Repairing Cracks in Concrete

Left unchecked, cracks in concrete surfaces—including sidewalks, driveways, and patios—can allow water to penetrate and cause further deterioration as well as potentially undermining the slab.

Using a cold chisel to widen the crack and cutting caulking tube nozzle at a 45° angle.
Widen crack with chisel (left). Cut caulk tube nozzle at a 45° angle (right).

To repair cracks in concrete:

Widen Crack: Use a cold chisel to widen the crack, if needed, to allow the caulk to adhere.

Clean Crack: Clean out the crack of any dirt or concrete dust.

Cut Caulk Tip: Cut the tip off a tube of concrete sealant or sanded, acrylic concrete caulk at a 45° angle with the opening wide enough to fill the crack.

Apply Caulk: Use a caulking gun to apply the caulk into the crack.

Smooth Caulk: Smooth the caulk so it fills the crack evenly.

Allow Caulk to Cure: Allow the caulk to set before walking on it.

Applying concrete caulk to crack in patio.
Applying concrete caulk to crack in patio.

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Further Information

Cracks in your concrete are not just unsightly; if left unrepaired, they can lead to further deterioration. Flexible sealants are the best option for repairing cracks since they allow the concrete to shift without affecting the repair.

These sealants are also easy to apply using a standard caulk gun. Just cut the tip of the tube on an angle to match the size of the crack, and slowly draw the gun down the crack forcing the sealant in.

You can also choose a sanded, acrylic caulk designed to match the color and texture of the existing surface.

These tips are brought to you by Quikrete – What America’s Made Of.


  1. Dear sir, Enjoy your program, the repair video and instructions.
    I need help to repair our stairs. They are made of man made marble-like slabs each step is a one piece. At very bottom the first step piece cracked about half inch gap across the whole lengh of the step, from wall to hand rails, right in middle. To replace it cost too much. How could I repair this?
    Is it good idea to fill up the gap, cover up with a coat of epoxy paint, and spray with fine sands on it. the steps is black color with stone in it.

    Appreciate any your suggestions. please reply to my email. I do not want to miss your recommandations. Many thanks.

  2. When repairing the ceiling crack, won’t that application leave a big bulge compared to the regular height of the ceiling? Usually paper tape on a brand-new sheet rock leaves a bit of evident unevenness. Thanks for the help with home repair.

    • Hi, Erin,

      Of course, every situation is unique, but since we have no details on the structure in question, it’s good to remember this guideline: moisture, coupled with movement, often leads to cracks.

      Hope this helps!

  3. Your site would be more user-friendly if there weren’t all these ads popping up while trying to read your advice. Just sayin’…


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