Black Mould: Health Risks and What Landlords Must Do

Black mould is no longer something a landlord can treat as a cosmetic nuisance or blame on "lifestyle" and move on. The death of two-year-old Awaab Ishak from prolonged mould exposure changed the legal and moral landscape, and the obligations on landlords are now explicit. This is what the health risks actually are, and what the law requires landlords to do.

What black mould is

"Black mould" is a catch-all term for the dark fungal growth that appears on persistently damp surfaces — commonly species such as Aspergillus, Cladosporium, and Stachybotrys. It grows wherever a surface stays damp long enough, which is why it is a symptom rather than a cause: the mould is telling you there is a moisture problem to find and fix.

The health risks

The health effects of damp and mould are well established by public health bodies. Exposure is associated with:

• Respiratory irritation — coughing, wheezing, and shortness of breath.
• Allergic reactions and the worsening of existing conditions such as asthma.
• A higher risk of respiratory infections.

The risks are greater for vulnerable groups: infants and young children, older people, and anyone with a pre-existing respiratory or immune condition. The Awaab Ishak case made the most serious end of that spectrum tragically clear — a coroner concluded that prolonged exposure to mould directly caused his death. Landlords should treat mould affecting a vulnerable occupant as urgent, not routine.

What the law requires of landlords

Several overlapping duties now apply to damp and mould:

• The Landlord and Tenant Act 1985 (section 11) — the long-standing repairing obligations covering the structure and exterior of the property.
• The Homes (Fitness for Human Habitation) Act 2018 — requires rented homes to be fit for habitation, with damp and mould an express consideration of fitness.
• The HHSRS — under which local authorities assess damp and mould as a hazard and can enforce against it. See our guide to HHSRS hazards.
• Awaab's Law — places social landlords under statutory timeframes to investigate and address damp and mould. Our surveyor's guide to Awaab's Law sets out the detail, and the Renters' Rights Act 2025 extends similar expectations toward the private rented sector.

The "lifestyle" trap

A landlord's instinct is sometimes to blame condensation on the way the tenant lives — drying washing indoors, not ventilating. Even where condensation genuinely is the mechanism, the Housing Ombudsman has been clear that dismissing a complaint as "lifestyle" without proper investigation is not an acceptable response. The cause still has to be diagnosed, and where the building's ventilation or heating is inadequate, that is the landlord's responsibility, not the tenant's. Our guide on telling condensation, damp and mould apart explains why diagnosis comes first.

What good practice looks like

Wiping mould off and repainting treats the symptom while leaving the cause running. Good practice is to investigate promptly, diagnose the source of the moisture, fix that source, and keep a clear record of what was found and done — both to protect the occupant and to evidence that the duties above were met if the case is ever escalated.

SurveyMate is built to make that record the natural output of the work: capture the findings and photographs on-site, diagnose the cause, and generate an evidenced report — with Awaab's Law timeframes tracked for social landlords. See how SurveyMate supports compliant damp and mould handling.