120,000 sq ft City of London refurbishment innovatively jacks up trading floors in situ, converting 2 floors into 3 using CLT. Navigates constraints from adjacent Bank of America, underground tunnels,

20 Giltspur Street exemplifies innovative retrofit and sustainability through groundbreaking structural engineering. Facing exceptional constraints—unable to extend due to adjacent buildings, tunnels, archaeology and St Paul's sight lines—the project ingeniously jacks up existing trading floors in situ, converting two floors into three using CLT. Retaining 80% of original structure achieves outstanding 89kgCO2/m2 embodied carbon, while delivering 30% gross and 41% net area increases within the existing envelope. Green/blue roofs enhance biodiversity, and shell-and-core delivery prevents wasteful fit-out cycles, demonstrating pioneering methods in constrained urban regeneration.