20 Giltspur Street

This 120,000 sq ft commercial refurbishment in the City of London demonstrates exceptional innovation in overcoming significant urban constraints while prioritising sustainability. Originally connected to the Bank of America Building but since separated, the project faced a challenging brief: maximise potential while minimising environmental impact, despite being unable to expand upwards (St Paul's Cathedral sight lines), downwards (monument and Post Office Railway), or outwards (adjacent bank, public thoroughfares and roadways). The solution came through an ingenious "floors up" engineering approach, where existing trading floors were jacked up in situ, enabling the conversion of two existing floors into three new levels constructed from cross-laminated timber. This intervention delivered remarkable spatial efficiency—achieving a 30% increase in gross area and 41% increase in net usable area within the existing envelope. Sustainability sits at the heart of the design. By preserving 80% of the original steel structure rather than demolishing and rebuilding, the team dramatically reduced material consumption and construction waste, achieving an outstanding structural embodied carbon performance of just 89kgCO2/m2. The façade strategy retains as much existing cladding as possible, with necessary replacements designed for optimal thermal performance. Urban greening features prominently throughout, with green and blue roofs, façade planting, and landscaped terraces at the fifth and sixth floors enhancing biodiversity and occupant wellbeing. The roof plant has been consolidated to create valuable new office space offering unique views towards St Paul's Cathedral. The scheme celebrates its historic context by integrating and improving public access to a preserved section of the London Wall. A welcoming double-height reception and comprehensive end-of-trip facilities support modern workplace expectations, while office spaces are delivered to shell-and-core standard to prevent wasteful abortive fit-out cycles. Through thoughtful circular economy principles, including the reuse of raised access flooring from the original building, 20 Giltspur Street sets a new benchmark for commercial refurbishment in constrained urban sites. It demonstrates how innovative engineering can unlock substantial additional value whilst prioritising sustainability, breathing new life into an existing asset rather than starting anew.