How to Fix Cracks in Concrete

Has your concrete driveway or sidewalk seen better days? There are any number of causes for cracks in concrete including improper seam placement between slabs of concrete, moisture, frost heave, tree roots and movement of the earth. Another common cause of cracked concrete is that it was mixed with too much water when it was installed. This causes the concrete to be weak when it dries and leaves it more prone to cracking over time. No matter what caused the cracks in your concrete, with a little bit of elbow grease you can usually repair the cracks in the concrete and rejuvenate the surface of your sidewalk or driveway. Here are some tips on how to repair cracks in concrete.

It is best to tackle concrete crack repair as soon as you notice a crack appear. The larger the crack the more difficult it will be to repair. In some cases, if the cracking is too bad the concrete may even need to be replaced rather than repaired, so staying on top of concrete cracks from the beginning can wind up saving your money and headaches in the future.

The first step in repairing either small or large cracks in concrete is to remove any loose flakes or bits of concrete from the crack. A screwdriver or another narrow sturdy tool can help with this phase of the project. After removing any large pieces of concrete or loose flakes use a wire brush and some water to scrub away any remaining debris.

Small cracks in concrete – under 1/8in. – can usually be filled using a caulk specially designed for concrete. This caulk can be purchased at most hardware and home improvement stores. Simply follow the manufacturer’s instructions to apply the caulking.

For larger cracks in concrete (over 1/4in.) you will need to apply patching compound to the crack in the concrete. There are several different types of patching compound available so be sure to talk to the sales person at the store where you purchase it to ensure that you are getting the right kind for your project. Concrete patching compound can be purchased at most hardware and home improvement stores.

Mix the concrete patching compound according to the manufacturer’s directions and use a latex additive to help accommodate the natural expansion of the concrete in hot and cold weather. Using the latex additive will make the concrete patching compound more flexible. Concrete patching compounds will adhere better to the crack if it is wet so apply a small amount of water to the crack to dampen the surface before beginning.

Using a small putty knife trowel the concrete into the crack smoothing the surface as you go while the concrete patching compound is still moist. You should mix the patching compound in small batches because it hardens very quickly. If you mix too much it will harden before you have a chance to use it. You’ll also need to work quickly to get enough done before the concrete patching compound hardens.

Allow either type of patching job – caulk or patching compound – to dry thoroughly before you walk or drive on the surface.