. Apply the mixed cement to the crack, pressing it in as far as possible. You can also use small pieces of stone or already hardened cement to fill the gap. Ensure that they don't protrude from the wall.

For the best results, use the hydraulic cement within 10 to 15 minutes of mixing it. You must work quickly and thoroughly. To obtain a flatter finish to the wall, use a mortar trowel to apply the cement. Leave the cement to cure.

Step 5 - Waterproof Walls

Once you have filled the crack in the walls, apply a waterproof sealant to protect against future damage. These sealants should be applied to a wet or damp wall. They must dry completely before you apply a second coat.

Step 6 - Prevent Future Leaks

Now that you've repaired and waterproofed your basement, make sure it stays in the best possible condition. Check around the outside of your home for improperly connected gutters. Verify that drainage run-offs are not accumulating against the side of the house.

If you have a concrete slab or driveway next to your home, make sure that they are sloped away from the house. It is recommended to have a 1-inch slope for every 10-feet of the concrete slab.