Is Damp and Mould the Same Thing?

No. Damp is excess moisture in a building, while mould is a fungus that grows because of that moisture. When the weather starts to cool down in the autumn months, damp and mould can be two common issues in UK homes. Whether you’re buying, selling, or renting, understanding the difference is important for treating and preventing damp or mould.

What is the difference between damp and mould?

Damp is the presence of too much moisture in the walls, floors, or ceilings of a building. There are three main types of damp:

• Condensation: The most common type, caused when warm, moist air meets a cold surface like a window or external wall.
• Penetrating damp: Water getting in from outside, for example through a leaking roof, damaged guttering or cracked brickwork. Leaking pipes inside the home can cause similar problems.
• Rising damp: Moisture from the ground travelling up through walls, usually because a damp-proof course is missing or has failed.

Mould, on the other hand, is a fungus that likes to grow in damp environments and feeds on organic materials like wood, paper, or even fabric.

Can damp turn into mould?

If damp is not treated, then this can lead to a mould problem. A large amount of moisture creates a perfect breeding ground for mould spores. The speed at which mould forms can sometimes be as quick as 24 to 48 hours.

Damp and mould can also affect your health, particularly for babies and young children, older people, and anyone with asthma or other respiratory conditions. That’s why it’s important to tackle it early.

How to prevent damp and mould in cold weather

Cold weather alone doesn’t cause damp, but it does make condensation much more likely. When warm, moist air from cooking, showering or drying clothes meets cold walls and windows, it turns back into water. If that moisture is left to build up, mould can start to grow. Understanding the relationship between cold weather and damp or mould is the first step towards prevention.

Practical tips to prevent damp and mould

• Maintain a consistent room temperature: Keeping your home at a consistent, warm temperature can help prevent condensation, especially in the colder months of the year.
• Ventilate: Ensure rooms are well ventilated, especially those prone to damp like bathrooms and kitchens. Use extractor fans and keep window trickle vents open.
• Install insulation: Good insulation helps keep the warmth in and the cold out, which reduces the risk of condensation building up.
• Use a dehumidifier: These can help control moisture levels in your home.
• Reduce moisture day to day: Dry clothes outside where you can, put lids on pans when cooking, and wipe away condensation from windows each morning.

What to do about damp and mould if you rent

As soon as you discover damp or mould in your rental property, deal with it promptly. Notify your landlord or letting agent ASAP.

You and your landlord both have a role to play in tackling this issue. These include:

As a renter, you should:

1. Act quickly: Early action can prevent it from spreading further.
2. Document it: Take photos or videos to record the condition of the affected areas. You can then send this on to your landlord or letting agent so they can see the extent of the issue. It also serves as proof should disputes arise later on.
3. Report the issue: Tell your landlord or letting agent as soon as possible. If you call, be sure to follow up with an email and send any pictures or videos of the affected areas. Be sure to keep a record of all your communications.
4. Do your bit: While waiting for a response, ensure proper ventilation by opening windows and avoiding clutter that could encourage damp. Wiping away small patches of surface mould is fine, but do not attempt repairs or treatments without getting the go-ahead from your landlord.
5. Cooperate with inspections: Try to be available for any scheduled inspections or repair works. The sooner a professional can assess the situation, the quicker it will get sorted.

Your landlord or letting agent should:

1. Acknowledge and inspect: They should acknowledge your report of damp or mould promptly. Then organise for a professional to inspect the problem.
2. Identify the cause: They will work with professionals to determine whether it’s rising damp, penetrating damp, condensation, or a leak causing the issue.
3. Fix the issue: Depending on the cause, your landlord or letting agent should arrange for suitable treatments like damp proofing or improving ventilation.
4. Update you: You should be kept up to date about what steps are being taken and be given timelines for repairs.
5. Prevent future occurrence: Depending on the cause, preventative measures should be put in place, such as installing extractor fans or sealing gaps if there are any.

What the law says

Landlords in England have a legal duty to make sure their properties are fit to live in, and serious damp and mould can make a home unfit.

Awaab’s Law came into force for social housing in October 2025. It means social landlords must investigate and fix damp and mould hazards within set timescales, with faster deadlines for emergencies. The Renters’ Rights Act 2025 extends Awaab’s Law to private rented homes.

If your landlord doesn’t act, you can contact your local council’s environmental health team, who can inspect the property and take action. Social housing tenants can also complain to the Housing Ombudsman.

Rules differ in Scotland, Wales and Northern Ireland, so check the guidance for where you live.

Both you and your landlord are responsible for maintaining a damp-free, mould-free living environment. Open communication, prompt action, and a bit of teamwork can go a long way in resolving issues efficiently.

What to do if you find mould while viewing a property to buy?

Finding mould when viewing a property doesn’t necessarily mean you should abandon your interest. If this isn’t a game changer for you, then do the following:

• Ask questions: Enquire about the extent of the mould problem. How long has it been present, and have there been any previous treatments? If work has been done, ask whether it came with a guarantee that can be transferred to you. An honest dialogue with the seller or estate agent is key to addressing the extent of the issue.
• Consider a professional inspection: If you’re serious about the property, it may be wise to get a RICS Level 2 or Level 3 survey. An independent surveyor can give you an unbiased view, rather than a company that may also be selling the treatment.
• Negotiate: If you decide to proceed with the purchase, consider negotiating the terms to include mould removal or a reduction in price.

What to do if you’re selling a property with damp or mould

If you know about damp or mould in your home, be honest about it. You’ll need to answer questions about this on the property information form, and hiding a known problem can cause issues later on. Where you can, fix the cause before you go to market, and keep any paperwork or guarantees from previous treatments ready to share with buyers.

Next steps

If you’re concerned about potential damp or mould in a property, whether you’re renting or buying, then raise it with the letting or sales agent.

Their experience means they can help you understand the issue and what to do next, and point you towards the right professionals. If you rent, remember that keeping the property in good repair is your landlord’s responsibility. We’ve also created a seasonal guide on how to care for your property.

Frequently asked questions

Who is responsible for damp in a rented home?

In most cases, your landlord is responsible for fixing the cause of damp and mould. Tenants should report problems promptly and help reduce condensation day to day.

How quickly must a landlord fix damp and mould?

Social landlords must act within set timescales under Awaab’s Law. Either way, landlords should respond to reports promptly.

Is black mould dangerous?

Mould of any colour can affect your health, particularly for children, older people and those with respiratory conditions. It’s best to deal with the cause quickly rather than just cleaning the surface.

Last Updated: October 19th, 2026