How to Get Rid of Mould in a London Home (and Stop It Coming Back)

Black spots in the corner of the bedroom ceiling. A grey line along the shower sealant. A wet window every winter morning. If that sounds like your flat, you're not alone: mould is one of the most common problems in London homes. This guide explains why it grows, how to remove it safely, how to stop it coming back, and what to do if you rent.

Why London homes get so much mould

Mould needs moisture. In most homes, that moisture comes from condensation: warm, wet air from cooking, showers, kettles and even breathing hits a cold wall or window and turns back into water.

London has lots of the homes where this happens most:

• Older buildings. Many Victorian and Edwardian terraces have solid walls with no cavity, so the walls stay cold.
• Small flats. Less space means more moisture in each room, especially when the kitchen is part of the living room.
• Drying clothes indoors. Without a garden or balcony, most Londoners dry their washing on an airer inside.
• Old sash windows and single glazing, which get cold and wet in winter.

The numbers back this up. The government's English Housing Survey found that 5% of homes in England had a damp problem in 2023. For privately rented homes it was 9%, compared with 4% of homes lived in by their owners.

Is mould bad for your health?

It can be. The NHS says mould can cause allergic reactions like sneezing, a runny nose, red eyes and skin rashes, and it can trigger asthma attacks.

Some people are more sensitive: babies and children, older people, people with asthma, allergies or skin problems like eczema, and people with a weak immune system. The NHS advises them to stay away from damp and mould, so let someone else do the cleaning.

If you're worried about symptoms, speak to your GP or a pharmacist.

First, find the cause

Cleaning mould without fixing the cause is like mopping under a dripping tap. Where the mould is tells you a lot:

What you see	Likely cause	Who usually fixes it
Black spots in corners, behind furniture or on window frames, worse in winter	Condensation	You, with the tips below
A damp patch that grows after rain, near the roof, gutters, windows or pipes	A leak	The owner or landlord, often with a roofer or plumber
A tide mark low down on ground floor walls, with crumbly plaster or white powder	Rising damp	A damp specialist or surveyor

Not sure? If the mould keeps coming back after you've tried the tips in this guide, ask your landlord or a damp surveyor to check.

What you need

• Rubber gloves
• Goggles and a mask that covers your nose and mouth
• A mould remover spray (follow the label), or warm water with a little washing-up liquid
• Cloths you can throw away afterwards, and a bin bag
• An old toothbrush for grout and sealant

Before you start:

• Never mix mould sprays or bleach with other cleaners, especially limescale removers, vinegar or anything with ammonia. Mixing them can release dangerous gas.
• Open the windows and close the door to the rest of your home, so spores don't spread.
• Don't brush dry mould. Brushing throws spores into the air.
• Test on a small hidden spot first, especially on paint, wallpaper and coloured grout.
• Get help for big or deep mould. If it covers a large area, comes from a leak, or has got into plaster, wood or carpet, it's a job for a professional.

How to remove mould from walls and ceilings

1. Lightly spray the mould (or wipe on soapy water). Don't soak the wall.
2. Leave it for the time on the label.
3. Wipe gently with a damp cloth, working from the edge of the patch inwards. Turn the cloth often and use a fresh one when it gets dirty.
4. Dry the area well with a clean cloth. Mould loves damp, so drying matters.
5. Put the used cloths in a bin bag, tie it and throw it away.
6. Wash your hands, then vacuum the room to pick up any loose spores.

When the wall is completely dry, you can repaint it with an anti-mould paint. Never paint over mould without cleaning it first, or it will grow back through the paint.

How to remove mould from shower sealant and grout

1. With the window open, spray a mould remover along the sealant and grout lines.
2. Leave it for 15 to 20 minutes.
3. Scrub with an old toothbrush, then rinse and dry.

If black marks are still there after two or three tries, the mould has grown inside the silicone, and no cleaner can reach it. The fix is to cut out the old sealant, let the area dry fully and reseal it. If you rent, ask your landlord first.

Window frames and sills

Wipe the water off your windows and sills every morning in cold months, using a cloth or a window vacuum, and wring the cloth out in the sink. Then clean the frames, rubber seals and sills with mould spray or soapy water, and dry them. On old sash windows, check the bottom corners, where water collects.

Clothes, curtains and furniture

Wash mouldy clothes and curtains at the hottest temperature the care label allows, then dry them fully, outside if you can. Check wardrobes that stand against outside walls: they are a favourite spot for mould.

Mould on a mattress, sofa or carpet is hard to remove at home. If it has soaked in, get professional advice or replace it.

How to stop mould coming back

Mould usually comes back because the air is still too wet. These everyday habits make the biggest difference.

In the kitchen

• Put lids on pans and use the extractor fan when you cook.
• Keep the kitchen door closed while cooking.

In the bathroom

• Run the extractor fan during and after a shower, or open the window.
• Squeegee the shower walls and wipe the sealant dry.
• Keep the door closed so the steam doesn't spread.

Drying clothes

• Dry washing outside when you can.
• Indoors, use one room with the door closed and the window open, or the bathroom with the fan on.
• If you use a tumble dryer, make sure it's vented to the outside, or empty the water tank often if it's a condenser dryer.

Around the home

• Open a window a little or keep the trickle vents open, and don't block air vents.
• Keep low, steady heating on in cold weather. Cold walls attract condensation.
• Leave a gap between big furniture and outside walls, and don't overfill wardrobes.
• Wipe away condensation every day.
• In a small flat, a dehumidifier can help, especially if you dry clothes indoors.

Habit	How often
Wipe windows and sills dry	Every morning in cold months
Fan on or window open while showering and cooking	Every time
Open the windows to air your home	Every day
Check corners, behind furniture and inside wardrobes	Weekly
Mould spray on shower sealant and grout	Weekly

For the rest of your routine, see how often to clean your home. Want gentler products? Our eco-friendly cleaning guide has ideas. If you also fight white crust on taps and showers, read our guide to removing limescale.

Renting in London? Who fixes what

If you rent, a lot of damp and mould is your landlord's job, not yours. The housing charity Shelter says landlords must fix the causes of damp, such as leaking pipes and roofs, broken boilers or heating, cracked walls, rotten window frames, poor ventilation and extractor fans they put in. They should also repair damage the damp has caused, like ruined plaster.

What to do:

1. Clean small patches and try the tips above, so you can show you've done your part.
2. Tell your landlord or letting agent in writing, by email or message. Say where the mould is, add photos with dates and keep copies. Shelter has a free template letter.
3. Let them in to inspect. If they can't find the cause, Shelter says they should arrange a damp survey at no cost to you.
4. If nothing happens, contact your council's environmental health team. Every London borough has one. For example, Tower Hamlets Council says it usually writes to the landlord first, and it can inspect, serve a formal notice and even fine or prosecute landlords who don't act.
5. Keep paying your rent. Stopping can put your home at risk.

In council or housing association housing? Since 27 October 2025, Awaab's Law has made social landlords fix reported damp and mould within strict time limits. For example, they must investigate a possible significant hazard within 10 working days, and deal with emergencies within 24 hours. These rules don't apply to private landlords yet, although the government plans to bring similar rules to private renting.

This is general information, not legal advice. For help with your own situation, contact Shelter or Citizens Advice.

Moving out?

Mould left to build up in the bathroom or on window frames can cost you money at check-out. Our end of tenancy cleaning checklist shows everything to clean before you hand back the keys.

Let TidyGo help with the cleaning

A TidyGo deep clean, at £22 an hour per cleaner, gets into the places where mould likes to start, including descaling taps, showers and tiles. Our end of tenancy clean includes mould treatment in bathrooms, plus window sills and frames. A normal clean every week or two (£18 an hour) keeps your bathroom fresh, and a cleaning plan saves you money. We cover areas across London.

Our cleaners deal with mould on the surface. Leaks, rising damp and mould inside walls need a builder, plumber or damp specialist.

Questions people ask

Does bleach kill mould?

Bleach-based mould sprays work well on hard surfaces like tiles and sealant. Always follow the label, open a window and never mix bleach with other cleaners.

Can I use vinegar on mould?

Some councils suggest white vinegar mixed half and half with water, left for an hour, then rinsed off. It's gentler but slower, and it won't shift mould that has grown into sealant. Don't use vinegar on natural stone like marble.

Can I just paint over mould?

No. Clean it, let the wall dry fully, then use an anti-mould paint. Paint on its own only hides mould for a short time.

Why does my mould keep coming back?

The cause hasn't been fixed. It's usually too much moisture in the air, or a leak. Try the habits above for a few weeks. If it still comes back, ask your landlord or a damp surveyor to find the cause.

Is a dehumidifier worth it?

It can help in a small flat, especially if you dry clothes indoors. Empty the tank often and keep the door of that room closed while it runs.