Architects Co-Partnership have designed two new extensions to the iconic Sir Alec Reed Academy in Northolt, West London.
Originally designed by Sir Norman Foster in 2005, the school has undergone an £8 million expansion to create a new early years unit called ‘the Arc’, and specialist Design & Technology facilities called ‘the Quad’.
The embodied carbon of the new structure was an important factor throughout the project, leading to timber being chosen as the structural material for the buildings. Compared to traditional alternatives, cross-laminated timber (CLT) and glulam offered significant reductions in terms of embodied carbon, and an accelerated construction process due to pre-fabrication.
Rob Brown, Senior Project Manager at Kier and contractor for the project highlighted the advantages of cross-laminated timber over a traditional steel and concrete frame.
“Choosing CLT has made a significant contribution to the speed, efficiency and cleanliness of our building operation. Off-site manufacturing means less energy and water are required on site, compared to traditional concrete/ steel structural frames, using CLT has also reduced waste on site.”
The standout feature of the project is a media centre called ‘the Zeppelin’, an elliptical shaped pod situated at the heart of the Quad building. Constructed from curved glulam beams and cross-laminated timber panels, the structure appears to “float”, supported from the ground by a number of narrow columns.
With approximately 1075m3 of timber used during the development, originating from European Spruce in Austria, the embodied CO2 within the structure is a quarter of that of the next feasible traditional construction method. When the amount of sequestered carbon within the timber is taken into account, the new structures actually have a negative embodied CO2 value of 640 tonnes.
Due to the choice of low embodied carbon materials, the Greater London Authority halved the 20% renewables requirement, leading to a 50% reduction in the area of PV panels required from 474m2 to 237m2. This ‘fabric first’ approach provided a project saving of approximately £150k making a timber solution even more attractive.
Although the renewable energy obligations have been relaxed this has not had a detrimental effect on the building’s environmental credentials. Both buildings have been accredited with a BREEAM rating of ‘Very Good’, an indication of exemplary sustainable design.