Mould on shower seals: remove & prevent

Why shower seals develop mould

Black or greenish coating on white rubber — most people know the picture. Mould on shower seals isn't just unsightly, it's also a health concern (spores, possible allergy triggers).

Mould needs three things to grow: moisture, organic material (soap residue, skin oils) and little air movement. In the shower all of this is in abundance — especially in the gaps between glass and sealing lip.

Identify: real mould or "just" limescale?

Before you start, take a moment to look:

• Black or dark green, patchy: mould.
• White or light grey, crusty: limescale.
• Pink-orange: bacteria (often Serratia marcescens) — superficial, can be wiped away.

Limescale and bacteria are relatively easy to remove. Real mould is stubborn — and infects the material if you don't act fast.

Removing mould: what works (and what doesn't)

What works

| Agent | Effect | Application | |---|---|---| | Chlorine bleach cleaner | very strong, better for mould than for limescale | leave for 5–10 min, rinse well | | Hydrogen peroxide (3 %) | medium-strong, gentle on materials | spray on, leave for 30 min | | Mould remover spray (DIY-store) | specially formulated | follow instructions | | Baking soda paste | mild but effective for surface mould | mix paste with water, work in |

What does NOT work

• Pure vinegar essence — great for limescale, mostly too mild for mould.
• Washing-up liquid — only removes the surface, mould stays in the material.
• Plain water & scrubbing — barely any effect on ingrown mould.

Step-by-step

1. Ventilate the bathroom! When working with chlorine bleach or concentrated mould remover, open the window, wear a mask if needed.
2. Apply the agent — spray or paste onto the affected area.
3. Let it act — per manufacturer instructions, usually 5–30 minutes.
4. Wipe off with an old toothbrush or sponge. Not too hard — the lip can be damaged.
5. Rinse with clean water.
6. Let it dry.

When does only replacement help?

If the mould sits deep in the material — i.e. dots or shadows remain after cleaning — it has already eaten into the material. Even if you get the surface clean, it will return within weeks because the spores sit in the porous rubber.

In that case: replace the seal. That's usually cheaper and faster than repeated cleaning.

→ Seal replacement guide → Launch configurator

Preventing mould: 7 effective measures

1. Squeegee after every shower

A glass squeegee (€5 from the DIY store) is the single most effective measure. 30 seconds of effort reduces moisture on glass and seal by 80 %.

2. Leave the door open

After showering, leave the door open so air can circulate into the cabin. Prevents the typical moist droplet pockets at the seal.

3. Ventilate the bathroom

5–10 minutes of cross-ventilation after every shower. If the bathroom has no window: run the extractor longer, or use a hygrometer — keep below 60 % relative humidity.

4. Don't turn the heating down in winter

Cold walls = more condensation. In winter, never let the bathroom drop below 18 °C if it is used frequently.

5. Wipe weekly

Once a week, wipe the seal with a mild bathroom cleaner — best right after a shower while the seal is warm and soft anyway.

6. Rinse soap off completely

Soap residue is food for mould. After showering, rinse walls and seals briefly with water.

7. Care sprays for seals

There are dedicated care products (e.g. silicone care spray) for shower seals — they keep the material elastic and prevent the cracks where mould settles.

Special case: mould inside the click profile

Sometimes mould sits not on the lip but in the profile groove of the aluminium profile — you only see it when you pull out the seal.

When replacing a seal: always check the profile groove. If mould sits there:

1. Treat the groove with mould remover or hydrogen peroxide.
2. Wipe dry with a microfibre cloth.
3. Only then install the new seal.

Otherwise mould infects the new seal from inside, and the effort was wasted.

Lifecycle of a seal

Even with perfect care, shower seals have a limited service life:

• 0–2 years: visually and functionally flawless.
• 2–4 years: first discolouration possible, but kept clean.
• 4–6 years: material fatigue starts — cracks, mould susceptibility.
• 6+ years: time to replace, regardless of care.

If your seal is older than 5 years and growing mould, replacement is the most sustainable solution.

Summary

• Real mould differs from limescale through dark colour and stubbornness.
• Chlorine bleach or mould remover spray are the most effective agents.
• If dots remain after cleaning: replacement is more efficient.
• Prevention is easy: squeegee, ventilate, weekly wipe, heating on in winter.
• Check the profile groove at every replacement — otherwise mould comes back.