How to Seal Expansion Joints in a Concrete Driveway

Cracks in the expansion joints in a concrete driveway can cause problems if they’re not sealed properly. Cracks can allow water to seep under the concrete, creating a void that can cause the concrete to sink.

To solve this problem, use a masonry blade on a circular saw to clean out the crack, then fill it with a bead of silicone caulk that’s made especially for concrete. The caulk will seal the expansion joint and keep water out.

Watch this video to find out more.

Further Information


  1. i would say in the video he needs ,first to clean out the joint from concrete dust a long the side and depending on depth apply a backer rod ,and would go back with a urethane caulk , in my opinion it sticks better to concrete than silicon.

  2. In all my research on this topic (filling control/expansion joints in concrete slabs), it seems that industry leaders (Sika, Titebond, Tremco) all recommend Polyurethane sealants, as well as the use of a foam backing rod to prevent three-side adhesion, as well as to ensure proper bead shape (hourglass). You might consider revising this video to include those details so that people aren’t getting “bad” (not really bad, just not up-to-date with industry standards) information.

  3. To start, I am a commercial caulking contractor that has been in the industry for 38 years and self employed in this field for 33 years.
    Dap, “the product shown” is not a 100% silicone product. They only manufacture latex, “water base” products.
    Dow Corning makes a 100% silicone “traffic grade” for this. Dow Corning 888, comes in Gray only.

  4. Sir, I have about one inch wide crack almost around my brick house. How can I fill it? It is too wide for caulking? I’m desperate and recently I saw mold in the basement. I feel water is seeping in the basement. Please help me.

  5. Silicone is not the thing to use, this will not stay sealed through freeze and thaw! Polyurethane self leveling caulk is the best to use it gives about 25% movement and stays sealed unlike silicone. Non sag on slopes!

  6. How do you repair driveway areas where the concrete is really broken up (spots up to a sq ft) before applying the Quikrete Resurfacing product?

  7. I keep seeing these “experts” cleaning out cracks and joints with masonry blades. But I also see them making damage to the concrete that they never fix. On a normal expansion joint, I would not use a masonry blade. Use a stiff brush and clean the joint, then vacuum up loose debris. Also, for joints, you very likely need a backer rod to hold up the sealant.

  8. What is a backer rod? Also the space between my house foundation and the driveway varies and can be up 1 .5 to 2 inches wide with earth between. How do I fill that and what do I use?

    Thank you.

    • Hi, Mary! You can use a foam backer rod to fill gaps between building materials. The backer rod controls the sealant depth and reduces caulk consumption.

      For your second question, please include a photo so we can understand the issue.
      We accept photos at
      Thanks so much!

    • Hi, Jerry,
      It depends on the width of the crack. For a small gap like this one, caulk gets the job done.
      Anything larger would require backer rod, a foam rope that helps fill wide cracks before applying sealant.


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