Engineering The Circular Building

Called The Circular Building, this architecture and engineering project looks to shift from the ‘take, make dispose’ model of the industrial, linear economy, to a circular economy.

Stuart Smith, a Director at Arup engineering company has provided his structural engineering skills to some visually dramatic projects. He helped artist Doris Salcedo to create the crack in the Tate museum’s giant Turbine Hall for her 2007 work “Shibboleth”. He also worked on the barely conceivable shape of the CCTV building in Beijing – the locals nicknamed it ‘big pants’. 

But perhaps his most challenging engineering project yet was a simple looking structure located outside The Building Centre in London – the Circular Building. The building is a collaboration developed by Arup, The Built Environment Trust, Frener & Reifer and BAM Construction. 

Waste as a resource

It was the third in a recent series of collaborations working with Lewis Blackwell, Executive Director of Strategy at The Building Centre in London. ‘We did the Wikihouse (2014) and A House for London (2015),’ says Smith, and they were both intended to explore different technologies and construction methods that were emerging at the time.

Open source design and digital fabrication were the themes of the Wikihouse, while modular construction, and the housing crisis were themes for A House for London.’ In conversation with colleagues at Arup, they decided they wanted to explore materials, resources and waste in the construction industry. 

The construction industry provides the infrastructure, offices and homes essential for our cities and neighbourhoods, but it is also has a huge impact on the environment. ‘The figures I have for 2008 for London we generated about 20 million tons of waste, and 10 million tons of that is from construction.’ While the industry is improving practices, the disposal of waste is an issue. There is also the environmental damage caused by the extraction of materials, and the energy used to form them into building materials. So the idea of the Circular Building emerged. But the Circular Building isn’t actually physically circular, the adjective ‘circular’ describes a materials journey. 

From Circular Sailing to Circular Economy 

On 7th February 2005, after over 71 days at sea, Ellen MacArthur sailed into Ushant, in Brittany, France and broke the solo record for sailing non-stop around the world. In September 2010 she began another circular journey when she set up the Ellen MacArthur Foundation, an organization dedicated to promoting ‘the circular economy’. Unlike the ‘take, make, dispose’ model of our industrial linear economy which depletes resources, the circular economy regenerates and recirculates materials in biomimetic fashion. Through pre-planned design processes, it turns waste into food. 

The idea behind Arup’s engineering explains Smith, was to ‘keep the materials at their highest value as long as possible, and you keep your building and your infrastructure at its highest utility for as long as possible.’  The model of circulation of materials proposed (originating in the ‘cradle-to-cradle’ thinking (coined by Swiss architect Walter Stahel and expanded on by German chemist Michael Braungart and American architect William McDonough) is via what is called the ‘biosphere’ and ‘technosphere’. 

Materials as nutrients

Recirculation of materials in the biosphere could be as compost. In the technosphere, materials are recycled and re-circulated in other products. Materials are seen as ‘nutrients’, feeding back into the system. What makes the circular economy different to conventional approaches of sustainability is that it doesn’t seek to make a situation or process ‘less bad’. It aims to make a virtuous circle of production.   

‘We thought we would build a prototype building, we would take a series of components from the construction industry, we would put them together, to make a building,’ explains Smith. ‘Then we would take them apart and feed them back into the supply chain. The suppliers then that would become responsible for remanufacturing, for repurposing all of those materials.’

This new vision of material engineering and circulation is only made possible by digital technologies. ‘At the same time that we would make material choices that would be as low-embodied energy and low-carbon impact as we could, we would make a complete digital model and introduce the idea of material passports into our work,’ says Smith. ‘So that when we took the building apart, we would have a complete record of everything that we had used and where it went.’  So the building then becomes a material resource, an archive for future use. 

How Buildings Learn

Engineering and design in the circular economy is a process of collaboration especially with the suppliers of materials. ‘People really got engaged with the thinking,’ says Smith, ‘with the process, the ideas, and started to use all of the things that we’ve now got available to us such as modular construction, digital fabrication, cradle-to-cradle specification for materials. To frame it all, we used Stewart Brand’s “How Buildings Learn”.’

Stewart Brand is an American writer and visionary, who famously produced the “Whole Earth Catalog” in 1968. His 1994 book “How Buildings Learn: What Happens After They Are Built” used the idea of Shearing Layers, developed by architect Frank Duffy. This envisions a building not as a single entity but as a structure with elements that evolve according to different timelines. 

These layers of a building are called the Six ‘s’: Site (location); Structure; Skin (surface); Services (electrics/plumbing/heating etc ); Space Plan (design layout); and Stuff is the furniture and all the things we fill our homes with. The different spatial elements live according to different timelines. 

‘It gives you a good way of responding to the circular economy,’ says Smith, ‘because the series of layers can be thought of in a different way. You could have a relationship with a supplier that could be on-going and they could be replacing and remanufacturing the goods in five years time, whereas the site and the structure you might be talking about in 100 years time, so it can be a different conversation around the different layers.’ 

The interiors, the ‘Stuff’, can be designed differently too. So carpet suppliers such as Desso allow you to lease the carpets, and then at the end of the lease you give the carpets back and they’ll make a new carpet using the same material. The same model can be applied to electrical goods as as with carpet. ‘We’re starting to see the “pay-per-lux” model that Phillips has got for lighting,’ says Smith, where a user (not a consumer) pays for light rather than the materials – these can be endlessly upcycled. 

Traditional materials with a twist

They have also made use of traditional materials that have been re-imagined through chemistry. ‘For the cladding we used accoya,’ says Smith. ‘Accoya is a bit of a game changer, it’s a fast growing softwood but it is treated through a process called acetylation, which is best described as “pickled wood”. Imagine when we soaked our conkers in vinegar it basically hardens the wood and stops the moisture movements within the wood. You get the durability of a hardwood so you can use it again and again, which is fabulous material.’ 

Though still not mainstream the ideas of the circular economy are growing. ‘We got a massive response, we could not have done it without the rest of the construction industry joining us,’ says Smith. ‘It’s an important step in construction and engineering. ‘It’s very exciting and we will probably be spending the next decade finding out how to deliver it. It will transform how we use materials where we get them from, what we do with them and how we use them.’