Ways to Repair Damage to Concrete Garage Floors

A garage with concrete floors.

Despite their durability, concrete garage floors can become damaged. If a heavy object falls on the floor, the concrete can crack or even cause a chunk to fly out. When this happens you can save money by repairing the damage yourself. You will need the right equipment and it will take a little time and effort, but the results will be worthwhile.

Minor Damage

Where the damage is minor, as with a ridge or a small dip, it can be fixed by grinding down the ridge or filling the dip with leveling compound. Finish with a sealer on the concrete to help protect it. This is the simplest type of repair and one that’s easily carried out.


Cracks can develop in concrete over time or can be caused by a sudden accident. By filling and sealing them quickly you prevent water from coming up from the ground. Start by removing any debris. Widen any cracks in the concrete garage floors so you can fill them. Wash out the cracks with a pressure washer and then use a wet/dry vac on the area.

For small cracks, you can use pourable grout on the concrete garage floors. If the cracks are deep, allow one level to dry before adding more to the crack.

Wide Cracks

Wide cracks need to be chiseled out so the part under the surface is wider than the surface itself. This needs to be filled with a vinyl concrete patch. However, each layer of the patch on the concrete garage floors should only be ¼ inch. Allow one layer to dry before putting the next layer on top.

As you get to the surface, use a steel trowel or a wood float to level and texture the patch so that it blends in with the rest of the concrete garage floors.


Where the damage is larger than a crack, you still need to clean out the area as you would for a crack. From there, mix up filler that’s 1 part Portland cement to 2.5 parts clean masonry sand. Add a polymerized liquid bonding agent to the dry ingredients.

Dampen the area when you’ll be filling the concrete. Work the concrete mix into the area, pushing it down to eliminate any air bubbles.

At the surface, leave the patch slightly higher when you level it. This allows for shrinkage. After an hour use a steel finishing trowel to smooth the surface. About two hours later, go over the area again with the trowel. Dampen the area if it needs it.

Fire Damage

Although concrete is largely fire-resistant, it can still be damaged. The important thing is to check that it’s structurally sound before beginning any repairs of fire-damaged concrete garage floors.

A concrete rebound hammer can help you determine how good the concrete is. After that, blast off the soot with dry ice to clean it. Use a bonding product to strengthen the surface of the concrete. Once it’s dry you can mix up some concrete mortar and put it in the damaged area, smoothing in on the surface.