Repair Large and Small Cracks in Concrete
Cracks in concrete are a fact of life and are caused by various factors, but it is relatively easy to repair small or large cracks with ease.
01/2019
In this article we discuss how to repair small or large cracks in concrete, whether it be a floor in your home or garage, or driveway repair. The repair process is a simple one that only requires a few basic tools, plus a suitable concrete repair product that you should be able to find at any Builders store.
In the first section of this article we look at repairing a large crack in a garage, that is also fairly small at one end. At the bottom of this page we discuss what needs to be done to repair a smaller crack, and although the process is very similar, there is an extra step that needs to be done when repairing small cracks in concrete - or in plaster walls for that matter.
You can see that the large crack in the concrete floor is a long one and also quite wide. It is about 4mm wide along most of the length and about 8 to 9mm deep. Above we show the repaired crack with details below on how to fix cracks in any concrete floor.
BELOW: While large along most of the length, there is also an area where the crack in the concrete floor is quite small and this also requires attention as soon as possible.
HERE'S HOW:
FIXING WIDE OR LARGE CRACKS
Where cracks are about 3 to 5mm wide it is a relatively quick and easy repair process. The first step will be to clean out all debris in and around the crack. Use a screwdriver or sharp tool to remove any loose bits along the length of the crack. You can also fit a wire brush onto your drill to remove any loose concrete along the edges of the crack.
After loosening along the crack you can use a vacuum cleaner or shop vac to clean out the crack. If you are unable to get deep enough to clean all the debris out, use a pressure blower to clean out any remaining grit or dust. It is important to remove all the dirt and debris for good adhesive for the concrete crack repair product.
With the crack cleaned out you can apply a suitable concrete repair product. There are several brands that you can find at any Builders Warehouse and all will do the job. Use a paint scraper to apply the product deep within the crack. It is recommended that you overfill the crack and let this sink before wiping away and smooth on the surface of the floor.
Whatever concrete crack repair product you are using, be sure to check the instructions for allowing the product to cure properly. This is especially important if you are doing a crack repair on a driveway or garage floor. Don't drive you car over the area until the product is fully cured.
FIXING NARROW OR SMALL CRACKS
To fill a narrow or small crack it is essential to 'chase' the crack along its length. Crack chasing involves making the crack wider - almost a 'V' shape - at the top to allow for crack filler to fill up the crack and have more adhesion area.
To chase out a smaller crack you can use an angle grinder or Dremel DSM20, or buy a special crack chasing blade to fit onto your angle grinder (but I wasn't able to find this anywhere locally). Alternatively, you can use a hammer and cold chisel, but this is time consuming and hard work.
To repair the crack you can now follow the same instructions as above for filling a larger crack.
Take a look at the video below that provides a long, detailed explanation and detailed instructions for the processed mentioned above. Bear in mind that many of the products mentioned in the video are not available locally, but you will find a.b.e and other concrete repair products at any Builders Warehouse or Builders store.