Embodied carbon accounts for half of all emissions over a school’s lifetime, and it will be subject to increasingly challenging targets. We explain what a whole-life carbon approach means, and why it doesn’t have to cost more

The energy a school uses is only one part of its carbon emissions. Around half of its total carbon impact will be emitted before systems are even switched on, during construction and the production of materials such as concrete, steel and glass. To be genuinely Net Zero, rather than just Net Zero in operation, this “embodied carbon” must also be taken into account. 

Right now, the DfE doesn’t set limits, only a requirement to carry out an embodied carbon assessment. “That’s because our understanding of embodied carbon is a little bit behind where we’re at on operational energy, but the direction of travel is that there will eventually be targets associated with it,” says Kat Adair, Senior Associate in the Sustainability team at Ridge.  

Understanding what Net Zero means

One indication of what that could look like is the Net Zero Carbon Building Standard, launched in October 2024. This has a specific route for schools, with targets for both energy and embodied carbon, and for new builds and retrofits of different kinds. “That’s really going to help the education sector understand what’s meant by Net Zero,” says Kat.  

As for how to achieve it, she highlights two misconceptions: that low-embodied carbon buildings always cost more, and that only a timber structure will do. “Timber is low-carbon material, but it’s not the only option and it is expensive. You can build a low-carbon school using steel and concrete, if you have a design team that is really good at communicating and working in a multidisciplinary way.”  

Low-carbon construction

This means close coordination between sustainability advisors and structural engineers to ensure the building is not overdesigned using excessive material, and that the steel and concrete specification is appropriate. “There are a lot more opportunities now to have low-carbon steel and low-carbon concrete, at no extra cost, but you need to factor it into the design and the programme early on. Low-carbon concrete takes longer to cure, so if you don’t think about it until construction is about to start, it can be difficult to manage.”  

Ultimately, what embodied carbon targets will mean is a much greater presumption in favour of retrofitting.  

“As soon as you knock a building down and start again, your embodied carbon is going to shoot through the roof, because at this point in time, all our building materials have some kind of carbon impact,” says Kat. “Right now, the only way you can get to Net Zero for embodied carbon is by not building. If we’re looking at the hierarchy of approaches, feasible refurbishment has always got to be the number one goal.” 

You can contact Kat on katadair@ridge.co.uk