Designing buildings that work for people and planet – that is Architype’s ethos. This pioneering architecture practice – and TDUK member – has always championed sustainability.
From its early days of self-build houses in the 1990s to its major Passivhaus projects today, Architype has thought long and hard about the materials it specifies. “It’s thinking about sustainability in terms of wanting to help people – the social purposes of architecture – that led us to develop the systems we use,” states Christian Dimbleby, Associate at Architype. “And that includes our use of timber.”
“In our early domestic projects back in the 1990s, we used lightweight timber I-joists that people could build themselves. We were keen for clients to understand how things were built.”
Making joyful buildings is, he emphasizes, a big part of Architype’s ethos. Buildings that engage people are the goal – not the unveiling of a flashy set piece. “Timber is a joyful material to build with – one that people can relate to.”
A green-roofed temporary building that became permanent
The green-roofed Education Centre at South London’s Horniman Museum.
From domestic projects Architype moved into small-scale commercial projects and then educational centres. The Horniman Museum’s Centre for Understanding the Environment (CUE) is a great example. The project brief required flexible exhibition space, an auditorium accommodating 60 people, a seminar room, office and ancillary space and an overall construction timeframe of 6 weeks. Built in 1995, it was intended to be only a temporary building. But so popular was it among staff and visitors that it is still in daily use today.
“It used ply laminate dividers for its structure, put together by furniture and kitchen makers,” recalls Christian. Built from sustainable timber, CUE is insulated with recycled newspaper and finished with organic paints and stains.
“You can put a really well-insulated, airtight building together using timber studs,” he affirms. “Then pump that full of Warmcel – a cellulose fibre insulation made of recycled newspaper – to make a low toxic, breathable façade or roofscape.” This is the ‘breathing wall’ system, bringing moisture out through the building naturally, that Architype started using some 20 years ago. An emphasis on natural insulation and fabric-first principles led them to towards Passivhaus.
The UK’s first Passivhaus secondary school
Timber is ideal for attaining Passivhaus standards, Christian enthuses, because of its ability to avoid thermal bridges. This is much harder when metal cladding or metal fixings are involved.
Architype started to win commissions for nurseries and children’s centres in the early 2000s, leading them into primary and secondary schools and universities. With their timber-framed Harris Academy project in Sutton, completed just before lockdown, It’s both the UK’s largest Passivhaus school and the country’s first Passivhaus secondary. The school achieved an exemplary air leakage score of 0.3ACH, and it is anticipated that the low-energy building will save some 90% on its heating bills compared to standard school buildings.
“It has lovely timber cladding – it’s beautifully curved on the corners,” Christian enthuses. “It really brings home timber’s relationship to nature, improving the learning environment by partially taking you away from the urban setting.”
Off-site and mass timber: a good model for big projects
The CLT for Harris Sutton was provided by suppliers and consultants KLH and a mini-factory was set up onsite. Because the frame was so much lighter than concrete, the foundations for Harris Sutton were minimal, bringing down the embodied carbon cost.
For Hackbridge Primary School, another timber-frame school for the London Borough of Sutton, Architype used a frame system from fellow TDUK members Cygnum. Architype had already used Cygnum for their Enterprise Centre at the University of East Anglia: they manufacture the system and deliver it in component form.
Schoolchildren enjoying the greenery at Hackbridge Primary School
“We use a mix of construction techniques, including wholly offsite,” Christian explains. “But mostly we use panelized systems. For Hackbridge Primary, the cladding was done by a bespoke company that 3D modeled it before creating the panels and dropped them into place in a very precise way.”
Standardising systems simplifies construction, he believes. Builds take less time, are more efficient and quality is assured.
Using homegrown timber
Christian emphasizes that Architype will only use CLT where it needs to. If they can make a lighter weight timber structure then they will. He points out that CLT is invariably imported from Northern Europe, which does add embodied carbon. But they have managed to use locally sourced wood in some of their projects. For the Enterprise Centre at the University of East Anglia they used timber from Thetford Forest.
They worked with BRE to classify and select the right kind of wood – it was all due to be used for fenceposts. This meant manually grading it. In some cases, a slightly lower grade of timber was used, which meant the design needed to be ‘bulked up’ in places, though without altering the design’s essence. For several projects based in Wales – the schools at Bury Port and Ysgol Trimsaran among them – Architype were also able to use local timber.
Meeting the challenge of net zero
The school has been performing exceptionally well in terms of operational energy and is predicted to be below the RIBA’s 2030 target. Hackbridge Primary School, a project they completed after Harris Sutton, performs even better on operational energy – around a quarter of the 2030 target. But the challenge is harder when it comes to embodied carbon.
Impressively, Hackbridge Primary very nearly hit the RIBA 2030 target for embodied carbon. This, Christian affirms, is thanks to timber and bio-based materials. But for buildings to consistently achieve net zero embodied carbon targets, we need more than low-carbon materials: the whole construction industry needs to decarbonize. After all, inert materials like timber can’t get much lower. What will tip the balance is the supply chain.
“To hit embodied carbon targets we need to see the industry invest in hydrogen and electric vehicles as well as designers specifying low-carbon materials.”
Ensuring the whole team understands the project
“We’ll routinely carry about ‘toolbox talks’ with the contractors – usually onsite,” Christian explains. This is to ensure they understand the practice’s vision, and any technical details specific to the project. Doing so is important for any kind of project of course, but particularly so when you are aiming for a low-energy sustainable building.
Architects at Architype adjusting a project model.
Christian mentions water management as an example that has particular relevance to timber. For Harris Sutton, getting the waterproofing in place was a priority onsite. The roofs at Harris Sutton are timber, so they were designed with a fall to them in order to avoid any water pooling on the surface.
“We cut holes for the rainwater pipe levels at a lower level so we could get a temporary roof on before starting to build up the insulation,” he explains. “Later you infill that gap and put rainwater pipes at the correct level.”
How timber can adapt to changing client needs
Both Harris Sutton and the Enterprise Centre at East Anglia University were built on flexible grids: the partitions were internally changeable. In fact, about a month before East Anglia was finished, the client wanted certain areas to be larger.
It was an easy matter to remove the walls that this required. Architype briefed the client on how to change internal layouts in future if they had smaller or larger groups. This is a big plus for an educational building, providing scope for meeting changes in class sizes or demand for different subjects.
“Timber structures are extremely solid but timber partitions inside can be easily demountable, movable and changeable,” Christian points out. “It’s much harder to drill holes in concrete to open up a space. Timber can add a lot of value for a client.”