Lumi in Uppsala is one of Sweden’s most ambitious reuse projects and serves as a testbed for new solutions in large-scale circular architecture. The project has attracted significant international attention for its design approach and its high level of material reuse. In a unique transformation, the concrete frame of a 1970s building has been extended and re-clad, while everything practically possible has been reused – including plasterboards, bricks, doors, radiators and electrical boxes. The result is a modern laboratory and office building with a very low climate impact.