Propertymark is urging tenants and homeowners to watch for damp and mould as temperatures fall and condensation risks rise, while reminding landlords and letting agents that reports need investigating at the source.
The professional body for estate and letting agents said early action protects both homes and the health of the people living in them.
The warning follows the death of two-year-old Awaab Ishak in December 2020 from a severe respiratory infection after prolonged exposure to damp and mould in his home. His death brought the health risks into sharp focus and prompted changes to legislation designed to protect people in rented accommodation.
With the problem still affecting households across the UK, Propertymark said knowing what to look for and how to cut the risk can stop issues becoming serious.
Four types of damp
Rising damp occurs when moisture moves upwards from the ground through a building’s masonry. Many properties have preventative measures, but these can deteriorate and need maintenance, and rising damp can be harder to address in older buildings because of differing construction methods and standards.
Penetrating damp, by contrast, comes from water entering from outside, often through leaking pipes, damaged roofs or blocked gutters. These faults can often be identified and repaired before they cause wider damage.
Construction damp stems from how a property was designed or built and should be investigated promptly to prevent long-term damage. Condensation damp arises when too much moisture meets insufficient ventilation or airflow. Cooking, bathing, showering and drying clothes indoors all add moisture, and poor ventilation lets condensation build up and feed mould growth. Identifying the underlying cause matters, Propertymark said, because cleaning visible mould without tackling the source can let it return.
Health effects
Exposure can aggravate respiratory symptoms and allergies. Children, older people and those with existing respiratory conditions or weakened immune systems can be particularly vulnerable. Damp conditions can raise the presence of mould spores, allergens and other irritants in a home, and excess moisture supports the growth of mould and other fungi, as well as dust mites and other biological contaminants. Anyone with respiratory problems, infections or allergic symptoms who is concerned about exposure should consider seeking medical advice, the body added.
Reducing the risk of damp and mould
Good ventilation limits excess moisture. Propertymark recommends opening windows regularly after cooking, showering or bathing, or using extractor fans in kitchens and bathrooms where they are fitted. Drying clothes indoors can also raise moisture levels, particularly where ventilation is limited, so an indoor airer should sit in a room with a regular flow of fresh air.
In colder months, heating and ventilation work best together, since switching on the heating without addressing poor ventilation may not fix the underlying problem. Furniture can restrict airflow too, so large items are better kept off tight against external walls, with air able to circulate around the room.
Tenants who notice persistent damp, mould, condensation or signs of water entering the property should not ignore them. Renters should report the problem to their landlord or letting agent as soon as possible, with details of where it has occurred and when it was first noticed. Landlords and agents, in turn, should investigate the underlying cause rather than simply treating visible mould, and keep a record of reports, inspections and remedial work so problems are followed up appropriately.
Landlord and agent responsibilities
Landlords and letting agents have an important role in making sure rented properties are safe and that reports are taken seriously. In England, the Renters’ Rights Act has strengthened the enforcement powers available to local authorities, while landlords remain responsible for addressing hazards and maintaining safe homes.
The UK government is consulting on how Awaab’s Law will apply across the private rented sector in England, with the consultation closing on 18 December 2026. The responses will help determine the timescales for when the new protections come into force.
In Scotland, the Investigation and Commencement of Repairs (Scotland) Regulations 2026 came into force on 6 October 2026. They set specific timescales for landlords dealing with reported damp and mould: an investigation within 10 working days, a written summary of findings within three working days of completing it, and the start of required safety work within five working days.
The regulatory framework differs across the UK, Propertymark said, but landlords and agents should have inspection, maintenance and reporting processes in place to identify problems and deal with them promptly.
“As temperatures fall and homes become more susceptible to condensation and moisture, the fear of seeing familiar signs of damp and mould return can be a real concern for tenants and their families,” said Kim Lidbury, president of ARLA Propertymark, the Association of Residential Letting Agents.
“Living with persistent damp and mould can have a significant impact on the comfort and enjoyment of a home, as well as potentially affecting physical and mental wellbeing.
“The real-world consequences of living with damp and mould can be catastrophic, which is why it is so important that concerns are taken seriously and addressed in a prompt, robust and effective manner. For families, particularly those with children or other vulnerable household members, the consequences of allowing problems to persist can be devastating.
“Landlords and letting agents have an important role to play in ensuring that reports are acted upon quickly, the underlying cause is properly investigated, and any necessary remedial work is carried out to a high standard. Simply treating the visible symptoms without addressing the root cause risks allowing the problem to return and leaving tenants facing the same concerns repeatedly.”
