Cleaning bathroom mould

Mould is often found in warm, damp places, which is why it can be a common sight in bathrooms. Caused by excess moisture, the substance can cause various health issues, including breathing problems and damaging your immune system.

In most cases, you can remove mould yourself using a cleaning solution which can be made at home. Read on for our complete guide to bathroom mould, how to spot it, remove it, and prevent it from forming.

What is black mould and why does it form?

Mould is a fungus that grows in damp, warm conditions, such as a bathroom, where there is very little airflow. It can start as mildew, a white form of fungus found on a flat surface.

The growth of black mould on bathroom walls and ceilings is due to excess moisture, which may start with condensation building up over time following a shower or bath. The warm, moist air meets a cold surface and clings to it, like windows.

Mould can build-up for many reasons, apart from a lack of ventilation in your bathroom; these include leaking pipes, poor insulation or if condensation has not been removed following a shower.

What are the health risks of black mould?

According to the NHS, mould can cause various health problems, the most likely being breathing problems. These would include infections, allergies or asthma attacks.

Health risks associated with mould include allergic reactions, such as sneezing, a runny nose, red eyes and skin rash. This is especially true if you touch or inhale any spores, which can cause an asthma attack.

Therefore, those most likely to be affected are children, the elderly and anyone with existing skin problems and respiratory issues.

According to Asthma UK, 42% of respondents to their 2019 annual survey said mould can trigger their asthma. They advise that if you experience cold-like symptoms in warm, damp environments, you could be allergic to mould.

Furthermore, the World Health Organisation believes that many of the 300 million cases of asthma cases among children have originated or been worsened by mould exposure.

How can I get rid of mould in my bathroom?

Depending on the scale and location of the mould, you may be able to remove it yourself. The NHS advises that you only remove mould if it’s caused by condensation (rather than sewage or contaminated water) and covers an area less than one metre squared.

If this is not the case, you will need to call a specialist, such as a mould remediation and removal company or damp repair company.

Before you look at removing any mould from your home, it is important to identify the source. Common areas where mould forms include the walls, ceiling, on bathroom tiles, grout, basins and bathtubs, drains and behind shower tiles - which can result in large repair costs if the damage is extensive.

How can I identify mould in my bathroom?

There are various ways of identifying mould in your bathroom. Remember, mould forms from the inside out, so if you can see it, the issue may already be severe and will need fixing as soon as possible. Below are tell-tale signs of mould forming in your bathroom:

  • Smell: A constant damp smell, even when your bathroom looks completely dry and clean, is a sign of mould forming. This can be down a hidden leak in a pipe or a build-up of moisture.
  • Dark Appearance: If your wall or tiles look brown and muddy with a damp and slimy looking appearance, this could be black mould growing.
  • Damaged Walls: Crumbling plaster, off-coloured walls, blistered paint or cracked tiles, or warped walls may mean that moisture has got into the walls, causing mould to grow.
  • Unstable Floors: If your flooring feels soft and spongy - perhaps under tiling - you may have moisture underneath, result in mould forming.

How should I stay safe when removing mould?

If you are trying to remove mould yourself, there are certain safety precautions you should take.

Protect yourself from spores with eyewear, long rubber gloves and a mask that covers your nose and mouth. Remember to open the windows for ventilation and keep doors closed to prevent spores from spreading to other parts of your home.

Bathroom cleaning equipment

As previously mentioned, do not try to remove any mould that's been caused by sewage or contaminated water.

Put any clothing you’ve worn while cleaning straight into a bucket with warm water and some mild detergent to hand-wash them.

Any rags, cloths or sponges you’ve used should be put into a plastic bag and thrown away.

Where can mould form, and how do I remove it?

How you remove mould can depend on where it’s located. It can often be found on surfaces like tiles, grout, sealant or a shower curtain. You can remove mould with various home-made cleaning solutions or with one bought from a shop.

Mould Cleaning Solutions: Buying vs Making

When it comes to removing mould, you can create your own cleaning solutions:

  • Non-toxic: Vinegar is a great option for killing mould. It may smell unpleasant, but it won’t have the toxicity of bleach. Pour it straight onto the spores or use a spray bottle. Try mixing it with water with a ratio of 2:1, leave for 30 minutes before wiping.
  • Borax: A natural insecticide and fungicide, this solution mixes sodium tetraborate decahydrate - or baking soda - with water. It doesn’t need to be rinsed off and can prevent mould from growing. You can buy baking soda in many supermarkets.
  • Bleach: The heavy-duty and last-resort option. Bleach will kill mould on showers and tiles etc, but it is a toxic substance, so take great care when using. Mix it with water at a ratio of 1:10. Rinse away afterwards if children or pets are around.

If are unsure about these mixtures, you can buy ready-made cleaning solutions and mould removers from supermarkets. The benefit of store-bought products is that you don’t have to worry about mixing substances, you can be sure of their measurements. However, most are bleach-based, so you will need to be aware of any fumes.

Cleaning Tiles and Other Smooth Surfaces

To remove mould from smooth bathroom surfaces, including tiles or a basin, spray a cleaning solution onto the affected area and wait for it to soak in. There should be a visible coating, but try not to over-saturate the affected area.

Using a cloth or sponge, wipe the mould away, remembering to use a new side of the cloth when the first side becomes too saturated or dirty. You may need to use more than one cloth or sponge if you are cleaning a large area. If the mould isn’t coming away, use a dedicated scrubbing brush.

Removing Mould from Grout

Mould found in grout can be more difficult to remove. Spray your cleaning solution onto the affected area, bleach or borax may be used for its strength, combined with scrubbing the mould away with a brush.

A toothbrush can help here so it fits in the tighter space, though remember to rinse it every so often while cleaning to remove spores. If you are using bleach, keep a window open, wear protective gloves and eyewear, and take a break from cleaning due to fumes.

https://www.youtube.com/watch?v=xmnKWqLphZA
Watch this video for an example of removing mould from grout

If you cannot get the mould off entirely, scrape the grout away with a screwdriver, for example, and replace it with a new mixture. Applying sealer to the grout afterwards can help prevent mould forming.

Removing Mould from Sealant

For sealant, similar to grout, you may need to replace it entirely. If the mould is on or around your tiles, you should be able to scrub or brush it away with your cleaning solution, potentially bleach-based or borax for its strength.

Like removing grout, use a flat-headed screwdriver to lift it away and apply new sealant. Remember to clean the tiles, grout and sealant regularly.

Mould on grout and sealant

When using bleach, remember that it is a toxic substance that can cause eye, lung and skin irritation. Take great care and make sure you have enough ventilation to remove fumes.

A handy trick is to roll a few pieces of toilet paper into a sausage shape, pour the bleach onto the affected sealant and let it soak in. Place the toilet paper on top, allowing it to absorb the bleach. Leave it for 12 hours and then remove it. You may need to repeat it. Watch the video below for an example.

Removing Mould from Shower Curtains

A shower curtain offers privacy to your bathroom but also acts as a means of catching condensation. Mould can develop at the bottom where liquid collects, or over the rest of the shower curtain if moisture is left to settle for too long.

Remember to regularly clean it in a washing machine or in a large bucket. You can soak the curtain in a mixture of warm water, bleach and washing detergent. A non-toxic option is adding baking soda and vinegar into a solution of washing liquid and water.

You may need to do this more than once, as plastic blocks water, or scrub the curtain with a brush. If that doesn’t work, you may need to replace it.

Always remember to dry the shower curtain thoroughly once you’ve cleaned it and removed the mould.

There are also mould remover liquids available to tackle surfaces that include showerheads, drains and taps. Find out more about cleaning your bathroom properly.

How can I keep my bathroom mould free?

The most important thing to consider is to get some air into your bathroom. Mould and mildew thrive in warm, damp environments, so it’s vital to keep your bathroom ventilated.

Use an extractor fan during or after a shower or bath, depending on your home’s airflow. Remember to keep the door open when your bathroom isn’t in use and open a window every so often to keep it ventilated.

Extractor fan

Read more about how to properly ventilate your bathroom.

After a shower or bath, always wipe down your walls and surfaces – this will prevent moisture building up. A shower screen will catch moisture and is a great help in combating condensation, but needs to be cleaned regularly.

Paint your bathroom walls with mould killer or steriliser that will kill any spores already there, then clean off. Using a barrier solution - a fungicide additive mixed with emulsion - before painting your bathroom will also stop mould growing.

If you follow these steps, you should prevent a build-up of condensation and mould returning.

Find more bathroom advice and DIY tips here by reading our blog. You may also like these posts…

Natural Ways to Clean Your Bathroom | Bathroom Cleaning & Simple Repairs | How to Remove & Replace Grout


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