A low carbon office design, and it's restoration 30 years later. In 1996, we completed an innovative energy-efficient office at the heart of the Building Research Establishment (BRE) campus. Devised as part of the BRE Energy Efficient Office of the Future project, it was intentionally ahead of its time. It was to meet stringent targets for energy consumption, achieved using an experimental wave form slab which was able to incorporate ventilation routes, Ventilation stacks, bore holes and solar panels to the south elevation. It achieved Breeam ‘Excellent’ with the highest score recorded at the time. Our 2022 retrofit of B16 and B17 on the BRE Campus demonstrates a repeatable and cost-effective approach to modernising office buildings to adapt to market demand and alternative future uses. As an exemplar of a low cost, low carbon refurbishment, it prioritised low embodied carbon materials, local supply and reuse of existing materials were possible. The result is a flexible mix of updated spaces for work and collaboration, meeting rooms and print hubs, reconfigured unisex superloos and new accessible WCs and the all-important tea points on each floor. An early adopter of circular economy principals, 96% of the material from demolition of the redundant workshops on site was recycled and this was the first UK use of recycled aggregate for concrete superstructure. Other recycled materials included brickwork, screeds made from recycled power station gypsum and wood block floors recycled from County Hall in London. In revisiting our building and its neighbour to update the cellular spaces to flexible, healthy workplaces prioritised the reuse of materials where possible – including carpets, ceiling tiles, lighting fixtures and the refurbishment and reuse of existing furniture. In total, 252kg of light fittings, and 24,566kg of furniture were diverted from landfill, with the furniture refurbishment ( using fabric made from post consumer plastics) saved 9906kg CO2