The statistics about the emissions produced by buildings remain stark and challenging. The construction sector accounts for about a third of all materials demand. And around 37% of CO2 emissions are the result of built environment processes, from the formation of steel and concrete to the production and lifecycle operation of buildings. With consumption of materials driven ever upwards by population growth, urbanisation and market preferences for new buildings, the industry could benefit from new ideas and practices.

At Arup, our materials and design teams have been considering this issue for years. It’s become clear that the problem is both about ending certain habits, building support and capacity for greater material recycling, and proving that a more enlightened approach to resource consumption is not just desirable, but technically practical and commercially viable.

How we tackle this issue:

Circular thinking

For decades now, the idea (and ideal) of a circular economy has held great promise. It’s a simple idea, that we should design things according to the principle that all materials remain as reusable and valuable as possible. In some sectors, like consumer electronics, where products comprised of many components have the potential for reuse, adoption of circular principles has presented clear enough commercial sense to take hold. We have been knowledge partners to the Ellen Macarthur Foundation (EMF) for over a decade, a period in which the built environment industry has shown growing interest in circular approaches. But we have yet to see the ethos become widespread in real world projects. 

A new business model?

Martin Pauli, Circular Economy Leader, explains the commercial appeal of the circular economy.

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To bridge the gap between novel idea and day-to-day practice, in 2022 Arup and EMF developed the Circular Buildings Toolkit, to help designers and engineers adopt the approach in their work. And for the built environment sector to really embody circular economy principles, we need to focus as much on sustainably disassembling materials from existing buildings at the end of their life, as we do to assemble them.

Circular economy explainer video cover
How circular economy principles can realise a net zero built environment

Recover, reuse, reimagine

One of the greatest obstacles to sustainable building practices, is the amount of material lost in the demolition process. Arup teams have also been looking at ways to recover and reuse elements like structural steel, using new digital tools to assess and classify the components so that they can re-join the pool of available resources for designers. This is key, as developers need to be assured that the desired level of quality and performance can be maintained with used materials and components. With evidence and evaluation, confidence can be built.

Darius Cook, a senior structural engineer, explains how a new energy infrastructure project adopted this approach to its structural steel. Read the article.

In a related piece, Kristian Winther, architect, explains how digital scanning and analysis innovations are making waste materials more useful and a circular built environment more achievable. Read the article.

Seeing the potential

Graeme DeBrincat has been exploring practical approaches to the recycling of architectural glass – a promising practice, but one that's still finding a foothold in the industry. Read his article here.

The widespread use of glass is a key factor in buildings' carbon emissions. Arup Fellow Graham Dodd, provides an insight into new practices that can bring down the energy use from this all key building material.

Can buildings use glass more sustainably?

Graham Dodd, materials expert, explores some promising, innovative approaches to sustainable glass façades

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Data-driven precision

Another promising way to reduce waste potentially lies in the use of data-driven methods of construction, which include additive (‘printing’), subtractive (cutting) and forming/placing operations. In their different ways, these techniques use the precision of digital design to create varied or custom components with far greater efficiency while producing near zero waste. Arup has pioneered these approaches on projects like the 3D printed house and the MX3D steel bridge in Amsterdam. And at the Sagrada Familia in Barcelona, data-driven 3D machining of stone and steel components proved that structural innovation can also lead to lower use of resources and materials.

These represent some of the most sustainable building practices yet developed, and we remain optimistic about their future relevance and value. Learn about our work on a demonstration 3D printed house. You can also learn more about the MX3D bridge in Amsterdam – a pioneering example of additive construction, now in use in the city.

Making a material difference

We recognise the challenge to transform how we build and with what – in any industry traditions, habits and expectations can be hard to change. Yet at the same time the urgency to change is real. What we extract from the Earth and harvest from the living world, what we release deliberately or unwittingly into that world, and what vital materials surround us every day, are parts of a closed system that humans and all living things share. It is encouraging to see the emergence of new ideals for what we build, new approaches to how we do that and new visions of beauty that can help us restore our system to balance.