Understanding the Options
When walls are damaged — cracked, dented, water-stained, or bulging — homeowners face a choice: repair the existing plaster or replace the GIB (plasterboard) entirely. Both approaches have valid applications, and the right choice depends on damage type, extent, and your long-term plans.
Plaster repair involves filling cracks, sanding, and re-stopping the affected area. It's faster, less disruptive, and cheaper for minor to moderate damage. The limitation is that very large repairs or multiple damage points may never blend perfectly with the original surface.
GIB replacement removes the damaged plasterboard sheet and installs new. It provides a completely fresh surface but requires more demolition, generates dust and debris, and costs significantly more. The advantage is perfection — no joins, patches, or texture differences.
When to Repair Plaster
Hairline cracks from settling or temperature movement are ideal for repair. We clean the crack, apply flexible filler, sand smooth, and prime. These repairs are invisible under paint and cost $80–150 per crack.
Small dents and holes (nail holes, doorknob damage, minor impacts) are easily filled with standard joint compound. Cost: $50–100 per repair depending on size. A room with 5–10 small repairs costs $400–600 total.
Water stains without plaster swelling or delamination can be sealed and painted. We use stain-blocking primer (like Resene Sureseal) before repainting. This works when the leak source has been fixed and the plaster is structurally sound.
Patching is economical when damage is localised. A single damaged area on an otherwise good wall doesn't justify replacing the entire sheet. Our skilled plasterers blend repairs so they're undetectable under normal paint finishes.
When to Replace GIB
Water-damaged plasterboard that has swelled, softened, or delaminated must be replaced. Once the paper facing separates from the gypsum core, the structural integrity is gone. Repair fillers won't adhere properly and the damage will reappear.
Extensive cracking across a full wall or ceiling suggests structural movement, poor original installation, or failed stopping. Patching 20+ cracks is often more expensive than replacing the sheet, and the result is superior.
Mould-affected plasterboard should usually be replaced. While surface mould can be cleaned, mould inside the gypsum core will regrow. We cut out affected sections and install moisture-resistant GIB in bathrooms and kitchens.
For renovations where walls are being opened up (new doorways, windows removed), replacing the affected sheets is logical. The new GIB matches the modified layout perfectly, and there's no need to blend old and new surfaces.
Asbestos concerns: pre-1980 homes may have asbestos-containing textures or joint compounds. If disturbance is required, full sheet replacement with modern, safe materials is the only responsible approach. We can arrange asbestos testing.
Cost Comparison
Plaster repair costs $80–200 per linear metre of crack, or $50–150 per small patch. A typical room with scattered minor damage costs $500–1,200 to repair and repaint.
GIB replacement costs $55–80 per m² for the plasterboard, stopping, and painting. A full standard wall (12 m²) costs $660–960. Add $200–400 for demolition, disposal, and protection of the work area.
The crossover point is approximately 30–40% wall damage. If more than a third of the wall surface needs repair, replacement becomes cost-competitive and delivers a better result.
Ceiling replacement is more expensive due to working overhead and supporting fixtures. Budget $70–100 per m² for ceiling GIB replacement, versus $60–80 for wall replacement.
Making the Right Decision
We provide free assessments to help you decide. Our process: inspect the damage, test for moisture, assess structural issues, measure the affected area, then recommend repair or replacement with detailed pricing.
Consider your timeline. Repairs can often be completed in 1–2 days. Replacement typically takes 2–4 days due to demolition and drying time between stopping coats.
Think about paint finish. Repairs under flat or low-sheen paint are virtually invisible. Under gloss or semi-gloss, replacement is safer to avoid visible patch edges.
For rental properties or quick sales, repair is usually sufficient. For your forever home or premium renovations, replacement delivers the flawless finish that justifies the investment.