EXPERT ADVICE
Preventing mould on walls: simple steps to protect your home & health
Updated 03/26
Many homeowners face an ongoing (and painstaking) battle with mould on walls in the UK due to:
Hidden water ingress
Room humidity
Lack of sufficient airflow around a room
The good news? With the right approach, you can prevent mould before it starts and protect both your home and your health.
Find out about the simple steps to remove mould from your walls - and when to call in the professionals.
The simplest and safest way to get rid of mould on walls
Why preventing mould on walls matters
Black mould on walls causes
When to get help from a professional
Why preventing mould on walls matters
They say prevention is better than cure, and there’s no truer case than when tackling mould. Left to its own devices, mould on walls can:
Affect your health – Mould spores can trigger allergies, worsen asthma, and cause respiratory irritation
Spread quickly – To walls, ceilings, and hidden areas
Damage furniture and belongings – Spores can settle into soft furnishings, carpets, and mattresses
Create nasty odours – Musty smells that linger
Weaken surfaces over time – Causing paint, plaster, and wallpaper to peel or flake
The sooner you tackle the cause of mould, the easier (and cheaper) it is to prevent long-term damage.
Black mould on walls: causes
Mould thrives in damp, humid conditions – something many UK homes experience, especially in colder months.
If mould is appearing on your walls, it’s usually down to:
1. Condensation from drying clothes:
Look for: Water droplets on windows, damp patches on walls, mould behind furniture or near radiators
2. A water leak:
Look for: Damp spots, staining, peeling paint, or a sudden musty smell
3. Water ingress from the roof or external walls:
Look for: Damp patches on ceilings or upper walls, marks that worsen after rain, flaking plaster
4. Rising damp
Look for: Tide marks on lower walls, crumbling skirting boards, white salt deposits (efflorescence)
5. Lack of suitable ventilation
Look for: Persistent condensation, stale air, mould in corners, behind furniture, or around windows
Identifying the cause of mould on walls early is key – simply cleaning mould won’t stop it coming back unless the underlying issue is fixed.
Finding the cause of your mould
If you have mould growing on your wall, the temptation is to get rid of it as soon as possible by washing it or painting over it. But let's go back a step first.
Before removing mould from your wall, it's advisable to try to understand why it's there in the first place.
A simple touch test is a good place to start when figuring out the causes of black mould on walls:
1. Is the wall dry?
Could be humid room conditions that are supporting mould growth
Try opening windows, or vents on your windows, more regularly
Invest in a dehumidifier with a built-in moisture meter
Then learn how to get rid of mould on walls in our steps below
2. Is the wall damp?
Could be a sign of water ingress behind the plaster
As well as cleaning the existing mould from your walls, you'll also need to get a local plumber, roofer or leak detection specialist in to check for the cause
Find mould removal professionals local to you
Tools required to clean mouldy walls
Now you've established what the cause might be for the mould, you can get on with removing it.
Using the right materials means you'll get the job done efficiently and effectively the first time around. Here's what you'll need:
Bleach
Water
Bucket
Rubber gloves, goggles, face mask and a full-body PPE suit (to protect clothes from gathering spores)
Spray bottle (optional)
Damp soft cloth
Dry soft cloth
Remember, cleaning mould is not a long-term solution. You'll also need to tackle the cause of the mould to make sure it doesn't come back – whether that means improving the ventilation in your home or getting in a professional to sort a leak or damp issue.
How to remove mould from walls
When it comes to getting rid of mould on walls, soapy water isn't going to cut it. You'll need to use a bleach and water mixture to kill and remove mould spores.
Here's what it involves:
Protect yourself – Put on your gloves, goggles, face mask, and PPE suit to protect your clothes from gathering spores
Prepare the cleaning mix – Mix one part bleach to four parts water in a suitable container. Judge the total amount of solution needed by the size of the mouldy patch
Scrub – Using your damp cloth, gently scrub and wipe away mould
Dry – Mould loves moisture, so be sure to dry the area well with a soft cloth after cleaning
Be aware that in the process of removing the mould, you will more than likely rub some of the paint off the wall too. So be prepared to potentially repaint the area cleaned.
Cost to professionally remove mould
Rather leave it to a mould removal professional? We don't blame you. Cleaning mould from walls can be an unpleasant job.
Mould removal costs vary depending on the extent of the problem and the treatment required. As a guide:
Mould inspection: £100
Mould removal per hour: £30 per hour
Mould removal per room: £300
Mould removal whole house: £1,200
Is mould rearing its ugly spores in your bathroom, too? Our guide to removing mould from bathroom ceilings can help.
Hear from homeowners like you...
This Birmingham homeowner hired Pure Maintenance UK to tackle mould in their home:
"We had the mould treatment carried out in January. Very happy with the final results. We were advised to purchase a dehumidifier, recommended by the company. This we have done and it is amazing how much water is collected from the home. I recommend this company."
Questions to ask before hiring a mould removal service
What type of mould treatment do you use?
Will you identify the cause of the mould, not just remove it?
Is ventilation or damp work recommended alongside removal?
How long should the treatment last before mould returns?
Are follow-up visits included if mould reappears?
What preparation do I need to do before work starts?
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If you’d rather not tackle wall mould removal yourself, a professional can usually handle the job quickly, efficiently, and safely.
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Our damp prevention guide explains how to reduce unwanted moisture in your home in a series of simple steps.
FAQs about how to stop mould on walls
Mould growth is caused by moisture, which is accelerated by humidity and a lack of ventilation. This is why mould is most common in bathrooms, where there is a constant supply of water, water vapour and heat.
Black mould (or Stachybotrys Chartarum) is a particularly nasty form of mould, and it should be dealt with very carefully as it can release harmful spores into the air.
For this reason, the best way to remove black mould is to hire a professional to do it safely.
A specialist mould remover spray is usually the most effective option, as it’s designed to kill mould spores and remove stains. For smaller areas, diluted bleach solutions can also work. But always follow safety guidance and treat the root cause to stop mould returning.
It’s best to wait until the room is fully ventilated and dry before sleeping in it. Open windows, use fans if possible, and follow the product instructions, especially if strong chemicals are involved.
Hire a mould removal specialist, and they will advise on the exact timescales.
Yes, most mould removers are safe for painted walls, but always check the label first. Some products can cause discolouration, so it’s a good idea to test on a small, hidden area before applying more widely.
To stop mould from coming back after cleaning it, you need to deal with the cause of the growth. This will be because of excess moisture due to a leak, condensation, rising damp or poor ventilation. Remove the moisture supply and you'll stop mould coming back.
Permanently getting rid of mould is all about preventing moisture build-up. Fixing a leak, preventing condensation, or dealing with rising damp in basement and ground floor rooms will all help.
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