Ways to Repair Cracks in Concrete Surfaces Fastbuild

Cracks in concrete can be quite an alarming spot for property owners. Whether the problem is largely cosmetic or more fundamental, you’ll want to get it fixed as quickly as possible.

There are many different methods for repairing cracks in concrete surfaces, most of which depend on the nature of the crack itself. Here are some of the most common methods of repairing concrete cracks, from cosmetic fixes to structural repairs.

For Hairline Cracks: Apply Resins or Sealants

Small cracks in concrete are fairly common, often caused by the weather and temperature changes over time. If you’re dealing with a hairline crack and there is no indication of structural issues, a popular cosmetic fix is to apply a concrete sealant or resin.

Before applying the resin – and with many concrete-repairing methods in this blog – you’ll need to clear the crack of loose debris first. Use a steel brush alongside a leaf blower or vacuum to remove as much debris from the area as possible.

There are many types of concrete resins available, but most of them perform the same job. They are designed with elastomeric properties, some of them using latex, so they can withstand any future enlargements or shrinkages in the concrete.

Concrete resins are usually available in sealant-style bottles with a nozzle and can be applied directly into the crack with a caulk or sealant gun.

One thing to look for is making sure the resin you are using is waterproof. If it isn’t you will need to apply a waterproof (commonly epoxy) resin over the top to avoid the issue reappearing.

For Larger Cosmetic Cracks: Apply Concrete Patching Compound

If the crack in the concrete is larger – usually more than ¼ of an inch – but isn’t a structural issue, it’s usually recommended to use a concrete patching compound.

Sometimes available pre-mixed, this compound has a similar texture to grout and will set like new cement after application. This method is common for horizontal cracks – on driveways or pavements – but some compounds (particularly those marketed as non-slag) can also be used on vertical wall cracks.

To prepare the crack for the concrete patching compound and help it key to the concrete, you need to widen the crack along the exposed face, usually by chipping against the concrete to form a V-shape leading into the crack. The crack will then need to be cleared of loose debris before application.

The concrete compound is applied with a knife or trowel and needs to be pressed into place to avoid air bubbles. For deep cracks, the compound often needs to be applied in layers and allowed to dry before building to the surface.

Concrete patching compounds will set with the appearance of new concrete, so may need to be painted to blend in with the existing concrete.

To Reestablish strength: Cross-Stitch or Reinforce

Major cracks in concrete – often defined as those larger than ½ an inch wide or where one side has risen above the other – need to be assessed and repaired by professionals, as these can lead to significant issues. Repairs in these scenarios will often involve some form of reinforcement, where metal rods or bars are inserted to carry some of the pressure that caused the crack.

Conventional reinforcement for cracked concrete usually involves the addition of reinforcing bars. These are often applied by drilling through the crack at an angle, filling the holes with a resin (similar to that mentioned above) and placing the reinforcing bars into those holes before setting.

Another popular method of reinforcing concrete is through cross-stitching, where metal rods with short legs – similar to a large staple – are inserted into each side of the crack, again through drilling and resins.

For Vertical Cracks: Drill and Plug 

For vertical cracks in things like retaining walls – where the crack can be accessed from the top – an alternative method of repairing cracks is drilling and plugging. Here, a hole is drilled near the crack and filled with grout.

This method is particularly useful because it stops excess movement from the concrete next to the crack. This method can also be useful for water-sealing concrete, which can be particularly important for retaining walls.

As mentioned, it’s important to assess concrete cracks, particularly if they’re larger than a hairline crack, before any of these methods are applied. If you need building supplies such as sealants and adhesives, be sure to check out our range, which has low trade prices.