The geometry does the work. That's where efficiencies are gained.
As the built environment confronts its carbon debt, the new president of the Institution of Structural Engineers is asking the profession to look not at what buildings are made of, but at how they are shaped. The argument is ancient in its logic — medieval cathedral builders knew that geometry could do what material alone cannot — yet urgent in its application, as flat concrete slabs quietly account for the majority of embodied carbon in modern construction. In an era of digital acceleration and climate pressure, this leader is calling engineers back to first principles, not as a retreat, but as the surest path forward.
- The construction sector's fixation on material substitution is obscuring a more powerful lever: the structural system itself, where inefficient geometries like flat concrete slabs silently generate 70% of a building's embodied carbon.
- Advanced materials — ultra-high-strength steels, bi-metallic composites, reclaimed structural steel — offer genuine gains, but only when paired with smarter structural thinking rather than deployed as isolated fixes.
- Designing for disassembly and circularity transforms buildings from permanent carbon commitments into temporary arrangements of reusable material, with reclaimed steel projects achieving up to 99% embodied carbon reductions.
- The profession faces a quiet crisis of competence as AI and digital tools proliferate — if engineers cannot calculate from first principles, no one can reliably verify what the machines produce.
- IStructE is responding with stronger CPD requirements, peer supervision models, and a push for formal registration, treating professional infrastructure as the foundation beneath all other innovation.
The Institution of Structural Engineers has a new president, and his message to the profession is quietly radical: stop fixating on materials, and start thinking about the shape of the thing itself. The real opportunity to cut embodied carbon, he argues, lies not in swapping concrete for timber, but in rethinking how forces move through a structure.
The flat concrete slab is his central exhibit. A workhorse of modern construction, it accounts for roughly 70% of a building's embodied carbon — not because concrete is inherently wasteful, but because a flat slab puts the material into tension, forcing engineers to compensate with steel reinforcement. Medieval cathedral builders understood the alternative: vaulted arches that work in compression, letting geometry carry the load. The material does less, and achieves more.
This doesn't mean abandoning material innovation. The president's own research spans high-strength steels more than twice as strong as those used in the Sydney Harbour Bridge, bi-metallic composites that layer stainless steel or titanium over conventional steel for corrosion and fire resistance, and the circularity potential of reclaimed structural steel — which can reduce embodied carbon by roughly 99% compared to new material. A 250-ton stainless steel flagpole at Parliament House in Canberra stands as proof that these advances are already in practice.
But materials and systems only deliver their potential when engineers truly understand them. The president is pushing IStructE to strengthen continuing professional development, establish proactive peer supervision models, and advance formal registration as a benchmark of practice. Most pointedly, he continues to teach hand calculation methods — traditional first-principles techniques — even as AI reshapes the profession. Without that foundation, he warns, engineers lose the ability to judge whether digital outputs make sense at all. The future of structural engineering, it turns out, is inseparable from its past.
The Institution of Structural Engineers has a new president, and he wants the profession to think differently about how to build with less carbon. The conversation isn't really about swapping concrete for timber or finding the next miracle material. It's about the shape of the thing itself—the bones of the building, the way forces move through space, the fundamental logic of how we hold things up.
This shift in thinking sits at the heart of IStructE's five-year strategy, released this year, which frames structural engineering as a people-first discipline navigating an increasingly digital and climate-conscious world. The president, a Scientia Professor at the University of New South Wales with deep expertise in high-performance materials, sees his role as one of reaffirming what the profession is for: advancing it, supporting the people in it, and raising the standard of practice itself.
The embodied carbon challenge is real and urgent. Infrastructure must decarbonize, and the sector has responded by fixating on materials—swapping out cement, experimenting with alternatives to concrete, hunting for the low-carbon substitute. But this approach, the president argues, misses the bigger picture. Take the flat concrete slab, a workhorse of modern construction that accounts for roughly 70 percent of a building's embodied carbon. The problem isn't the material alone; it's what we're doing with it. A flat slab puts concrete into tension, which means engineers must add steel reinforcement to compensate. The concrete itself becomes inefficient, underutilized. Compare this to the vaulted and arch-supported structures of medieval cathedrals, where the material works in compression—its strongest state. The geometry does the work. "That's where a lot of efficiencies can be gained," the president says. "It's about looking at the system itself and trying to choose efficient solutions."
This doesn't mean abandoning material innovation. The president's own research agenda spans high-strength steels—materials twice as strong as the steel used in the Sydney Harbour Bridge, now covered by Australian and New Zealand standards—and experimental bi-metallic composites that layer stainless steel or titanium over conventional steel to gain corrosion and fire resistance without the full cost of premium materials throughout. Steels exceeding 1000 megapascals of strength, triple the traditional 300 megapascal baseline, are being explored. A 250-ton stainless steel flagpole at Parliament House in Canberra stands as proof of concept. These advances matter, but they work best when paired with smarter structural thinking.
Circularity adds another dimension. Designing for disassembly—building structures that can be taken apart and reassembled—opens the possibility of reusing structural steel. A project using reclaimed steel can achieve embodied carbon reductions of roughly 99 percent compared to new material. The structure becomes not just a static thing but a temporary arrangement, a loan of material from one purpose to the next.
But none of this works without people who understand it. The president is pushing IStructE to strengthen its continuing professional development requirements, ensuring that engineers stay current with research and can genuinely calculate embodied carbon rather than treating it as a compliance checkbox. He's championing a supervision model—engineers talking one-on-one about difficult technical problems, seeking advice before issues arise, the proactive counterpart to the reactive learning that happens after failures. Registration for structural engineers, he believes, is critical to benchmarking best practice.
Underlying all of this is a conviction about fundamentals. As machine learning and AI reshape how engineers work, the president still teaches hand methods—the traditional analytical techniques for calculating forces, stresses, and deformations from first principles. Without that foundation, he argues, who checks the outputs of digital tools? Who understands whether the answer makes sense? "Without strong foundations, it doesn't really matter what digital tools you've got," he says. The future of structural engineering, it seems, runs through the past.
Notable Quotes
With the big push to focus on reducing embodied carbon in the sector, a lot of the emphasis has been placed on materials, but I want to place more of a focus on structural systems. That's where a lot of efficiencies can be gained.— IStructE President
Without strong foundations, it doesn't really matter what digital tools you've got. You still have to have that understanding of the science and engineering behind solving problems.— IStructE President
The Hearth Conversation Another angle on the story
You're arguing that we've been looking at embodied carbon all wrong—that the problem isn't the materials themselves but how we arrange them. That's a pretty fundamental reframing.
It is. We've been in substitution mode: swap this for that, find the low-carbon alternative. But a flat concrete slab is inefficient not because concrete is bad, but because we're using it in tension when it wants to work in compression. The geometry is the problem.
So you're saying medieval cathedral builders understood something we've forgotten?
Not forgotten exactly. We optimized for other things—speed, standardization, the economics of flat floors. But yes, those arch and vault structures were geometrically honest. The material was always in its strongest state. We can learn from that without building cathedrals.
But materials innovation still matters to you. You're researching steels that are three times stronger than standard steel.
Absolutely. Stronger materials let you use less of them. If you double the strength, you don't always halve the carbon, but you move the needle. The point is that materials and systems thinking aren't opposed—they're complementary. You need both.
What worries you most about the profession right now?
That we'll let digital tools and AI do our thinking for us without understanding the fundamentals underneath. An engineer who can't hand-calculate a structure, who can't sense whether a computer's answer is reasonable—that's dangerous. The tools are only as good as the person using them.
And the supervision model you're pushing—that's about catching problems before they happen?
Exactly. Right now we learn from failures. That's reactive. Supervision is proactive—engineers talking through difficult problems, seeking advice, building a culture where asking for help is normal. It's about safety before something breaks.