Embodied carbon: the hidden bill of a building
As green building certificates multiply, the real question becomes clearer: does a building's impact come from the energy it uses over the years, or from the carbon released before it is even finished?
When we talk about a building's environmental impact, we usually think of the electricity and gas bill. Yet a large share of the carbon a building produces over its life is released before a single lamp is switched on: in firing cement, melting steel and transporting materials. We call this embodied carbon.
Why we are talking about it now
Thanks to insulation and efficient systems, the operating energy of new buildings has fallen sharply over the last twenty years. That is good news with a side effect: embodied carbon now makes up a bigger share of the total. In a new, well-insulated office, almost half of the carbon over the first 30 years may come from construction.
What timber changes
In the Ataşehir Timber Office, most of the structure is cross-laminated timber (CLT). Timber draws carbon from the air as it grows and stores it for as long as the building stands. By our calculation, the building's embodied carbon is half that of an equivalent concrete structure.
This does not mean every building should be timber. Concrete is still the right material for foundations, basements and cores. What matters is using each material where it performs best.
A certificate is a beginning
Certificates such as LEED and BREEAM create a shared language and give investors confidence. Seven of our projects are LEED certified. But a scorecard cannot replace design. Correct orientation, natural ventilation, long-lived materials and details that are easy to repair are small lines on the scorecard, yet they make the biggest difference over a building's life.
Three questions for clients
At the start of each project we ask our clients: how many years will this building be used? Can it be converted if its use changes? Can its materials be reused at the end? The answers shape many decisions, from material choice to column spacing.
