Having formed in 2019, Subteno are a young but growing engineering practice, and now comprise a team of seven engineers and CAD modellers. We signed up to the UK Structural Engineers Declare Climate and Biodiversity Emergency following a powerful presentation on the effect that the built environment has on climate change, delivered at an Institution of Structural Engineers Council Meeting in 2018.
Having signed up to the Declaration, we realised how little knowledge we had regarding embodied carbon within materials and construction activities. We did not even know how to measure the carbon within our designs and, to be blunt, had never really given it much thought. We had always been passionate about designing cost and material efficient solutions that were simple to construct. However, embodied carbon now brought another metric into our considerations.
At the time of signing the Declaration, we shared with our team what we had committed to, and how we wanted to ensure that Subteno was a responsible company, being fully accountable for our carbon footprint.
We started to accumulate knowledge and useful data, but it wasn’t until the launch of the Institution’s Carbon Counting Tool, and the excellent guidance within The Structural Engineer journal, that we felt confident and empowered to make a real step change.
We now include carbon counting in our default setting for every new project, in the same way as we have with CDM (Construction Design and Management Regulations 2015) responsibilities.
After a slow start, we are now actively measuring and counting our embodied carbon and continuously looking at ways to reduce it. We typically add a boxed note onto our drawings stating the level of embodied carbon. In doing so have received feedback that some of our clients are now noting this figure and becoming more aware themselves of the magnitude of embodied carbon within construction. However, we are yet to see any real change in client activities and priorities as a result.
We have also had some minor setbacks. One example is where we specified the lowest grade of concrete (by cement content) that we could on a sub-structure project, to suit the site conditions and design requirements. Having proudly ‘patted ourselves on the back’ for saving several tonnes of embodied carbon, we later discovered that the contractor had ordered ‘the concrete he normally uses’ assuming that as it was stronger it would be okay. We only found this out from reviewing the concrete certificates and cube test results!
We are finding it relatively easy to have open discussions with our clients regarding the climate and environmental implication of construction and can discuss design options for reducing embodied carbon. However, to date, the climate emergency has clearly been a lower priority for our clients, who are still driven primarily by financial costs and construction timescales. It may take government carbon taxation before this truly changes.
We are still at an early stage in our journey and realise that there is still much to do. We need to continue to capture more data in order to really start to benchmark our designs and we still need to make carbon awareness second nature. However, we are at least moving in the right direction: we are learning, we are aware, and we are changing.