Tackling the carbon dilemma requires a fresh perspective. Stuart Smith reveals how considering a building’s entire life cycle impact can simplify carbon reduction decisions, guiding us towards more sustainable choices.
A Berlin-based structural engineer, Stuart is Director and Global Circular Economy Skills Leader for international design and engineering firm Arup. He has spent years forging pathways through the carbon equation, grappling with the gaps and unknowns.
In this episode, he draws on his expertise in low-carbon buildings and the circular economy to guide us through key considerations and strategies. There’s no one-size-fits-all solution, but there’s much we can do to inch closer to low-carbon targets.
| 00:03:34 | What will transform material use? |
| 00:05:30 | “So, you might be able to throw enough technology to make, in the lab, a carbon-neutral cement, but trying to scale that so that we could use it on every project — at the moment, that’s not foreseeable.” |
| 00:06:01 | “There’s a roadmap for the [concrete] industry to reduce emissions quite substantially by 2030.” |
| 00:07:43 | “What we’re trying to do by 2030 to meet those targets is get to a point where our buildings are net zero in operation and where we’ve reduced the embodied carbon — so that’s all of the carbon in the materials and the construction — by 40%. So, there’s a lot of work to do there.” |
| 00:08:23 | Designing for carbon reduction |
| 00:14:08 | “The majority of the carbon is still in the structure and the facades. So, the basic shell and core of the building.” |
| 00:17:21 | “As a starting point, you have to ask yourself whether you can build less and then once you’ve done that, you’ve really got to make sure that you are building efficiently.” |
| 00:20:40 | “What I’m against […] is having absolutes like that. Is retrofit always better? Is timber better than concrete? Those kinds of big statements.” |
| 00:29:44 | “I would like us to start to see tall buildings as kind of fixed infrastructure in the city. You know, if you put up a tall building, it’s a fixed point and you might reclad it or upgrade it, and so on.” |
| 00:42:01 | The future of making |
| 00:43:07 | “Offsite manufacture and digital manufacture are two of the components we can use.” |
| 00:45:26 | “So, you can actually just put the material where it’s needed [via] 3D printing and digital design and manufacture. Then you can save — probably on most components — […] tending towards 30% [of materials].” |
| 00:46:48 | Becoming Stuart |
| 00:48:08 | “A big part of my journey was joining Arup as a multidisciplinary consultancy with so many colleagues from different perspectives.” |
As Stuart shares his wide-reaching insights into minimising the carbon tied to our buildings, a central theme emerges: time. It underpins the incremental development of strategies and methods for carbon reduction. Time is also central to how we must calibrate our thinking when we propose, design, construct, and operate a building.
Taking things a step further, we can beat time, so to speak, by eclipsing the end of a building’s life through reuse of the whole or its parts.
Stuart Smith (left) is an Academic Chair at the Norman Foster Institute for Sustainable Cities and collaborates with the Norman Foster Foundation.The discussion begins with materials and the emergence of another central theme: context. The decarbonisation of building materials is critical, says Stuart, particularly cement and concrete. However, it is just as important to make the best material choices for a project’s location and context.
Stuart mentions the photography of Edward Burtynsky, which highlights the environmental impact of nickel processing. Nickel is a key ingredient of stainless steel.There are many methods for reducing both operational and embodied carbon. Stuart discusses the hierarchy of strategies that he and his colleagues at Arup employ to do so.
These range from passive systems and the on-site production of renewables (in the case of operational carbon), to supply chain, structural efficiency, construction process, and adaptability (in the case of embodied carbon).
There are gaps in the data on embodied carbon in the supply chain, he acknowledges, which is why constructing as efficiently as possible is a crucial piece of the embodied carbon puzzle. The majority of a building’s embodied carbon sits in its structure and facade, he says, but over time, interior refits represent another substantial amount.
The Circular Building was a prototype created by Arup for the London Design Festival in 2016. It showcased circular economy principles in the design, construction, and operation of a small building.Arup’s work on the H7 building in Münster, Germany, resulted in the adoption of timber-concrete composite floor slabs. H7 Münster was one of the earliest examples of this method, which Stuart is still exploring in projects today.
The timber-concrete composite floor slabs used in H7 Münster, designed by Andreas Heupel Architects and completed in 2016, enabled a 30% reduction in embodied carbon.With reference to the adaptive reuse and refitting of existing buildings, Stuart points to the need for improvements in the market for secondary materials. The process of diverting materials from waste streams, and then procuring them for new projects, needs to be easier, he says.
Arup worked with Boeri Studio on the high-rise residential project Bosco Verticale in Milan, completed in 2014. The aim was a new model for urban regeneration.He also encourages a rethink of tall buildings, suggesting they ought to be considered as pieces of fixed yet adaptable infrastructure. Arup explored this direction for the Leadenhall Building in London. Offsite construction accounted for 80% of the building, with a view to easy adaptation of components in the future.
Off-site construction of component parts allowed for the rapid construction of the Leadenhall Building in London, which was designed by Rogers Stirk Harbour and Partners and completed in 2014.Stuart’s insights reveal that there are many areas in which we can build up our design intelligence to drive down carbon, and the data bank is starting to grow. Rather than resorting to reductive ‘this versus that’ thinking, we must take a nuanced approach from the outset.
The stainless steel MX3D Bridge in Amsterdam (completed in 2018) was 3D-printed in a factory before being craned into position. Arup worked on the project with MX3D, Joris Laarman Lab, and a host of collaborators.What is the best material choice given the supply chain and broader context of the location? Could digital manufacturing unlock material savings? Could a building be designed for densification in the future? Listen to the episode to hear about these topics and more.
There’s no shortcut to the right answer in the complex carbon equation, Stuart reveals. There are only informed, incremental steps towards the best possible solution for the context.
This episode is brought to you by:
| The Holcim Foundation for Sustainable Construction The Holcim Foundation helps drive systemic change towards a more sustainable built environment. It was founded in 2003 to define and promote the key principles of sustainability for the construction sector and is committed to accelerating the sector’s transformation so that people and the planet can thrive. The Foundation has investigated various aspects of sustainable construction via a series of roundtables and conferences with international experts. It has also recognised excellent contributions to this field with the Holcim Awards which are considered the world’s most significant competition for sustainable design. Committed to a holistic approach that recognises the equal importance and interdependence of four key goals, the Foundation combines the collective knowledge, ideas, and solutions of our global community of experts with a recognised platform of international competitions to democratise thought leadership for the entire sector. |  |
This episode is brought to you by:
The Holcim Foundation for Sustainable Construction
The Holcim Foundation helps drive systemic change towards a more sustainable built environment. It was founded in 2003 to define and promote the key principles of sustainability for the construction sector and is committed to accelerating the sector’s transformation so that people and the planet can thrive.
The Foundation has investigated various aspects of sustainable construction via a series of roundtables and conferences with international experts. It has also recognised excellent contributions to this field with the Holcim Awards which are considered the world’s most significant competition for sustainable design.
Committed to a holistic approach that recognises the equal importance and interdependence of four key goals, the Foundation combines the collective knowledge, ideas, and solutions of our global community of experts with a recognised platform of international competitions to democratise thought leadership for the entire sector.
Stuart Smith is the Global Circular Economy Skills Leader for Arup responsible for growing and developing the firm’s capabilities for decarbonising the built environment using circular principles.
He contributes to the themes of circular economy in the built environment, regenerative design, and the development of low-carbon buildings through active projects, research, and thought leadership with clients and industry organisations.
Working as a structural engineer for Arup based in Berlin, he has been engaged in the design of some of the world’s most challenging building projects including CCTV with OMA in Beijing and Perez Art Museum Miami with Herzog & de Meuron. Stuart has collaborated on projects worldwide of various scales and typologies from artist installations to major urban masterplans.
Stuart has an interest in new, innovative materials and construction techniques. He has experimented with prototype buildings such as the Wikihouse, the world’s first open source, digitally printed house built, and The Circular Building in 2016 that explored the application of circular economy principles to the built environment.
Stuart studied civil engineering at City University and Imperial College in London. He is a member of the Board of the Holcim Foundation for Sustainable Construction and an Academic Chair at the Norman Foster Institute for Sustainable Cities. He is currently collaborating with Norman Foster Foundation on a masterplan for the reconstruction of Kharkiv in Ukraine and with David Chipperfield Architects on the new Nobel Center in Stockholm, Sweden.
E | berlin@arup.com
W | Arup
If you heard it in this episode, we likely have a link for it right here. Click on any topics, people, buildings, places, products and/or technologies listed below to learn more about each of them.
| 00:03:45 | “…we were at the Venice Biennale in November…” “Biennale Architettura 2023” | La Biennale di Venezia |
| 00:06:01 | “…there’s a roadmap for the [concrete] industry to reduce emissions…” “CONCRETE FUTURE: The GCCA 2050 Cement and Concrete Industry Roadmap for Net Zero Concrete” | Global Cement and Concrete Association |
| 00:06:09 | “…deep dive is carbon capture and storage…” “Carbon Capture” | Center for Climate and Energy Solutions (C2ES) |
| 00:07:47 | “…get to a point where our buildings are net-zero in operation…” “What is a net zero carbon building?” | World Green Building Council (WorldGBC) |
| 00:08:29 | “…what decarbonisation means…” “DECARBONIZING BUILDING” | Holcim |
| 00:09:04 | “…worth looking up, is an image of nickel tailings…” “Gallery: Edward Burtynsky’s extraordinary images of manufactured landscapes” | TED Blog |
| 00:09:27 | “…what do we actually use nickel for…” “Stainless steel: The role of nickel” | Nickel Institute (NI) |
| 00:13:23 | “…a report that we produced […] with the World Business Council for Sustainable Development: ‘Where do we stand?’…” “Net zero buildings: where do we stand?” | Arup |
| 00:14:15 | “…one component, which is the embodied carbon…” “What is ‘embodied carbon’?” | Yale Climate Connections |
| 00:14:27 | “…The other is to do with operational emissions…” “Operational & Embodied Carbon: Explainer Guide” | UKGBC (UK Green Building Council) |
| 00:14:38 | “…I don’t have a choice of the energy mix of the electrical power that I purchase…” “Energy Mix” | Our World in Data |
| 00:15:06 | “…looking at what passive systems you could employ…” “What passive architecture is and how it works” | Domus |
| 00:22:03 | “…put them into secondary material chains…” “What role do secondary materials play in new constructions and in buildings renovation?” | European Union Economy Stakeholder Platform |
| 00:39:33 | “…whole life carbon analysis, or whole life cycle analysis…” “Whole Life Carbon: what is it and how do we reduce it?” | Arup |
| 00:43:07 | “…off-site manufacture and digital manufacture are two of the components…” “What is Offsite Construction?” | Offsite Construction Network |
| 00:43:07 | “…off-site manufacture and digital manufacture are two of the components…” “Digital manufacturing” | Wikipedia |
| 00:08:46 | “…a Canadian photographer called Ed Burtynsky…” “Gallery: Edward Burtynsky’s extraordinary images of manufactured landscapes” | TED Blog |
| 00:10:44 | “…I was listening to Johan Rockström…” “Johan Rockström” | Wikipedia |
| 00:10:48 | “…a climate scientist from the Potsdam Institute for Climate Change…” Potsdam Institute for Climate Impact Research |
| 00:13:25 | “…which is also worth looking up, with the World Business Council for Sustainable Development…” World Business Council for Sustainable Development |
| 00:17:04 | “…the work of Lacaton & Vassal who now, of course…” Lacaton & Vassal |
| 00:22:50 | “…the architect baubüro in situ worked…” “baubüro in situ” | ArchDaily |
| 00:28:42 | “…I worked on a masterplan with Rem Koolhaas in London, White City…” “Rem Koolhaas” | OMA |
| 00:30:14 | “…a good example, Leadenhall in London — the ‘Cheesegrater’ — with Richard Rogers…” “Richard Rogers” | RSHP (Rogers Stirk Harbour and Partners) |
| 00:30:23 | “…with Laing O’Rourke […] a very innovative contractor…” Laing O’Rourke |
| 00:39:15 | “…you mentioned the Arup database…” Arup |
| 00:03:41 | “…our preliminary conversation in Venice…” “Venice” (Venezia, Italy) | Britannica |
| 00:04:52 | “…we have in Europe…” “Europe” | Britannica |
| 00:10:08 | “…I’m living in Berlin in Germany at the moment…” “Berlin” (Germany) | Britannica |
| 00:10:08 | “…I’m living in Berlin in Germany at the moment…” “Germany” | Britannica |
| 00:10:48 | “…course, heat temperatures in Africa…” “Africa” | Britannica |
| 00:19:55 | “…very good example of that is H7 in Münster with Andreas Huepel…” “The highest timber hybrid building in North Rhine-Westphalia” | Arup |
| 00:22:41 | “…which was a project called K. 118, which…” “Extending the Cycle in Switzerland” | Holcim Foundation |
| 00:28:42 | “…I worked on a masterplan with Rem Koolhaas in London, White City…” “London” (United Kingdom) | Britannica |
| 00:28:42 | “…I worked on a masterplan with Rem Koolhaas in London, White City…” “White City” | OMA |
| 00:30:14 | “…a good example, Leadenhall in London — the ‘Cheesegrater’ — with Richard Rogers…” “How integrating architecture and engineering unlocks speed and space” | Arup |
| 00:34:27 | “…number 1 Triton Square, which we…” “1 Triton Square: How can existing buildings combat climate change?” | Arup |
| 00:36:15 | “…I am reminded of a project in Sydney, Australia, the Atlassian…” “Sydney” (New South Wales, Australia) | Britannica |
| 00:36:15 | “…I am reminded of a project in Sydney, Australia, the Atlassian…” “Australia” | Britannica |
| 00:36:15 | “…I am reminded of a project in Sydney, Australia, the Atlassian…” “Atlassian Headquarters” | SHoP Architects |
| 00:38:42 | “…Bosco Verticale in Milan was an extreme example…” “Vertical Forest Milan” | Boeri Studio |
| 00:38:42 | “…Bosco Verticale in Milan was an extreme example…” “Milan” (Milano, Italy) | Britannica |
| 00:42:45 | “…it’s a problem in Copenhagen…” “Copenhagen” (Denmark) | Britannica |
| 00:19:44 | “…with the industry timber-concrete composite slabs…” “RESEARCH SPOTLIGHT: WOOD-CONCRETE COMPOSITE SYSTEMS” | University of Massachusetts Amherst |
| 00:31:06 | “…if you have design for disassembly…” “A Guide to Design for Disassembly” | ArchDaily |
| 00:05:32 | “…make, in the lab, a carbon-neutral cement, but trying to scale that…” “Six material innovations aimed at slashing concrete’s outsized carbon footprint” | Dezeen |
| 00:18:17 | “…for example, BubbleDeck is a system, a concrete slab system…” BubbleDeck |
| 00:26:17 | “…the biogenic timber gets reported separately…” “The Role of Mass Timber in a Biogenic Materials Revolution” | Woodworks |
| 00:39:37 | “…There’s a tool, One Click LCA […] That’s a database…” “LCA for buildings” | One Click LCA |
| 00:41:10 | “…our database, our platform Zero, which is collecting all of the data…” Zero |
| 00:43:44 | “…with 3D-printed houses now…” “The affordable 3D-printed home that could transform African urbanization” | World Economic Forum |
Host
Nirmal Kishnani
Producer
Maxime Flores
Editor-at-large
Narelle Yabuka
Managing editor
Kruti Choksi Kothari
Senior communications executive
Sana Gupta
Senior editor
Tyler Yeo
Art director (video)
Alexander Melck | Phlogiston
Sound technician and editor
Kelvin Brown | Phlogiston
Video editors
Guellor Muguruka | Phlogiston
Madelein Myburgh | Phlogiston
Graphic designer
Stian van Wyk | Phlogiston
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