How to remove mould from walls without damaging paint

Person cleaning mouldy wall with spray and sponge
(Image credit: Getty Images)

Want to know how to remove mould from walls without damaging paint? Of course you do. It’s ugly, unhealthy and needs to be dealt with quickly. The longer you leave it the worse it will get and the further it will spread. As soon as you spot a patch of small black dots appearing on a wall you need to get on the case and start cleaning.

There can be a host of different reasons why mould is making an appearance on your walls. It can be condensation, especially in areas where moisture is prevalent like a bathroom. It could be a leaking pipe or a broken down damp course. 

Whatever the reason, your first step is to clean to keep the mould at bay until the underlying problem is dealt with. Once you have cleaned and sorted the problem it's time to think of painting a wall or walls to restore them back to their former glory. 

How to remove mould from walls without damaging paint: Two quick steps for clean walls 

Here we take a look at a couple of options for getting rid of mould on walls.

Removing mould without bleach
If your walls are painted with a colour it is best to use a solution that doesn't contain bleach. By the very nature of bleach it will most likely remove colour from the paint and leave an obvious patch on the wall meaning you will need to repaint.

To remove mould from a coloured wall it is a better choice to use warm water, a mild detergent like washing liquid and a kitchen scourer. Add a splash of washing up liquid to a bowl of warm water. Now soak the scourer and use the sponge side to wash over the affected area.

Now wring out the sponge and wipe down the washed area and repeat until all the mould has gone and the wall is almost dry. Use kitchen roll to wipe the wall clean, with a fresh piece of kitchen roll for each wipe. Note this method only works well on surface mould.

Removing thick mould or mould from white walls
Surface mould on white walls can be removed using the non bleach method above. But if the mould has penetrated further into the paint you can use a solution that contains bleach.

Make up a mixture of four parts water and one part bleach. When you have made up the bleach/water mixture add a squeeze or two of washing up liquid. Put into a squeezy spray bottle and apply to the wall. Use a kitchen scourer, use the sponge side first, and wash the wall. Repeat until all mould has been removed. Now dry with kitchen roll. The scourer side of the sponge can be useful for the stubborn areas such as bathroom ceilings. You can also use a very effective mould killing product called HG, available here on Amazon for £4.99, which contains chlorine.

Any kind of water and scrubbing will take a very thin layer of paint off, so it might be worth considering painting a ceiling or wall after you have removed the mould - and addressed the problem that caused it.

Does vinegar remove mould from painted walls? 

Vinegar is another option for getting rid of mould on walls. It is less harsh than bleach and does a good job of removing surface and ingrained mould, which makes it a good choice for coloured walls. But if you are cleaning painted white walls, bleach is a better choice.

Mix three parts water with one part vinegar and add a squeeze of washing up liquid. Spray onto the wall and wipe clean with a damp sponge and dry with kitchen roll. 

What causes mould to grow and how do I stop it from coming back?  

There are multiple causes for the growth of mould, but they all have a common connection, moisture. Condensation is a regular reason for the growth of mould. This occurs where warm air comes into contact with cold surfaces and is common in bathrooms and on windows. Follow our how to stop window condensation guide which offers 9 tips to keep windows dry. 

Other reasons can be cooking in kitchens which is made worse by bad ventilation. Open a door, window or switch on a cooker hood if you have one. Bad ventilation in general is not good, so it's a  good idea to learn how to reduce humidity in a house to help keep mould away. 

Finally, there may be more serious underlying problems such as a leaking roof, windows that need new caulking, leaking pipes or a broken down damp course. If these are the cause of the mould growth they will need to be dealt with quickly.

Can I paint over mould? 

Yes you can. But painting over mould needs some preparation to make sure that the mould won’t come back. First you will need to remove any surface or ingrained mould, you can’t simply paint straight onto mould. 

After removing the mould you will need to dry the wall and deal with any underlying issues that might be causing the mould i.e damp, if needed. Once this has been done, start with a coat of mould resistant paint and leave to dry. You can add a coat of oil-based paint such as Dulux Trade Undercoat for extra protection. Finally, add your top coat such as an emulsion. 

Steve Jenkins

Steve is Homebuilding & Renovating's DIY content editor, and has been a writer and editor for two decades. He is an avid DIYer with over 20 years of experience in transforming and renovating homes. He specialises in painting and decorating, but has strong all-round building skills, having previously worked in the industry for 10 years.