Damp and mould in London flats: who fixes it

Black spots in the bedroom corner aren't a lifestyle choice. In most London flats they're a building problem, and the law increasingly says so.

The short version

Most damp in London flats is condensation: warm, wet indoor air hitting cold walls and single-glazed windows. Old buildings, small rooms and drying washing inside make it worse [1].
Official guidance says it is "totally unreasonable" for landlords to blame damp and mould on tenants' lifestyles. The root causes are usually the building, ventilation, heating or insulation [1].
Awaab's Law timescales already apply to social housing. For private renters in England they are still at consultation stage, which closes on 18 December 2026 [2].
Private landlords already have to keep the structure in repair and the home fit to live in. Your council can inspect and force repairs [2].
From 1 October 2026 the Ofgem price cap puts a typical dual-fuel bill at £1,723 a year. Heating smartly beats heating less [3].

Why London flats get damp (and Australian homes don't)

Most Australian houses are designed to shed heat. Think airy weatherboards, slab floors, ceiling fans and windows you open for a cross-breeze. In a Sydney or Brisbane winter you might grab a jumper and switch on a split system for an hour.

London is the opposite. The housing stock is old, much of it Victorian or Edwardian terraces converted into flats, plus post-war blocks. Winters are long, grey and wet rather than bitterly cold. Air stays humid for months, and you spend far more time indoors with the windows shut.

The UK government's damp and mould guidance names three types [1]:

Type	What causes it	Typical signs
Condensation	Moisture from cooking, showers, breathing and drying clothes settling on cold surfaces	Water on windows in the morning, black spots in corners, behind wardrobes and around window frames
Penetrating damp	Water getting in from outside through defects in walls, roofs, gutters or windows	Damp patches that grow after rain, often on one wall or ceiling
Rising damp	Ground moisture rising through walls, usually in older buildings with a failed damp-proof course	A tide mark low on ground-floor walls, flaky plaster, salt deposits

Condensation is by far the most common [1]. It's also the one landlords love to blame on tenants. The guidance pushes back hard: cooking, bathing and drying laundry are normal life, and the real fix is usually better ventilation, heating or insulation. Changes in tenant behaviour should add to that, not replace it [1].

Why it matters for your health

Damp and mould mainly affect the lungs. Think coughs, wheezing, chest infections and worse asthma. They can also bring on eczema and eye irritation. The guidance says dampness alone raises health risks even without visible mould. Children, older people, pregnant women and anyone with asthma or a weak immune system are most at risk [1]. If you've moved over with a baby, or you're asthmatic, take it seriously from day one.

Who has to fix it: your landlord's legal duties

Here's where London differs from home. In NSW or Victoria you'd lodge a repair request under the state tenancy act and head to the tribunal if ignored. In England the rules sit across several laws, and some of the newest ones are still arriving.

What already applies to private renters

Repair duty. Your landlord must keep the structure and exterior in repair, along with heating, hot water and sanitation, under section 11 of the Landlord and Tenant Act 1985 [2].
Fitness for human habitation. Under section 9A of the same Act, the home must be fit to live in. Serious damp and mould can make it unfit [2].
Council enforcement. Councils assess homes using the Housing Health and Safety Rating System (HHSRS), which now lists 21 hazards after changes on 23 June 2026. They must act on the most serious (Category 1) hazards. From June 2026 they can also fine landlords up to £7,000 for not taking reasonable steps on those hazards [2].
Court. You can take your landlord to court, starting with the Pre-Action Protocol for Housing Conditions Claims [2].

The catch: existing law sets no specific deadline. Repairs must be done "within a reasonable time" [2].

Awaab's Law: where it's up to

Awaab's Law is named after two-year-old Awaab Ishak, who died in December 2020 after exposure to mould in his family's social housing home in Rochdale. It sets strict deadlines for landlords to investigate and fix hazards [4].

Who it covers	Status (November 2026)
Social housing (councils, housing associations)	In force for damp, mould and emergencies since 27 October 2025. Phase 2, covering more hazards, is due on 30 November 2026, subject to Parliament [2][4]
Private renters in England	Proposed. Consultation published 9 October 2026, closing 18 December 2026. No start date yet [2]

For social tenants the current rules are: investigate significant damp and mould within 10 working days, send written findings within 3 working days, make the home safe within 5 working days, and deal with emergencies within 24 hours [4]. For private renting, the government is asking whether those deadlines should be the same, shorter or longer, so treat the private-sector numbers as proposals for now [2].

Two more changes are coming. The Decent Homes Standard is due to cover private rentals from 2035, and private landlords are expected to join a new landlord ombudsman in 2028 [2].

How to report damp and get it fixed

Document it. Take dated photos of the mould, the windows in the morning, and any leaks. Note when it started and any health symptoms.
Report it in writing. Email your landlord or agent. Describe the problem, attach photos, and ask for an inspection and a date for repairs. Keep it polite and factual.
Ask about the cause. A dehumidifier and a bottle of mould spray isn't a fix if the extractor fan is broken, the gutter overflows or the wall has no insulation.
Clean small patches safely in the meantime. The guidance suggests a mould and mildew cleaner, with gloves and a mask. Large areas need a professional [1].
Chase after a reasonable time. If nothing happens in a couple of weeks, send a second email referring to section 11 and the fitness for habitation duty.
Contact your council's private sector housing or environmental health team. Search "[your borough] private sector housing". They can inspect and serve notices on the landlord [2].
Consider legal action using the Pre-Action Protocol. Free advice is available from housing charities and law centres.

Since 1 May 2026, landlords in England can no longer use "no fault" section 21 evictions, even where an old tenancy agreement says they can. That makes it much harder for a landlord to evict you just because you complained [5]. Still, keep everything in writing.

Heating a London flat without a frightening bill

Energy is often the bill that surprises Australians most. From 1 October to 31 December 2026, Ofgem's price cap sets a typical household's annual dual-fuel bill at £1,723 on direct debit, up from £1,663. Gas prices rose about 8%, while electricity stayed broadly flat after VAT was removed from household electricity bills [3]. A one-bed flat usually uses less than the "typical" household, but a draughty Victorian conversion can blow that out.

The price cap limits unit rates and standing charges, not your total bill. Use more and you pay more. Ofgem notes fixed tariffs were available from £100 or more below the October cap, so it's worth comparing [3].

Warm and dry, not freezing and mouldy

Turning the heating off to save money is the fastest way to grow mould. Cold walls attract condensation. A few habits help:

Keep a steady, moderate temperature rather than blasting the heating for an hour, then letting the flat go cold.
Learn your boiler. Most London flats have a gas combi boiler and radiators, controlled by a thermostat and timer. Radiators often have their own thermostatic valves (TRVs) numbered 1 to 5.
Bleed your radiators if they're cold at the top. You need a radiator key from any hardware shop.
Ventilate little and often. Run extractor fans, crack a window after showers, and keep trickle vents open [1].
Dry washing smartly. If you have no outdoor space, use a dehumidifier or dry clothes in a closed room with the window ajar.
Pull furniture off outside walls by a few centimetres so air can circulate [1].

Check the EPC before you sign

Every rental in England needs an Energy Performance Certificate (EPC), rated A (most efficient) to G. You can look up any property's certificate free on GOV.UK using the postcode [6].

At the moment, private rentals must be rated E or better unless an exemption applies. The government has confirmed that all private tenancies must reach C by 1 October 2030, with landlords' spending capped at £10,000 per property [7].

An EPC of D or below is a hint to ask questions. Is there double glazing? Wall or loft insulation? Which way does the flat face? Is there an extractor fan in the bathroom? A top-floor flat with a poor rating can be costly to heat, while a ground-floor flat in an old terrace is more prone to damp.

Questions to ask at a viewing

Has there ever been damp or mould in the flat? (Look behind wardrobes and in the bathroom ceiling.)
What's the EPC rating, and roughly what do the current tenants pay for energy?
Is the heating gas or electric, and how old is the boiler?
Is there a working extractor fan in the kitchen and bathroom?
Where do people dry their washing?

Ask fellow Aussies which buildings and agents to avoid. Join Cooee UK, our Facebook group for Australians in the UK. Members trade tips on everything from dehumidifiers to dodgy landlords.

Damp and mould in London: who fixes it, and how to stay warm