Black Mould on Your Walls? How BerlinCleaner Removes It and Restores a Fresh Wall
Black mould in the corner? You
are not alone in Berlin
Black spots creeping up a wall corner are one of the most common problems we see in Berlin apartments. The photo below is from a real job: mould spreading along the corner and behind the heating pipes, right down to the floor edge.
Before treatment: surface mould in a cold corner behind heating pipes, a classic Berlin pattern.
The good news: most surface mould like this can be removed and the wall brought back to a clean, fresh white. Here is why it happens, why you should not ignore it, and exactly how BerlinCleaner deals with it.
Why mould grows in Berlin apartments
Mould needs moisture and a cold surface. Berlin flats often supply both, especially from October to March.
Cold corners and outer walls: warm indoor air meets a cold wall and condenses, just like a cold glass.
Behind pipes and furniture: air cannot circulate, so damp stays trapped. Wardrobes and beds pushed against outer walls are hotspots.
Altbau walls and old plaster: thick, porous walls absorb moisture and dry slowly.
Daily moisture: cooking, showering and drying laundry indoors can release several litres of water vapour a day.
Too little airing: tilted windows (Kipplüftung) cool the wall without really exchanging the air.
Why you should not ignore it
Your health. Mould releases spores into the air you breathe. It can irritate eyes, nose and airways, and is a particular concern for children, older people and anyone with allergies or asthma.
Your deposit (Kaution). When you move out, visible mould is one of the first things a landlord or Hausverwaltung checks at the handover (Wohnungsübergabe). Untreated mould and stained walls can lead to deductions from your deposit.
Your walls. The longer mould sits, the deeper it gets into paint and plaster, and the harder it is to remove cleanly.
How BerlinCleaner removes mould and restores a fresh wall
We treat mould in six steps, from first photo to a clean white wall.
Photo check on WhatsApp. Send us a photo like the one above. We assess the size and type of the affected area and give you a flat-rate quote in writing, with no hourly surprises.
Protect the room. We move furniture away from the wall, cover floors and nearby surfaces, and ventilate the room. Our team works with gloves and masks.
Remove surface mould. The affected area is carefully wiped and treated with an anti-mould solution applied to the wall, so spores are not brushed into the air or spread to clean areas.
Deep treatment and drying. The wall gets a second treatment to reach mould in the paint and upper plaster layer. We clean the floor edges, skirting and pipes too, where mould often hides. The wall is then left to dry fully.
Stain-blocking primer. Dark mould stains bleed through ordinary paint. We apply a stain-blocking primer so the marks do not come back through the new coat.
Fresh white finish. We repaint the treated area, or the whole wall for an even result, with anti-mould wall paint. You get a clean, fresh wall ready for everyday life or your apartment handover.
Moving out? Combine mould treatment with our move-out cleaning and wall touch-up in one booking, so the whole flat is handover-ready in one visit.
Before and after photo coming soon.
How to keep mould from coming back
Treatment removes the mould; these habits stop it returning.
Air properly (Stoßlüften): open windows wide for 5-10 minutes, 2-3 times a day, instead of leaving them tilted.
Heat evenly: keep rooms at a steady temperature, around 18-20°C, even in rooms you rarely use.
Give walls space: leave 5-10 cm between furniture and outer walls.
Deal with daily moisture: use the extractor fan, air after showering, and avoid drying laundry in small rooms.
Watch humidity: a simple hygrometer costs little. Aim for around 40-60% indoor humidity.
Report leaks early: a damp patch that keeps returning may be a leak or structural issue. Tell your landlord in writing.
When you need more than surface treatment
We handle surface mould on walls, corners, ceilings and around windows. Some cases need a building expert first:
Mould covering a very large area, or coming back within weeks after treatment
Soft, crumbling or wet plaster
A water leak, rising damp or damage inside the wall
In these cases, tell your landlord or Hausverwaltung in writing, as the cause usually has to be fixed in the building itself. We are happy to clean and refresh the walls once the cause is solved.
FAQ
How long does mould treatment take? Most single corners or walls are done in one visit. Drying time before painting depends on the wall.
Can I stay in the apartment? Yes. We ventilate during and after the treatment and keep the work area contained.
Is it included in move-out cleaning? It can be added to any move-out or deep clean booking, together with a wall touch-up.
Do you speak English? Yes, our team is English-speaking, and we are used to working with international tenants in Berlin.
Are you insured? Yes, BerlinCleaner is covered by €5 million liability insurance.
Get a free mould quote today
Send a photo of the affected wall on WhatsApp to +49 176 61054647 and get a flat-rate quote, usually the same day. Book mould treatment on its own or together with move-out cleaning and wall touch-ups, and hand back a fresh, clean flat.
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