Reflections on Concrete Elegance - Sustainable Education

14 May 2019

Two very different examples of educational buildings were featured in this year’s first Concrete Elegance lecture:
Bobby Moore Academy Secondary School, Stratford is a new school with an ambitious programme 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 new Student Centre for University College London was presented by David Tompson of Nicholas Hare Architects and Jeffrey Blaylock, Curtins Engineers, and is a new university building providing over a thousand flexible workspaces for students 24 hours a day in central London.

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 6 stories high and was achieved with cast insitu concrete structure.

Space was at such a premium that the building was built right up against the boundary with the running track, despite the resulting periodic shutdowns of site operations required while it was used for training. Programme was therefore also a particular 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 adaptations by the school and therefore longevity. 

“The concrete flew up” she reported. The flat slab also simplified in the installation of internal partitions and suspended ceilings reducing waste on site and having a further positive impact on programme. The exposed soffits were painted to improve light reflectance and being prefinished before the suspended services were installed. The concrete of course also provided thermal mass as part of the building’s low energy services strategy, reducing need for additional cooling and keeping running costs, energy use and carbon footprint down.

Since the site was on a busy flight path daytime ventilation though windows were impractical, leading to the development of a mixed mode ventilation system, controlled by the teachers in each room. 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 5 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, open less than a month before the evening event. The design team reported that already it was proving to be a popular place for students. Arranged around a central atrium space the seeming 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 that offered robust and flexible spaces, adaptability of the life of the building and thermal mass. Since the building is to be occupied 24/7 the opportunity for nighttime cooling wasn’t an option, but rather it was ‘supercharged’ by embedded pipes cooled by the ground.

There is a raised floor for services and the 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, 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 wornwall containing 100% local recycled (secondary) aggregates. A low carbon 50% GGBS mix was used for all exposed cast insitu surfaces and precast frame.

For the long balustrades spanning the atrium, the percentage was reduced to facilitate troweling the internal exposed face. The building achieve BREEAM outstanding, including, impressively the extra innovation point for recycled aggregates in the waste category.

By Elaine Toogood - Senior Architect, 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