Feilden Clegg Bradley Studios explain how close-knit collaboration, natural materials and carbon counting leads to truly sustainable buildings – and very happy clients.
The fact that you’re reading this means you’re probably already a timber and sustainable building advocate. You know how important it is to reduce the embodied carbon of our buildings – and that bio-based materials such as timber are an important part of that. But helping clients along this path can be a challenge.
Feilden Clegg Bradley Studios (FCBStudios) is a long-established architecture practice which has found highly effective ways to do this. “Engineers and architects often talk about carbon as a series of numbers,” states Simon Branson, Partner at FCBStudios’ Manchester office. “But not everyone can engage with that. They need something more visual, more intuitive, to show them what carbon costs and materials means.”
The practice has developed its own carbon calculating software, FCBS Carbon, which can provide a client with graphics that clearly spell out the carbon impacts of different design choices. Branson has found it has made a real difference in changing the direction of a project – for the better.
He points to the recent Staffordshire University Nursery project as an example. This is an on-campus nursery school designed by FCBStudios, completed in 2022. “We had conversations with the client’s executive team about what their carbon journey would be,” Branson states. “We discussed the implications of standard construction versus timber construction with air source heat pumps and PVs. FCBS Carbon was used at the beginning as a tool to bring this home.”
The practice was able to present their client, Staffordshire University, with a simple-to-read graph that modelled the embodied carbon of the proposed building over a 60-year lifecycle, comparing:
- Standard blockwork and steel construction
- Timber cassette system
- Timber cassette system with cement-replacement concrete
- Timber cassette system with cement-replacement concrete and an air source heat pump (ASHP)
- Timber cassette system with cement-replacement concrete, an ASHP and renewables
This, Branson found, was a clincher in the client’s conclusion that timber construction was the way forwards – the last option is what was specified.
A long history of sustainable building
Feilden Clegg Bradley was founded in Bath in 1978 by Peter Clegg and Richard Feilden. It now has a team of around 200 staff, based in Bath, London, Belfast and Manchester. Branson describes the practice’s mix of work as typically: one third residential, one third higher education and one third a mix of cultural, mixed-use and other projects. The Manchester office where he is based was set up following significant projects delivered for Manchester Metropolitan University and developers Manchester Life.
The latter were the clients for the Murrays’ Mills project: FCBStudios redesigned the world’s oldest surviving steam-powered cotton mill into smart modern residences. 124 contemporary yet sympathetic dwellings now surround the old mill yard, which has been redesigned as a water garden and a social space.
Other work based in northern England followed on the back of these successes. A long-standing relationship developed between FCBStudios and Staffordshire University, which has signed up to have net zero operational emissions from its built estate by 2030.
FCBStudios designed the Catalyst for them, a teaching building that was required to reach DEC A standard. “Students are essentially the clients of the university,” Branson suggests. “And in all the consultations we did for the Catalyst Building, sustainability was everything.”
A forest school nursery: timber all the way
When Staffordshire University commissioned FCBStudios to design their new on-campus nursery, the previously mentioned modelling of materials and embodied carbon led to the decision to use timber. Timber was especially apt, given that part of the brief was a forest school, making the most of the site’s neighbouring nature reserve.
“One forest school tenet is that ‘the environment is the third teacher’ – after parents and teachers,” Branson enthuses. “We took this to heart across the whole project.”
Built in an existing car park, an L-shaped building was proposed. It is formed of two single storey wings which enclose a garden. Entry to the classrooms is through a canopy area.
As Branson explains, a forest school means the classrooms themselves can be ‘lightweight’ – the interior classroom itself is not the entirety of the learning space. Accordingly, each classroom is laid out very simply and can open its doors, allowing pupils to move though a covered space into the courtyard and garden.
The nursery has a concrete slab (with cement replacement) but used no cement above this. The floor is a timber frame system with rubber flooring, while the walls are timber cassettes – structural insulated panels (SIPs) provided by Innovare Systems. These were fabricated offsite and are softwood on the inside; Sterling OSB board on the outside.
“We did look at CLT and glulam, but it was important for us to not use more material than we needed,” Branson points out, explaining why the cassette system was chosen. “Heights and sizes in the design were informed by the materials that were available and deliverable.”
The roof structure is also timber. Steel use was limited to the connections.
Exposed timber interiors
The continuity from the classrooms inside to the woodland outside was an important aesthetic and psychological consideration, encouraging a calm atmosphere.
The interiors use exposed timber throughout – birch-faced plywood. The exposed softwood beams were not treated and simply lightly sanded. This was cost-effective but also added to the building’s character, lending a light, natural feel to the spaces. The shutters, the dedo rail and the furniture were all made of plywood.
Above the exposed timber interior ceiling, wood fibre insulation was used. This has good acoustic properties.
A larch-clad exterior
For the external cladding, pre-treated larch was chosen because it can be sourced from relatively fast-growing trees in the UK. It is a tough and dense softwood that is naturally insect-repellent and appearance was also a plus, redolent of mottled trees.
Branson recalls an anecdote regarding the cladding. At one point, the clients were informed they were unlikely to meet the programme schedule if all the larch cladding was screwed on: it would be much quicker to just nail it all. But nailing would compromise any future deconstruction.
The spec was for screws, so that the cladding could always be carefully removed, re-used or recycled. Encouragingly, the spec won out and the panels were screwed on.
Involving the whole team in the low-carbon mission
“We gave the full version of our FCBS Carbon software to the contracting team,” Branson reveals. “Contractors put in real data from the EPDs they were getting and all the suppliers then inputed into it.”
This made the assessment of the project’s embodied carbon more accurate, and kept everyone mindful of the carbon tally.
“Carbon was on the agenda during the value engineering process,” he states. “So that if, for example, blockwork or the adding of more services was suggested, these were weighed against their carbon costs. It is rare to have a client willing to do that so readily.”
Looking to the future
FCBStudios have a multitude of ongoing projects across their many offices. They have signed up to the RIBA’s net zero 2030 challenge and have a roadmap in place to get there.
“We’re ready,” Branson enthuses. “We can design most buildings to net zero carbon using natural materials. Councils are putting net zero into their briefs. Developers have it on the table, and are keen to discuss it. They might not all be at the same speed, but they are all on the right journey.”
This article is from issue 03 of Designing Timber. Read more articles from the magazine here.