How to Patch and Seal Foundation Cracks How to Patch and Seal Foundation Cracks

What You'll Need
Masonry waterproof sealer
Liquid poly urethane foam
Grinding Wheel
Portable power drill
Coarse wire wheel attachment
Wire brush
Cold chisel
Protective eye-wear
Home repair books


The foundation under the house bears the weight of your house and you must patch and seal foundations cracks for safety reasons. Cracks in the foundation look unpleasant and pose a risk to the structure, if not repaired.

The cracks in foundations develop for many reasons. Weather and changes in the ground cause the cracks. A building will therefore move and settle each year because of variations in ground temperature and the extreme moisture present in the ground near the foundation. This continued shifting and excess moisture weakens and harms the foundation and the cement begins to crack due to stress. Over time, cracks get larger and broader if the foundation is not immediately repaired.

You should regularly check your home or building to find out if there are any cracks that must be repaired. It is better to fix small cracks right away before further damage is done.

The non-structural cracks in foundations are often vertical cracks whereas the structural cracks are generally horizontal. If cracks cause movement they should be evaluated by a professional. Even if you repair the foundation cracks yourself, keep in touch with home repair professionals for their guidance and help.

Patching and repairing your foundation cracks involves a number of steps. Here are a couple of steps for repairing foundation steps: 

Step 1- Develop Necessary Skills

It is easy to repair simple cracks in foundations. If there are big and complicated cracks, you may have to get the services of a professional to do the repairs. You can study home repair books or explore the Internet. If you learn to repair the cracks yourself, you can save a lot of money and time.

Step 2-  Assess the Extent of Cracks

Find out the extent of cracks in your foundation and how severe they are. In case the cracks lead to the underground, you have to dig out the dirt to completely expose the crack so that it is clearly visible. 

Step 3.- Clear and Open the Crack

Grind away all the paint or sealant over the crack using a grinding wheel/coarse wire wheel that is attached to a power drill. Remove all the old paint and silicone.

Clear all loose material from the crack and open it up using a hammer and chisel. Make an undercut on the edges of the crack. Clean and wipe out all debris or dirt from the crack. Use a dust mask while grinding. Always work in a properly ventilated area and preferably use a fan. Always wear gloves and use protective eyewear while doing any of these operations.

Step 4- Wash the Cracks

Wash the crack using Lime Away bathroom cleaner to remove any grinding dust or any leftover residue. After using the cleaner let it dry overnight. Use a wire brush with small bristles and wipe out any remaining residue or dirt.

Step 5- Fill the Cracks

Use liquid polyurethane foam to fill the cracks using a gun. Apply a little amount of epoxy into the crack’s surface for an effective repair of cracks. Polyurethane foams are injected into the foundation cracks in a liquid form. The foam should completely fill the cracks. The polyurethane reacts with the moisture in the crack and starts foaming. Water works as a catalyst and converts the liquid polyurethane to foam. The foam is an efficient filler and provides a strong bonding as it fills the foundation cracks and will resist any pressure to destroy the bond.

Step 6- Apply Sealer Coat

Coat the epoxy with masonry waterproof sealer. Make sure that the polyurethane epoxy has completely dried before you apply the sealer coat. The polyurethane foam repairs non-structural as well as medium structural type cracks.  

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