How to Get Rid of Mould on Walls Permanently
Last reviewed
Mould on walls is one of the most common complaints in UK homes — and one of the most frequently “fixed” in a way that doesn’t last. The secret to getting rid of it permanently is simple to say and easy to skip: clean it off, then fix the cause that’s feeding it. This guide covers both.
General guidance. For large areas, recurring mould, or if you rent your home, get the cause properly diagnosed. Health points are flagged — see is mould dangerous?
Why mould grows on walls
Mould needs moisture to grow. On internal walls that moisture almost always comes from one of:
- Condensation — the most common cause, where warm, damp indoor air meets a cold wall surface. Tied to heating, insulation and (especially) ventilation. See what causes mould on walls?
- Penetrating damp — water getting in from outside through a defect.
- Rising damp — ground moisture rising up the wall.
- A leak — plumbing or rainwater.
Clean mould off without removing its moisture source and it will come back. That’s why “permanently” depends on diagnosis.
Step by step: cleaning mould off walls
1. Protect yourself and ventilate
Open a window. Wear a mask, goggles and gloves — cleaning disturbs mould and releases spores.
2. Clean the mould off
Wipe the area with a mould remover or a mild detergent solution, then go over it with a clean, damp cloth. Don’t dry-brush — it spreads spores.
3. Dry the area thoroughly
Let the wall dry completely, with ventilation and gentle heat. Lingering moisture invites regrowth.
4. Find and fix the cause
This is the step that makes it permanent. Work out whether you’re dealing with condensation, penetrating or rising damp, or a leak — and fix it. See the types of damp explained. If you can’t tell, get a damp and mould survey.
5. Prevent it coming back
Improve ventilation and heating, cut indoor moisture, and watch the area. Only redecorate (anti-mould paint can help) once the cause is fixed.
How to stop mould returning
Most wall mould is condensation-driven, so prevention is about managing moisture and ventilation:
- Ventilate when cooking, showering and drying clothes.
- Keep some background heat in cold rooms to lift surface temperatures.
- Don’t block air bricks or trickle vents.
- Address cold spots and poor insulation where you can.
More on this in how to stop condensation on windows and condensation explained.
When to call a professional
If mould keeps returning, covers a large area, or there’s an unexplained damp patch, the cause needs proper diagnosis. An independent damp and mould surveyor finds the real cause without trying to sell you treatment.
Renting? Your landlord is usually responsible for fixing building-related damp and mould — see your rights as a tenant.
Related advice
Frequently asked questions
How do I get rid of mould on walls permanently?
Cleaning the mould off is only half the job. To stop it returning permanently you must fix the underlying cause — usually condensation (a ventilation and heating issue) or damp getting into the wall. Treat the cause, not just the symptom.
What kills mould on walls?
Proprietary mould removers, or a mild detergent solution, will remove surface mould. Some people use diluted bleach or white vinegar. Whatever you use, the mould comes back unless the moisture feeding it is dealt with.
Should I just paint over mould with anti-mould paint?
Anti-mould paint can help as part of a fix, but painting over mould without addressing the cause simply hides it — it will usually grow back through. Clean, fix the cause, then redecorate.
Is it safe to remove mould myself?
Small patches of surface mould can usually be cleaned safely with protection (mask, gloves, ventilation). Large areas, or mould affecting anyone with health conditions, are better handled professionally. See is mould dangerous?
Need a professional damp & mould survey?
Independent, HHSRS-based inspection and reporting from a qualified surveyor.
About damp & mould surveys