St Sidwell’s Point, located in the heart of Exeter city centre, is a landmark achievement in sustainable construction. It is the world’s first Passivhaus-certified, multi-zoned leisure centre, with a project value of £44 million. As part of its cutting-edge specification, the building includes the Wraptite® external air barrier system from the A. Proctor Group—critical to the construction of its highly efficient external wall assemblies.
An Ambitious Vision, Expertly Delivered
The project was designed by Space & Place Architects, working alongside Passivhaus specialists Gale & Snowden, and delivered on site by main contractor Kier.
In addition to Passivhaus certification, St Sidwell’s Point was designed and built in accordance with Building Biology IBN best practice for healthy building design. Climate resilience was also a priority: the building incorporates data from University of Exeter climate scientists to ensure it remains efficient and habitable in predicted climate conditions up to the year 2080.
Applying Passivhaus Standards to a Complex Building Type
Leisure centres pose unique challenges due to their wide range of internal environmental conditions. The design must account for vastly different zones—from warm, humid swimming pool halls to cool, controlled fitness studios—while maintaining a unified energy strategy.
In Passivhaus construction, the building fabric performance is always the starting point. At St Sidwell’s Point, the facade systems were designed with high thermal insulation, minimal thermal bridging, and extremely low levels of unplanned air movement—all essential criteria for achieving the target U-value of 0.14 W/m²K.
Three primary external wall build-ups were used: steel frame construction, blockwork, and cross-laminated timber (CLT). Regardless of the structure type, all wall assemblies placed insulation and the airtightness layer externally, a strategy that significantly improves thermal and moisture performance.
Achieving Airtightness with Wraptite
The Wraptite® membrane, a self-adhered, airtight and vapour-permeable system, played a crucial role in achieving the required airtightness. Installed externally, it removes the airtightness layer from the internal service zone, simplifying detailing and reducing the risk of air leakage through penetrations.
As a Passivhaus-certified product, Wraptite was an ideal choice for this project. To ensure best practice on site, the A. Proctor Group provided toolbox talks and hands-on training with mock-up panels for the installation team.
For St Sidwell’s Point, a leisure centre-specific airtightness target of 0.4 m³/m²/h @50Pa was established by the Passivhaus Institute. With Wraptite’s help, the building surpassed this goal, achieving a measured rate of 0.3 m³/m²/h @50Pa—equivalent to an air leakage opening the size of just 1¼ sheets of A4 paper across the entire building envelope.
This exceptional result demonstrates that even large, complex buildings like leisure centres can achieve—and exceed—Passivhaus airtightness standards.
Moisture Management and Hygrothermal Analysis
In a warm and humid environment like a swimming pool, airtightness must be matched with robust moisture management to protect the building fabric. With insulation placed externally, the wall assemblies are inherently less prone to internal condensation, but careful risk assessment remains essential.
To validate performance, the A. Proctor Group’s technical team undertook detailed hygrothermal analysis of the proposed wall systems. Initial steps included U-value calculations to BS EN ISO 6946, and condensation risk assessments to BS EN ISO 13788, identifying dew points and temperature gradients throughout the assemblies.
Given the moisture loads expected in a leisure facility, the team conducted a further dynamic moisture assessment using WUFI® software to the BS EN 15026 standard. This allowed a deeper understanding of hourly variations in temperature, relative humidity, and water content through the wall build-ups.
The analysis confirmed that humidity levels within and on the outer surface of the insulation stayed well below the 70% threshold where condensation risks increase. Moisture absorption was minimal and mostly stored by the hygroscopic sheathing board, ensuring that the insulation maintained performance without risk of degradation.
Summary: A Sustainable Flagship for Exeter
Built on a brownfield site, St Sidwell’s Point includes a 25-metre main pool, a 20-metre learner pool, a confidence water pool, and a 100-seat spectator gallery. Dry-side facilities feature a gym, health suites, spa, café, soft play area, and more.
But its value goes far beyond amenities. From supporting T-level student placements during construction to creating long-term employment opportunities, the project has become a key part of Exeter’s regeneration efforts.
It also provides a national benchmark for what sustainable, healthy, future-ready public buildings can look like. By combining Passivhaus design, building biology principles, and advanced product solutions like Wraptite, St Sidwell’s Point represents the best of modern construction—a legacy of quality, innovation, and community benefit.
Wraptite® – Technology you can rely on from a brand you can trust.
Find out more: www.proctorgroup.com
