Repair Larger Wall Cracks



Repairing Larger Wall Cracks

Cracks that are larger than 4mm can appear in your home at the least opportune time. Just when you don’t want any more expense, you notice a crack in the house wall, or often in a boundary wall. They’re caused by the structure settling, just a slight movement which you wouldn’t normally even notice. The good news is that you can repair them yourself and it’s not difficult or expensive.

The product that we’re going to use to fill the crack is a Masonry Patching Plaster. This is sold in powder form and becomes a plaster when mixed with water. It’s great for filling cracks that are larger than 4mm.

The first step is to clean out the crack. Remove any loose material and scrape away the powdery plaster along the edges of the crack with a paint scraper or an old screwdriver. Using a paintbrush, remove any dust in the crack.

Prime the crack with plaster primer and leave it to dry overnight. Priming will seal the pores in the plaster inside the crack to prevent any moisture from getting in over time.

In the morning mix up a batch of Masonry Patching Plaster in an old plastic container – old ice cream containers are just the right size.

Follow the manufacturer’s mixing instructions and when the plaster is ready trowel it into the crack, finishing just above the surface of the wall.

Masonry Patching Plaster is a product with a lot of strength. It can be used on the edge of steps to fill chips and for a multitude of other small plaster repair jobs.

The drying time will depend on the size of the crack as this is a water based product, but once the product is starting to dry, after about half an hour or so, it can be scraped down to the level of the wall with a paint scraper and smoothed off with a wet sponge.

A good finishing tip is to apply a coat of  waterproofing paint to the repair. Apply it over the crack and feather out the edges. It’ll mask the crack well and, of course, it’ll provide a waterproofing barrier to that area.

Apply an undercoat to the area of the repaired area. When that’s dry finish with two topcoats.

Once again, it’s important to paint the topcoat from corner to corner, over the entire wall. Just covering the repaired area is a very attractive alternative, but you’re likely to see a difference in sheen or texture in that spot which will be very noticeable in certain light conditions.


Larger cracks