How to tell condensation from rising or penetrating damp, practical ways to reduce condensation, cleaning mould safely, health risks, and your rights if you rent in England.
Damp and mould are among the most common problems in UK homes, especially in winter. They damage decorations and belongings and can harm health, particularly for children, older people and anyone with breathing problems. The right fix depends on the cause, so the first step is to work out which kind of damp you have.
The three main types of damp
Condensation
By far the most common. Warm, moist air from cooking, washing, drying clothes and breathing meets a cold surface, such as a window, an external wall or a corner, and turns to water. Signs: water on windows in the morning, black mould spots in corners, behind furniture and around window frames, and a musty smell. It is usually worse in winter.
Penetrating damp
Water getting in from outside through a defect, such as a leaking gutter or downpipe, damaged roof, cracked render or failed pointing. Signs: a damp patch that grows after rain, often on a ceiling or one wall, sometimes with tide marks.
Rising damp
Ground water drawn up through walls, usually because a damp-proof course is missing, bridged or damaged. It is less common than often claimed. Signs: a tide mark up to around a metre from the floor, damaged skirting boards and salts on the wall. Get an independent survey before paying for expensive treatment: many "rising damp" problems are actually condensation or bridging by raised ground outside.
Reducing condensation: practical steps
- Ventilate while you create moisture: use extractor fans or open windows when cooking and showering, and keep the kitchen and bathroom doors closed.
- Leave trickle vents open on windows.
- Dry clothes outside if you can. If not, dry them in a closed room with a window ajar or the extractor on, or use a vented tumble dryer or a dehumidifier.
- Put lids on pans.
- Keep heating at a steady low level in cold weather, rather than letting rooms get very cold. Cold walls attract condensation.
- Leave a gap between furniture and external walls so air can circulate.
- Wipe windows and sills each morning.
- Consider a dehumidifier for persistent problems.
Cleaning mould safely
- Protect yourself with rubber gloves, goggles and a mask, and open a window.
- Use a mould remover following the instructions, or a cloth with warm water and washing-up liquid for light patches.
- Do not brush or vacuum mould, which spreads spores.
- Dry the area thoroughly afterwards.
- Bag and dispose of the cloths.
Cleaning only treats the symptom. Unless you deal with the cause, mould will return. Large areas or mould caused by leaks need professional attention.
Fixing penetrating and rising damp
- Check gutters, downpipes, roof tiles, flashing and window seals, especially after storms.
- Repair cracked render and failing mortar joints.
- Make sure outside ground or paving is below the damp-proof course, and air bricks are clear.
- Use a qualified surveyor for persistent problems before agreeing to chemical treatments.
Health
Damp and mould can cause or worsen respiratory problems, infections, allergies and asthma, and affect the immune system. The government's guidance for rented housing providers stresses that damp and mould should be treated as a health hazard, not a lifestyle issue.
If you rent in England
- Your landlord is generally responsible for repairs to the structure and exterior and for problems such as leaks, and must keep the home free from serious hazards.
- Report damp and mould in writing, with photos, and keep a copy.
- If your landlord does not act, contact your local council's environmental health or private housing team.
- Awaab's Law, in force for social housing in England since 27 October 2025, requires social landlords to investigate significant damp and mould hazards within 10 working days and act within set timescales. The government is consulting on extending it to private renting; it does not yet apply to private tenancies.
Frequently asked questions
Will a dehumidifier fix damp?
It helps with condensation but does not fix leaks or structural damp.
Sources and further reading
- GOV.UK: Damp and mould, health risks guidance for rented housing providers
- GOV.UK: Awaab's Law guidance for tenants in social housing
- GOV.UK: Private renting, repairs
- Energy Saving Trust
Facts checked on 20 October 2026. Spotted an error? Tell us and we will correct it.