Old lime plaster can be removed safely by working methodically with the right hand tools, protecting your framing from impact damage, and taking proper precautions against dust and debris. With patience and care, most homeowners can tackle this job themselves — but there are a few important things to check before you start swinging a hammer.
Understand What You're Working With
Lime plaster was the standard wall finish in New Zealand homes built before roughly the 1950s. It was typically applied in two or three coats over timber lath (thin horizontal strips of wood nailed to the studs) or, in some cases, directly onto masonry. The plaster itself is a mix of lime putty, sand, and sometimes animal hair for reinforcement.
Before you begin, identify your wall construction:
- Lath and plaster — timber laths are nailed across the studs; the plaster is keyed behind them.
- Direct-applied plaster — plaster applied straight onto brick, block, or stone.
The framing risk is greatest with lath and plaster walls, where aggressive removal can split or dislodge the laths and even shift or crack the studs if you lever too hard.
Important: Homes built before the 1980s may contain asbestos in textured coatings, cornice cement, or backing compounds — though pure lime plaster itself rarely contains asbestos. If you're unsure, have a sample tested by a licensed asbestos assessor before disturbing anything. WorkSafe NZ has clear guidance on managing asbestos in residential settings.
Tools You'll Need
- Bolster chisel (wide, flat) and club hammer
- Wrecking bar or pry bar (short, for controlled leverage)
- Stiff-bladed scraper or plasterer's scraper
- Heavy-duty dust sheets and plastic sheeting
- P2-rated respirator mask
- Safety glasses and heavy gloves
- Sturdy work boots
- Large rubbish bags or a skip bin
Avoid angle grinders or rotary hammers for general removal — they create enormous amounts of fine dust and make it very easy to damage framing.
Step-by-Step Removal Method
1. Prepare the Space
Clear the room and lay heavy-duty dust sheets on the floor. Seal doorways with plastic sheeting to contain dust. Turn off power to any circuits running through the wall at the switchboard — old wiring in lime-plaster homes can be fragile and may not be earthed to modern standards. Check with a registered electrician if you're unsure; see the Electrical Workers Registration Board for finding a licensed professional.
2. Score the Plaster
Using your bolster chisel and club hammer, score horizontal lines across the plaster between studs. Work in manageable sections — roughly 300–400 mm wide. Scoring first reduces the chance of large sheets falling unexpectedly and gives you control over where the plaster breaks.
3. Break and Remove in Sections
Angle the bolster chisel at roughly 30–45 degrees to the wall surface and tap firmly — don't strike hard. The goal is to crack the plaster away from the lath, not to punch through the wall. Work from the top of a section downward so debris falls clear.
Once the top coat and brown coat are loose, use a stiff scraper or pry bar to lever the pieces away. Keep the pry bar against the lath, not the stud, to avoid putting lateral force on the framing.
4. Deal With the Laths
Decide whether you're keeping or removing the laths. If you plan to re-line with GIB plasterboard, the laths usually need to come off so you can fix the new board directly to the studs at the correct centres (typically 600 mm for standard 10 mm GIB). Remove laths by pulling them away from the studs by hand or with a pry bar — they're only lightly nailed and should come away without much force.
5. Clean Up the Framing
Once the plaster and laths are removed, check each stud and nogging for:
- Protruding nails — punch them in or pull them out
- Splits or cracks — minor surface splits are usually fine; deep splits in load-bearing studs should be assessed by a professional
- Moisture damage or rot — old lime-plaster walls sometimes hide long-term leaks; if you find soft or discoloured timber, get a builder to assess it before re-lining
Ceiling Removal — Extra Caution Required
Removing lime plaster from ceilings is significantly more hazardous. Large sections can fall without warning, and the weight of old plaster is considerable. Work in very small sections, always wear a hard hat and safety glasses, and consider hiring a plasterer or builder for ceiling work. Never work directly beneath the section you're breaking.
Disposal of Lime Plaster
Lime plaster is generally classified as inert fill and can often go to a general construction and demolition landfill. Check with your local council for accepted disposal methods and whether a skip permit is required if you're placing one on the road.
Do You Need a Building Consent?
Removing internal linings is generally exempt from building consent under Schedule 1 of the Building Act 2004, provided you are not altering or removing structural elements. However, rules vary and your local council is the definitive authority — always confirm before starting. See MBIE Building Performance for guidance on consent exemptions. If you're re-lining with new plasterboard afterwards, that work is also typically exempt, but again, check with your council.
When to Call a Professional
Call a qualified plasterer or builder if:
- You discover asbestos or suspect its presence
- The framing shows signs of structural damage, rot, or significant movement
- You're removing plaster from ceilings over large areas
- The wall is load-bearing and you're unsure about the framing condition
- You want the re-lining done to a standard that meets the NZ Building Code
A licensed plasterer will also be able to advise on the best re-lining system for your home. You can find qualified local plasterers and builders on tradedirectory.co.nz.
Sources & Further Reading
- WorkSafe NZ — Asbestos guidance
- MBIE Building Performance — Building consent exemptions
- GIB — Plasterboard systems and installation guides
- BRANZ — Renovation and existing buildings
- Electrical Workers Registration Board — Find a licensed electrician
- Licensed Building Practitioners — Find a qualified builder
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