If your home was built before roughly the 1960s, the walls are probably solid plaster rather than plasterboard. They behave differently, they fail differently, and repairing them the modern way can make things worse.
How to tell what you have
- Knock on the wall. Plasterboard sounds hollow between studs. Solid plaster sounds dense and dull everywhere.
- Look at a cut edge, for example behind a power point. Plasterboard has paper facing; solid plaster does not.
- Check the thickness at a doorway or window reveal. Solid plaster is usually noticeably thicker.
- Age of the house. Pre-war homes are almost always solid plaster over lath or masonry.
Why the difference matters
Solid plaster is typically lime-based, applied in coats over timber lath or directly onto masonry. It is harder than plasterboard but more brittle, and crucially it is breathable. Moisture can pass through it and evaporate.
Modern plasterboard and many modern compounds are not breathable in the same way. Patch a solid plaster wall in an old home with a hard, sealed modern product and you can trap moisture behind it, which shows up later as bubbling paint, damp patches or the surrounding plaster deteriorating.
| Solid plaster | Plasterboard | |
|---|---|---|
| Era | Pre-1960s | 1960s onward |
| Breathability | Yes | Limited |
| Hardness | Harder, more brittle | Softer, more flexible |
| Typical failure | Cracking, bulging, delaminating from lath | Cracks at joins, water damage |
| Repair approach | Match the material where possible | Cut out and patch |
Common problems in older homes
Cracking. Expected with age and seasonal movement. Usually cosmetic, repaired with flexible fillers rather than rigid compound.
Bulging or drummy areas. The plaster has separated from the lath or masonry behind. Tap it: a hollow sound means it has let go. This needs cutting out and rebuilding, not filling.
Crumbling at skirting level. Often rising damp. The plaster is a symptom; the damp needs diagnosing first.
Damage after renovation. Removing walls, chasing in wiring or installing downlights all disturb old plaster well beyond the immediate work area.
Repair, or replace with plasterboard?
This comes up constantly in period homes. Sheeting over old plaster is faster and cheaper, but it changes the wall thickness at reveals, can bury a moisture problem and, in a heritage home, loses original fabric.
Repairing in matching material keeps the character and the breathability. It costs more and takes longer. For a heritage-listed or overlay property it may also be what is expected.
A reasonable middle ground many people choose: repair solid plaster in the significant rooms, and sheet over in secondary spaces where the original surface has little value.
Painting old plaster
Old, previously unpainted or limewashed plaster is absorbent and needs sealing before top coats, or the paint dries patchy. And in homes with damp history, a breathable paint system matters for the same reason breathable plaster does.
Talk to your local team
Expert Painting and Renovation is a family-run, Aussie-local company based in Richmond, an area full of period homes, with more than 9 years of experience in plastering and painting.
See our plastering services, our interior painting service, or our guide to plastering near me.
FAQ
How do I know if my walls are solid plaster?
Knock on them. Solid plaster sounds dense everywhere; plasterboard sounds hollow between studs.
Can solid plaster be patched with modern compound?
Small repairs often can, but matching materials is better in older homes, particularly where damp is a factor.
What does a hollow-sounding patch mean?
The plaster has separated from what is behind it. It needs cutting out and rebuilding rather than filling.
Is it cheaper to just sheet over old plaster?
Usually yes, but it changes reveals, can hide moisture problems and loses original fabric in a period home.
Related guides
Working on a period home? Contact Expert Painting and Renovation for advice.
About Expert Painting & Renovation
Expert Painting and Renovation is an Aussie-local, family-run company based in Richmond, Melbourne, with more than 9 years of experience in residential and commercial painting and renovation. Our specialists deliver premium workmanship, timely service and durable finishes designed for Melbourne homes.
- Ceiling crack repairs
- Sagging ceiling restoration
- Water‑damaged ceiling repairs
- Cornice replacement
- Full plastering services
- Interior & exterior painting
- Weatherboard restoration
- Deck & timber maintenance
- Roof painting
- Rendering & texture coating
- Commercial Painting
- Plastering Services
- House Painting
Whether you need maintenance advice, a single-room refresh or a full home makeover, our team is just a call away.
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