How To: Seal Foundation Cracks

If you have some cracks in your foundation, it’s important to address them as soon as possible. The first step to fixing them is to contact a qualified foundation repair specialist. They will be able to assess the damage and determine the necessary steps for repair based on the severity of the cracks. If the foundation cracks are not too severe, you can follow the steps below to seal them.

Step One: Prepare the Surface

If the cracks in your foundation are not severe, you may be able to fill them yourself. Here’s how to prepare the surface:

1. Clear the area in front of the cracks. Remove grass, tree limbs, bushes, and plants so you can examine the damage up close and have more room to work.

2. Remove any loose debris or materials from the cracks. Use wire brushes, a screwdriver, or a small putty knife to do this. Alternatively, you can use an air compressor to blow out dust and debris.

3. Widen the crack slightly using a hammer and small chisel. This will give the sealant something to adhere to.

4. Rough up the edges of the crack and clean the opening with a brush to remove any dust or loose chips. Depending on the type of sealant you’ll use, you may need to wet the surfaces down with water before applying the sealant.

Step Two: Apply the Sealant

Once you’ve properly prepared the crack, you’re ready to apply the sealer. There are several options to choose from, including:

  • Epoxy sealers
  • Vinyl concrete patching compound
  • Cement mixture
  • Hydraulic cement
  • Polyurethane-, latex-, or silicone-based caulk
  • Concrete/masonry waterproofing sealer (this is a product that you should use at the end)


When filling a crack in your foundation with any of the sealants listed above, you have several tools to choose from, including a putty knife, trowel, flat-head screwdriver, and paint brushes. You can also use a baker’s cone to fill the cement into the crack for a deeper depth. If you’re using polyurethane-, latex-, or silicone-based caulk, a caulking gun may be simpler to use.

For cracks that are half an inch wide and/or deep, you can place a foam backer rod into the void and then apply caulk or a cement mixture on top of it. Backer rods help fill the cavity and provide a base for your application.

Regardless of the products you choose, it’s important to follow the instructions carefully for the best results. For example, some products require a certain thickness on the surface to seal the crack properly. Most products also need to be completely dry before applying a second layer or another product.

If you have deep or wide cracks or cracks that go all the way through your foundation, it’s best to have a professional foundation repair contractor fix the problem. They have the necessary equipment and sealants to ensure there are no water and pest intrusion issues afterward.

It’s a good idea to check your entire foundation for any signs of potential problems. If you notice any issues, try to determine the cause before sealing any cracks. Possible causes of foundation problems include excess water, drought, and tree root intrusion.

Even if you have cracks in your foundation, you may be able to fix them yourself. However, if you need help or information, don’t hesitate to contact our professionals. They will be happy to assist you from start to finish.

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    If you live in the Houston area and have foundation cracking, there is only one call to make. Trust the professionals of AAA Foundation Service to provide honest information about your foundation crack issues. Call us today and we will get you setup with an in-depth inspection, free repair estimate, and a list of solutions.

    Chris Bartlett
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