Façade Consultant: Eckersley O’Callaghan
Client: The Office Group
Architect: Waugh Thistleton
Façade Contractor: Contrasol and Pacegrade
The Black & White Building, a commercial development in Shoreditch, East London, epitomises innovation in timber construction and facade engineering, this project stands as a beacon of sustainable architecture and engineering excellence.
The building is a six-storey structure providing 52,000 square feet of office space, with a single-storey basement. It showcases the exemplary use of timber, with its structural frame entirely constructed from glue-laminated and cross-laminated timber, except for the concrete ground floor and basement foundations. This pioneering approach positions the building as a unique entity in London’s commercial office market.
The facade of The Black & White Building is a testament to meticulous engineering and aesthetic design. It features a composite timber-aluminium curtain wall system supplied by Raico, with timber shading fins provided by Contrasol. These fins, crafted from American Tulipwood, are integral to the building's environmental performance, offering solar protection and enhancing glass transparency.
The facade engineering presented several challenges, primarily due to the inherent properties of timber, such as greater movement from moisture changes compared to concrete. This required precise sizing of joints and careful assessment of movements during installation. In addition, the shading fins, spaced at 375mm, necessitated an external secondary structure to transfer loads back to the mullions at 1200mm intervals, demanding both aesthetic and functional detailing.
The curtain wall system of the project demonstrates superior technical performance. It spans from floor to floor, accommodating differential movements through its bracketry connections. Key environmental performance metrics include a U-value of 1.6 W/m²K, airtightness exceeding 600 Pa, water-tightness surpassing 600 Pa, light transmittance of 72%, a G-value of 0.37, and acoustic performance of Rw (C;Ctr) = 36 (-1;-3) dB. Fire safety was another critical aspect, with certain areas requiring EI30 fire-rated façades due to boundary proximity. This was achieved using fire-rated glass within the composite system, obviating the need for additional fire testing.
Sustainability was a cornerstone of this project. The embodied carbon (EC) for the building was meticulously measured and monitored, achieving a total EC of 410kgCO2e/m², compared to 670kgCO2e/m² for a conventional concrete and aluminium building. Considering carbon sequestration in timber, the EC value drops to 180kgCO2e/m², a 70% reduction, meeting LETI A+ criteria. The timber shading fins contribute significantly to the building's passive solar design, reducing cooling loads. The building also incorporates natural ventilation as part of a mixed-mode strategy, with manually operated windows integrated into the curtain wall system, fostering a healthy internal environment and reducing cooling demands.
Architecturally, the project harmonises with its urban surroundings while showcasing the aesthetic and functional benefits of timber. The exposed timber beams, columns, and slabs offer a warm, inviting interior, illuminated by natural light. Externally, the raw timber finish complements the urban texture of Rivington Street and Shoreditch, with the transparent facade providing glimpses into the dynamic co-working spaces within.
Extensive research underpinned the project's design decisions, particularly in selecting Tulipwood for its durability, structural integrity, and aesthetic appeal. The timber was thermally modified to enhance its resistance to rot and reduce moisture-induced movements. Fire-retardant treatments were applied, and specific fire tests were conducted to ensure compliance with safety standards, addressing the lack of pre-existing data for Tulipwood in this context.
The project demonstrates integrated and collaborative design, with close coordination between structural, facade, and MEP engineers. This collaboration ensured that structural movements were accommodated in the facade design, optimising shading fin configurations to enhance thermal performance and light transmittance.
The Black & White Building is a pioneering project that demonstrates the potential of timber in modern construction. It sets a new standard in sustainable design and engineering, contributing significantly to the fields of facade engineering and architecture. The collaborative efforts of the project team, coupled with rigorous research and innovative solutions, have resulted in a building that is both environmentally responsible and architecturally compelling.
