How to Patch a Leaky Basement Wall

Leaks can occur in basement walls at any time and in any season. They are commonly located in poor masonry work and between the concrete slab foundation and joining walls. Water leaks can cause substantial damage to the structure if left unrepaired.

Difficulty: Moderate

Instructions

Things You'll Need:

• Small brush
• Compressed air
• Hydraulic cement

1. Identify the location of the leak. Leaks can appear in one area, yet have their origin elsewhere. Follow the moisture to where it enters the wall. Leaky walls may result from natural causes or from plumbing issues.

2. Use a chisel and hammer to open up any cracks or voids appearing in the wall. Inspect the mortar between cement blocks for holes or any separation. Ensure that the chisel leaves the inside of the crack larger than the outside of the crack for best results.

3. Take a small brush and sweep out any loose debris in any crack or void that is allowing water to enter. Use a small can of compressed air to blast out any remaining particles or debris.

4. Purchase hydraulic cement from a home improvement or hardware store. Consult with the staff to decide on the best material for the project. Many stores offer detailed help on the task.

5. Mix the hydraulic cement according to the instructions provided. Apply the cement to the leaky area. Push the cement into the void as far as it will go. Fill each crack with cement from the point of origination to the very end of the damage. Let it cure.

Tips & Warnings

• When filling the cracks with cement, add small pieces of stone or hardened cement to the mixture and push into cracks. Do not allow the material to protrude from the void.
• Apply a quality commercial sealant after repairing the leaky wall.
• Wear gloves and eye protection during this project.