CIBSE AWARD WINNER | STREATHAM AND CLAPHAM HIGH SCHOOL LESSON IN CONTINUITY Collaboration was key for the design and construction teams involved in the low-energy extension of Streatham and Clapham High School, in London, which had to remain fully operational throughout. Andy Pearson reports PROJECT TEAM Client: Girls Day School Trust Building services and acoustics: OR Consulting Engineers Architect: Cottrell & Vermeulen Architecture Structural engineer: Engineers HRW Project manager: Quantity surveyor: Woodley Coles Breeam: Method Main contractor: Rooff Mechanical contractor: Morgan Clark Building Services Electrical contractor: Moyne London T he Girls Day School Trust wanted to extend Streatham and Clapham High School by creating a new, flexible sixthform space, plus a dining hall big enough for use by the entire school. It wanted these spaces to be lowenergy and to promote sustainable design to the pupils. The trust also wanted to retain the schools existing buildings, partly to avoid the cost of demolishing and rebuilding, but also because the school had to remain operational throughout the project. Site constraints The schools location on a tight, urban site in a residential South London neighbourhood, adjacent to Streatham Common meant space was at a premium. The innovative solution, developed by Cottrell & Vermeulen Architecture, working with OR Consulting Engineers, was to place the new sixth-form centre on the roof of the schools main threestorey building and to slot the dining hall into a compact space between the schools eastern elevation and the street. Collaboration and communication were key to the design and construction teams being able to extend the school while keeping it fully operational. (See panel, right). In recognition of its use of integrated processes to facilitate this, OR Consulting won the Collaboration Award at this years CIBSE Building Performance Awards. The judges said the project showed a clear structured and collaborative approach with an exemplar use of post-occupancy evaluation. Phase 1 was to construct the sixth-form centre. It comprises a row of south-facing classrooms, offices and a science laboratory, all of which are entered from a connecting spine corridor at the rear. The corridor is bookended by a study space to the west and the sixthform common room to the east. The centre is constructed from lightweight cross-laminated timber (CLT) panels mounted on a steel subframe. Internally, the CLT panels are left exposed, along with the crossed-glulam columns supporting the roof and the timber window mullions. The exposed timber gives the rooms a warm, natural appearance, enhanced by daylight, Once people understand the controls why they are there and what they do they get more comfortable with their use Peter Roberts which floods the space from a southfacing curtain wall that is set beneath an overhanging roof to limit solar gain. The south-facing, full-height glazing is supplemented at the back of the spaces by a linear, north-facing clerestory window. The clerestory introduces daylight deep into the space, to provide a daylight factor of around 5%, says Peter Roberts, director and founder of OR Consulting Engineers, the projects building services consultants. To save energy, daylight-level sensing is integrated with absence-detection controls; there is also local lighting control for interactive teaching. Ventilation strategy The clerestory window is fundamental to the rooftop extensions ventilation strategy. 26 August 2021 www.cibsejournal.com CIBSE Aug 21 pp26-28, 30 Collaboration award.indd 26 23/07/2021 12:08