Bringing circular economics to the built environment

Thomas Rau was 10 years old when he forged his philosophy for life. He was at a barbecue party with his friends when it started to rain. Determined to fire up the grill, Rau took a jerry can full of petrol and poured it on the flames. It exploded in his hands, leaving Rau with serious burns across his body. He spent the following year in recovery, much of that time alone in a dark room. “I had the feeling that maybe I’m going to die,” he says. “But I also realised that everything is temporary – that it’s a gift to be alive.”

This notion of temporality shaped Rau’s career as an architect and thought leader. His Amsterdam-based architecture practice, RAU, founded in 1992, has long been at the forefront of sustainable, carbon-neutral buildings. It designed one of the first buildings in which the roofs were rented out to produce energy; then the first building in which the ventilation system was guided by CO2 levels. At first, he says, “it was tough”. In the 1990s sustainability was relatively niche in the market. “I think some people there were just laughing,” says Rau, “saying, ‘He’s the sustainable guy. We’re making the real architecture’.”

For many years, Rau explains, it was challenging to persuade clients to buy into his uncompromising perspective, but just as ideas around sustainability began to be absorbed into mainstream thinking, Rau himself was growing frustrated with it. “I was sure that sustainability was the tool to change everything,” he says. “But then I started to feel more and more uncomfortable. We have done all these buildings now, but nothing changed. So how is that possible?”

A meeting with Ellen MacArthur at Davos, led Rau to refocus his thinking around circular economics. Taking these ideas and applying them to the built environment, Rau developed an approach for “architecture with a circular potential”. Perceiving the world as a “closed-loop” system, with a finite amount of materials, this method of construction views buildings as temporary assemblages of materials that can – when needed – seamlessly enter the supply chain again for reuse. Such thinking is perfectly encapsulated by the Triodos Bank headquarters in the Netherlands, completed by RAU in 2019; a large-scale wooden office building built with 165,312 screws that can be completely dismantled and rebuilt. Another world first. 

If sustainability was a “trick” – as Rau puts it – circular architecture is facing up to a total change in attitude for humanity: the realisation that “we are the guests on earth and not the host”. Along with his wife, Sabine Oberhuber, also an expert in circular economics, Rau founded Turntoo, a company that offers consultancy and support to organisations that want to develop their business model according to these values. And in 2017 he co-founded the Madaster Foundation, which helps facilitate circular architecture by providing the tools to document, value, and register parts and components in building projects. Just as Rau bucked the trend with sustainability, his ideas around circular architecture are building momentum. Today, Madaster has nearly 3,000 buildings on its registry by 1,750 users in seven countries in Europe and Japan. 

RAU has about 15 to 20 staff, and Turntoo has between five and seven. What its founder looks for in his staff is less about experience and more about mindset. On one project, for example, Rau needed to find someone to build a 6,500sq m steel roof. The obvious choice would be a steel roofing company – but, as he explains, their business model is to sell as much, not as little, steel as possible. Instead, he employed a rollercoaster company. A rollercoaster needs to be built so that it can be regularly disassembled, moved and reassembled. “I said: ‘Imagine you are building a horizontal rollercoaster and we can just call it a roof,” says Rau. “We used 34.7 per cent less steel.”

Circular architecture can take many learnings from the world of product design and manufacturing lines. Rau’s team consists of many industrial designers; people who can think in terms of scalable products. He has also worked as a consultant for a major car manufacturer. Cars are designed with near endless options for personalisation, and are able to create a sense of uniqueness by reshuffling the same stock of parts in different combinations. Buildings should be thought of in the same modular way, says Rau. By simplifying the constituent parts – ensuring there are substantial quantities of each element – it makes it cheaper to order, and more viable for the parts to be resold and readopted when the building reaches the end of its lifespan.

One of the biggest obstacles to wider adoption of circular architecture, and circular economics in general, is mindset. How does someone determine if a building project is cheap or expensive? For many developers, that is still calculated on upfront cost. Rau would challenge that: “What does cheap mean? Do you want low investment, or low maintenance costs? Or do you want the highest value at the end of the process?” A circular building, he points out, retains value even at the end of its lifecycle. 

Financial incentives, as with the electric car, and higher taxation on CO2 are two ways circular architecture could be boosted. “Because if you have a circular building, then the CO2 is much lower,” says Rau. “You can reuse all the materials again and again.” But the third way is education – for more people to make the mindset shift that he has done. “Sustainability is the wrong tool for transformation,” he says. “It’s optimisation in the existing system. If we don't change the architecture of the system, nothing will fundamentally change. And I think everything has to be fundamentally changed.”