Cracks often appear in interior walls when your house reacts to seasonal weather changes or settles on the soil it has been built on. These cracks are fairly common and should be quite easy to fix. While the cracks are likely to be cosmetic, it is always worth investigating their cause so you don’t have to worry about more sinister structural problems.
Assess and prepare
Once you have established that your home's foundations are still solid, you should assess the size of the crack or cracks you wish to repair. If the cracks are fairly small, you can repair them with filler. Small holes can also be fixed with filler.
There are numerous types of filler available. For example, some are better for fixing cracks radiating out from doors or windows while some are meant for the cracks in the crevices between ceilings and walls. Assess what your walls are clad in, as there are fillers formulated especially to be used on either plaster or plasterboard walls. If you're not sure which filler you need to buy, ask someone working at the hardware store.
Before you begin filling your small crack or hole, ensure you have the following tools and materials:
- Soft brush
- Water mister / spray bottle
- Filling blade
- Fine grade sandpaper
- Paint primer
- Matching wall paint (ideally the original paint)
How to repair the crack
Once you you have your filler, read and follow any instructions on the packet to prepare the filler - if it's a powder, you may need to mix it with something. Scrape away any loose plaster or paint from the crack or hole, then brush the crack to clear any dust. A vacuum cleaner can also be used to remove debris from the damaged area.
Once it is clean, spray the crack or hole with water. When the water has absorbed into the plaster or plasterboard, apply a small amount of your filler to the filling blade and smooth it across the crack/hole at right angles, pressing it in firmly. Don't worry if it looks like there's too much on there, because you will eventually sand it back.
Allow the filler to dry for at least 4 hours (or however long the filler packet recommends). Apply a second coat of filler if necessary. Using a fine grade sandpaper wrapped around a flat-surfaced block, gently sand the filler back until it's level and smooth with the wall. Paint over the area, using a primer to avoid any discoloured patches.