Overview

Intelligent Membranes were commissioned to install Passive Purple Liquid Vapour Control Membrane as part of a major project at Dudley College. In line with the college’s sustainability goals, the new facility involved a deep retrofit of a 1950s building located on the northern side of the Broadway campus. By combining modern airtightness solutions with the preservation of the existing structure, the project demonstrates how education buildings can be upgraded for energy efficiency, comfort, and long-term sustainability.

Background

Before applying Passive Purple Brush, the building required careful preparation. Damaged bricks and mortar joints were repaired, while redundant windows that no longer suited the new design were blocked up. Service penetrations and gaps around existing windows were then sealed with Passive Purple Brush, ensuring a solid airtight base before the main liquid membrane application. Fortunately, the original structure was in relatively good condition, which meant minimal disruption during preparation and a smooth path towards achieving airtightness.

Solutions

To guarantee long-term performance, Passive Purple Liquid Vapour Control Membrane was applied to all external walls, making the building completely airtight and smoke-tight before the installation of external wall insulation. This sequence is crucial in modern methods of construction (MMC), as it locks in airtightness at the core of the fabric. The result is a high-performance building envelope that improves energy efficiency, indoor comfort, and air quality, while also meeting strict fire safety and sustainability standards.

Results

The project achieved an impressive air test score of 0.91 ACH (air changes per hour). To put this into perspective, UK Building Regulations typically require airtightness levels of around 5.0 ACH for new builds, while Passivhaus certification demands 0.6 ACH or below. Achieving 0.91 ACH on a deep retrofit of a 1950s building is therefore a standout result, especially considering Intelligent Membranes were not involved with the installation of the windows or the external façade.

This airtightness performance highlights the proven reliability of Passive Purple in delivering low-energy, sustainable buildings. The result not only reduces heat loss and improves comfort for occupants, but also demonstrates how airtightness and MMC (Modern Methods of Construction) can work hand-in-hand to futureproof education buildings.

AIR TESTING

Air testing- also known air testing, air permeability testing, air leakage testing, and air pressure testingmeasures the amount of air escaping through a buildings envelope.