Why Black Mould Is a Growing Problem in London
Black mould, also known as Stachybotrys chartarum, thrives in damp, humid environments — exactly the kind found in many London homes. Whether it’s a poorly ventilated flat, a basement conversion, or an older Victorian property, the city’s housing stock is especially vulnerable to excess moisture and mould growth.
The problem isn't just cosmetic. Black mould poses a real health risk, particularly to vulnerable groups like children, the elderly, and people with respiratory issues. It’s also a major concern for landlords, who can face legal consequences if it’s not dealt with properly.
What Causes Black Mould to Form?
Mould is the visible result of prolonged damp and excess moisture. The most common causes include:
Condensation from poor ventilation in kitchens and bathrooms
Rising damp from failed damp-proof courses
Penetrating damp through damaged roofs, brickwork, or gutters
Leaks from plumbing or rainwater ingress
Insufficient heating or air circulation in colder rooms
Once moisture is present and indoor humidity is high, mould spores settle and multiply on walls, ceilings, windowsills, and even furniture.
The Health Risks of Black Mould: NHS Guidance
According to the NHS, exposure to mould can lead to a range of health issues, including:
Respiratory infections
Worsening of asthma and allergy symptoms
Persistent coughing, wheezing or throat irritation
Skin rashes or eye irritation
Weakened immune response over time
NHS Advice: “If you have damp and mould you're more likely to have respiratory problems, respiratory infections, allergies or asthma. Damp and mould can also affect the immune system.” — NHS.uk – Damp and mould health risks
Children, babies, the elderly, and people with pre-existing breathing conditions are at much higher risk. For landlords, this raises not only health concerns but also legal responsibility.
Legal Duties for Landlords in the UK
Under the Homes (Fitness for Human Habitation) Act 2018, landlords are legally required to keep rental properties free from hazards — including damp and mould. Failure to act on complaints may result in:
Legal action from tenants
Fines and compensation payouts
Mandatory enforcement from local authorities
If you’re a landlord managing properties across London, it’s critical to investigate any reports of mould swiftly — and have formal documentation to show you’ve taken action.
Why DIY Mould Cleaning Is Not Enough
Many property owners attempt to clean black mould with bleach or mould sprays. While this may improve appearance temporarily, it does not address the root cause. In most cases, the mould will return — and often spread — unless the underlying damp is properly diagnosed and treated.
DIY cleaning fails because:
It doesn’t remove spores inside walls or behind surfaces
It ignores moisture coming from rising or penetrating damp
It delays professional intervention, often increasing long-term repair costs
Why a Professional Damp Survey Is the Right Step
A professional damp survey is the only reliable way to understand why mould is forming in your property. Our expert surveys go beyond surface symptoms and provide a clear roadmap to treatment.
Our damp survey includes:
Moisture and humidity readings using industry tools
Thermal imaging to detect hidden damp zones
Identification of rising, penetrating, and condensation-based damp
Assessment of ventilation and property construction
A detailed written report with photographic evidence and treatment advice
We charge for our damp surveys because they require expertise, site visits, and a thorough reporting process — typically taking three hours to prepare. Our surveys have uncovered hidden moisture issues that even £3,000 HomeBuyers Reports have missed.
Don’t Wait — Act on Black Mould Now
If you’ve spotted black mould in your home or rental property — or can smell damp in the air — now is the time to act. Mould rarely stays in one place. The longer it remains, the greater the risk to your property, your health, and your legal standing as a landlord.
We cover all areas of London and provide expert, trusted support to both homeowners and property managers.