A hole in your GIB plasterboard wall can look daunting, but most small to medium repairs are well within reach of a capable DIYer. With the right materials, a bit of patience, and a good eye for finishing, you can achieve a result that's virtually invisible once painted. Here's how to do it properly.
Understanding Your Wall
Most interior walls in New Zealand homes are lined with GIB plasterboard — a gypsum-based board manufactured by GIB. Standard thickness is 10 mm for walls and 13 mm for ceilings, though older homes may vary. Before you start, identify what's behind the wall — power cables and plumbing pipes can run through cavities, so always check with a stud finder and cable detector before cutting or drilling.
What Size Is the Hole?
The repair method depends on the size of the damage:
| Hole Size | Best Method |
|---|---|
| Up to ~20 mm (nail/screw holes) | Filler or spackle |
| 20 mm – 100 mm | Backing patch or mesh patch |
| 100 mm – 300 mm | Timber backing or California patch |
| Larger than 300 mm | Full sheet replacement (consider a pro) |
Tools and Materials You'll Need
- Utility knife and drywall saw
- Sandpaper (80-grit and 120-grit)
- Putty knife and broad finishing knife (150–200 mm)
- GIB Basecoat or all-purpose joint compound
- GIB Finishing Compound for top coats
- Fibreglass mesh tape or paper jointing tape
- Timber backing strips (for larger holes)
- Drywall screws
- Primer and paint to match your wall
All of these are available at Bunnings, Mitre 10, or PlaceMakers.
Step-by-Step: Patching a Small Hole (Up to ~20 mm)
- Clean the area — remove any loose paper or crumbling plaster around the hole.
- Apply filler — use a pre-mixed filler or GIB Basecoat. Press it firmly into the hole with a putty knife, slightly overfilling.
- Let it dry completely — drying times vary by product and humidity; check the manufacturer's instructions.
- Sand smooth — once dry, sand flush with 120-grit sandpaper.
- Prime and paint — always prime before painting to prevent the patch showing through as a dull spot.
Step-by-Step: Patching a Medium Hole (20 mm – 300 mm)
1. Prepare the Opening
Use a drywall saw or utility knife to cut the hole into a neat square or rectangle. This gives you clean, straight edges to work with.
2. Install Timber Backing
Cut two strips of timber (a piece of 45 × 19 mm DAR pine works well) slightly longer than the hole's height. Slide them into the cavity behind each side of the opening and screw them to the existing GIB from the front using drywall screws. These act as a solid fixing point for your patch.
3. Cut and Fix the Patch
Cut a piece of GIB to fit snugly in the opening and screw it to the timber backing strips. Don't overtighten — the screw head should sit just below the surface without breaking the paper face.
4. Tape the Joints
Apply fibreglass mesh tape or paper jointing tape over all four seams. Bed the tape into a thin coat of GIB Basecoat using your broad knife, feathering the edges outward.
5. Apply Coats and Sand
Allow each coat to dry fully before applying the next. Typically you'll need three coats — a base coat, a fill coat, and a finish coat — sanding lightly between each with 120-grit paper. Feather each coat wider than the last (aim for 200–300 mm wide on the final coat) to blend into the surrounding wall.
6. Prime and Paint
Once you're happy with the surface, apply a quality primer. Resene and Dulux both offer suitable interior primers. Finish with your wall colour — two coats usually gives the best result.
Getting a Seamless Paint Finish
The most common DIY mistake is skipping the primer or not feathering the compound wide enough, leaving a visible hump or dull patch. Take your time with sanding and use a lamp held at a low angle (raking light) to spot any ridges before you paint. If your walls have a texture (such as a skip-trowel or orange-peel finish), you'll need to replicate it before painting — this takes practice.
Safety Notes
- Always use a stud finder and cable detector before cutting into any wall.
- Wear a dust mask when sanding — plasterboard dust is a nuisance and can irritate your lungs.
- Check WorkSafe NZ guidance if your home was built before the 1990s, as some older textured coatings may contain hazardous materials.
When to Call a Professional
Some situations are best left to a qualified tradesperson:
- Large holes or structural damage — if framing (studs or noggs) is damaged, a builder or Licensed Building Practitioner (LBP) should assess the work.
- Holes near electrical wiring — any work on wiring is restricted electrical work and must be carried out by a registered electrician licensed with the Electrical Workers Registration Board (EWRB). Do not attempt this yourself.
- Wet areas (bathrooms, kitchens) — repairs in wet areas must comply with NZ Building Code clause E3 and may require specific waterproofing. BRANZ has detailed guidance on wet area construction.
- Extensive damage or insurance claims — a professional finish is important for property value and landlord obligations under the Healthy Homes standards.
For any of the above, find a trusted local handyman or plasterer on tradedirectory.co.nz.