How to Spot When Your Walls Need Replastering
Your walls might be trying to tell you something. Cracks appearing out of nowhere, damp patches that won't go away, or that hollow sound when you knock on the wall – these are all signs that your plaster could be on its way out.
But how do you know when it's time to call in a professional? And when can you get away with a simple patch repair instead of a full replaster?
In this guide, we'll walk you through the common warning signs that your walls need attention. We'll also help you understand when a quick fix will do the job and when it's worth investing in a complete replaster.
The 5 Warning Signs Your Walls Need Replastering
1. Cracks Spreading From Corners
Small hairline cracks around door frames and window corners are fairly normal in most homes. They usually appear as the building settles over time.
However, when cracks start spreading outwards from corners, getting wider or longer, this is a sign of a bigger problem. These spreading cracks often mean the plaster has lost its bond with the wall behind it.
What to look for:
- Cracks that branch out like tree roots
- Cracks wider than 3mm
- Cracks that keep coming back after you've filled them
2. Damp Patches That Keep Returning
If you've noticed damp patches on your walls that keep coming back no matter how many times you paint over them, the plaster itself could be the issue.
When plaster absorbs moisture over a long period, it loses its strength and starts to break down. Simply painting over the problem won't fix it – the damp will keep coming through.
What to look for:
- Discoloured patches that reappear after painting
- A musty smell near affected walls
- Paint that bubbles or peels in the same spots
3. Hollow Sounds When Tapped
Here's a simple test you can do right now: gently tap your wall with your knuckles and listen to the sound it makes.
Solid plaster should produce a dull thud. If you hear a hollow, drum-like sound, this means the plaster has separated from the wall behind it. This is called "blown" plaster, and it's only a matter of time before it starts cracking or falling away.
How to check:
- Tap the wall gently in several spots
- Compare the sound to areas you know are solid
- Mark any hollow-sounding areas with masking tape
4. Crumbling or Flaking Surfaces
When plaster starts to crumble or flake when you touch it, the material has reached the end of its life. This often happens in older properties or in rooms with high moisture levels like bathrooms and kitchens.
You might notice:
- Sandy or powdery texture when you rub the wall
- Small pieces falling away when touched
- Dust gathering at the base of walls
5. Bulging or Uneven Plaster
Bulges in your plaster are a clear sign that something has gone wrong behind the surface. This could be caused by moisture damage, structural movement, or simply old age.
Bulging plaster is unstable and can fall away suddenly, so it's important to get it checked sooner rather than later.
Patch Repair vs Full Replastering: Which Do You Need?
Not every plastering problem needs a full room replaster. Here's a helpful guide to understanding when each approach makes sense:
When a Patch Repair Works Well
Patch repairs are ideal when:
- The damage is limited to a small area (less than 1 square metre)
- The underlying cause has been fixed (like a leak that's been repaired)
- The rest of the plaster is in good condition
- You're on a tight budget and the damage isn't structural
When Full Replastering is the Better Choice
Full replastering becomes the smarter option when:
- Damage covers large areas or multiple walls
- You're renovating and want a perfect finish
- The plaster is original to an older property and past its best
- Patch repairs would be visible and affect the final look
- You're planning to sell and want walls that look their best
What Happens If You Ignore the Signs?
Leaving damaged plaster too long can lead to bigger problems:
- Structural issues – Moisture trapped behind damaged plaster can affect the wall itself
- Higher costs – Small repairs become major jobs when left untreated
- Health concerns – Damp plaster can encourage mould growth
- Poor decoration – Paint and wallpaper won't stick properly to failing plaster
Get a Professional Opinion
If you've spotted any of these warning signs in your home, the best next step is to get a professional assessment. An experienced plasterer can quickly tell you whether you need a simple repair or a full replaster – and give you an honest answer about what's really necessary.
At McHandy, we offer free, no-obligation assessments for homeowners across York and the surrounding areas. We'll inspect your walls, explain what we find in plain English, and give you a clear quote with no hidden surprises.
Ready to find out what your walls really need?
Contact McHandy today for your free plastering assessment. You can also browse our full range of plastering services to see how we can help transform your home.
