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How to Get Rid of Mould on Walls Permanently

Updated Sep 12, 2022 | Posted Jul 29, 2022 | Product Advice | 0 comments

As a professional decorator, tackling mould is something I have had to do on many occasions. A lot of people quite wrongly assume you can just paint over mould, which may cover it for a certain amount of time but won’t deal with the problem in the long term.

In this blog, I’m going to explain how to get rid of mould on walls permanently. I’ll start by explaining what mould is and what causes it. Then I’ll go onto killing the spores, painting an affected area, then how to prevent it form coming back. I hope you find it useful.


What is Mould and What Causes it?


Quite simply, mould is caused by the growth of a certain fungi in your home. What you see on your wall is the formation of spores. These spores are dust-like and can become airborne, which then seeds more patches of fungi in other parts of your room or home.

Conditions need to be right for mould to grow. You normally find it in rooms that are very humid or have issues with excess moisture. Possibly from damp coming in from the outside of your home, but sometimes from a leaking pipe or similar. Condensation is the main cause of mould growth.

The most common places to find mould are bathrooms and kitchens because of the excess steam, which normally condenses on the coolest wall / window and keeps it wet for long periods.


As a decorator, I tend to come up against walls full of mould when working for landlords. This might be for a few reasons, including properties being empty for weeks or months at a time, poor ventilation, people drying their clothes inside the house, or cheap paint being used to decorate.


More Issues Caused by Mould


Mould isn’t exactly pleasant to look at, and I’ve already touched on the possibility of mould spreading to other areas of your home. It effects air quality too. If you have mould patches on your walls in a room, then you can guarantee some spores are already airborne.

This is a particular problem for people with asthma as the spores can trigger an attack. I know this first hand because I used to suffer quite badly. It also affects people with other breathing difficulties, including chesty coughs. Allergies like hay fever can also be triggered by mould spores, so stuffy noses and sneezing can be common in homes with mould.


How to Get Rid of Mould on Walls Permanently


Right, now you know what mould is and the issues associated with it, let’s get down to the good stuff!! How to get rid of it. Do not fall into the trap of thinking you can just paint over it!!

You should wear some sort of protective clothing (PPE) when tackling mould, as the spores can irritate your skin. Rubber gloves, a long-sleeve top and a mask will help protect your health while you work. Pop all your clothes in the wash once you’ve finished treating the mould.

The first thing you need to do is kill the spores. Otherwise, it’ll just come back anyway. HG do a brilliant mould killer which you can buy online. This is perfect because you can just spray it on, leave it for 10 minutes, and then wipe it off.


If you don’t want to buy a specialist product, then you can use a diluted bleach solution. Bleach will kill the spores and as a rule, will not penetrate a porous surface (like your walls). If you do use bleach, then make sure you wipe over again with clean water to remove as much as possible, simply because bleach can breakdown the polymer in some paints.


Blocking the Stain


If you don’t paint your walls, the mould may come back unfortunately. Before decorating your room, you will need to block the stains caused by the mould. There are several products you can use for this. You only need to block stains in the affected areas.

The cheapest way to block a mould stain is to use oil-based undercoat. Just be aware that applying an oil-based product in an enclosed space will cause unpleasant fumes, so open a window and continue to wear a mask. If you do use undercoat, you should leave it at least 16 hours to dry before you apply a water-based paint over the top.

Zinsser Cover Stain is another great product for this and will not take as long to cure before you can paint over it. HB42 Primer Sealer Stain Block is a better product with less smell.


Decorating Your Room


Right, so we know what mould is, we’ve killed the spores and we’ve blocked the stain. The point of this blog is to explain how to get rid of mould on walls permanently, so there is more we need to consider. That includes paint.

Cheap retail matt emulsion, or contract matt does not contain much in the way of polymer binder, so remains porous. This is a major issue in the fight against mould because it will hold onto water and create the perfect habitat for this fungus.

You could opt to use a good quality trade eggshell. Although there is nothing in the paint to kill spores as they land, the product itself dries waterproof. Condensation will just run off the walls and help keep them dry.

There are other products you can use which will actively kill any mould spores in the room. Zinsser Perma White is the perfect example of this. Dulux make a product called Mould Shield which is worth having a look at. Or, if your issue is with condensation, then maybe even an insulating paint like SureTherm!


You have plenty to look at. I can personally vouch for Zinsser Perma White. It is available online in any colour, it dries durable, and mould will never grow on your walls again. The opacity in white isn’t very good, so expect to need an extra coat. You can even use Zinsser Perma White on your woodwork.


Preventing Moisture Build-Up


If you really want to get rid of mould on walls permanently, then you will need to do what you can to prevent condensation in your rooms. I mentioned in one of the opening paragraphs that condensation is the main cause of mould, and I stand by that.

Simple things like regularly opening a window and not drying wet clothes inside will help, but you may need to do more. An extraction fan in your bathroom or kitchen will almost certainly make a difference. In fact, an extraction fan may be the silver bullet needed to prevent mould from coming back.

A vent will also help and will not cost as much as an extraction fan. Anything to bring fresh air in and allow moist air to leave.

Sometimes the placement of radiators play a big part too. Ever wondered why more times than not, you’ll find a radiator on an exterior wall, or under a bay window? It’s because this is the coldest wall in your room, so most prone to condensation when you put your heating on. Having your radiator on the coldest wall will stop this.

A dehumidifier is a fantastic short-term solution. These handy little gadgets suck air in and run it over a cold metal radiator. Moisture in the air condenses on the radiator and is collected, so the air that comes out is a lot dryer. The only issues with dehumidifiers are they’re bulky and loud, so they’re not really a practical solution.


If your mould is caused by damp coming into your home from the outside, then you should ask a builder to help you diagnose the problem. It may be a simple fix like cleaning your gutters or changing the sealant around a window. It may be something a bit more sinister like rising damp due to a failed membrane.


Final Thoughts


Sorry if I’ve gone on a little bit. I just wanted to touch on everything you should look at when working out how to get rid of mould on your walls permanently. Follow the steps outlined in this blog and you should solve the issue. I hope it’s helped.

Updated Sep 12, 2022 | Posted Jul 29, 2022 | 0 comments

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