Cracks in plaster walls are common, especially in older UK homes. While some cracks are purely cosmetic, others need filling properly to stop them coming back.
Using the right type of wall filler is key. Some fillers dry too brittle, while others remain flexible and handle movement better.
This guide explains the best fillers for cracks in plaster walls, when to use each type, and how to get a lasting repair.
Why Cracks Appear in Plaster Walls
Common causes include:
- Natural house movement
- Temperature changes
- Drying shrinkage
- Old plaster
Most small cracks are not structural, but they still need the right filler to avoid reappearing.
Types of Filler for Plaster Cracks
1. Ready-Mixed Lightweight Filler
Best for:
- Small cracks
- Hairline gaps
Pros:
- Easy to use
- Smooth finish
- Quick drying
Cons:
- Not suitable for deeper cracks
2. Flexible Crack Repair Filler
Designed to handle slight movement.
Best for:
- Reappearing cracks
- Older walls
Pros:
- Less likely to crack again
- Strong bond
Cons:
- Slightly longer drying time
3. Powder Filler (Mixed with Water)
Best for:
- Deeper cracks
- Larger repairs
Pros:
- Very strong
- Cost-effective
Cons:
- Needs correct mixing
- Less flexible
Comparison Table: Plaster Crack Fillers
| Filler Type | Best For | Ease of Use | Durability |
|---|---|---|---|
| Lightweight filler | Small cracks | Very easy | Medium |
| Flexible filler | Moving cracks | Easy | High |
| Powder filler | Deep cracks | Moderate | Very high |
Which Filler Is Best for Most Cracks?
For most plaster cracks, a flexible crack repair filler gives the best balance between ease of use and durability.
Lightweight filler works well for cosmetic repairs, but flexible filler is less likely to crack again.
When Filler Isn’t Enough
If cracks:
- Widen over time
- Reappear quickly
- Run diagonally across walls
They may indicate movement that needs further investigation.
Final Thoughts
Choosing the right filler saves time and avoids repeat repairs. Matching the filler to the type of crack is more important than buying the strongest product available.