A tenant emails about a black patch above the bedroom window. The agent forwards it to the landlord. Someone wipes it down, suggests opening the windows more often, and everyone moves on.
Six months later the patch has spread across the wall, the tenant has complained to the council, and nobody can say when the problem started or what was done about it.
That gap in the record is now one of the most expensive mistakes a landlord can make. In this guide we explain why damp and mould has become a serious compliance issue, and how a detailed tenancy inventory gives landlords and letting agents the evidence they need to act early and protect themselves.
The rules for private landlords in England have tightened sharply in 2026:
One small patch of mould will not automatically lead to a fine. But when a council investigates, the first questions are always the same: when did the problem appear, how bad was it, who was told, and what was done? Landlords who can answer with dated, independent evidence are in a far stronger position than those relying on memory and email chains.
Many inventory reports still record damp and mould in two or three words: "minor mould noted". That tells the reader something was there, but almost nothing else. It does not say where, how large, whether it was getting worse, or whether anything nearby might be contributing.
Compare that with a properly detailed entry in a letting inventory:
Bedroom 1, external wall: black spotting to upper wall and window reveal, approx. 1 m wide. Heavy condensation on inside of glazing at time of inspection. Paint flaking locally below window. Trickle vent present, closed. Recommend landlord/agent investigation.
That entry is factual. It does not guess the cause. But it gives the landlord enough information to act, and it creates a clear, dated record if the issue is ever questioned.
When our clerks find signs of damp or mould, the report covers:
A single report is a snapshot. A series of reports is a timeline, and a timeline is what protects you.
It depends on the cause, and that is exactly why it should not be guessed.
Damp and mould can come from structural problems such as leaks, failed guttering, poor insulation or faulty extraction, which are the landlord's responsibility. It can also come from day-to-day living, such as drying clothes indoors with the windows shut or turning off extractor fans. Often it is a mix of both.
An independent inventory clerk is not a damp surveyor and should not diagnose "rising damp" or "tenant condensation". Our job is to record what is visible, accurately and impartially, and flag when a qualified specialist should investigate. That keeps the report credible and fair to both sides, and it is the kind of evidence that holds up with deposit schemes and councils.
London has some of the oldest rental housing stock in the country, from Victorian conversions with solid walls to post-war blocks with single glazing. Many flats are small, have limited outdoor drying space and are heavily occupied. Together, that makes condensation and mould a common issue every winter.
For London landlords and letting agents managing large portfolios, a consistent London inventory standard across every property means problems are spotted, reported and followed up the same way every time, whatever the borough.
InventoryFlex is an AIIC- and ARLA Propertymark-accredited inventory company with more than 15,000 inspections completed across every London borough, Essex and Kent. We are proud to have been named AIIC Best Inventory Company of the Year, following AIIC Best Newcomer 2024 and AIIC Newcomer 2025.
Every InventoryFlex report gives you:
Prices: inventory reports from £110, check-ins from £120, mid-term inspections £65 and check-outs from £100.
Can a landlord be fined for damp and mould? Yes. Since 22 June 2026, councils in England can issue fines of up to £7,000 where a serious Category 1 hazard, including severe damp and mould, is not dealt with. Serious or repeated breaches under the Renters' Rights Act can attract penalties of up to £40,000.
Should damp and mould be included in a tenancy inventory? Yes. A detailed tenancy inventory should record the location, size and appearance of any damp or mould, related signs such as condensation, the condition of ventilation, and clear photographs. This creates a dated record that protects landlords, agents and tenants.
Can an inventory clerk say what caused the mould? No. Unless specifically qualified, an inventory clerk records what is visible and recommends further investigation where needed. The cause should be established by a surveyor or damp specialist.
How often should a rental property be inspected for damp? At check-in, at least once mid-tenancy (ideally during autumn or winter), after any repair work, and at check-out.
Don't let a small patch of mould become a £7,000 problem. Book a check-in, mid-term inspection or check-out with InventoryFlex today.
Call 020 3488 9191, email info@inventoryflex.co.uk or get an instant quote.
