The brief for Eclipse Leisure Centre was unprecedented: create the UK’s largest 50/50 wet and dry leisure centre designed to Passivhaus standards, while meeting strict budget constraints and sustainability targets.
Located in Staines-upon-Thames, the £50m project needed to consume 60-70% less energy than conventional leisure facilities – a significant challenge in a sector notorious for high energy consumption and comfort issues. Now one of the world’s most advanced leisure facilities, B&K Hybrid Solutions’ (BKHS) expertise in hybrid timber construction was key to the project’s success.
Eclipse Leisure Centre offers a comprehensive range of facilities, including an eight-lane 25m main pool and 20mx10m learner pool with a movable floor, a six-court sports hall and 950sqm of fitness space. The facility also features a flagship rooftop with four artificial football pitches, an open-plan café area, and a feature staircase, to create a welcoming biophilic entrance.
The project team selected a hybrid material solution that balanced aesthetics, performance and sustainability, exceeding a single system approach. The design needed to overcome complex structural, acoustic, and moisture management challenges, particularly in high-humidity environments.
While timber was primarily specified for aesthetic reasons, with significant areas left exposed, the hybrid timber-steel approach maximised the benefits of each system: timber’s visual warmth, carbon sequestration properties and prefabrication benefits and steel’s excellent structural performance.
Working alongside GT3 Architects, structural engineer Engenuiti, and main contractor Willmott Dixon, BKHS’ technical knowledge helped deliver timber applications in areas typically dominated by concrete, including the lift cores, pool hall, and spectator seating. A cost analysis by Willmott Dixon confirmed that a hybrid timber-steel solution could meet the council’s budget, without sacrificing the desired aesthetic or performance requirements.
BKHS delivered more than 2,195m³ of precision-manufactured, PEFC-certified engineered timber, comprising 127m³ of glulam and 2,067m³ of Stora Enso Cross Laminated Timber (CLT). Critical to the project’s success was BKHS’ rigorous moisture management strategy. Regular moisture readings were taken throughout the construction phase, with comprehensive procedures such as the application of end grain sealant and removal of standing water ensuring timber integrity. All joints were sealed to achieve Passivhaus levels of airtightness, which are 95% better than standard building regulations.
The visual-grade timber panels removed the need for additional finishes, reducing material use and long-term maintenance requirements. Factory-controlled manufacturing ensured consistent quality and precise tolerances, while pre-installed lifting devices and protective treatments accelerated installation.
Alex Brock at BKHS said: “The solution enabled remarkable performance achievements in both airtightness and energy efficiency. The timber structure sequestered 1,668 tonnes of CO₂e, while a whole-life carbon assessment showed a 12.97% reduction in embodied carbon compared to a composite steel alternative. The building achieves airtightness of 0.4 m³/hr/m² at 50pa and targets operational energy consumption of just 120 kWh/m²/year.”
Eclipse Leisure Centre stands as a benchmark for leisure facility design, demonstrating that complex, high humidity buildings can achieve Passivhaus standards.
www.bkhybridsolutions.co.uk