Students at Kings College, University of Cambridge, are weeks away from moving into a new accommodation type – using a lightweight cross-laminated timber system clad in traditional brickwork and uses fully recyclable materials that deliver Passivhaus-certified accommodation that is not only biophilic but also slashes energy bills.
The award-winning design by Feilden Clegg Bradley Studios (FCBS) comprises three crescent-shaped apartment blocks made from cross-laminated timber, which is, in effect, net zero. Known as Stephen Taylor Court, the development consists of 84 apartments in what is dubbed a future student accommodation model.
“The lightweight CLT structure of the buildings reduces foundation loads, allowing the use of a thin reinforced concrete raft foundation ‘floating’ on rigid insulation,” according to Smith and Wallwork structural engineer Tristan Wallwork, who spoke to Dezeen about the design in late 2022.
“This not only reduces the amount of concrete used in the substructure but provides a perfect Passivhaus foundation solution,” Mr Wallwork said, adding that the detailing of any inherent thermal bridges, such as facade restraint ties, “is also drastically simplified due to the robust and solid CLT structural envelope – providing complete flexibility on the location of any fixings required.”
So, how did they do it? According to the built environment publication The Cool Down, the FCBS developed a new carbon calculation tool, known as the FCBS Carbon, and chose building materials and construction methods to minimise lifetime carbon pollution: “By prioritising recycled materials, local sourcing, and carbon-capturing CLT, they achieved a carbon-negative design,” according to FCBS partner Hugo Marrack.
Introducing FCBS Carbon: A building lifecycle calculator
FCBS Carbon is a tool that Mr Marrack said architects can now use free of charge. It considers all the CO2 produced by a building, including the building material, construction, and demolition (but not furniture, fixtures, and equipment (FF&E) and mechanical, electrical, and plumbing (MEP)).
Wood Central understands that FCBS is using the project as a “test case”, demonstrating that buildings can be “net-zero” for the first 10-15 years of their lifecycle – and can be boosted with renewable energy options such as photovoltaic panels.
The 4,300-square-metre development is located within a conservation area on campus known for its arts and crafts houses, influencing Feilden Clegg Bradley Studios’ design. Mr Marrack added that “the central triptych of three crescents creates an open and informal court which provides depth and breadth to views from the streetscape to the leafy context beyond.”
Steep-pitched roofs, dormer windows punctuating the roofline and oriel windows on the gable ends of the apartments reference the arts and crafts buildings in the area.
“The sympathy with the arts and crafts approach is in celebrating the joy in each of these building details and the material’s properties, rather than ironing them out, as one might with a more minimal approach,” Mr Marrack said. “This being said, the results aim towards a leaner, contemporary expression of its time rather than forms of reproduction. In some respects, the outcomes are almost brutalist.”
- To learn how cross-laminated timber is now being used in Passivhaus design, click Wood Central’s special feature on Kingsway Residence, a three-storey cross-laminated timber residence.
