Plaster is an essential component of a home’s interior, providing a smooth, durable surface for walls and ceilings. Over time, wear and tear, moisture, or structural movement can cause plaster to deteriorate.
Recognising the early warning signs can help prevent costly repairs and ensure your walls remain in good condition. If you’re unsure whether it’s time to replaster a wall, here are the key signs that indicate your house may need replastering.
1. Cracks In The Plaster
Hairline Cracks
Small, thin cracks can appear as a result of the house settling over time. While these may not seem serious at first, they can widen and spread if left untreated.
- Often found near windows, doors, or ceilings.
- Usually caused by natural settling or minor movements in the structure.
- Can be repaired with a skim coat, but extensive cracking may require replastering.
Deep And Widening Cracks
Larger cracks can be a sign of structural movement or poor plaster adhesion. These require more than just surface patching.
- Can extend across entire walls or ceilings.
- May indicate underlying foundation issues or significant shifts in the structure.
- Can lead to chunks of plaster breaking off if ignored.
Stair-Step Cracks
Cracks that form a step-like pattern along walls can be a warning of foundation movement.
- Typically found in older homes with shifting foundations.
- May require both plaster repairs and structural reinforcement.
- A professional should inspect the cracks if they continue to expand.
2. Peeling Or Flaking Plaster
Plaster that starts to peel or flake away from the wall is a strong indication that the surface is compromised. This is often due to moisture damage or poor application.
- Surface peeling – Can be caused by poor adhesion during initial application.
- Flaking paint over plaster – A sign that moisture is affecting the plaster beneath.
- Plaster crumbling when touched – Indicates a need for full replastering.
If left unaddressed, flaking plaster can expose the wall underneath, making the problem worse over time.
3. Discolouration And Water Stains
Water stains on plaster are a clear indication of moisture issues. These can appear as yellow, brown, or dark patches on walls or ceilings.
Common Causes Of Discolouration
- Leaking pipes – Water seepage from plumbing behind the walls.
- Roof leaks – Stains near the ceiling may indicate water ingress from above.
- Rising damp – Staining on lower walls suggests moisture wicking up from the ground.
Why Staining Is A Problem
- Stains weaken plaster and lead to further deterioration.
- Persistent moisture can encourage mould growth.
- Even if the stain dries, the plaster may remain weakened and require replacement.
Before replastering, it’s essential to resolve any water leaks to prevent the problem from recurring.
4. Bulging Or Uneven Walls
If your walls appear to have uneven surfaces, bulging spots, or lumps, it’s a sign that the plaster is no longer adhering properly.
Causes Of Bulging Plaster
- Trapped moisture – Causes plaster to swell and detach from the wall.
- Structural movement – Shifts in the foundation or walls can loosen plaster.
- Ageing plaster – Older plaster can weaken over time, leading to separation.
Signs To Look For
- Soft or spongy areas when pressed.
- Visible bulging or sagging in sections of the wall.
- Plaster that sounds hollow when tapped.
Bulging plaster should be removed and replaced to ensure wall integrity.
5. Mould Growth On Plaster
Mould on plaster is not just an aesthetic issue—it can be a health hazard. This is usually a result of excess moisture and poor ventilation.
Signs Of Mould Growth
- Black or green spots on walls.
- A persistent musty smell in the room.
- Mould returning after cleaning.
Why Mould Indicates A Plaster Problem
- Mould weakens plaster, making it prone to cracking and flaking.
- It suggests excessive moisture that may require a more thorough investigation.
- Replastering with moisture-resistant materials may be necessary to prevent regrowth.
6. Hollow-Sounding Plaster
If you tap your walls and they sound hollow, it may indicate that the plaster has detached from the surface behind it. This is a common sign of deterioration.
Why Hollow Plaster Is A Problem
- This means that the plaster no longer provides structural support.
- Loose plaster can start crumbling, leading to significant repairs.
- The problem often spreads if not addressed early.
If hollow areas are widespread, full replastering is usually required to restore the wall’s strength.
7. Fine Dust Or Powder From Plaster
If you notice a fine layer of dust forming on surfaces near your walls, it may be due to plaster degrading. This process, known as “blown plaster,” occurs when the plaster starts to break down into powder.
Signs Of Plaster Deterioration
- Dust accumulating at the base of walls.
- Plaster crumbling when touched.
- Small particles falling from the ceiling or upper wall sections.
This indicates that the plaster has weakened significantly and should be replaced.
8. Wallpaper Or Paint Not Adhering Properly
If you are experiencing issues with paint or wallpaper peeling off, the plaster underneath may be compromised.
Causes Of Adhesion Problems
- Plaster that has absorbed too much moisture.
- Flaky or crumbling surfaces preventing paint from bonding.
- Uneven plaster leading to bubbles under wallpaper.
Signs To Watch For
- Paint peeling in sheets rather than small flakes.
- Wallpaper lifting at the edges or forming bubbles.
- There is a need for multiple coats of paint due to poor surface absorption.
If these issues persist, replastering may be the best long-term solution.
Conclusion
Recognising these signs early can prevent further damage and reduce repair costs. Cracks, flaking plaster, discolouration, and mould all indicate that your walls may need attention. If the damage is widespread or worsening, a full replastering job may be necessary.
Addressing moisture issues and ensuring proper plaster application will help keep your home’s walls in good condition for years to come.
Frequently Asked Questions
How Often Should Plaster Be Replaced?
Plaster can last several decades if maintained properly. However, high-moisture areas or homes with structural movement may require replastering every 10-20 years. Regular inspections can help determine when repairs are needed.
Can I Paint Over Damaged Plaster?
Painting over cracked or peeling plaster will not fix the underlying problem. It is best to repair or replaster the damaged areas first to ensure a smooth and durable finish. Applying paint over damaged plaster may cause it to flake or peel sooner.
What Is The Cost Of Replastering A House?
The cost depends on the extent of the damage and the size of the area that needs replastering. Small repairs may be inexpensive, while full replastering can cost thousands of dollars. Hiring a professional ensures high-quality work and long-term durability.\