Tackle condensation and mould across your home

Diagnose the real cause, clean up mould, then fix ventilation room by room over a few weekends so it does not come back.

Guides in this project

01Dry washing indoors without causing damp 02Cut condensation in a bedroom 03Cut condensation in a bathroom 04Remove black mould from walls and ceilings 05Clean an extractor fan so it actually extracts 06Use anti-mould paint: when it helps and how to apply it 07Use trickle vents to cut condensation 08Tell condensation from rising or penetrating damp

CM-01Diagnose the damp type before spending moneyFollow 'Tell condensation from rising or penetrating damp' to rule out other causes before you start. If you see tide marks low on walls, bubbling paint near skirting, or damp patches that match a leaking gutter or cracked render outside, that is rising or penetrating damp, not condensation - get a damp specialist or builder to look before doing anything else. This whole project usually takes 2 to 3 weekends spread over several weeks, and costs roughly £150 to £450 depending on how many rooms need treating and whether you replace a fan or buy a dehumidifier. Buy a torch and a cheap damp meter now so you can check walls as you go.

1 each · Damp meter

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1 each · Torch

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CM-02Clean off all existing mould firstFollow 'Remove black mould from walls and ceilings' in every affected room, including inside wardrobes, behind furniture, and in corners you normally ignore. Doing this before you fix ventilation means any mould that comes back later is easy to spot and tells you a room still needs work. Wear gloves and a mask, and open a window or run an extractor while you work. Plan on a full weekend for a typical house.

2 bottle · Mould remover spray

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1 box · Disposable gloves

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5 each · FFP2 mask

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2.5 litre · Mould-resistant paint

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CM-03Change how washing gets driedFollow 'Dry washing indoors without causing damp' straight away, even though later phases deal with individual rooms - drying washing indoors badly is one of the biggest everyday causes of condensation. Start this habit change this week so it has time to make a difference before you judge later phases. A dehumidifier helps but is not essential if you can dry washing outside or in a well-ventilated room.

1 each · Dehumidifier (optional)

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1 each · Clothes airer

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CM-04Tackle condensation room by room, starting with the bedroomFollow 'Cut condensation in a bedroom' for any bedroom with damp windows, musty smells, or mould returning in corners. Do one room at a time so you can still sleep in it, and allow a weekend per room. Before drilling any wall for a new vent or fixing, check for cables and pipes with a detector first, and still expect to find something unexpected behind plasterboard.

1 each · Cable and pipe detector

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1 pack · Anti-condensation window strip

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CM-05Tackle the bathroomFollow 'Cut condensation in a bathroom' next, since bathrooms usually produce more moisture than any other room. If any step involves touching a shaver socket, light switch or fan isolator, switch off the circuit at the consumer unit and prove it is dead with a tester before removing the faceplate. Bathroom electrical work beyond a simple like-for-like swap must be done by a registered electrician, and some of it is notifiable under Part P.

RULES

1 tube · Anti-mould bathroom sealant

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1 each · Extractor fan timer (if missing)

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KNOW THE RULES

Bathroom electrics beyond like-for-like replacement need a registered electrician, and work near the bath or shower is notifiable under Building Regulations.

CM-06Get the extractor fan actually pulling airFollow 'Clean an extractor fan so it actually extracts' once the bathroom itself is sorted, so you know whether the fan is the problem or just one part of it. Before removing the fan cover, switch off the circuit at the consumer unit and prove it is dead with a tester. If cleaning does not fix weak airflow, or the fan is wired in with no visible isolator switch, get an electrician to check it - swapping a fan like-for-like is not notifiable, but a new circuit, or new wiring near the bath or shower, is. This phase is a half day.

RULES

1 each · Extractor fan cleaning kit

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1 each · Replacement fan (if needed)

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KNOW THE RULES

Like-for-like fan replacement is not notifiable, but a new circuit, or new wiring near the bath or shower, is - use a registered electrician for that part.

CM-07Fit or clear trickle vents lastFollow 'Use trickle vents to cut condensation' once habits, mould and extraction are already sorted, so you can judge whether background ventilation is still needed anywhere. Before drilling into a window frame or wall for a new vent, check for cables and pipes with a detector, and still expect something unexpected to be there. This phase usually takes an afternoon once vents are bought, often less if you are only clearing existing ones that have been painted shut.

2 each · Trickle vent kit

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1 set · Masonry/wood drill bit set

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1 tube · Silicone sealant

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Travis Perkins, Tooled Up and Machine Mart links are affiliate links: if you buy after clicking, we may earn a small commission at no extra cost to you. B&Q and Amazon links are plain searches and earn us nothing.

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