Why damp and mould deserve your attention

Damp and mould are more than a cosmetic nuisance. Prolonged exposure to mould spores can worsen asthma, trigger allergic reactions and cause persistent coughing, eye irritation and skin problems. If you have a young child, an older relative or anyone with a respiratory condition living in the property, the risks rise sharply. Damp also damages furniture, clothing, bedding and plasterwork, and it makes a home cold because wet walls hold the chill.

The legal position is clear: landlords must rent out homes that are fit for human habitation and free from serious hazards, including damp and mould. In the social sector, Awaab's Law now sets firm deadlines for landlords to investigate and fix these hazards, and the same principles are being extended across the private rented sector. Knowing the warning signs early puts you in a much stronger position.

The warning signs to look for

Mould does not appear overnight. It usually follows weeks of unnoticed moisture, so it pays to check regularly, especially in winter. Look out for:

• A musty, earthy or "wet cardboard" smell, particularly in bedrooms and hallways.
• Dark speckling in the corners of ceilings and behind furniture pushed against external walls.
• Black or green patches around window frames, seals and reveal edges.
• Peeling wallpaper, bubbling paint, or plaster that feels soft or crumbly.
• Water stains that grow larger over time, or tide marks on a wall.
• Condensation on windows and cold walls each morning, or water pooling on windowsills.
• Damp patches behind the washing machine, under the sink or around the bath and shower tray.
• Mould on the backs of wardrobes, under beds, or on shoes and bags stored against outside walls.
• Clothes and towels that never quite dry indoors.

Take dated photographs as you go. A simple moisture meter or hygrometer, widely available for under £15, can record humidity levels above 65 per cent and gives you evidence that is hard to argue with.

Working out what is causing it

There are three broad causes, and they are fixed in different ways. Condensation is by far the most common. It happens when warm, moist air from cooking, showering, drying laundry and even breathing meets a cold surface. It is often worst in flats with poor ventilation, single-glazed windows or no extractor fans.

Penetrating damp comes from outside: a cracked render, a leaking gutter, a faulty roof, a blocked downpipe or failed pointing. It tends to show as a distinct patch on one wall or ceiling, often darker after heavy rain. Rising damp affects ground-floor walls, usually up to about a metre high, and leaves a tell-tale tidemark with salty, crumbling plaster.

Many homes have a mix of all three. That matters, because a landlord who simply blames your lifestyle when the real problem is a leaking gutter is not addressing the cause. Similarly, a tenant who never opens a window or uses the extractor fan makes condensation far worse. Most cases need action from both sides.

How to raise it formally

Start with a written report, even if you have already mentioned it verbally. Email or a dated letter creates a paper trail, and it is reasonable to ask for a response within a set period, such as 14 days.

Your report should include:

• The date you first noticed the problem and where it is in the property.
• Photographs with dates, plus any humidity readings and temperature notes.
• What you have done to reduce moisture, such as using extractor fans, opening windows and drying laundry outdoors.
• Any impact on your health or your household's health, with dates.
• A clear request: an inspection, a diagnosis of the cause, and a repair plan with timescales.

Keep copies of everything, including texts and messages sent through a letting agent. If you rent through an agent, write to both the agent and the landlord where you have their address, and state clearly that the issue is being reported formally.

What your landlord must do

Once notified, a landlord has a duty to investigate, not to dismiss. In the social sector, Awaab's Law requires a prompt investigation, a written summary of findings and repairs completed within fixed deadlines. Private landlords are expected to meet the same standard of decency, and ignoring a reported hazard can lead to enforcement action.

In practice, a proper response means arranging an inspection, identifying whether the cause is condensation, penetrating damp or rising damp, and then carrying out the right remedy: repairing the leak, clearing gutters, improving ventilation, installing or repairing extractor fans and trickle vents, or upgrading insulation and heating. Fobbing you off with a tub of mould spray and a "just open a window" instruction is not a repair.

Some landlords will ask you to contribute to the cost of repairs or claim the problem is your fault. Unless you have caused actual damage, such as blocking a vent or overflowing a bath, that is rarely reasonable, and you should say so in writing.

If nothing happens

If your landlord stalls, escalate rather than suffer in silence. Contact your local council's environmental health or private rented sector team and ask for a Housing Health and Safety Rating System inspection. For social housing, you can make a formal complaint and then refer the matter to the Housing Ombudsman. In Scotland, Wales and Northern Ireland, similar routes exist through your council or housing regulator.

Throughout, keep records, keep reporting and keep the tone factual. Councils can issue improvement notices, and in the most serious cases they can take over repairs and recover the cost. You are entitled to a dry, mould-free home, and asking for one is not being difficult. It is simply holding your landlord to a standard the law already sets.