Cut a groove on both sides of the crack
Photo 1: Cut a chiseling groove
Using a diamond blade on your circular saw, cut a 1/2-in.-deep groove along each side of the crack. Wear an N-95 respirator and turn on a fan to blow the concrete dust out of the garage. Chip out the cracked portion with a maul and cold chisel.
Concrete cracks are caused by sideways expansion, poor drainage conditions or settling soil beneath the concrete. If your concrete is the same height on both sides of the crack, you can fix it yourself. But you have to enlarge the crack (Photo 1). Then power-wash the area and squeegee off the excess water before applying the filler. Fill with a polymer-modified cement such as Quikrete concrete resurfacer No. 1131. Our crack was wide and deep, so we chiseled out the entire opening and refilled it (Photos 2 and 3). However, if one side of the crack is lower, call an expert to diagnose and fix the underlying soil/drainage problem. Then either replace the sunken portion or call a mud-jacking company to raise it.
Remove the cracked concrete
Photo 2: Knock out the old stuff
Chip out the cracked portion with a maul and cold chisel. Remove the chipped pieces and vacuum out the crack before power washing.
Chip out the cut concrete to get a fresh surface so the new concrete can bond to it.
Fill in the opening
Photo 3: Fill groove with concrete
Add latex modifier to regular concrete mix and pack it into the channel. Fill to within 1/2 in. of the original height. Let it set up for a few days, then fill with resurfacer.
Establish a solid base for the resurfacer by filling the opening with concrete and letting it dry (see Photo 3).
Add the resurfacer
Photo 4: Spread the resurfacer
Pour concrete resurfacing mixture into the crack and smooth it out with a rubber floor squeegee. Feather the edges to get the best appearance.
Add water to the resurfacer mix to get the consistency of pancake batter. Then fill the remainder of the groove and smooth it over.
Required Tools for this Project
Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.
- Circular saw
- Cold chisel
- Dust mask
Required Materials for this Project
Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.
- Concrete mix
- Concrete resurfacer
- Latex modifier