Remove mould in the bathroom

Black spots in the grout, a dark edge along the silicone joint: mould in the bathroom is common, as a lot of moisture is generated here every day. You can remove small, superficial patches yourself. This guide shows which products are suitable, why vinegar and chlorine-based cleaners are not a good choice, and what helps if the mould keeps coming back.

Status: September 2026

Mould in the bathroom: the most common causes

Mould needs moisture and something to feed on. In the bathroom, it finds both: steam from showering that settles on cool walls and in corners, as well as soap residue and skin flakes in the grout and on silicone. If the room is not ventilated often enough or the shower remains wet after use, that is already sufficient.

Less commonly, damage is the cause: a leaking silicone joint allowing water to run behind the bath, a cracked tile joint, or a leaking pipe. If mould keeps returning to the same spot despite ventilation, the cause should be investigated.

Removing mould in the bathroom: how to do it

The German Environment Agency gives the following rule of thumb: You can remove superficial mould up to about half a square metre yourself, provided you do not have allergies, chronic respiratory diseases, or a weakened immune system. For larger areas or if the mould has penetrated deep into the material, renovation should be carried out by a professional company.

When removing mould, wear gloves, ideally also safety goggles and an FFP2 mask, and ensure good ventilation throughout.

Removing mould from tiles and grout

The right product: alcohol

For smooth surfaces such as tiles, the German Environment Agency recommends 70 to 80 percent alcohol, for example methylated spirits or isopropanol from chemists and pharmacies. It kills the mould and then evaporates without leaving any residue. Important: alcohol is flammable. Use only small amounts, do not smoke, avoid open flames, and keep windows open.

Apply alcohol to a cloth and wipe the area while damp; do not scrub dry (this spreads the spores)
Leave to work for a few minutes, then wipe again with a fresh cloth
Remove stubborn residue in tile grout with an old toothbrush and alcohol
Dispose of cloths in household waste afterwards, allow the area to dry and ventilate well

Why vinegar and chlorine-based cleaners are not a good choice

Vinegar is often listed as a home remedy, but the German Environment Agency advises against it: lime-based surfaces such as grout and plaster neutralise the acid, and what remains of the vinegar can even serve as food for the mould. Acid also makes silicone porous more quickly.

Chlorine-based mould removers do visibly bleach the stains, but they pollute the air, especially in small bathrooms without windows. If you still choose to use them:

Good to know: chlorine only bleaches. If the mould is deep in the grout, it will return after a few weeks, and coloured grout may become permanently discoloured.

Removing mould from silicone joints

With silicone, mould rarely sits only on the surface. It grows into the soft material, which is why the black spots soon return after wiping. The only permanent solution is to completely remove the joint, clean the substrate with alcohol, allow it to dry, and regrout. Our guide shows you how to do this. Renew silicone jointsIf you do not wish to do this yourself: During joint renovation, we remove and treat the mould at the same time.

Preventing mould in the bathroom: 6 tips

Mould will not return if it lacks moisture. This is what matters:

After showering or bathing, ventilate intensively for 5 to 10 minutes by fully opening the window. Windows left permanently ajar cool the wall and actually encourage mould growth
Bathroom without a window: use an extractor fan with run-on function and leave the door open after showering
Wipe down shower screens, tiles and the edge of the bath with a squeegee to remove most of the water
Heat the bathroom even in winter, as cold walls attract moisture
Do not leave wet towels and bath mats to dry in the bathroom
Check silicone joints regularly and renew them as soon as they become cracked or come loose

If the mould keeps coming back

If mould returns despite ventilation and new silicone joints, it is often due to the joints themselves: old tile grout becomes porous, absorbs water, and hardly dries out anymore. In this case, reducing the area exposed to attack can help.

Joint renovationSilicone and tile joints are renewed, with mould removed and treated in the process, usually within a day.
Seamless wall coatingThe coating is applied over the old tiles. Where there are no joints, mould cannot take hold.
Wall panels For the shower area: large, smooth surfaces with minimal joints, installed directly over the old tiles.

If you have damp walls, a musty smell, or mould behind the bath, the cause should be identified first. We will assess this during the free inspection.

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