Precon Products, A leading national independent supplier of construction products

How To Repair Concrete

Concrete is one of the most durable construction materials available. However, faulty installation, wear and tear, chemical exposure and environmental impacts can end up causing damage to concrete surfaces. You may have some concrete that has seen better days, but don’t worry, there is every chance that it can be repaired. We have outlined below a few tips and tricks to get your concrete back to its former glory.

 

Is Repairing Cracked Concrete Easy?

The common misconception is that repairing cracks in concrete is easy, although. As we will see it is not always a simple job.

Trying to force concrete repair mortar into a small crack can be quite difficult as the aggregate is often too large for such small areas. The stones in the concrete mix will make it difficult to finish the job well enough. As it is so difficult to get the concrete repair mortar into the gap you can never be certain that it has filled the gap completely. You may end up with just the surface repaired and a crack remaining underneath.

 

When Concrete Repair Mortar Dries

When the concrete repair mortar you used to patch the crack cures it shrinks and pulls away from the edges of the crack you’ve just filled. This leaves another crack, albeit smaller, that can let water in. The water that gets into the crack is liable to freeze in cold temperatures which then expands when it turns into ice. This expansion creates an even larger crack which can fill with more water.

When render or brick work has been blown off it is due to this “Freeze-Thaw” action of expansion and contraction.

 

What Do You Need To Repair Concrete?

What you need to repair concrete all depends on the type of concrete and its application. For example, repairing a spalling driveway will require different tools and materials than if you need to repair or replace worn patio expansion joints.

For the purposes of this guide, we will be looking at repairing small cracks in concrete that you may find on a patio, driveway or walkway. For other concrete repairs, we will go into more depth on in our other guides, such as:

  • Repairing and resurfacing concrete driveways
  • Walkway repairs
  • Textured concrete patio repairs
  • How to repair leaking basement cracks in concrete
  • Repair concrete foundation cracks

 

What Do You Need To Repair Concrete Correctly?

Concrete surfaces cannot be repaired with concrete for the reasons outlined above. Instead, you will need to use a concrete repair mix with options including epoxy compounds, latex patching material and mortar mixes. Mortar mixes, such as Weber’s 5 Star Repair Concrete is a perfect solution for large cracks. A strong epoxy resin based mortar like Epomast from Adomast creates a frost resistant and highly durable repair that has virtually no shrinkage.

 

How To Prepare Cracked Concrete For Repairs

You will need to use a hammer and chisel to break away all the cracked and crumbling concrete to ensure there is no loose material. Chisel to a depth of 1 inch below the surface.

Brush away all the debris from the crack with a wire brush to make sure all dust and loose particles have been removed. You can use a vacuum cleaner and pressure washer to make extra sure the area is clean. Make sure all water has been removed from the area. It is fine if it is damp but there should be no pools of water left behind. 

 

How To Apply The Concrete Repair Mortar

For cracks that are ⅛-inch wide or even narrower you will need to apply an epoxy resin or latex patching product mixed to the manufacturers specifications. You will need to force the material into the crack with a putty knife or a mason’s trowel. Smooth it down and level it off with the surrounding concrete. When using an epoxy or latex based repair mix such as Nitofill you will need to apply it with a cartridge gun.

When using a concrete repair mortar mix for larger damaged areas you will need to create your own mix. Always follow the manufacturers guidelines on how to mix the mortar correctly. Dampen the area to be repaired and then apply the mortar mix with a putty knife or a mason’s trowel. Force the mix into the crack to ensure all air pockets are removed, then smooth and level. Let the mortar cure for two hours before covering with a plastic sheet to keep the area moist. Every day for the next three days sprinkle water under the covering until the surface has fully cured.

Author Lydia Swallow. Category Brands. First published Fri, 11 Jun 2021 12:00:00 +0100