Can you paint over mould?

Can you paint over mould?

By Ruth MacEachern

Product Manager

If you have discovered mould growing on walls in your home – either behind a wardrobe or in your bathroom, you may be worried about the potential health risks that it poses, as well as wanting to get rid of the problem as quickly as possible.  For many people, the first reaction is to try and cover up the problem rather than dealing with it properly.  On seeing mould, you may be asking whether you can paint over mould, and while this may be tempting, it won’t solve the underlying issue and before long, the patches of mould will return.

Why is mould growing in your home?

Moulds grow when their spores settle onto damp patches where they can develop into colonies.  In homes, one of the most common causes for damp patches to form is condensation – when moisture from humid air is able to settles onto cold surfaces and soaks in.

Once mould is established on a damp patch, it will thrive in areas where there is limited air flow to disturb it.  You can’t prevent mould spores from entering your house completely.  The spores are microscopic and are carried by air, although by making your home unfriendly to mould, you can prevent them from being a problem.

Why you can’t simply paint over mould

Just painting over mould will not kill it, so it can grow back easily.  Although the mould is visible on the surface, the colony actually extends into the underlying material such as wood or plaster and extracts nutrients like a plant’s roots.  Even if you’ve cleaned the surface before painting over the mould, some of the mould colony will survive below the surface, and before long, it will penetrate through the new layer of paint and start to bloom in new patches. 

Painting over mould can in fact make the problem worse.  Hidden beneath a layer of paint, the mould can spread across a larger area and emerge in other areas that were previously unaffected.

Does Cleaning Walls before Painting Kill off the Mould

While cleaning walls with bleach or a fungicide will kill off the surface mould, it will grow back eventually.  Even if the colony you have painted over is completely eradicated, fresh spores can find a new damp patch to grow in.

Prevent Mould for Good

If you want to stop mould problems coming back for good, you need to remove the underlying dampness that creates the mould’s preferred environment.  This means reducing the amount of moisture in the air inside your home coupled with improved air flow to reduce the opportunity for mould to grow.

Better ventilation in the form of extractor fans in kitchens and bathrooms, or whole house solutions such as Positive Input Ventilation (PIV) help remove moisture rich air from your home which prevents the condensation that often leads to damp.

Find out more

If you are troubled by mould problems, don’t just paint over it, and hope it goes away.  Talk to one of our local ventilation specialists.  They will be able to conduct a free survey of your home to identify the cause of the mould and provide you with advice about how to prevent it for good.