Watch our AT Schüco webinar, which explores the challenges of embedding Passivhaus principles in major building projects and how can we measure the benefits.
If Passivhaus is to play a significant role in our response to the climate emergency, it has to be relevant to more than just a few, idealised projects. It must contend with a variety of constraints, whether financial or physical, and work with a range of aesthetic requirements. While many of us are aware that this is happening, the AT Schüco webinar on 28 July made it clear just how much progress is being made.
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Speakers from left to right: Gwilym Still, Matthew Traub, Ann-Marie Fallon, and Adam Booth
Adam Booth of Feilden Clegg Bradley Studios described a planned project in St Helier, Jersey, of 150 apartments on the site of a former quarry. This is a fantastic location, with views of the harbour, and FCBS is determined to make the most of it by optimising both the location and form of the three apartment blocks, as well as integrating them in the landscape.
At the same time, the architect wants to help Jersey realise its ambitions for reducing carbon. The aim is to set a new benchmark for sustainability, something that fits with FCBS’ long-standing commitment to sustainable design and its more recent determination to integrate Passivhaus into new schemes.
Site model and visualisation of FCB Studios’ South Hill residential development in St Hellier, Jersey
The scheme has already gone through three iterations, largely in attempts to balance stunning views and the need for solar gain at certain times against restricting glazing to achieve thermal performance. In Passivhaus terms this is a far from ideal challenge, not least because the rear wall of the main apartment block is nestled against a cliff retained from the quarry. But, said Booth, ‘The most important themes are how the glazing and the balconies interplay. For us the biggest learning curve is the time needed for this non-linear process to come around. Passivhaus requires collaboration.’
The Garden Building at Cranmer Road, King’s College, Cambridge, designed by Allies & Morrison with Max Fordham (ph: Nick Guttridge)
Allies & Morrison is a practice that cares passionately about how things look. So, when commissioned to design student accommodation for King’s College Cambridge, it faced an interesting challenge to fulfil its own aesthetic aspirations and the client’s brief – and at the same time design to Passivhaus standards. The architect embraced the challenge and succeeded magnificently.
King’s College, as owner, occupier and developer, wanted buildings that would be low-maintenance, robust and long-lasting, and that would provide value over time. That phrase ‘value over time’ should be music to the ears of any intelligent architect, most particularly if they are embarking on a Passivhaus design.
A kitchen in the Stephen Taylor building at Cranmer Road, King’s College, Cambridge, designed by Allies & Morrison with Max Fordham (ph: Nick Guttridge)
The resulting two buildings, in contrasting styles as they respond to both the arts and crafts tradition and to more modernist buildings in this part of Cambridge, are both brick-clad. The architect designed them initially with no thought of Passivhaus construction, only coming to this conclusion at RIBA stage 2.
In 2016, during design, statistics showed that Passivhaus construction resulted in a 20 per cent increase in costs related to a Building Regulations compliant design. But it should start to show cost benefits in operation after 30 years – and this was a project with a 100-year design life. On this basis, said Matthew Traub, associate with Allies and Morrison, ‘the college was happy to proceed’. In fact, by the time the project was complete, there was no discernible cost difference.
Student accommodation at Cranmer Road, King’s College, Cambridge, designed by Allies & Morrison with Max Fordham (ph: Nick Guttridge)
The buildings have a warm slab and a low-carbon CLT superstructure. Taped joints between panels and taped windows meant that airtightness could be achieved early and was the responsibility of only a couple of contractors.
Gwilym Still, Passivhaus leader at Max Fordham, explained the choice of electricity for heating and that, with low energy demands overall, it was important to consider ancillary systems, such as access control, and make them as efficient as possible.
Traub summarised the project: ‘What we discovered was that Passivhaus was no impediment to getting the aesthetic result we wanted. What it gave us were principles, tools and targets.’
Currie Community High School, Edinburgh, designed by Architype (cgi: Architype)
Ann-Marie Fallon, associate director at Architype, spoke not about residential design but about schools, a field where the practice has pioneered the use of Passivhaus. She described the Currie Community School that it has designed for Edinburgh council. The school, which is, Fallon said, currently the largest Passivhaus school project in the UK, has a more complex form than Passivhaus is believed to dictate. This is in response to pedagogical demands. It also has a Passivhaus swimming pool, which differs in several significant ways from a conventional school.
Architype’s North Muirton/Balhousie primary school replacement scheme in Perth (cgi: Dalgety Design)
Research is fundamental to the practice’s work, and Fallon described projects to see if EnerPHit (the version of Passivhaus for existing buildings) can work at scale. It is upgrading the Cambridge Institute for Sustainability Leadership, and also studying retrofitting education buildings in Edinburgh. In addition, a number of currently theoretical projects are showing that it should be able to exceed the RIBA targets for new buildings when upgrading existing ones. Fallon stressed that the projects are complex, not so much in terms of technology as of organisation and justification. ‘How do we enable clients to have appropriate procedures in place?’ she asked.
Interior view of North Muirton/Balhousie primary school replacement scheme in Perth, designed by Architype (cgi: Dalgety Design)
Doubters may well like to be referred back to the Allies & Morrison project in Cambridge. The pair of buildings there have exceeded targets, despite this being the first Passivhaus scheme for the architect and some other members of the team. It isn’t easy but it can be done and, crucially, it can be affordable.