How to Fix Cracks in Concrete Slabs
Cracks in concrete slabs are common and easily fixed as long as there isn't a significant underlying problem: large cracks or multiple cracks that reappear shortly after being repaired should be examined by a knowledgeable contractor. When repairing concrete, be proactive and fix cracks quickly. Moisture often works its way into small cracks, causing the crack to enlarge during the freeze-thaw cycle. Does this Spark an idea?
Things You'll Need
- Power washer
- Concrete filler
- Putty knife
- Chisel
- Ball peen hammer
- Wire brush
- Sand (if necessary)
- Concrete bonding adhesive
- Paintbrush
- Concrete patching mix
- Trowel
Instructions
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Hairline Cracks
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1
Clean out the crack as thoroughly as possible using a power washer. Allow the concrete to dry completely before continuing.
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2
Fill the crack in the concrete using a tube of concrete filler. The most suitable types of concrete fillers for slabs are epoxy based, which require that the epoxy be mixed according to the manufacturer's instructions prior to application.
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3
Smooth the top of the repair using a putty knife, feathering the edges to make the patch less apparent.
Large Cracks
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4
Enlarge the crack slightly by creating a backward angle using a chisel and ball peen hammer. This will help prevent the concrete patch from popping out of the slab.
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5
Clean out the crack thoroughly, using a wire brush. If the crack is deeper than three inches and wider than one inch, fill it with sand until the crack is no more than three inches deep.
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6
Paint a concrete bonding adhesive onto the interior surface of the crack using a paintbrush. The bonding agent, combined with a crack that is narrower at the top than at the bottom, will help prevent problems in that area in the future.
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7
Mix a batch of concrete patching material, following manufacturer's instructions regarding the recommended proportions of water to use.
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8
Fill the crack with the concrete patching material using a trowel. Smooth the top of the patch carefully, feathering the ends to conceal the former crack as much as possible.
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1
Tips & Warnings
If the concrete slab has multiple cracks, consider resurfacing the area after the repairs are finished. Resurfacing concrete can be accomplished without professional help and only requires a few basic tools and some inexpensive materials.
After using a power washer to clean out any hairline cracks in the concrete slab, take the time to wash the rest of the area thoroughly. A good cleaning may expose other areas in need of repair.
When working with a chisel always wear safety glasses to protect your eyes.
