In the UK, the built environment is accountable for 42% of all UK greenhouse gas emissions. Decarbonisation of the grid and increased efficiency have reduced the impact of operational carbon, meaning the reduction of embodied carbon is now one of the biggest challenges our profession faces. We need to quickly learn to navigate a route to reducing whole-life carbon emissions (modules A to D) in the process of designing buildings.

Although embodied carbon is not currently regulated, we recognise the need for clear guidance. We support proposals for ‘Part Z’ of the building regulations to regulate whole life carbon and limit upfront embodied carbon, and as members of the UKGBC, are putting ourselves forward to contribute to the first Net Zero Carbon Buildings Standard and address the specific challenges involved in large-scale buildings.

As signatories to Architects Declare, Hopkins is working towards estimating the whole life carbon impact of the practice’s completed and current work in order to better understand our impact and make meaningful change. We have an internal energy database providing a live and accessible resource of measurable targets in one place and are training staff in One-Click LCA software to analyse the embodied carbon of architectural elements. This process allows us to measure our design intent, understand the scale of the impact which material choices can have, and react by making improvements where it matters most. This iterative process improves our carbon literacy and empowers people to manipulate material selection at all design stages, particularly in the early design process, making informed sustainable decisions with the most up to date data.

Once quantities are known, comparison studies can help shed light on the impact of material selection and their carbon emissions. Balanced decisions can be made, taking into account production, travel distance, the opportunity for materials to act as carbon sinks, material replacement over the building’s lifespan as well as potential recovery at end-of-life.  The context of what an appropriate material is, the scale at which it will be used and the long-term benefits that can be gained differ between projects and are important to consider carefully.

At Hopkins, we are generally involved in large, complex projects where the biggest challenge is minimising carbon in the volumes of materials used. Some of the biggest projects we work on can have embodied carbon reaching tens of thousands of tonnes of total CO₂e (Modules A-D), even with a low benchmark of kgCO₂e/m² applied. For this reason, we ensure that we work with structural engineers at the earliest possible stages of a project to identify those areas where we might be able to make the biggest reductions and minimise upfront emissions in the superstructure.

Our functionalist and innovative design ethos embodies this sustainable approach, reducing the volume of materials involved and pushing materials to perform efficiently.

The modular ‘kit-of-parts’ Patera Building System that we used to construct our own office in London features a simple palette of standard size modular components using a regular structural grid for maximum efficiency. In the 2012 Velodrome, we developed a lightweight cable net roof solution saving 1000 tonnes of structural steelwork. The concept, inspired by the functional efficiency of a bicycle, had the added benefit of reducing programme and costs. We are currently researching the carbon reductions we can achieve in a steel framed office building in central London, specifying recycled steel where possible and procuring new steel which has utilised renewable energy sources, such as an electric arc furnace, during processing.

Architects are well placed to expand their role as sustainability champions within the industry, taking ownership of the building envelope and internal elements to fine tune informed, sustainable decision-making, and balance carbon alongside performance, aesthetics and economics.