The aim of the façade renovation at Herostrasse 5 in Zurich was to energetically, ecologically and aesthetically renew a 50-year-old school building while at the same time maximally preserving the existing structure. The outcome is a technically optimised and resource-efficient building envelope that preserves a substantial portion of the original materials through innovative strategies of Re-Use and Re-Manufacturing. During the process, existing 50-year-old spandrel glazing was technically evaluated, reconditioned and connected to a new supporting structure using laminar silicone bonding. A similarly comprehensive upgrade was carried out on the ground-floor façade by directly reusing the existing Profilit glass: It was assembled into rectangular slats and used in part for passive shading or converted into lighting fixtures. The distinctive skeletal structure, with its red enamelled spandrel glass cladding, was preserved both in character and proportions. Modern aluminium windows, improved insulation and ventilation flaps with sound-absorbing elements meet today’s comfort and energy requirements. The renovation was triggered by the need to refurbish the façade, which had remained untouched since 1972, and the desire to set a forward-looking benchmark for sustainable construction.