How to Spot Damp and Mould in a Rental Property

Damp and mould are more than an eyesore. They can affect your health, damage your belongings and, left unchecked, turn a minor maintenance issue into a serious dispute with your landlord. The good news is that catching the early signs gives you far more options. Here's what to look for, where to look, and how to raise it properly.

Why It Pays to Act Early

Mould spores thrive in damp conditions, and prolonged exposure can worsen asthma, trigger allergies and cause respiratory problems, particularly for children, older people and anyone with a weakened immune system. Beyond health, damp damages plaster, wallpaper, skirting boards and furniture, and it can creep into soft furnishings and clothing before you notice.

From a tenancy point of view, the longer a problem goes unreported, the harder it becomes to prove it wasn't your fault. Landlords are responsible for keeping the structure and exterior of the property in repair under section 11 of the Landlord and Tenant Act 1985, and for making sure the home is fit for human habitation under the Homes (Fitness for Human Habitation) Act 2018. But that duty depends on you telling them about the problem. A dated written report protects you.

The Tell-Tale Signs

Mould doesn't always announce itself with a big black patch. Often the first clue is subtler:

• A musty, earthy smell that lingers even after you've aired the room. This is often the earliest sign, especially in bedrooms and cupboards.
• Dark speckling or patches near windows, in corners where two external walls meet, and along the ceiling line.
• Peeling, bubbling or lifting wallpaper, or paint that flakes away from the plaster.
• Black or green staining on window frames and reveals, usually where condensation collects.
• Crumbling plaster or soft, stained skirting boards — press gently with a fingernail.
• A cold, clammy feel to walls, or a damp patch that doesn't dry out.
• Warped floorboards, lifting lino or a spongy feel underfoot.
• Clothes, shoes or bedding in wardrobes that feel damp or develop a fusty smell.

Photograph anything you find, with something for scale, and note the date. Timestamped photos are worth far more than a verbal complaint later on.

Where to Check, Room by Room

Mould likes cold surfaces, poor airflow and anywhere water sits. Work through your home methodically:

• Bedrooms: behind wardrobes and beds pushed against external walls, in the corners of the room, and on the ceiling above windows.
• Bathrooms: grout and sealant around the bath and shower, the ceiling above, behind the toilet, and around the extractor fan.
• Kitchens: under the sink, behind the washing machine or dishwasher, around window seals and on the ceiling above the hob.
• Living rooms: chimney breasts, bay windows and any wall that backs onto the outside.
• Hallways and cupboards: under-stairs cupboards and airing cupboards are classic trouble spots.
• Anywhere you've had a leak: check the ceiling and walls below a bathroom or roof, even months later.

It's also worth checking outside, if you can see the relevant elevation. Loose roof tiles, blocked gutters, cracked render and overflowing downpipes all push water into the building, and they're the landlord's job to fix.

Condensation, Penetrating Damp or Rising Damp?

Knowing which one you're dealing with shapes what needs to happen next.

• Condensation is the most common cause in rented homes. It shows as water running down windows, black spotty mould in corners and a musty smell. It usually comes from everyday cooking, showering, drying laundry indoors and poor ventilation — often combined with inadequate heating.
• Penetrating damp appears as a distinct wet patch, often on an external wall or ceiling, and gets worse when it rains. Look for a tidemark or a brownish stain.
• Rising damp shows as a damp band up to about a metre high on ground-floor walls, sometimes with a white, salty deposit on the plaster.

Condensation is where your habits and the building's design meet, and both may need attention. Landlords sometimes blame tenants entirely for condensation, but if the property has no working extractor fan, no trickle vents, or heating that doesn't work, that's a repair and fitness issue — not simply your lifestyle.

How to Report It to Your Landlord

Always report in writing, even if you've mentioned it in passing. Email is ideal because it's automatically dated; a text message works too. Keep a copy of everything.

In your message, include the rooms affected, when you first noticed it, what you've observed, and photographs. Ask for a written response within a reasonable timeframe — 14 days is a sensible benchmark for a non-urgent issue, and much sooner if there's an active leak, no heating or a risk to health. If you rent through an agent, copy them in.

In the meantime, take reasonable steps to reduce moisture: open windows for short bursts, use extractor fans, keep furniture slightly away from external walls, dry clothes outdoors or in a well-ventilated room, and keep the heating on a low, steady setting where you can afford it. Report everything you do — it shows you've been reasonable.

If the landlord or agent fails to act, escalate. Contact your local council's environmental health team, who can inspect and issue an improvement notice. Tenants in social housing can also complain to the Housing Ombudsman, and social landlords in England now have strict timescales for investigating damp and mould hazards under Awaab's Law. Never let a fear of eviction stop you reporting a genuine problem: retaliating against a tenant for reporting repairs is unlawful, and you can raise it with the council.

Damp rarely fixes itself, but it's far easier to resolve when it's caught early, documented clearly and put in writing. Your home should be dry, warm and safe — and you're entitled to ask for that in plain terms.