Engineering the Future: Low-Carbon Innovations in Structural Design – A Conversation with Jensen Hunt

Interview with James Mickelburgh and Arij Mroue of Jensen Hunt

Interviewer: Sean Ronnie Hill, Director of RISE Design Studio

Sean Ronnie Hill: James, Arij - thank you both for joining me. Structural engineering is undergoing a significant transformation, especially with the growing emphasis on sustainability. As an architect, I’ve seen first-hand how structural choices impact the feasibility and carbon footprint of a project. How are you seeing this shift impact your work at Jensen Hunt?

James Mickelburgh: Thanks, Sean. Yes, there has been a major shift in the industry towards low-embodied carbon solutions. Clients and architects are far more aware of the impact that structural choices have on a building’s carbon footprint. As structural engineers, we’re increasingly exploring alternatives to conventional high-carbon materials, integrating more timber, low-carbon concrete, and innovative steel solutions into our designs.

Arij Mroue: Absolutely. In the past, structural integrity and cost were the primary drivers of material selection, but now sustainability is just as critical. There’s a strong push - not only from designers but clients and stakeholders also - to reduce embodied carbon without compromising on performance or buildability. For instance, we are seeing greater use of hybrid structures that balance strength and sustainability by combining timber with recycled steel or low-carbon concrete. However, I would argue that sustainable structural design should also begin with doing the basics really well. It’s not always about using these new-age materials, instead, it’s about using conventional materials with a more conscientious approach.  

Sean: That aligns with what we’re experiencing at RISE Design Studio. More than ever, clients are looking for holistic sustainability strategies that go beyond operational efficiency and address the embodied carbon of the building itself. What specific materials and construction techniques are proving most effective in reducing embodied carbon in structures?

James: Timber, particularly cross-laminated timber (CLT), has been a game-changer for us. It’s renewable, sequesters carbon, and can significantly reduce the overall carbon footprint of a building. But we’re also looking at innovations in concrete, such as ground granulated blast-furnace slag (GGBS) and alkali-activated cementitious materials (AACMs), which can lower the embodied carbon of concrete by up to 50% compared to traditional Portland cement mixes.

Arij: Another area of focus is optimising structural efficiency which, again, goes back to what I said about doing the basics really well. Structural efficiency is an inherent part of good structural design. However, structural engineers can take this further by using advanced digital modelling and parametric design tools, which allow us to refine structures to optimise our material usage. This ‘lean’ approach reduces waste and the overall carbon expenditure. Evaluating construction processes is also an integral aspect of sustainable structural design. For example, modular and prefabricated elements can help lower emissions associated with transportation and on-site construction waste.

Cross-laminated timber (CLT) structure – a renewable material that sequesters carbon and helps significantly reduce a building's overall carbon footprint.

Sean: The concept of adaptive reuse and retrofit is gaining traction in architecture. At RISE, we actively encourage clients to explore retrofit solutions where feasible, rather than defaulting to demolition and new build. How does structural engineering contribute to making existing buildings more sustainable?

James: Retrofitting existing buildings is one of the most effective ways to cut carbon emissions. The structural challenge often lies in evaluating and reinforcing old materials so they can support new uses. Our role is to assess load-bearing capacities and identify solutions that strengthen the structure without excessive material use. In some cases, we employ carbon fibre reinforcement or steel augmentation to extend the life of an existing structure.

Arij: Exactly. One of our recent projects involved repurposing an old industrial building into a modern office space. Rather than demolishing and rebuilding, we worked on reinforcing the existing frame, integrating lightweight timber elements, and strategically placing structural supports to avoid excessive steel use. These interventions significantly reduced the embodied carbon of the project compared to a full rebuild. 

Sean: That’s something I’d love to explore more with you both. The construction industry’s shift towards net-zero goals is driving regulatory and industry changes. What trends are shaping the future of structural engineering?

James: The industry is adapting to stricter regulations and sustainability targets, such as the UK’s net-zero commitments. The shift towards Environmental Product Declarations (EPDs) is helping clients make more informed material choices. Additionally, regulations like Part Z, which aims to mandate embodied carbon assessments in building design, could soon become a legal requirement, pushing everyone towards greener solutions.

Arij: Beyond regulations, there’s an evolving mindset in the industry. Developers and clients are increasingly prioritising sustainability in procurement decisions. Structural engineers are now expected to have in-depth carbon knowledge, using life cycle assessments (LCAs) to quantify the environmental impact of our designs. It’s no longer just about compliance; it’s about innovation, responsibility and a cultural shift.

Sean: I completely agree. At RISE, we’re seeing growing interest from clients in material passports and circular economy principles, ensuring that materials can be repurposed at the end of a building’s life cycle. Given these challenges and innovations, how do you see structural engineering evolving over the next decade?

James: I think we’ll see a greater reliance on AI - driven design optimisation and digital twin technology. These tools allow us to model structures in unprecedented detail, reducing over-design and unnecessary material use. Additionally, new material technologies, like bio-based composites and carbon-negative concrete, will become more mainstream.

Arij: Collaboration will also be key. The lines between disciplines - architecture, engineering, and sustainability consulting - are blurring as we work together to create truly holistic, low-carbon buildings. Structural engineers will need to be at the forefront of material science and computational design to drive the next wave of sustainable construction.

Sean: This has been a fascinating discussion. James, Arij, thank you both for sharing your insights on the future of low-carbon structural engineering.

James: Thank you, Sean.

Arij: It’s been a pleasure. Looking forward to seeing how these innovations take shape in our projects together.

Shaping a Low-Carbon Future, Together

At RISE Design Studio, we believe that the future of architecture lies in collaboration and innovation. Engineering and design go hand in hand to create structures that are efficient and sustainable and inspire a better way of living.

Every project is an opportunity to push boundaries, rethink possibilities, and reduce our environmental impact. Let’s work together to create low-carbon, high-performance spaces that stand the test of time.

Ready to build something future-proof?

If you would like to talk through your project with the team, please do get in touch at architects@risedesignstudio.co.uk or give us a call on 020 3947 5886

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