Episode 48. AJ Climate Champions with Hattie Hartman and Joe Jack Williams. Structural engineer Eva MacNamara of Expedition Engineering explains how we can radically reduce our use of concrete and how to better understand the biodiversity impacts of material choices.
In this episode, we dive into the tricky topic of concrete and unpick the widespread mantra that ‘concrete is bad’. Concrete is ‘an addiction’ that has led to an obese construction industry, says Expedition’s MacNamara; it is not going to go away but we can radically reduce our use of it. She describes a porposed slab design for the Eden Project site in Dundee which would achieve an 80% reduction in concrete volume.
MacNamara stresses that ‘using less’ is much more impactful than substituting low-carbon concretes and notes that she repeatedly sees practitioners over-specifying. We discuss some of the nuances of concrete use: which applications are most appropriate, how to reduce the volumes we use, and why low-carbon concrete – especially GGBS – is not a silver bullet. We also touch on upcoming innovations including Seratech, ‘funnel’ slabs and smart crushing.
McNamara explains how to bring both carbon and biodiversity into the concrete procurement process. Highlighting findings from the recent report The Embodied Biodiversity Impacts of Construction Materials (Expedition/ICE, November 2023), she notes that 95% of biodiversity impacts occur off site and that the new biodiversity net gain requirements only address the 5% on site, so designers must look beyond a site’s boundary.
Finally, MacNamara advocates finding a place to innovate on every project. ‘We can make the most difference by using our projects as springboards for incubating innovation,’ she says.
For show notes and to catch up on all AJ Climate Champions episodes, click here.
Thamesmead Waterfront and Home of 2030, two competitions wins where ‘landscape is the glue’
Landscape architect Jo Gibbons on why trees matter, urban forestry and greening our cities
Barnabas Calder revisits architectural history through the lens of energy and climate
Guy Shrubsole on rewilding Britain and greening our cities
Steve Webb & Wilf Meynell: ‘We’re brainwashed into steel and concrete mode’
Harry Paticas on empowering communities through the low-carbon retrofit of primary schools
Owen Hatherley on Modernism + Will Hurst explains RetroFirst (bonus episode)
Anna Heringer: 'You can build with clay in a very modern way'
Sarah Wigglesworth: 'Sustainable architecture is fantastically creative'
Haworth Tompkins' Diana Dina: 'We want to share ideas with other practices'
Sofie Pelsmakers: 'Sustainable architecture is "architecture on steroids" – it needs to perform'
Annalie Riches: 'We need more projects that show sustainable design isn't ugly'
Maria Smith: 'It's depressing how much architects are the problem'
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