How to Remove Mould from Walls and Ceilings

Removing mould from walls and ceilings is not merely a cosmetic concern: dark marks point to damp, poor ventilation or water ingress, and they can also worsen allergies and respiratory problems. Professional decorators therefore usually tackle the issue on two fronts, clearing away visible fungal growth and taking steps to stop it returning so quickly, using straightforward products, ventilation improvements and, where required, suitable repainting.

How can you identify the source of mould on walls?

Before beginning the cleaning process, professionals establish where the damp is coming from, as this determines whether cleaning alone will be enough or structural repairs are needed. Signs including blown plaster, paint peeling away in sheets or marks spreading rapidly suggest water ingress and require a plumber or waterproofing technician.

Where the damp is on the surface, usually because of limited air circulation or steam from showers and cooking, careful cleaning and minor repairs may be all that is required. Even so, monitoring the wall for several days helps confirm that the issue has genuinely been brought under control.

Watch a video on the Clube do Pintor YouTube channel about effective homemade mixtures for cleaning damp marks and preventing mould from returning:

https://www.youtube.com/watch?v=qMiwKIn0N7w

How do you clean mould from walls step by step?

The most widely used method for removing mould from a wall is to combine water and bleach in equal parts, then apply it directly to the marks with a sponge, cloth or spray bottle, always keeping the windows open. Some decorators also add a small amount of mild washing-up liquid to lift grease and built-up dirt, leaving the solution on for a few minutes before gently scrubbing.

Another common alternative, particularly in small bedrooms or for people who are sensitive to the smell of chlorine, is undiluted white spirit vinegar. Apply it to the mould, leave it for 20 to 30 minutes, then wipe with a dry cloth. In larger areas or where mould is advanced, specialist anti-mould products can be used alongside the initial cleaning.

How should a mouldy wall be prepared for repainting?

Once the visible mould has been removed, leave the affected area to dry fully for several hours or for up to a full day, and never paint while the wall remains damp. When the surface is dry, many decorators lightly sand it with fine-grit sandpaper to smooth it and remove loose residue, filling minor holes with filler before sanding gently again.

Next, it is advisable to use an acrylic sealer or stabilising primer, which improves paint adhesion and helps block mild damp. For the finish, washable acrylic paints or paints labelled anti-mould are preferable. In kitchens, bathrooms and utility rooms, products designed for humid environments provide greater resistance to steam and condensation.

What measures help prevent mould from returning?

Getting rid of mould is only one part of the solution: daily habits reduce trapped moisture and maintain airflow, making marks less likely to reappear. In cold or rainy locations, a quick visual check whenever the season changes can identify early mould spots, which are much easier to deal with.

Several straightforward measures recommended by decorators and home-maintenance specialists can be used routinely:

• Open doors and windows for a few minutes every day to refresh the air.
• Avoid drying clothes in bedrooms or living rooms; use outdoor washing lines or ventilated areas instead.
• Use extractor fans, fans or dehumidifiers in naturally damp rooms.
• Check gutters, roofs and pipework regularly to identify water ingress.
• Position large furniture a few centimetres away from walls to reduce condensation.

If small marks appear, dealing with them promptly using the methods described and improving ventilation will usually prevent major refurbishment work. This keeps the space visibly cleaner, reduces unpleasant odours and lowers the risk associated with fungi inside the property.