How to Repair Cracks in Concrete

Concrete work is expensive, and when a concrete sidewalk or concrete driveway is poured, no one expects a crack to form. If expansion joints or control joints aren’t properly constructed or if the ground isn’t properly compacted before the concrete is poured, the concrete might eventually fail. If a crack develops in concrete, even the smallest crack will generally continue to expand until the concrete sidewalk or driveway becomes a cracked and broken mess. Besides making a home appear neglected, cracks in concrete often cause that concrete to eventually buckle and heave, making it dangerous for passers by to walk upon.

Although cracks in concrete can’t be made completely invisible, cracks can be repaired and made to look better. Anyone can repair cracks in concrete. It doesn’t take a professional to repair a simple crack and improve the appearance of a concrete driveway or sidewalk.

Hairline Crack Repair

It’s obviously best to patch a hairline concrete crack when it is first noticed. Patching a hairline crack in concrete can help prevent that crack from expanding into a much larger crack. Concrete sealer can be used to fill a hairline crack. Concrete sealer is available at most larger home improvement stores, and it is well worth the cost of preventing a much larger problem further down the road.

Large Crack Preparation

A hairline crack that isn’t repaired right away often turns into a larger crack when winter weather arrives. Freezing water settles into the crack causing it to expand. Those with slightly cracked concrete sidewalks and driveways sometimes notice the crack expanding in the winter. That’s why it’s important to take care of hairline cracks as soon as possible.

If a hairline crack in concrete has turned into a large crack, it will need to be cleaned out before the patching and repairing process. Remove any loose concrete and brush out any other bits and pieces with a wire brush.

It will be necessary to expand the crack so it is wider at ground level than on the surface. Use a cold chisel and sledgehammer to properly widen the crack. If the concrete has not cracked all the way to the base, the crack must be at least ½ inch deep for the repair to be effective. Deepen the crack if necessary.

Remove the concrete chips, brush away any debris with a wire brush, and sweep out the crack with a broom. Finish cleaning the crack with a mixture of trisodium phosphate (TSP) and water. To clean concrete, the proper solution is ½ cup of TSP mixed thoroughly with 2 gallons of warm water. Wear rubber gloves, and thoroughly scrub the crack with the trisodium phosphate mixture. TSP contains sodium meta-silicate and can cause burns to eyes, skin, and mucous membranes, so take care using the product.

Large Crack Repair

For the best results, patch large cracks using vinyl concrete patch cement. This product is easy to use, and it bonds quite well to existing concrete. The finished results are worth the extra money to buy this concrete repair product.

Fill the crack using a cement trowel. Pack the crack well, and smooth the top of the concrete patch cement. Cover the repair with a piece of wet burlap, and be sure to keep the burlap damp for about two days. After two days have passed, the cement should be dry and solid.