Post by Simon Matthews

2023 has already seen extremes of weather across all seven continents, with record breaking temperatures globally, wildfires in Europe, Chile and Canada, deadly floods in south Asia, and powerful ice storms in the southern United States. So what can architecture do in the battle against climate change?

Approaching 40% of global carbon emissions can be attributed to our built environment, with embodied carbon – the carbon associated with the materials in a building’s construction – a major factor. In the first of a series of articles, Simon Matthews, Sustainability Lead at Stephen George + Partners, looks at the next steps in achieving Net Zero by measuring and reducing these carbon emissions in our building design.

Let’s start at the very beginning…

You have to start somewhere, and I began with a purely personal mission to see how my family and I could reduce our own household carbon emissions. That quickly led me onto a bigger consideration – and action – how could I help Stephen George + Partners as a company cut its carbon footprint. Moving on further still, we realised how big a carbon footprint was accounted for in the buildings that we designed and how we, as architects, had the opportunity to significantly reduce those carbon emissions. If we considered taking the sustainability savings seen in designing an individual home for example and scaling it up into a whole development of some 500 homes, we would be able to deliver, in real, tangible terms, a massive sustainability win.

What is measured can be addressed

Embodied carbon is, in many ways, the unseen part of a building’s carbon footprint. Yet it is the factor that needs to be addressed before the building is built, at the stage where the development is planned and the structures designed. Because the carbon emissions from the materials used are emitted before the building is even occupied, they will be contributing to global warming from the outset. Although over the 50/60 year lifetime of a building, the operational carbon emissions may be higher than the embodied carbon, operational emissions are an on-going process and can be reduced at any stage by taking advantage of new technologies, refurbishing and refitting elements like heating systems or insulation. That is not possible for embodied carbon.

Embodied carbon’s “hidden” impact on carbon footprints is important, as we need to make every contributor to carbon emissions visible, and, as importantly, measured. Most people do not know what carbon emissions or carbon footprints are, and so do not take it into account when making day-to-day decisions, using other, more “real” factors instead. When a person buys a loaf of bread, cost and taste are more likely to be a deciding factor than the loaf’s embodied carbon. Similarly, in architecture, a design tends to start with aesthetics and budget, but if we want to put carbon emissions at the heart and beginning of the design process, then we, as architects, need to know what the emissions are.

That is why SGP has supported the revision of our RIBA Award-winning Guide to Building Materials and the Environment, authored by Chris Halligan, Chartered Architectural Technologist at NPS Leeds. It gives fellow designers access to clear, independent, rational information on the embodied carbon contained in, and the sustainability of, a wide range of building materials.

What is legislated must be addressed

What is measured can be addressed, but what is legislated must be addressed, and relevant legislation in the UK is falling way behind what is being achieved in much of the rest of Europe.

Proposed by Jerome Mayhew, a private members’ bill, The Carbon Emissions (Buildings) Bill, was introduced to parliament in February 2022. It mirrored the industry’s proposals for Part Z to ensure that embodied carbon is assessed on all projects as part of a comprehensive whole life carbon assessment. But, despite the measures having widespread support within the built environment industry, including from major league players such as Lendlease and Landsec, Morgan Sindall and Laing O’Rourke, the bill stalled when the Government declined to support it.

Precedents for this sort of legislation are widespread across Europe. The Netherlands, France, Sweden, Denmark and Norway have already mandated reporting and either have limits in place or planned in the near future. The remainder of the EU will catch up in 2027, by when legislation for reporting of carbon is proposed – for all buildings and in all countries – many of which are currently less prepared than the UK.

The lack of legislation to provide impetus and clarity, makes it harder for the architect to challenge their own ways of working and evolve designs away from the traditional process to one where sustainability and carbon measurement is embedded at the start. Traditionally, architects will create a concept that they think is best, based on the client’s brief and budget. Once a client has engaged with and is enthusiastic about the design, of course it makes it harder to change that design to incorporate elements of sustainability. Think of being offered a holiday to California from the UK before an alternative to Catalonia is proposed. Even though the latter will deliver the same weather and scenery, only more sustainably, you’ve already set your heart on California.

Unless the client has focused on sustainability in the brief, the emphasis on the aesthetics and budget may relegate sustainability to bolt-on options, compromised elements which deliver fewer benefits than considering sustainable design with different materials and construction methodology from the very beginning.

Roman arch, St Andrews Church, Corbridge, Credit: Photo © David Dixon (cc-by-sa/2.0)

Roman arch, St Andrews Church, Corbridge

Architects have the opportunity to take the lead on this. We already develop strong, open relationships with our clients and evolve a deep understanding of the client’s beliefs, needs and aspirations. From that foundation, an architect can challenge themselves, embracing their natural talents as problem-solvers, and consider sustainability in the same basic mind set as budget and site constraints

And, if we have the scope and confidence to challenge a client’s perceptions and brief, we also need to develop our own commercial courage to promote more sustainable methodologies. Demolishing a building and clearing the site may be the obvious solution, but we need to ask ourselves if a more sustainable alternative, such as retrofitting or re-using an existing building, would equally meet the client’s needs?

Re-using the built environment

Retrofitting a building may be a more sustainable option than a new build, but a new methodology, the concept of urban mining, takes the idea of reuse another step forward.

An architect can – maybe should – approach a site from the viewpoint of “What if we had no new materials available? What is there already here that we can reuse?” We can visualise any existing structure, no matter how derelict, as a container of existing materials that can be deconstructed and re-used, like LEGO blocks, in an infinite variety of new structures, rather than just being demolished and carted away for road fill.

Urban mining is not a new concept. In less materially rich times, robbing out an existing building to make a new one was common practice. There are many Medieval buildings in the UK, from churches to barns, that have readily identifiable pieces of good Roman stonework in their fabric.

Architects can make this process simpler, not only by designing buildings that are relatively easy to dismantle, maximising the quality and quantity of materials that can be reclaimed, but also by logging and recording what materials have gone into a building. With the growing power of digital BIM systems and emphasis on keeping a Golden Thread of information about the structure, construction and management of a building, developing these materials banks is more practical now than ever before.

The bigger picture

I seemed to have strayed a little away from embodied carbon and measuring a building’s carbon footprint, but everything here is connected to the “bigger picture”, the drive to reduce carbon emissions and achieve Net Zero. In a period where our planet is experiencing scorching temperatures, wildfires and devastating floods with a frequency that is truly terrifying, we as architects, as human beings, need to do everything we can, on a personal, corporate and professional level, to protect the planet we all call home.

Understanding more of the impact our building materials make is a great place to start.

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