Airtight Coating for Durham History Centre

Introduction

Durham History Centre, housed within the Grade II listed Mount Oswald Manor House, required a precisely controlled environment to protect sensitive historical archives. UCL Ltd was contracted to install a BBA-approved liquid airtight membrane system, ensuring the building envelope met the strict performance standards required for long-term archive preservation.

Our Solution

UCL Ltd applied a three-coat spray-applied system of Blowerproof — a BBA-approved, water-based polymer liquid airtight membrane — to interior blockwork walls and structural concrete columns throughout the facility. Floor and ceiling joints were first prepared using fireproof backer rod and mastic sealant, followed by the application of airtight tape at all junctions. A fibre-reinforced coat of Blowerproof was then hand-applied over each joint to ensure a continuous, unbroken airtight seal across the entire building envelope. The system was designed and installed to satisfy the stringent performance criteria required for archival storage environments.

Key Benefits

• Achieved below Passivhaus airtightness standard of 0.6 air changes per hour (ACH)
• BBA-approved Blowerproof membrane used throughout, ensuring certified performance
• Spray and hand-application methods combined to address both large surface areas and complex junctions
• Fibre-reinforced detailing at joints provided durable, long-term airtight continuity
• Suitable for sensitive heritage settings — applied within a Grade II listed structure without intrusive intervention

Conclusion

UCL Ltd delivered a compliant, high-performance airtightness system within a Grade II listed building, achieving sub-Passivhaus results. This project demonstrates UCL's capability to specify and install certified membrane systems within technically demanding and heritage-sensitive environments.