Replacing a damaged section of GIB plasterboard is a satisfying DIY project that most handy homeowners can tackle themselves. With the right tools, a bit of patience on the stopping and sanding stages, and a good paint finish, the repair can be virtually invisible. Here's how to do it properly.
What You'll Need
Gather your materials and tools before you start:
- GIB standard plasterboard (typically 10 mm for walls, 13 mm for ceilings) — available from Mitre 10, Bunnings, or PlaceMakers
- Stud finder or a thin nail to locate framing
- Utility knife and/or a drywall saw (jab saw)
- Tape measure, pencil, and straight edge
- GIB plasterboard screws (suitable length for the board thickness — check GIB's technical guides at gib.co.nz for fixing specifications)
- Timber nogging timber (90 × 45 mm — treatment requirements depend on location; check with your supplier or council)
- GIB jointing tape (paper tape or fibreglass mesh)
- GIB stopping compound (pre-mixed is easiest for small repairs)
- Broad-bladed stopping knives (150 mm and 250 mm)
- Fine-grit sandpaper (120–180 grit) and a sanding block
- Primer and topcoat paint to match your wall
Step 1 — Locate the Studs and Mark Your Cut
Use a stud finder or probe gently with a thin nail to find the nearest wall studs on either side of the damage. Standard NZ stud spacing is 400 mm or 600 mm centres under NZS 3604.
Mark a neat rectangle around the damaged area so that your cut lines fall on the centre of a stud on each side. This gives you a solid fixing edge for the new board. If the damage is small and doesn't reach a stud, you'll need to install timber noggings (horizontal timber blocks between studs) to support the patch edges — see Step 2.
Step 2 — Cut Out the Damaged Section
Score along your marked lines firmly with a utility knife and straight edge, then cut through with a drywall saw. Cut slowly and carefully to avoid damaging wiring or plumbing hidden in the wall cavity.
⚠️ Safety note: Before cutting into any wall, check for electrical cables and pipes. If you're unsure, use a cable/pipe detector (available at hardware stores). Never cut into a wall near a power point, light switch, or wet area without being certain of what's behind it.
Remove the cut-out piece and inspect the cavity. Check for any moisture, mould, or insulation issues before proceeding — if you find mould or signs of a leak, address the source first.
Installing Noggings (if needed)
If your cut edges don't land on studs, cut lengths of 90 × 45 mm timber to fit snugly between the studs. Angle-screw (skew nail or screw) them into place so their face is flush with the stud faces. These become your fixing points.
Step 3 — Cut and Fix the New GIB
Measure the opening carefully and cut your replacement GIB piece to fit with a 2–3 mm gap on all edges (this allows for stopping compound). To cut GIB, score the face paper deeply with a utility knife, snap the board over a straight edge, then cut the back paper.
Fix the new piece with GIB plasterboard screws at 200 mm centres along each stud or nogging. Drive screws so the head sits just below the surface (a slight dimple) without breaking the face paper. Check GIB's technical information for fixing specifications if you're unsure.
Step 4 — Stop and Tape the Joints
This is the stage that separates a professional-looking result from an obvious patch. Take your time.
- First coat: Apply stopping compound into the joints and over screw dimples with your 150 mm knife. Bed paper jointing tape into the wet compound over each joint, smoothing it flat. Allow to dry fully (usually overnight).
- Second coat: Apply a wider, thinner coat with your 250 mm knife, feathering the edges out 150–200 mm from the joint. Fill screw dimples again. Allow to dry.
- Third coat (if needed): A final skim coat feathered even wider gives the smoothest result. Sand lightly between coats once dry.
- Final sand: Sand the entire stopped area smooth with 120–180 grit paper. Wipe away dust with a damp cloth.
For best results, BRANZ recommends a minimum of three stopping coats on butt joints.
Step 5 — Prime and Paint
Always prime the stopped areas before painting — bare stopping compound is very porous and will show through topcoat as a dull patch (flashing). Use a quality plasterboard primer or sealer, then apply your topcoat to match the surrounding wall.
For colour matching, take a chip of your existing paint to Resene, Dulux, or Wattyl — they can often match it closely.
Does This Work Need a Building Consent?
Minor like-for-like repair of internal plasterboard is generally exempt from building consent under Schedule 1 of the Building Act 2004. However, if the damage is extensive, involves structural elements, or is in a wet area (bathroom, kitchen), check with your local council before starting. You can find guidance at MBIE Building Performance.
When to Call a Professional
Call a licensed plasterer if:
- The damaged area is large (more than a panel or two)
- The damage is on a ceiling, which is physically demanding and harder to finish well
- You find mould, rot, or signs of ongoing moisture — a builder or waterproofing specialist should investigate first
- The wall is in a wet area and may involve GIB Aqualine or similar moisture-resistant board requiring specific fixing methods
- You need a result that matches a fine or textured finish
For electrical work near the repair area — such as relocating a power point — this is restricted work under the Electricity Act and must be carried out by a registered electrician. Check EWRB for details. Similarly, any plumbing work is restricted and must be done by a licensed tradesperson registered with the PGDB.
You can find qualified local plasterers and other tradespeople on tradedirectory.co.nz.
Master Painters NZ member
