How to Fill Concrete Cracks

September 22, 2014


Concrete can develop cracks due to drying, temperature changes, ground movement, and excessive loads. Once a crack develops, you should seal it to prevent further deterioration.

Repairing cracks in concrete is easy. Here’s what you’ll need: eye protection, gloves, a hammer, chisel, brush, vacuum, concrete filler, and trowel. The entire process should be relatively inexpensive.

First, you’ll need to clean up the area where you’ll be applying the filler. Make sure there’s no oil or dirt on the floor. If you find some, use a cleaner that cuts grease. This will bond the filler to the concrete.

Before you begin, check to make sure the crack is dry. If it’s a little damp, dry it with a blow dryer and wait fifteen minutes. If it stays dry, go ahead with the patching. If the water comes back, water is seeping into the cracks and you probably have other problems to deal with. Always wear eye protection and waterproof gloves.

Next, use a chisel and a hammer to rid yourself the large pieces in the crack. Widen the crack to a minimum of a quarter inch and break away any deteriorating concrete. Hold the chisel at an angle and pound with the hammer to chisel out the crack. Brush and vacuum. Get rid of dust and debris. Use a whisk broom, then vacuum the crack thoroughly.

By this time, you’ll need to have chosen a concrete filler. You have many choices when it comes to these. There are many good concrete fillers available on the market. Go to your nearest home repair store and ask about concrete filler; the salespeople there should be eager to help you find something that will work for your house. A good, heavy-duty polyurethane filler is a good choice for this. Water-based polyurethane dries quickly and doesn’t smell as bad as other types of sealer.

Slowly fill the cracks. If you’re using mixed concrete patch, mix according to the manufacturer’s directions, then trowel the patch into the crack. Look at the cracks after a few minutes to see whether the filler has settled; you may end up having to add more. Use a trowel to get the cracks smoothed out. If the crack occurred in the heavy-traffic area, it’s a good idea to apply multiple coats.

Allow the filler to cure overnight, or whatever duration the manufacturer recommends. Then, check it again to see if any additional patching is needed. There you have it! You’ve filled the cracks in your concrete.