Did you know that almost 40% of global carbon emissions are attributed to the built environment? Or that, in the UK, Embodied Carbon (the emissions associated with raw material extraction and their subsequent use in construction) also accounts for up to 51% of a residential building’s whole-life carbon?
Life Cycle Assessments
When searching for causes and how to mitigate the impact of our built environment on our climate, without proper regulation, embodied carbon remains an unaccounted cost, which is where Life Cycle Assessments (LCAs) are so important. LCAs form our industry’s methodology for holding ourselves accountable while evidencing our action against climate change. It is, after all, our duty as architects to understand the impact of our designs and reduce our emissions accordingly, and the use of LCAs allows us to quantify the carbon footprint of our projects and track our progress as we work to realise a zero-carbon future. The results of these assessments also allow us to be transparent with clients who share our goal for a sustainable future; they enable us to facilitate low-carbon design, and apply pressure on our supply chains to be transparent with verified environmental product declarations.
At present, there is no industry standard for Life Cycle Assessments, but that doesn’t mean they’re not important. Smaller businesses like ours are looking to larger practices across the country with more experience to pave the way for SMEs in rural and coastal communities like Cornwall. Here at Arco2, we currently use them as a means of beginning our own transformation into a more carbon-literate firm, until a time where we can be more certain about the robustness of the results.
That said, one key area where the results are already proving useful and applicable to our work, is in highlighting which materials are the biggest emitters of carbon. Having this information enables us to open up conversations with clients in order to reduce the use of harmful materials where appropriate, and to ‘optioneer’ other, more suitable alternatives. One option, of course, is to use natural materials. These are an efficient means of reducing a project’s impact because they act as carbon sinks, and we regularly incorporate products such as Warmcel (cellulose insulation), sheep’s wool, green roofing systems, and clay or lime plasters. Other steps we take to reduce our impact include specifying materials that are manufactured with a percentage of recycled content, and by taking steps to introduce a circular economy through material reuse and recycling, we’re able to actually make a carbon ‘saving’ at the end of a building’s life.
So, what are the most carbon intensive materials? Cement is one of them, alongside ready-mix and pre-cast concrete, steel, and aluminium. In fact, the global warming potential (GWP) of cement alone is enormous when compared to other construction materials, primarily due to the manufacturing processes, which involve extreme heat, and one of the key issues here in the UK is that our construction industry relies so heavily upon it. Indeed, at least at present, we cannot as a practice completely eradicate our use of it. But this is where LCAs become relevant, as they allow us to make informed choices and thereby reduce the amount of cement and concrete that are required to bring a project to life. For example, we can explore the immediate benefits of reducing spans, avoiding over-design, or using formers, all of which can help to reduce the volume required. And whilst we cannot completely eradicate it from our operations, a silver lining to its use here in Cornwall is that one of the raw materials required in order to produce cement, is clay. The Duchy is home to one of the largest China clay deposits in the world, and it seems fitting that whilst we cannot currently completely cut out the use of cement, we can reduce its impact on up-front emissions by specifying locally. Although the transportation footprint is relatively minor in the wider scope of an LCA, it is, nonetheless, a small step in the right direction of holding ourselves accountable.
So, what about concrete? Again, it’s difficult to eradicate entirely, so pervasive is its use in the UK construction industry. However, similarly to cement, there are ways in which we can, at least in part, mitigate emissions. Insulated Concrete Formwork (ICF) is a popular construction method, employing a system of formwork moulds which allow concrete to be poured into different shapes, like walls, floors and roofs. The void between the forms, which are usually made from rigid insulation, is then used for reinforced concrete. As a practice, we will always consider the most appropriate building methods for each project, and on some of our current coastal commissions we have opted to use R-wall – an ICF system created by a local company in Bude. Their partner manufacturers all operate within the UK, and even incorporate recycled plastics manufactured just over the border in Devon. We consider this a best-practice method wherever concrete is specified as, again, it means we can reduce the emissions associated with transportation.
As for those Embodied Emissions, generally speaking, architects are beginning to assume accountability for their designs, by either conducting their own LCAs or enlisting the expertise of external consultants. At Arco2, we are among the first architectural practices in Cornwall to implement LCA as an in-house tool, as we believe it’s an essential step towards decarbonisation. It provides reliable data to clients to help rationalise designs, and is a useful tool to educate our team on the implications of design and specification. But the assessment of embodied carbon is still optional as far as our planning system is concerned, and without regulation, it simply cannot progress at the rate that is needed if our industry is to make the changes required to halt the climate emergency.
At Arco2, we are firmly in support of the ‘Part Z’ proposal to regulate the calculation of whole-life carbon. We also feel that there is a need to broaden the conversation around decarbonisation, to better represent varying architects and settings. As a rural and coastal practice, it can sometimes feel as though we are excluded from the discussion, with resources commonly focusing on the concerns of the larger companies with sites in urban centres. Yet here in Cornwall, where we are surrounded by the ocean with endless miles of rolling, verdant countryside in between, we would argue that nowhere is the impact of unsustainable practice more keenly felt; it is the coastal and rural communities of counties like Cornwall that stand to lose the most, especially if practices such as ours – who know, love and cherish the landscape – are not invited to help inform these most important of conversations.