When we first walked through the old foundry in Sheffield, the roof leaked, pigeons owned the upper gantries and the developer's original plan was to clear the site. Three years later it is Foundry Lofts — 120 homes, a food hall and a courtyard, built around a steel frame that is more than a century old.
Keeping it was not nostalgia. It was the single biggest carbon decision on the project.
The carbon is already spent
Every tonne of steel, brick and concrete in an existing building represents carbon that was emitted when it was made. Demolish it, and that investment is thrown away — then spent again on the replacement. At Foundry Lofts, retaining 85% of the original structure saved an estimated 3,400 tonnes of embodied carbon compared with a new build of the same size.
Before we ask what to build, we now ask what we can keep.
Working with old bones
Reuse asks more of the design team, not less. A few lessons we carry into every project now:
- Survey early and thoroughly — the existing structure is your first consultant.
- Design the new to be lighter than the old, so it can sit on what is already there.
- Let the history show. Patched brick and riveted steel are what people remember.
Not every building can be saved. But far more can than we assume, and the ones that are often become the most loved places in a city. That is a brief worth taking on.
