How to fix small cracks in plaster walls: tips on Plastering and Painting

Repairing Gib Board Walls

In my previous blogs I’ve given a few tips on painting and decorating. But before you paint a room, you better make sure the walls are in good condition. Paint won’t hide any cracks or dips and dents; on the contrary, paint is far more likely to highlight any flaws.

To clarify, in this blog I’m talking about repairing walls lined with Gib board. Normally these walls have timber frames. These are the most common interior walls found in New Zealand houses.

Plaster walls usually have cracks due to the house "settling" in its foundation, or are damaged where furniture or doors have struck the plaster. At first, repairing plaster damage seems like a daunting task. But take your time to plaster and paint properly, and you will get solid, long-lasting results. If it still seems a bit daunting after reading the below, call me at Banks Building Maintenance.

Fixing small cracks in a plaster wall

Note that in today’s blog I will focus on fixing small cracks in a plaster wall. For large cracks which run through the entire Gib board (so the board is basically cracked right through, this usually happens where boards are joined) a more extensive repair is required. I’ll write more on fixing larger cracks and holes in another blog. Can’t wait? Call me for a quote to plaster and paint it for you.

Tip: Safety first, so make sure you are wearing a dust mask, eye protection and work gloves. Keep the area where you are working well ventilated. If you are repairing a larger crack, you might also want to move furniture away and put down drop-sheets to protect from dust.

Before you start your plaster and painting project, clean the area with Sugar Soap. This will take all the fat and grease of the wall, which will help the repair products stick a lot better. Selleys sells a great product for this purpose, called Selleys Liquid Sugar Soap. Wait for wall to dry thoroughly. 

First make sure the crack is dry. Then clean the crack, using a scraper to rake out any loose material. Remove dust from around the crack, you can use a vacuum cleaner for this. Loose dust can prevent your new plaster or filler from bonding with the existing plaster.

Ideally the crack is at least 1-2mm wide, which helps to make sure that the filler gets into the crack. With a very fine crack, open it a bit further if necessary, using a utility knife.    

Using a putty knife, fill the crack slowly with filler. Rigid fillers are designed for filling gaps, cracks or holes in a solid surface where a smooth and even finish is required, for example repairing walls and ceilings.

Selleys sells a good product which you can use for this: Selleys Spakfilla Squeeze & Scrape. Make sure that the product gets into the crack. You will only need to use one application.

Wait 30 minutes for the filler to dry (or longer, if the crack is deeper than 2mm), and then sand the area until it is smooth and level. 

Clean any dust or filler particles away, and then you’re ready to paint. If you’re using water-based paints, you can apply the paint straight away. If you are using oil-based paints you should wait for 24 hours before painting.

Tip to achieve a high quality finish: After repairing the cracks, apply sealer/primer before painting your 2 topcoats of coloured paint. You can use a product like Resene Broadwall 3 in 1 or Resene Broadwall Surface Prep& Seal. These products are easy to sand and help to smooth any minor surface irregularities. This will help you to achieve a professional looking finish. 

Lack the time to repair your walls? Call Banks Building Maintenance.

If the job is too large for you to fix, or you simply lack the time, please give Banks Building Maintenance a call to help you with your plastering and painting project.

Cheers,  Andre