Dudley College Animal Studies Centre Retrofit

Project Overview

Not every high-performance building starts with a new foundation.

As part of a £7.5 million investment programme, Dudley College of Technology transformed a redundant 1950s building on its Broadway Campus into a modern Animal Studies Centre. Rather than demolishing and rebuilding, the project team chose a deep retrofit strategy designed to extend the building's lifespan, reduce embodied carbon and significantly improve energy performance.

The completed facility now provides modern teaching spaces for animal care and animal science students while delivering improved comfort, reduced energy demand and enhanced building performance.

The Challenge

Retrofitting older buildings presents unique challenges.

Years of repairs, alterations and wear often leave hidden defects throughout the building fabric, creating multiple pathways for uncontrolled air leakage. Existing masonry walls, repaired openings, service penetrations and structural junctions all required careful attention before performance targets could be achieved.

The project required a continuous airtight and smoke-tight layer across the external structure before the installation of an External Wall Insulation (EWI) system. This airtightness strategy would play a critical role in reducing heat loss and improving overall building efficiency.

Creating an Airtight Foundation

Following repairs to damaged masonry and the closure of redundant openings, Passive Purple Brush was applied to critical junctions, penetrations and reinforcement areas to eliminate potential leakage paths.

Once preparation work was complete, Passive Purple Internal Airtight Vapour Control Membrane was spray-applied directly onto the external masonry walls prior to the installation of the EWI system. Although typically used internally, Passive Purple was selected because it could provide a seamless liquid-applied airtight layer across the entire building envelope.

Unlike traditional sheet membranes, the liquid-applied system conforms to uneven masonry surfaces and difficult junctions, creating complete coverage without overlaps, joints or taped connections.

The Purple Building Everyone Talked About

During construction, the Dudley College Animal Studies Centre became instantly recognisable thanks to the striking purple coating covering the external masonry walls.

While many people saw the colour, few realised they were looking at one of the most important elements of the entire retrofit strategy. Hidden behind the finished external wall insulation system, the Passive Purple airtightness layer would ultimately help the building achieve an impressive airtightness result of 0.91 ACH while supporting the wider sustainability goals of the £7.5 million redevelopment.

For a period during construction, however, it became known simply as "the purple building" - a visible reminder that some of the most important building technologies are often the ones that eventually disappear from view.

Airtightness Results

The completed project achieved an impressive airtightness result of:

0.91 ACH

This result demonstrates the effectiveness of the airtightness strategy and highlights the role that airtight construction plays in successful retrofit projects.

Why Airtightness Matters

Comfort

• Reduces draughts and cold spots
• Creates more consistent internal temperatures

Energy Efficiency

• Reduces heat loss
• Supports insulation performance
• Lowers heating and cooling demand

Building Performance

• Improves overall envelope efficiency
• Supports long-term sustainability goals

Why Passive Purple Was Selected

Passive Purple was chosen because it combines airtightness, vapour control and smoke-tight performance within a single liquid-applied membrane. Its ability to adhere directly to masonry substrates made it particularly suitable for the challenges associated with deep retrofit projects.

The seamless nature of the coating helped maintain continuity throughout the building envelope, reducing the risk of uncontrolled air leakage while improving long-term durability.

Project Outcome

Today, the completed Animal Studies Centre provides Dudley College students with a modern, comfortable and energy-efficient learning environment. Behind the finished façade sits an airtight building envelope that continues to reduce heat loss, improve thermal performance and support the college's wider sustainability objectives.

The project demonstrates how existing buildings can be successfully repurposed, upgraded and future-proofed through intelligent retrofit strategies and high-performance airtightness technology.

If you're planning a retrofit project and would like advice on airtightness, vapour control or building envelope performance, get in touch today.