Reflections on Concrete Elegance - Sustainable Education
14 May 2019
Two very different examples of education buildings were featured in this year’s first Concrete Elegance lecture:
- Bobby Moore Academy Secondary School, Stratford is a new school on a tight site in the Queen Elizabeth Olympic Park. The project was presented by Anna-Lisa Pollock of Penoyre & Prasad Architects and Richard Williams from Balfour Beatty.
- The Student Centre for University College London is a new university building providing over 1,000 flexible work spaces for students 24 hours a day in central London. The project was presented by David Tompson of Nicholas Hare Architects and Jeffrey Blaylock, Curtins Engineers.
Penoyre & Prasad Architects’ response to the ambitious programme of accommodation required for the Bobby Moore Academy was to stack it high, thereby maximising outdoor play space for the students. This resulted in one of the tallest school buildings in the UK at six storeys high and was achieved with a cast in situ concrete structure. Space was at such a premium that the building was built right up against the boundary, alongside a running track and there were periodic shut-downs of site to accommodate training sessions.
Programme was therefore a focus for the project. Richard described how the concrete frame and flat slab solution had significant programme benefits in that it provided flexibility. The construction of the building was able to progress while the detailed intended programme of internal spaces and wall locations were still being finalized. Anna-Lisa noted that this flexibility was also a long-term sustainability benefit, building in resilience for future adaptation by the school and therefore longevity. “The concrete flew up” she reported. The flat slab also simplified the installation of internal partitions and suspended ceilings which reduced waste on site and had a positive impact on programme.
The exposed soffits were painted to improve light reflectance and were pre-finished before the suspended services were installed. The concrete also provided thermal mass as part of the building’s low energy services strategy, reducing the need for additional cooling and providing running cost savings and reducing energy use and its carbon footprint. Since the site was on a busy flight path it was impractical to rely on daytime ventilation. Consequently, a mixed-mode ventilation system, controlled by the teachers in each room, was used. The concrete itself contained GGBS, which, together with avoidance of suspended ceilings, contributes to a lower carbon footprint. At the time of the presentation the school had been operational for five months and appears to be enjoyed by students and teachers alike.
The new UCL Student Centre was probably the newest building ever to be featured in the history of Concrete Elegance, opening less than a month before the lecture. The design team reported that already it was proving to be a popular place for students. Arranged around a central atrium space, the seemingly effortlessness and clarity of the circulation it contains belies the complexity that initially presented itself on the site, with existing plant equipment, fire and services routes criss-crossing the site at different levels. Here the inherent sound and fire isolation benefits of concrete were particularly useful with various construction solutions used at different site boundaries as required, including insulated precast sandwich panels, cast in situ walls and blockwork.
The decision to use concrete was taken early on, explained David Thomson, and in a similar vein to Bobby Moore Academy, a flat slab solution was chosen, that offered robust and flexible spaces, adaptability for the life of the building and concrete’s thermal mass. Since the building is occupied 24/7 the opportunity for natural ventilation and night-time cooling was ruled out, instead the solution was to ‘supercharge’ the system with embedded pipes cooled by the ground.
There is a raised floor for services and displacement ventilation. David also described the aspiration of an inclusive environment and that the strategy of self-finished materials was not only efficient and durable but attractive and the high floor-to-ceiling heights marrying the low energy service strategy with a sense of space and inspiration for occupants.
The concrete itself has impressive sustainability credentials, with recycled aggregate used in all unexposed areas and precast concrete supplied from Cornwall containing 100% local recycled (secondary) aggregates. A low carbon 50% GGBS mix was used for all exposed cast in situ surfaces and precast frame. For the long balustrades spanning the atrium, the percentage was reduced to facilitate troweling of the internal exposed face. The building achieved BREEAM Outstanding including, impressively, the extra innovation point for recycled aggregates in the ‘Waste’ category of the scheme.
Photo credits BMA Secondary Penoyre & Prasad (c) Dennis Gilbert, UCL Student Centre Nicholas Hare Architects (c) Alan Williams Photography
Written by - Elaine Toogood, senior architect at The Concrete Centre
The Concrete Elegance is a series of lectures that celebrates recent, exemplary, concrete architecture, chaired by Elaine Toogood and produced by The Building Centre and The Concrete Centre.
The Next Concrete Elegance event will take place on Wednesday 12th June at The Building Centre and further details and bookings can be found here: www.concretecentre.com/Training-Events/Events.aspx