How to Seal Concrete Basement Cracks

Seal cracks in concrete before they get too big.

Concrete is a strong and durable substance, but when it's exposed to extreme forces, it can crack. The concrete in your basement is exposed to moisture, extreme temperature changes, the weight of your home and, possibly, the ground shifting beneath it. If cracks appear, it's best to seal them right away. Water can seep into your basement through cracks, damaging your belongings. Water can also freeze in the cracks, expanding as it freezes and enlarging the cracks. This can lead to serious problems with your foundation.

Things You'll Need

• Hammer
• Chisel
• Wire brush
• Wet/dry vacuum
• Patching mortar
• Bonding agent
• Water
• Putty knife

Instructions

1. Chip away the area around the crack with a hammer and chisel. Work the chisel at an angle so that the space beneath the surface of the crack is wider than the crack itself.

2. Clean the crack with a wire brush or wet/dry vacuum, removing all dust and debris from the crack.

3. Mix up a batch of patching mortar, following the instructions on the packaging. Use bonding agent instead of water unless the instructions specifically prohibit this. This will help the mortar adhere to the concrete.

4. Fill the crack completely with mortar, using a putty knife. Smooth the mortar on the surface after you have filled the crack.

5. Let the mortar set, using the instructions on the packaging as a guide.

6. Brush the surface of the patch with a wire brush to help the patch blend in, if desired.

References

• This Old House: How to Fix a Leaky Basement Wall
• Lowe's: Make Simple Concrete Repairs