Understanding mould

Mould is a type of fungi that thrives in damp and humid conditions, often linked to issues such as rising damp, penetrating damp or moisture entering through poorly maintained external walls. When left unaddressed, mould can damage the structure of a property and create health risks for anyone living in the environment. Prolonged exposure is known to aggravate respiratory conditions, contribute to breathing difficulties, and trigger allergic reactions, particularly in individuals who already have underlying sensitivities.

Mould commonly appears on walls, ceilings and other cool surfaces as black, green or white patches. It develops where moisture levels remain high, usually due to inadequate ventilation, insufficient heating or hidden water leaks. For landlords, understanding the underlying cause is the first step towards preventing further deterioration and safeguarding the wellbeing of occupants.

Landlords' responsibilities for the management of mould in their rental properties

Landlords in the UK have several statutory duties that relate directly to damp and mould, supported by legislation such as the Housing Act 2004, the Landlord and Tenant Act 1985, and the Homes (Fitness for Human Habitation) Act 2018. These place clear obligations on landlords to keep properties safe, structurally sound, and fit for human habitation. In practice, this means landlords must:

• Comply with the Housing Health and Safety Rating System (HHSRS), which classifies damp and mould as a Category 1 hazard posing a serious health risk. This duty includes taking action to prevent mould, recognising the early signs of mould developing, and addressing issues such as inadequate ventilation or broken extractor fans that allow moisture levels to rise.
• Maintain the structure and exterior of the property, including the roof, external walls, windows and drainage systems. This requirement also covers repairing rotten window frames, restoring any damp proof measures, and resolving defects that lead to water ingress, rising damp or penetrating damp.
• Prevent and repair issues that cause damp, including faults that compromise damp proof courses, damaged gutters or leaking pipework. Any issue that increases the risk of mould developing must be identified and rectified promptly to maintain safe living conditions.
• Keep the property fit for human habitation, which requires landlords to take reasonable steps to prevent mould and damp. This includes reinforcing damp proof protections where necessary and actively monitoring areas where damp is likely to appear.
• Inspect the property regularly to identify damp or mould risks early. Routine checks help landlords detect problems such as condensation, tenant reported damp, ineffective ventilation or structural deterioration, enabling swift intervention before mould spreads.
• Provide adequate ventilation, including fully operational extractor fans in kitchens and bathrooms. Functional airflow systems reduce humidity, and landlords must repair broken extractor fans and maintain vents and windows to help prevent mould.
• Repair leaks, faulty guttering and defects that contribute to damp without delay. Any source of water ingress increases the likelihood of rising damp or penetrating damp, both of which create conditions where mould develops quickly.
• Provide sufficient heating to help control condensation. Maintaining an appropriate heating system encourages dry surfaces and reduces the risk of mould developing throughout the property.
• Respond to tenant reports of damp or mould promptly and professionally, addressing the underlying cause rather than focusing only on visible symptoms. Effective action reduces the chance of recurrence and supports compliance with statutory obligations.

These responsibilities work together to safeguard tenant health, reduce structural damage, and meet a landlord’s duties under UK housing law. If you need guidance on how to prevent mould or address damp-related issues within your rental property, AST Assistance is available to support you.

Tenant responsibilities

Tenants also have an active role in helping to prevent and manage mould in a rental property. Their actions can make a considerable difference to humidity levels, ventilation and the overall condition of the home. These responsibilities include:

• Reporting any signs of mould or dampness to the landlord promptly, including early indications such as condensation build-up, patches forming on walls or ceilings or musty odours. Early notification allows the landlord to investigate the underlying cause before the issue escalates.
• Ensuring proper ventilation by opening windows regularly and using extractor fans when cooking or showering. This helps remove excess moisture from the air and reduces the likelihood of mould developing in kitchens, bathrooms and other high-humidity areas.
• Avoiding drying clothes indoors without sufficient airflow, as this increases humidity and can cause mould to form on colder surfaces. If indoor drying is unavoidable, tenants should take steps to ventilate the area thoroughly.
• Keeping the property adequately heated to reduce condensation, particularly during colder months. Maintaining a consistent temperature prevents surfaces from becoming cold and damp, which are conditions where mould can thrive.
• Cleaning small patches of mould they discover promptly, especially surface-level growth caused by day-to-day living. Quick cleaning prevents mould from spreading and supports overall property upkeep.

While landlords must address the root causes of damp and mould, tenants play a vital supporting role in maintaining a healthy living environment by managing moisture and ventilation effectively.

What are the risks of failing to act on damp and mould issues?

Failing to address damp and mould can create serious difficulties for landlords. These issues affect the structure of the property, the health of the occupants and compliance with statutory duties. When damp or mould is left unresolved, landlords face a range of risks, including:

• Damage to the building: damp can spread through plaster, timber, roofing and external walls, leading to substantial repair costs.
• Health concerns for tenants: prolonged exposure may trigger respiratory problems or allergic reactions, increasing the likelihood of complaints or medical evidence being raised as part of a dispute.
• Local authority enforcement: under the HHSRS, mould is treated as a Category 1 hazard. Councils may issue improvement notices or take formal action that imposes additional obligations on landlords.
• Legal claims: tenants may pursue a claim if the property is not fit for habitation because of damp or mould, leading to potential compensation and legal costs.
• Tenancy disruption: tenants may move out early, decline to renew their agreement or escalate complaints if the problem persists, resulting in void periods and financial loss.

Taking swift and effective action protects both the property and the tenancy. If you need support managing damp or mould issues in your rental property, AST Assistance can guide you through your obligations and the practical steps needed to resolve the matter.

How AST Assistance can help landlords to meet their responsibilities

Managing damp and mould carries both practical and legal obligations, and many landlords choose to work with specialists to avoid the risks that come with non-compliance. AST Assistance provides targeted support for landlords who want clear guidance and effective solutions. Our team offers advice on mould prevention, damp investigations, legal duties and the steps required to keep your property safe, compliant and well-maintained.

By instructing AST Assistance, you gain access to experienced professionals who understand the demands of the private rented sector and the consequences of unmanaged damp and mould. We help you assess potential risks, respond to issues raised by tenants, and take the correct action to protect both your asset and your position as a landlord. This level of support allows you to focus on your investment, confident in the knowledge your property meets the standards set by UK housing law.

AST Assistance is committed to helping landlords maintain high-quality homes, reduce the likelihood of disputes, and uphold strong tenant relationships. To speak with our team, call 01706 619954 or complete the contact form below.