What causes sick building syndrome in London?

When occupants say a building makes them sick—headaches, fatigue, respiratory or skin symptoms—the cause is often the indoor environment. In London’s mix of older offices, converted flats and newer builds, several factors can trigger what’s often called sick building syndrome or building-related illness.

Common triggers

Poor ventilation
Inadequate fresh air and high CO₂ levels are common in sealed or poorly maintained buildings. Stuffy air can cause fatigue and concentration problems.

Damp and mould
Mould spores and damp-related allergens can cause respiratory and allergic symptoms. Hidden mould in cavities or behind units is a frequent culprit in London properties.

VOCs and off-gassing
New finishes, furniture and cleaning products can release volatile organic compounds (VOCs). In confined or poorly ventilated spaces, VOC levels can build up and cause irritation or headaches.

Humidity
Very high or very low humidity can worsen respiratory and skin symptoms. Condensation and mould go hand-in-hand with high humidity.

When to get a building-related health investigation

If you or others consistently feel unwell in a specific building and better elsewhere, an indoor environment health investigation or sick building syndrome investigation can identify likely triggers. We measure ventilation, humidity, CO₂ and—where appropriate—VOCs and mould. The report outlines probable causes and practical steps to improve the environment.

Building-related symptoms we often help with include:

• Recurrent headaches or fatigue at work or home
• Eye, nose or throat irritation
• Worsening asthma or allergies in one building
• Unexplained skin or respiratory issues that improve when leaving the building

We provide building-related illness and sick building syndrome investigation London services across London and the South East. Our reports are independent and evidence-based—we don’t sell air purifiers or remediation services.