How to fix cracks and holes in walls

Unsightly hairline cracks and crumbling plaster can make a real mess of your interior. We've rounded up the best DIY fixes to help you whip your walls back into shape

We all know the drill, just when you think you've finished overhauling your home interior, things start to look scruffy and the whole merry dance starts again.

Thanks to daily wear and tear, it doesn’t take long for marks, cracks and even holes to appear across walls. However, you don't always need to call in the professionals. Grab your toolkit and try out these budget-friendly tricks to repair the damage in no time.

Assess the damage

First up, you need to ensure that any holes and cracks in your walls aren’t down to anything serious.

Cracks in interior walls can sometimes be a tell-tale sign of subsidence, a serious issue that occurs when the ground beneath your home begins to collapse, which can require major remedial works to your foundations.

Image: pumatokoh/Shutterstock

According to Axa, if the crack is thicker than a 10p coin, wider at the top than at the bottom and close to windows or doors, you might want to call a surveyor in.

However, the good news is most small cracks are not a symptom of subsidence. Instead, they're most likely caused by natural swelling and shrinkage due to changes in temperature.

READ MORE: The ultimate DIY hacks

Once you've assessed the issue, you need to check whether the affected wall is plaster or plasterboard (also known as drywall) as this will dictate how you fix the problem. With plasterboard, you'll need to replace the section of board and plaster over, while if you're dealing with plaster, you'll need to fill the void before you replaster.

Getting prepared

Image: Stokkete/Shutterstock

As with any potentially messy DIY jobs, it's important to cover the floor and nearby furniture with protective sheets. It's also worth turning off any radiators in the room so the plaster doesn’t dry out too quickly.

To make your repairs, you'll need a plastering trowel, filler knife and a hawk – a special tool used to hold the plaster. It’s a good idea to have a bucket of water within easy reach so you can clean your trowel as necessary to ensure a smooth application.

Before you begin, you should remove any old bits of plaster, grease or dust from the problem area. It's also a good idea to wear safety goggles and gloves when you're preparing plaster.

How to repair cracks in plaster

There are many different fillers and plaster products available, so be sure to consider the range and select a product that is best suited to your job. For example, if you only need a small amount, you may find it easier to use ready-mixed plaster.

If the crack is quite shallow, you might want to dig it out a bit to give your filler a better chance of sticking. It’s also a good idea to spray the area with a little water to stop the filler from drying too quickly.

Be aware that some plaster products shouldn’t be applied to a depth of more than 12mm in one go. If this is the case, you may need to apply it in multiple layers, leaving an appropriate time to dry between each application.

Work with small amounts on your trowel so you can build up a rhythm and cover the problem area before the plaster sets.

How to fix a hole in the wall

If there’s a small hole in your plaster wall, it’s a good idea to widen it a little with your filler knife to give the filler a better chance of adhering.

Before you begin work, clean the area with sugar water and a clean sponge and then rinse with warm water. Press filler into the hole, smooth over and then leave to dry.

Once dry, use good quality sandpaper to create a level finish and then it will be ready to paint.

How to repair a hole in plasterboard

Most plasterboard comes in either 9.5mm or 12.5mm thickness, so try to replace like-for-like when making repairs.

Before you cut through any plasterboard, Wickes advises using a cable, pipe and stud detector to ensure it’s safe to cut through.

Next, clean up any rugged edges around the hole and measure the area. Using a plasterboard saw or Stanley knife, cut a new piece of plasterboard to size, adding an extra 25mm or so at the top and bottom to give you some leeway.

Drill a hole in the centre of your new piece of plasterboard and place a nail in it so that the long pointed end of the nail faces outwards. Add adhesive to the overhang at the top and bottom of the plasterboard and carefully slide it into the hole.

Image: Wickes
Image: Wickes

Use the nail to pull the plasterboard towards you so that the adhesive bonds. Once dried, push the nail through so that it falls behind the plasterboard. You should then apply the plaster or filler until the patch is level with the plasterboard. When fully dry, use sandpaper to smooth over.

How to patch up corners

Carrying out neat repairs to corners is a much fiddlier task than repairing a hole or crack in the middle of a wall. In the case of cracks and shallow plaster damage, one trick is to apply filler then add masking tape to both sides of the corner to help it keep its shape as it dries. 

Image: stockphotofan1/Shutterstock

For larger chunks of missing plaster, you might want to use metal or plastic corner beading. To do this, remove any crumbling plaster with a chisel and hammer first. B&Q advises cutting the beading to the right length then painting the cut ends with primer to seal them.

Dampen the wall and add plaster undercoat to each side of the exposed corner. Press the beading into place, allowing the plaster to seep through. Then build up the undercoat plaster and scrape it back to leave a gap of 2mm from the old edge. Apply a top coat of finishing plaster using a feathering motion to ensure it blends in.

If you use metal beading, you might want to brush metal primer over the corner before you decorate to prevent rusting.

READ MORE: World's worst property nightmares

Main photo: Dmytro Zinkevych/Shutterstock


Be the first to comment

Do you want to comment on this article? You need to be signed in for this feature

Copyright © All rights reserved.