How to paint a cracked or damaged wall

A fresh coat of paint is the easiest way to freshen up the interior or exterior of your home, but what do you do if your wall is cracked or damaged?

Repairing the damage

The repair you need to make depends on the extent of the damage. If there are hairline cracks in the paint itself, which have not gone down to the substrate, then you’ll simply need to remove the loose paint and feather the edges by sanding them. If the cracks go deeper, then you’ll need to remove all the paint before preparing the wall for repainting.

But if the wall itself is cracked or damaged, then you’ll need to undertake some DIY before you can prime and paint your wall. Hairline cracks are the easiest repair to make and you’ll only need a few simple tools.

First, you’ll need to widen the crack, otherwise the plaster patch will have nothing to adhere to. The professionals use a spackling or putty knife with a large, flat blade but you can use a flat bladed screwdriver or even a credit card to prise out some of the plaster around the crack. Clean away any dust or loose plaster with a cloth – an old towel will do. Now fill the crack with ready mixed plaster using a putty knife or any flat, flexible blade. Leave to dry for at least 24 hours before sanding to a level surface, if necessary.

For more serious damage, like larger cracks or holes, the process is a little more complicated. First use a paintbrush to remove dust and loose plaster. Now mix 5 parts of PVA glue with 1 part of water to make a bonding compound and paint all around the hole and some of the surrounding wall. Now press your ready mixed plaster into the hole firmly using a plastering knife, making sure you don’t use too much at once. Now smooth the plaster roughly level and leave it to go off for around thirty minutes. Now smooth the plaster as flat as you can and leave to dry completely before sanding smooth.

For any larger or more complicated repairs, consult a professional.

Priming for painting

Ensure that exterior walls are absolutely dry and that any efflorescence has ceased. Remove moss and algae by washing down with a 4:1 water to bleach solution then scraping to remove debris. Poor surfaces will need to be keyed with a wire brush and coated with bonding liquid. Your walls are now ready to be primed with an appropriate undercoat.
For interior walls, remove all dust and dirt and make sure the walls are dry. Key alkyd/oil based paint surfaces with sandpaper. Strip any poor surfaces. Undercoat with an appropriate primer.

Adding a topcoat

To apply paint to your walls you’ll need a two inch angular brush for woodwork, a two inch trim brush for areas where you need extra control like cutting in and a paint roller with extension handle for walls and ceilings. Choosing the correct application tools as well as using the correct application technique plays an integral part of the end result of your paint job. Find out more about paint applicator choices