Are you looking at a cracked concrete wall and wondering what to do next? Should you call in a building repairs specialists who'll be able to undertake a concrete repair for you? This may be the best option if the crack is in a foundation wall. A structural crack may influence the integrity of your house and will require more in-depth work to remedy. However, if the job is small and only superficial, you may want to have a go at repairing it yourself. Do you have the skills to undertake the job? This guide will tell you what's entailed so that you can decide whether you're up to it.
The Materials Needed
For most cracks, you can choose between an epoxy resin or polyurethane to repair the crack. If the repair is structural, then epoxy is the best choice. You'll need to familiarise yourself with the user instructions before you start. You'll want to adhere to the mixing instructions, taking note of the consistency that the mixed compound should have. You may need to mix it in small batches as many compounds need to be used within 15-20 minutes of being mixed. You can't prepare the weather, of course, but you can avoid weather that will make the job more difficult. Sunny days may seem like the ideal time, but this can reduce the working time you have with the compound you use, as it will dry faster. Overcast, damp days offer the perfect working conditions for this work.
The Preparation Required
To get good adhesion of the compound you'll use, you'll need to clean the crack. You can use a wire brush or power washer to clean any dirt, oil or debris from around the crack and inside. Wide cracks (more than ⅛ inch) will need to be chiselled out to remove any loose material that the wire brush or power washer failed to get rid of. You'll use a concrete chisel and hammer to create a V shape along the length of the crack, known as undercutting. This will help provide a stronger bond.
The Application Process
The application method will depend on the compound you've chosen. For example, if you're using a water-based compound, you'll need to wet the surface before applying the filling material. This prevents the dried concrete from sucking moisture out of the compound causing shrinkage to the patch. Your selected material will instruct you on the application method. Some patches are applied using a trowel or a gloved hand; some will be injected, perhaps with a caulking gun. Once the compound has been applied and allowed to dry for the required length of time, you can then decide whether the finish is good enough. If you need a smooth finish, you may need to sand the patched area using a grinder.