A garage floor is meant to be flat and smooth when finished.

How to Repair Chips in a Garage Floor

by Tim Anderson

A garage floor is generally made up of a thick layer of concrete, known as a slab, which can range from just a few inches thick to over 12 inches thick in the case of commercial garages. Although concrete is one of the most durable surfaces in existence, natural movement as well as human accidents can cause pits or chips to mar the surface, leaving behind a pockmarked area that detracts from the finish look of the floor. To bring your garage floor back into brand-new condition, fill the chipped areas with a concrete filler.

1 Clean the chipped area with a concrete cleaner. Apply the cleaner to the chipped-out area and the concrete surrounding it, and scrub it with a scrub brush to remove any dirt and debris filling the chipped area. Remove the excess cleaner with a damp sponge and allow the area to dry for at least 24 hours before you fill the gap.

2 Mix up some of the patch compound in a small container, such as a cup or bowl. Use the putty knife to mash the mixture in several different directions. Apply just enough water to achieve a cake batter consistency.

3 Allow the concrete patch compound to set for several minutes so that the powder elements can properly absorb the water. This is known as slaking. Remix the compound a final time with your putty knife.

4 Prime the chipped area while you are waiting for the compound to slake. Apply the primer directly to the concrete with a paintbrush and thoroughly coat the inside of the chipped area you are filling.

5 Fill the chipped-out area with the compound using the putty knife. Press the compound down into the void until the excess oozes out. Scrape this excess off flat with the edge of the putty knife so that the patch is flush with the rest of the concrete surface.

6 Wipe up any residue from the concrete face surrounding the chip with a damp sponge. Allow the patch to dry for at least 24 hours before walking or driving on it.

Items you will need

  • Concrete cleaner
  • Scrub brush
  • Sponge
  • Cup or bowl
  • Paintbrush
  • Concrete patch filler compound and associated primer bonding agent
  • Putty knife or flat metal trowel

Tips

  • Any patched areas will look slightly different than the surrounding concrete, because the original concrete has cured (aged and dried out) and faded over time. In the case of older garages, the concrete surface likely has absorbed oil, dirt and debris over the years. Filling a chipped area in a concrete surface is like patching a pool liner; it covers the hole, but it is a visible repair that cannot be hidden unless you plan on painting or staining the concrete floor at a later date.
  • For best results, use a primer that is recommended by the patch compound manufacturer. Otherwise, a general concrete bonding primer agent will work.

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