Most black mould in older homes is caused by condensation: warm, moist air from cooking, showers and drying clothes settles on cold walls and windows, and mould grows wherever it stays damp. Small patches can be cleaned with a mould remover, but the mould will keep coming back unless you reduce moisture, improve ventilation and keep the home steadily warm.
It’s a familiar problem in Hull, where many Victorian and Edwardian terraces have solid walls, bay windows and small back bathrooms that hold onto moisture. Coastal homes across East Yorkshire face the same issue, with damp sea air on top.
This guide explains how to tell condensation from other types of damp, how to clean black mould safely and what actually stops it returning.
Key takeaways
- Condensation is the most common cause of black mould in older homes, and it can usually be managed with ventilation and heating habits.
- Clean small patches promptly with the right protection; large or recurring mould needs the cause investigated.
- Rising and penetrating damp are building problems that cleaning won’t solve.
- Renters should report damp and mould to their landlord in writing, with photos.
Why do older Hull homes get condensation and black mould?
Older houses were built for a different way of living: open fires, draughty sash windows and no showers. Once homes are sealed up with double glazing and modern heating, moisture from daily life has fewer ways to escape.
Common causes we see in terraces around the Avenues, off Hessle Road and along Holderness Road include:
- Solid walls. Many older homes have solid brick walls with no cavity, so outside walls stay cold and condensation forms on them.
- Drying clothes indoors. A load of washing on an airer releases a lot of water into the air, especially in a small terrace without a tumble dryer.
- Kitchens and bathrooms without good extraction. Back extensions and small bathrooms often have weak extractor fans, or none at all.
- Furniture against outside walls. Wardrobes and sofas pushed tight to cold walls trap still, damp air behind them.
- Heating in short bursts. Walls cool down between bursts of heat, which encourages condensation.
- Blocked air bricks and sealed-up chimneys. These were there to let the house breathe.
Homes near the sea, in places like Hornsea and Withernsea, have extra challenges from salt air and wind-driven rain. Our guide to cleaning a seaside property covers these in detail.
Condensation, rising damp or penetrating damp: how to tell the difference
Condensation
Look for water droplets on windows in the morning, and black spots in corners, on window reveals, behind furniture and on bathroom ceilings. It’s usually worse in winter and on north-facing or outside walls. This is the type you can manage with cleaning and daily habits.
Penetrating damp
Damp patches that appear or spread after rain, often on one wall or near gutters, windows or chimneys. The cause is water getting in from outside, through a leaking gutter, damaged pointing or cracked render, for example.
Rising damp
A tide mark low down on ground-floor walls, crumbling plaster, white salts on the surface and damp skirting boards. Many damp problems blamed on rising damp turn out to be condensation or leaks, so get an independent surveyor’s opinion before paying for any treatment.
Penetrating and rising damp need building repairs. Cleaning the mould without fixing the cause will only buy you a few weeks.
How to clean black mould safely
Small areas of surface mould caused by condensation can usually be cleaned yourself. If mould covers a large area, returns quickly or follows a leak or flood, get the cause investigated first. Anyone with asthma, allergies or a breathing condition should avoid cleaning mould themselves.
- Protect yourself. Wear rubber gloves, goggles and a mask that covers your nose and mouth.
- Ventilate. Open the windows, but keep internal doors closed so spores don’t spread to other rooms.
- Don’t brush or hoover dry mould. Disturbing it releases spores into the air.
- Use a mould remover. Apply a product made for mould and follow the label exactly. Never mix it with other cleaners, especially anything acidic or containing ammonia.
- Wipe gently. Use a damp cloth, then put used cloths in a sealed bag and throw them away.
- Dry the area fully. Leave the window open or run a dehumidifier.
- Deal with fabrics. Wash clothes and curtains that have mould on them, or have them professionally cleaned.
Mould on the silicone around baths and showers often grows into the sealant itself. If it stays black after cleaning, the silicone needs replacing. Our bathroom deep clean guide covers grout and silicone in more detail.
For mould on several window frames, ceilings and tiles at once, a professional deep clean treats the affected areas across the whole home in one visit.
How to stop black mould coming back
- Ventilate every day. Open bedroom windows for a few minutes each morning, and keep trickle vents open if you have them.
- Use extractor fans. Run them while cooking and showering and for a while afterwards, with the bathroom door closed.
- Put lids on pans. It cuts the amount of steam in the kitchen.
- Dry clothes outside or in a tumble dryer. If you have to dry them indoors, use one room with the door shut and the window open slightly or a dehumidifier running.
- Keep the heating low and steady. A constant low temperature keeps walls warmer than short bursts of high heat.
- Leave a gap behind furniture. A few centimetres between furniture and outside walls lets air circulate.
- Wipe windows each morning. A squeegee or cloth removes condensation before it soaks into frames and sills.
- Keep air bricks clear. Check outside that they aren’t blocked by plants, soil or rubbish.
Tip: An inexpensive hygrometer shows the humidity in a room. If it reads high most of the time, a dehumidifier in the worst-affected room can make a real difference.
Mould on carpets, sofas and soft furnishings
Mould spores and musty smells settle into carpets, curtains, mattresses and sofas, especially in rooms with cold outside walls. Hoovering alone won’t remove them, and they can leave a room smelling damp even after the walls are clean.
Professional carpet and upholstery cleaning with hot water extraction lifts embedded dirt and odours, and our sofa cleaning guide explains what you can safely do at home.
Renting with damp and mould: who is responsible?
If you rent, your landlord is responsible for repairs to the structure of the property, including leaks, faulty extractor fans and damp caused by building defects. Serious damp and mould is a hazard landlords must deal with. If they don’t, you can contact Hull City Council or East Riding of Yorkshire Council for help. The government’s guide to private renting sets out your rights.
Report problems in writing, with dated photos, as soon as you notice them. Tenants are expected to heat and ventilate the home reasonably and to wipe down small patches of condensation mould.
At the end of a tenancy, mould left uncleaned can lead to a dispute. Our guide on how to get your deposit back explains how to avoid deductions, and our end of tenancy cleaning includes treating surface mould.
Getting help with mould and deep cleaning
Cleaning won’t fix a leaking gutter or a failed damp-proof course, but once the cause is sorted, a thorough clean gets the home back to a healthy starting point. Our team treats surface mould on walls, ceilings, window frames, tiles and silicone, and cleans the rest of the home at the same time.
We cover deep cleaning in Hull and right across East Yorkshire. Read more about our deep cleaning service, or contact us to arrange a fixed quote.
