Home Improvements

How to Fill a Wall Crack or Dent

Cracks happen. As houses settle they often result in a few cracks appearing around the house. A wall crack is most likely to appear where the wall meets the ceiling, but small foundation cracks are also normal.

Keeping your home looking brand new requires some effort and a little bit of know-how. With the right tools and enough patience, you can fix almost any imperfection you find in your home!

Knowing how to repair small cracks and dents can also save you a lot of money along the way. Keep reading to find out how to fix these small blemishes around your home.

Painted wall with cracks visible underneath the paint.

When Is a Wall Crack Dangerous?

When it comes to wall cracks you need to understand: you can’t fix them all. 

If the crack is too big it indicates that there are underlying issues causing the crack. It might mean major repair work, or even needing to partially rebuild.

The severity of a crack is measured by width, not length. Cracks up to 5mm in width are extremely easy to repair: they only need to be covered. You can also fix cracks between 5 and 15mm yourself, you’ll just need a few more supplies. 

It’s when cracks get wider that things get difficult. The National Home Builders Registration Council (NHBRC), recommends that you contact an experienced builder to complete the repair work if the crack is wider than 15mm. 

If the crack is wider than 25mm it’s considered a danger and needs to be addressed ASAP.

A deep-looking wall crack running horizontally along a cream coloured wall.

Fixing Minor Imperfections

Knowing how to fix minor imperfections is part of maintaining a home. Chipped paint, holes you needed for pictures, and dents from moving furniture can all make your home look less put together. 

By taking time to fix these small imperfections, you’ll see how big a difference it really makes. To fix most minor imperfections, all you’ll need is:

  • Sandpaper
  • A putty knife
  • Polyfilla
  • Paint

Patching peeling paint can seem like a big hassle, but if you do it right you can seamlessly cover the section without needing to repaint the entire wall. 

Use a putty knife to scrape away any loose paint. Don’t force the paint to flake off though! You just want to get the edges that are loose. 

Apply Polyfilla to the edges of the paint. Once it’s dry, you can sand the patch with 180-grit sandpaper until it’s smooth to the touch. After that, paint the area with matching paint. 

Painted pink wall with small chips and dents under where the paint has been peeled off.

Fixing holes left by nails is incredibly easy. After you’ve removed the nail and any spacers you used, use a putty knife to apply interior Polyfilla in and over the nail hole. 

Once the Polyfilla is dry, sand the area and use a damp sponge to wipe away any dust left over. Then simply apply some paint primer and paint the area with matching paint.

Fixing minor dents and imperfections combines the techniques used to patch peeling paint and fix nail holes. You need to remove any peeling paint with a putty knife and then fill in the dent with Polyfilla. Once the Polyfilla is dry, sand the area down until it’s smooth to the touch, and paint over it.

Corner of a wall with a huge tear in the paint. A little further away from the lifted paint, a large wall crack is visible through the paint.

Fixing Drywall

While drywall isn’t as prevalent in South Africa as in other countries, many homes use drywall on the inside to separate areas. And while they’re not as common, drywall wall cracks are the easiest type to fix.

Use a sharp utility knife to cut out a V-notch along the length of the crack and vacuum out any dust and debris. Using a joint compound and paper tape, or mesh joint tape, cover the entire crack. 

Then cover the tape with another thin layer of joint compound. You want the top layer to extend 5cm on each side of the tape to ensure it won’t lift.

Once the joint compound is dry, apply a second coat, but feather it out 10-20cm on either side of the crack. This will seal everything off and ensure your patch job lasts. 

Let everything dry overnight before gently sanding the surface until it’s smooth to the touch. Then your drywall will be ready for paint or wallpaper.

More than one drywall wall crack scattered across a yellow-beige wall.

Cracked Concrete

To fix cracked concrete you’ll need to get up close and personal with some epoxy. The epoxy ensures the crack is not only sealed but watertight.

First off you’ll need to gently tap 7cm finish nails partially into the crack. A good rule of thumb is to insert a nail every 30cm along the crack. 

Then attach injection ports to these nails. This will make the process of filling the crack much easier and cleaner.

Window frame with large wall cracks and chipped paint around the outside of the window.

Epoxy comes in two parts that need to be mixed before you use it. Follow the instructions on your epoxy repair kit when mixing the epoxy! Apply the mixed epoxy on each injection port tab before spreading the epoxy over the crack, making sure to cover 2-3cm on each side of the crack. 

You also need to make sure the flange (the round bottom part of the injection port) is completely covered. Then feather out the edges of the epoxy with a paintbrush dipped in mineral spirits.

You’ll need to leave the epoxy for at least 10 hours to dry. The best option is to leave it overnight.

Using a caulk gun, inject liquid concrete into the ports and fill it all the way up until it oozes from the port. Make sure the port is fully plugged in before you move on to the next one. Clean up any messes and leave the concrete to dry for at least five days.

Once the concrete has dried you can use a hacksaw to level the port with the wall or floor. Then simply sand the area down and paint it to match the rest of the area.

A shallow-looking crack in dark concrete.

Frequently Asked Questions About Wall Cracks

Won’t the patched paint be obvious?

If you’re afraid the painted area will look slightly off, you can feather the paint. 

After you’ve painted the patch, use the same paintbrush without adding more paint to drag the paint out and over the existing wall paint. This spreads the new paint and thins out the edges, helping it blend in with the rest of the wall. 

Think of it like blending out the fresh paint onto the older paint. 

What should I do if I don’t think I can fix this myself?

That’s a perfectly normal feeling! If you’ve never tackled a project like this, it can seem incredibly daunting. 

For small cracks, dents, and touch-ups you can hire a handyman to do the work for you. While they’re there you can also get assistance with any other maintenance jobs you have left over.

Brick wall with deep wall crack running through it, and lots of smaller wall cracks and chipped paint.

Don’t Let a Wall Crack Get You Down

Unfortunately, damage and cracks happen – they’re unavoidable. But how you deal with wall cracks and imperfections is what matters! Taking a few hours to fix these problems can really change the way you view your home because everything looks more put together.

Get in touch with our building home pros to start repairing any damage to your home.

You’re in good company