Mould in joints: How can you remove mould from joints?

Removing mould from joints with Villeroy & Boch

Mould in joints is a common problem in bathrooms. Even in well-maintained bathrooms, closer inspection can often reveal the dreaded black discolouration – on tile joints or silicone seals on shower trays and baths. These unsightly stains are not just a cosmetic problem – the greater danger is invisible: Mould spores, which can spread through the entire bathroom and even to other rooms in your home. As well as causing mould infestation, these spores can also lead to respiratory illnesses or trigger allergies – in particular in elderly or immuno-compromised people. Good news: The right tips can help you remove mould from tile joints before it becomes a serious problem.

More about mould in the bathroom

Tile joints in bathrooms are particularly vulnerable to mould

Fungal spores are a natural part of life and are present almost everywhere. They do not generally pose any risk to health and only in very rare cases do they cause a mould infestation. However, bathrooms provide ideal conditions forfungal spores as they thrive in damp environments. High air humidity and inadequate ventilationcan allow fungal spores to settle and spread.


Joints are very vulnerable to moisture: Condensation water can run down walls and accumulate in recesses. Joints at transitions between a shower tray or bathtub base and the floor are also highly vulnerable. Splashes of water and condensation run down the surface and accumulate in the joint which traps the moisture. Jointless bathrooms, flush-fitting, level showers and free-standing baths with feet are therefore less susceptible to mould.

While mould in mortar joints usually tends to be superficial and easier to remove, silicone joints can be far harder to treat: This soft, elastic material is often used for seals – such as on windows, shower trays, baths, washbasins or toilets. It is easy to process and also adapts to situations where sealed components need to work and allow slight lowering or movement.


It is this same flexibility that also makes siliconevery vulnerable to penetration of water and fungal spores. Tiny cracks and gaps allow water and spores to penetrate into the material where they then settle. Over time, mould can destroy the sealing material. As a general rule: If a joint is already showings signs of damage, i.e. cracks, holes or peeling, cleaning is no longer enough to solve the problem – you will need to call in a professional to repair yourtile joints. A specialist company is the best solution.

Check the following points before removing mould

Before you start removing mould, make sure you are properly protected. This applies even if you are using gentler everyday household products rather than aggressive chemical cleaners. Citric acid, vinegar essence or alcohol can damage skin and irritate airways. The process of removing mould can also cause the release of more spores which can make their way into your lungs or onto your skin. It is therefore important to consider the following points:

  • Face mask: Mould spores measure around just two micrometres – 25 times smaller than the thickness of a human hair. Without appropriate protective equipment, they can very easily be inhaled. This also applies to bacteria often found in damp areas of the bathroom – for example, rod bacteria. You can protect yourself with a respiratory mask, choose an FFP3 mask for maximum protection. Use a mask once only and then dispose of it.

  • Rubber gloves:Always wear rubber gloves when removing mould from joints. Contact with acidic products or aggressive cleaners can irritate skin and cause reactions. Mould spores can also come into contact with hands and potentially trigger allergies.

  • Safety glasses: Caustic fumes can irritate eyes, and when using acids there is always a risk of splashes landing in your eye – especially when treating the ceiling above your head. As well as entering the body through the airways, mould spores can also find a way in through the eyes. So you should always wear safety glasses if possible.

  • Disposable overall:It might seem a little excessive, but a disposable overall is advisable when removing mould. As well as preventing damage to clothing from splashes of acid, it will also stop mould spores from settling in fabrics. As with a respiratory mask and rubber gloves, protective clothing should also be disposed of after use.

  • Disposal of equipment: After treating mould, dispose of all cloths, sponges and brushes with household waste. Important: Put these items in a separate rubbish bag and seal it carefully without squeezing out the air. This air could be contaminated with spores.

Which products are particularly effective against joint mould?

There is a wide variety of commercially available mould removers for all areas of application. Many of these contain chlorine and therefore have adverse implications for health and the environment. In general, there is no need to purchase a special mould remover. You can find lots of products around your home to effectively treat mould in tile joints. In combination with actions to prevent any repeat infestation, these everyday products are all you need. For all products: After cleaning, rinse tile joints thoroughly with clean water.

The best household products

  • Alcohol: ‘Rubbing’ alcohol, also known as isopropanol, consists of 99.9 per cent alcohol. It can be purchased from pharmacies, chemist shops or online and is best applied using an old toothbrush or a lint-free towel. It reliably kills mould spores and bacteria and gradually evaporates after use, which makes it very environmentally friendly.
  • Methylated spirit: If you don’t have any pure alcohol at home, you can use methylated spirit instead. It has a lower alcohol content than pure isopropanol, but this is still sufficient for disinfecting and treating mould. Both rubbing alcohol and methylated spirit kill invisible spores and germs, but they do not remove visible traces of mould that have already permeated tile joints.
  • Hydrogen peroxide: Hydrogen peroxide is a bleaching agent that is widely known for lightening hair and disinfecting contact lenses. But a three per cent hydrogen peroxide solution can also be used for many applications around the home and is excellent for treating mould fungus. Unlike alcohol, it can also fade stains, but usually not completely.
  • Vinegar: Vinegar can help with minor mould infestations – but is generally not enough for more advanced cases.

Special products for removing mould

  • Mould removers with benzalkonium chloride: You can buy special chlorine-free mould removers containing benzalkonium chloride in shops. However, benzalkonium chloride is not entirely harmless and should be used with great caution. Careful rinsing with clean water and thorough ventilation after use are especially important when using benzalkonium chloride or chlorine mould removers.
  • Chlorine-based mould removers: Sodium hypochlorite, or chlorine, is extremely effective in removing mould. However, given its adverse effects on health and the environment, chlorine is best avoided. If a chlorine-based cleaner comes into contact with an acidic household product, toxic chlorine gases can be emitted. Full protective equipment and precise compliance with the manufacturer’s usage instructions are essential when using chlorine cleaners.

How to prevent mould in the bathroom: 8 simple tips

Once you have removed mould from joints,a few simple tips can help to stop it coming back. Pay particular attention to the following points:

  1. Dry the bathroom: After showering or bathing, thoroughly dry any residual moisture in the shower tray or bath and wipe any splashes from the walls and floor. This will stop the moisture evaporating and thus increasing air humidity, and will also prevent it from accumulating in corners, sills and joints where it would provide an ideal breeding ground for mould fungus. When drying surfaces, pay particular attention to joints and corners. Put the heating on as well to quickly dry any remaining moisture.

  2. Ensure adequate ventilation: Regular exchange of air helps to remove fungal spores and keep air humidity low. Ventilate the bathroom thoroughly at regular intervals with the door closed, and keep the window ajar or use an electric fan for continuous ventilation. If in doubt, consider installing an additional window.

  3. Ensure a warm temperature in the room: Heat the bathroom consistently, especially after showering or bathing. This will quickly dry any remaining water and damp textiles and prevent excessive air humidity.

  4. Make sure surfaces stay clean: Clean the bathroom thoroughly at least once a week. Mould thrives ideally on limescale and stains. Change bathroom textiles such as towels and bath mats regularly, clean the shower curtain and keep it dry.

  5. Use neutral-cure silicones: Cheap silicones are ‘acetoxy silicones’ which have little effect in combating mould. High-quality sanitary silicone with a neutral-cure structure is far more resistant to mould.

  6. Use a silicone that inhibits fungal growth: You can also purchase special silicones containing fungicides. However, these are not entirely recommended as their effectiveness is often limited. The fungicides can also be harmful for the environment and health.

  7. Seal connections: Mould frequently forms in places where unsealed connections allow moisture to accumulate – for example, a dripping shower or a leaking syphon. You should therefore check all connections in the bathroom and reseal them if required.

  8. Improve heat insulation: You can also improve your bathroom’s heat insulation. Gaps in heat insulation allow cold bridges to form which can encourage mould. A specialist building insulation company can provide assistance.


Mould can usually be removed effectively from joints using some everyday household products. Always wear adequate protective clothing. If the mould infestation is more advanced, seek professional help to treat it. A few simple actions can help to prevent any recurrence of mould – for feel-good cleanliness and a pleasant climate in the bathroom.