Health risks: Mould spores can trigger asthma, allergies, and breathing problems, particularly for children, older people, and those with health conditions.
Property damage: Damp damages finishes, plaster, walls, timber, potentially the structural integrity of your home.
Higher costs: A damp home is harder to heat, leading to increased energy bills.
Did you know?
The average UK household produces around 20 pints of moisture a day just through cooking, bathing, and breathing.
Damp homes can lose heat up to 25% faster, increasing energy use and bills.
This guide explains the causes of damp and mould, how to spot the signs, and what steps you can take. If you a social housing tenant or landlord, you need to be aware of Awaab’s Law which came into force in October 2025. See links in “where to find advice” at the end of this document.
What is damp and mould?
Damp is unwanted moisture that enters or builds up in your home. It may be moisture entering the building from outside, from internal leaks or from condensation caused by cooking, bathing or other activities.
Mould is a type of fungus that grows in damp conditions. It often appears as black, green, or white patches on walls, ceilings, windows, or furniture.
Things to look out for
– Black mould spots on walls, ceilings, or around windows
– Condensation on windows, especially in the mornings
– Peeling wallpaper, blistering paint, or crumbling plaster
– Musty smells
– Tide marks or white salt deposits on walls
– Patches of damp with no obvious edges
What is Condensation?
When warm, moist air meets a cold surface, such as a window or wall, the water vapour in the air cools down and turns into tiny droplets of liquid.
| Possible cause of condensation | Ways to minimise risk |
| Poor ventilation, especially in the kitchen or bathroom, when not opening a window during cooking or showering/bathing or using the fitted extractor fans. | Windows do not need to be open all the time to improve ventilation – about 5 minutes for each hour you are in a room is enough.
Fit and use trickle vents in windows. These are small devices, often fitted at the top of the window, which allow fresh air to circulate naturally through a room. Fit a secure window latch which allows windows to be locked securely in a partially open position. Opening windows does not always work when there is high humidity outside, so use extractor fans too. Always use extractor fans while cooking, bathing, or showering |
| Drying clothes over radiators | Dry outside where possible. Alternatives inside include using a heated airer, a drying rack (a clothes horse), or a dehumidifier to speed up drying and manage moisture. You can also improve airflow with a fan or by placing a drying rack near a well-ventilated window |
| Not covering pots when cooking | Cover pots and pans where possible during cooking to reduce evaporation. |
| Incorrectly vented tumble dryers or ‘recirculating-only’ cooker hoods (i.e. directing the moisture inside rather than outside) | If you use a tumble dryer, check that it is fitted with an external vent or condensate system.
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| Not heating and/or venting your home sufficiently | Keep your home well-ventilated and maintain internal heat levels, ideally between 18C and 21C. This will reduce the likelihood of condensation and mould spores forming.
Internal temperatures below 18C may impact the health of pre-school-aged children, the elderly and those with existing health conditions. |
| Overcrowding (people produce moisture, so the more people in a home, the more moisture is produced) | Ventilation is critical (read below) |
Check how well your home is ventilated.
- Fit bathrooms and kitchens with mechanical ventilation fans or extractors that can cope during peak periods: cooking, washing, bathing, showering and drying clothes indoors.
- Check extractor fans are the right size, working well, and cleaned regularly. Read the government guidance Ventilation: Approved Document F.
- Avoid where possible blocking radiators with furniture and leave a gap between furniture and walls.
- Do not block air vents, as they allow fresh air to circulate and reduce condensation.
Consider upgrading your windows.
You can address loss of heat by upgrading your windows (especially if you upgrade from single-glazing to double or triple-glazing or secondary glazing) − but remember that this will not address the source or amount of moisture in your home.
It’s a good idea to increase ventilation, as modern windows have tighter air seals than older, draughty windows.
Investigating damp issues
Penetrating damp causes moisture ingress – water getting in through leaks in roofs, defective flashing around chimneys, blocked or broken gutters and downpipes, defective or missing sealant around windows or through walls with defective pointing or render.
Rising damp is moisture from the ground moving up through walls or floors.
You may be able to investigate problems yourself. For example, when it rains you could see whether your gutters are overflowing.
Things to look for:
- leaking and/or blocked gutters and rainwater pipes
- internal plumbing leaks, e.g. below baths or broken mastic seals around showers
- leaking water main supply pipes
- failed underground drainage.
- ill-fitting doors and windows, including broken sealant or mortar.
- roofing defects, such as poor roof flashings and dislodged or broken roof tiles.
- open chimney pots
- poor external pointing
- cracked external wall render.
- raised external ground levels next to walls.
- excess rubble under suspended ground floors. This can stop ventilation under the floor and make floor timbers wet, bridge the damp-proof course, and block low-level through-wall air vents.
- bridged cavity walls, i.e. physical blockages such as rubble in the cavity wall void.
- blocked low-level through-wall vents for suspended floors.
What is mould?
“Mould” is the fungi that thrive in damp conditions. Of the thousands of different mould species found in the home, the most serious are those that release mycotoxins. Mycotoxins are very harmful poisons, which can be inhaled, eaten or absorbed directly through the skin. Mycotoxins can lead to poisoning, and in the long term can cause cancers and immunosuppression-related illnesses. Asthma and other severe respiratory conditions can also be triggered, especially in vulnerable, such as children or the elderly.
How do I control and remove mould growth?
The first step is to identify and remedy the source of moisture. Mould treatments can only address the symptoms of dampness, not the underlying causes. The cause needs to be identified with professional help. It is essential to remove mould in your home immediately to reduce health risks. For hard surfaces, use mould and mildew cleaning products (which are more effective and safer than bleach) and leave them to dry completely.
Mould removal itself presents a health risk, so during cleaning wear protective clothing such as gloves, mask, and goggles. Keep doors shut (so spores don’t spread) and keep windows open (for ventilation)
(If you have allergies, you can try a natural mould removal solution using baking soda and white vinegar). Always lock cleaning products away from children, as they can be very harmful if ingested.
Once treated, paint over the discoloured area with a fungicidal paint, dry-clean mildewed clothes and shampoo mouldy carpets. Try to prevent further mould by reducing the moisture level in your home and increasing heating and ventilation.
Larger areas of mould (such as a substantive part of a whole wall or ceiling) should only be addressed by qualified professionals. If you are renting your home, tell your landlord or managing agent about any mould that is causing you concern.
Absorbent materials such as carpets, soft furnishings and ceiling tiles might need specialist cleaning if they become mouldy. It may be difficult or impossible to remove the mould completely.
Repair, maintain, manage.
No home is completely immune from condensation, mould formation, or the risk of damp.
Repairs, maintenance, and management apply to everyone, whether you are a homeowner, tenant, or landlord.
| Do | Do not |
| Carry out regular maintenance to keep your home as dry as possible, for example:
– clear gutters, downpipes and drains – repair leaking pipes, baths, sinks and toilets – replace broken mastic seals around showers, baths, and sinks – cut back overgrown trees and vegetation – clean extractor fans (including ducting and vent covers) – maintain doors and windows – check for water splashing off hard surfaces back up against walls outside. |
Do not install expensive damp-proofing measures without carrying out routine maintenance work, or considering what has changed and addressing that, first. In some types of home (for example older buildings with solid walls), damp-proofing measures may not be appropriate and may exacerbate damp issues.
|
| Always seek advice from a building surveyor before making changes to your home or garden. This avoids the risk of creating problems. For example:
– installing a new path or decking area could raise ground levels and block air vents – using modern cement in mortar or render on older buildings can trap moisture in walls, making any damp problem worse. |
Key advice
– Deal with damp and mould early – small problems are easier (and cheaper) to fix.
– Wiping mould away with household cleaners may remove the stain, but unless you tackle the cause, it will come back
– If damp is affecting your health, contact your GP and seek professional help with your home
– Leave a small gap between furniture and walls to allow air circulation
– Try to maintain consistent heating in colder months
When to seek professional help
– If mould keeps coming back despite your efforts
– If you notice leaks, faulty guttering, or roof damage
– If you suspect rising damp (tide marks, salts, crumbling plaster)
– If damp is linked to health issues
Specialist surveyors, damp experts, or retrofit professionals can identify the cause and recommend lasting solutions.
Your rights as a tenant
Landlords must keep rented homes free from serious health hazards, including damp and mould. Report issues in writing to your landlord or managing agent. If no action is taken, contact your local council’s Environmental Health team.
Where to find trusted advice
A good starting point is for a surveyor is the Royal Institution of Chartered Surveyors https://www.ricsfirms.com/residential/ or find a business on TrustMark ( Government Endorsed Quality Scheme) https://www.trustmark.org.uk/homeowner/find-a-tradesperson
Citizens Advice offer clear guidance on who is responsible for repairs (tenant, landlord, or homeowner) and practical steps to get problems fixed. citizensadvice.org.uk
Various consumer rights organisations offer independent guidance on how damp and mould affect your home, your rights, and property value including consumer-rights.org – “Damp & Mould in the UK: How It Can Affect Your Home”
Most Local Authorities have guidance on their websites about damp and mould with advice and reporting options. Check your local authority’s housing or environmental health section. https://www.gov.uk/find-local-council
Awaab’s Law for social housing tenants came into force in October 2025. Here’s the link for the latest guidance.
Asthma + Lung UK offer health-focused advice for people with asthma, COPD or other conditions affected by poor housing. asthmaandlung.org.uk This guide is for general consumer awareness. It is correct at the time of writing, but advice and regulations may change. Always seek professional help if in doubt.
