Damp, mould & air
Removing black mould, safely and for good
A patch of black mould above the shower is common and fixable. Here is the safe way to clean a small patch, the point at which the job stops being DIY, and the only fix that stops it coming back.
By the Tickover team · Published 16 February 2026 · 4 min read
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Established mould does not improve on its own, and it is hardest on small lungs and sensitive chests. A small patch is a weekend job; keep moving on it.
What the mould is telling you
Mould only grows where a surface stays damp, so every patch is a message about moisture. In most homes that means condensation settling on a cold corner, a window reveal or a bathroom ceiling. Clean it by all means, but expect it back until the moisture stops.
The DIY dividing line is roughly half a square metre, about a folded bath towel. Under that, with gloves, ventilation and the method below, clean it yourself. Bigger, spreading across a ceiling, or back within weeks: bring in a professional, for the clean and for the diagnosis behind it.
Households change the maths too. Where there are babies, older people, or anyone with asthma, allergies or a weakened immune system, do not treat mould as a scrubbing job. Keep them out of the affected room and bring in a professional; mould spores are hardest on exactly those lungs.
The safe removal method
Clean a small patch
Kit up and open the window
Rubber gloves, an FFP2 mask if you have one, clothes you can wash hot. Window open, door to the rest of the house shut.
Pick one cleaner
A fungicidal mould wash, or diluted bleach on non-porous surfaces only: tiles, glass, sealant. One product, never a mixture.
Wipe, never brush
Wet the mould and wipe it away with a soft cloth. Dry brushing or sanding flicks spores into the air.
Bin cloths as you go
Tie them in a bag and bin them; no rinsing and reusing.
Rinse and dry the surface
A clean-water wipe, then a dry cloth. A wet finish is an invitation to regrow.
Watch it for a month
Regrowth within weeks means the moisture source is still live. Go hunting for it.
Mould rules
Do
- Wear rubber gloves and ideally an FFP2 mask
- Keep the window open for the whole job
- Use a fungicidal wash, or diluted bleach on tiles and sealant only
- Fix the moisture source the same week
Don’t
- Do not dry-brush, sand or vacuum a mouldy wall; it launches spores
- Do not mix bleach with anything, ever
- Do not paint over live mould; it grows straight through
- Do not leave vulnerable family sleeping in a mouldy room
Make it stay gone
Every returning patch has a supply line. In bathrooms it is usually steam without extraction: test yours with the toilet-paper trick. In bedrooms it is warm breath meeting cold walls behind furniture, plus washing drying on airers. The cure is drier air, and the full playbook is in stopping condensation.
Once the surface is clean and the moisture is under control, an anti-mould paint adds a layer of protection. Applied over live mould or a still-damp wall, it buys nothing except a repaint.
If you rent, report mould in writing with dated photos and keep copies. Landlords must keep homes fit to live in, and social landlords now face fixed deadlines to deal with mould under Awaab’s Law, with the same duties being extended to private tenancies. Persistent mould in a rented home is a repair matter, not a housekeeping debate.
If it goes beyond DIY
Professional mould clean
per room
Independent damp survey
Typical UK ranges, mid-2026, as a guide only. Your home, your area and the job itself all move the number — always compare real quotes.
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Find someone shows local trades Tickover has already scored, so you skip hunting through reviews. You contact them yourself.
Quick answers
Can I remove black mould myself?
Yes, if the patch is smaller than about half a square metre and nobody vulnerable lives in the home. Wear gloves and a mask, ventilate the room, wipe with a fungicidal wash rather than brushing, and bin the cloths afterwards. Larger areas, recurring growth, or households with babies, asthma or weakened immune systems need a professional clean.
Does bleach kill black mould?
On non-porous surfaces such as tiles, glass and silicone sealant, diluted bleach removes surface growth well. On plaster and wood it mostly strips the colour while the growth survives deeper in, so a fungicidal mould wash is the better choice there. Whatever you use, use it alone: mixing cleaning products can release toxic gases.
Why does mould keep coming back after I clean it?
Because cleaning removes the growth, not the moisture feeding it. A patch that returns within weeks means the surface is still getting damp, whether from steam without extraction, condensation on a cold wall, or a slow leak. Fix the airflow and the moisture first, then clean, then think about anti-mould paint as a final layer.
Is black mould dangerous?
It is a health risk to respect rather than a reason to panic. Mould spores can trigger and worsen asthma, allergies and chest infections, and babies, older people and anyone with a weakened immune system are most at risk. Small patches handled safely are manageable; large or persistent mould in living spaces deserves professional attention promptly.
This guide is general information for UK homes, not advice about your specific property. Anything involving gas must be done by a Gas Safe registered engineer, and notifiable electrical work by a qualified electrician. If you smell gas, call the National Gas Emergency line on 0800 111 999. If you’re ever unsure, stop and get a professional in — that’s exactly what Tickover is for.
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