Cracks in gib walls and ceilings are common in Auckland homes, especially where the house is older, the framing has moved slightly, or the interior finish has been exposed to changes in temperature and humidity. Some cracks are only cosmetic, while others point to movement or a poor earlier repair.
The key is knowing what type of crack you’re dealing with before you sand, fill, and paint. A proper fix starts with understanding the cause, not just covering the line.
Why cracks appear in gib
Gib is a stable lining material, but it still sits on a timber or steel frame that moves over time. In Auckland, seasonal moisture changes can cause timber framing to expand and contract slightly, which often shows up as hairline cracking at joints, corners, and ceilings.
Cracks can also appear where the original stopping was thin, the joint tape has lifted, or the plaster has not bonded well. In some homes, repeated vibration from foot traffic, nearby works, or door slamming can also contribute.
Newer homes can crack too. If the building is still settling after construction, small cracks near joints, cornices, or around windows and doors are fairly common.
- Hairline cracks at gib joints are often cosmetic
- Cracks near doors, windows, or ceilings can signal movement
- Poor previous stopping work often reappears through paint
- Humidity changes can make timber framing shift slightly
How to tell if the crack is minor or serious
A fine surface crack that stays narrow and doesn’t grow is usually a decorating issue rather than a structural one. These are often seen at plasterboard joints, internal corners, or where the ceiling meets the wall.
Cracks that widen, reappear after repair, or run diagonally from openings need more attention. If you can see movement, feel a step in the surface, or notice the crack opening and closing through the seasons, there may be an underlying building issue that needs checking before painting.
Water stains, soft gib, mould, or a sagging ceiling are different again. In those cases, the cause may be moisture damage, not just normal settling.
- Minor: fine, stable, hairline cracks
- Moderate: repeated cracking at the same joint
- Concerning: widening cracks, sagging, staining, or soft spots
The right way to fix gib cracks before painting
A lasting repair usually involves more than filler. The crack needs to be opened up or cleaned back where needed, loose compound removed, and the area re-stopped with the right jointing product and tape if the joint has failed. Then it should be sanded, sealed, and repainted so the finish blends properly.
If the crack is in a ceiling line or corner, careful prep matters even more because those areas are prone to showing shadows and hairlines after painting. Using the correct primer and topcoat helps reduce the chance of the repair flashing through later.
For good results, the surface should also be checked for previous coats, patched edges, dust, and any sign of dampness. Painting over movement or moisture rarely lasts.
- Don’t rely on paint alone to hide a crack
- Remove loose material before stopping
- Use the right tape or compound for the crack type
- Prime repaired areas before topcoating
When to call Steve
If the cracks keep coming back, are spreading, or are affecting a visible feature wall or ceiling, it’s worth getting advice before repainting. Steve is a Kiwi and a trade-qualified painter, and he can assess whether the issue is just surface cracking or something that needs a more durable repair approach.
For premium Auckland homes, a clean, long-lasting finish depends on proper preparation as much as the paint itself. Steve can help with gib crack repairs, stopping, sanding, priming, and repainting so the result looks neat and holds up better over time.
Frequently Asked Questions
Are cracks in gib walls normal in New Zealand homes?
Small hairline cracks are quite common, especially in homes where the framing moves slightly with changes in humidity and temperature. The important thing is whether the crack is stable or keeps returning.
Can I just paint over gib cracks?
You can, but it usually won’t last. Paint hides the colour of the crack, not the crack itself. Proper stopping, sanding, priming, and repainting are usually needed for a neat finish.
When should I worry about ceiling cracks?
If a ceiling crack is widening, accompanied by staining, sagging, or soft gib, or keeps reappearing after repair, it should be checked before painting.
Need a hand with your project?
Happy to tackle some of it yourself? Great — but for anything you’d rather leave to a professional, Steve Lunjevich is a Kiwi and a trade-qualified painter with 20+ years’ experience. Call or email for honest advice or a free, no-obligation quote.