The development retains 33% of the original 1960s primary structure, builds on the existing foundations, while also increasing lettable office floor area by 46%. This minimises embodied carbon, enabling the project to surpass the RIBA 2030 whole life embodied carbon target of <750kg CO2e/m2 and score ‘B’ on LETI’s scheme. The generous light filled atrium at the heart of the building features access stairs that encourages physical activity and chance encounters. An abundance of greenery at lower ground (with a rill of running water), planting in the lift lobbies and on the roof terraces, together with extensive timber panelling, all create a strong connection to nature. The shared space at the atrium’s base encourages social gatherings and promotes the building’s overall sense of community. The site-specific design includes a glazed feature window from which the building derives its name, as well as cascading pocket gardens on Hampstead Road, and masonry façades with 62% solid and under 38% glazed in line with LETI’s Climate Emergency Design Guide.