The Vision
20 Gresham Street is a commercial office refurbishment in the City of London, transforming an existing multi-let building to meet the expectations of modern occupiers. The targeted retrofit enhances occupier amenities, upgrades office environments and repurposes underutilised basement space to maximise asset value.
The scheme included the refurbishment of the main reception, CAT A refurbishment of two office floors, and the transformation of basement car parking into a high-quality end-of-journey facility complete with cycle storage, showers, lockers and changing facilities.
Drawing on our original shell and core design knowledge, we delivered solutions that responded to the building’s existing constraints while maintaining full operation throughout the works.
The project overcomes complex spatial and servicing challenges to successfully reposition the building, delivering improved performance, enhanced occupier experience and long-term flexibility for future tenants.
Our Contribution
Hilson Moran provided building services engineering and sustainability consultancy services throughout the project, working alongside JRA Architects, RLB and Waterman from RIBA Stages 2 to 4 before continuing as Contract Monitoring Team (CMT) during delivery.
Having originally delivered the shell and core design for the building nearly 20 years earlier, our team brought valuable insight into the existing infrastructure, helping the wider project team identify opportunities and navigate constraints within the occupied building.
A key technical challenge involved converting basement parking space into fully serviced shower and changing facilities. Working closely with the architect and structural engineer, we developed solutions that responded to restricted headroom, structural limitations and existing waterproofing constraints.
To address these challenges, we developed a carefully coordinated pumped drainage strategy that minimised equipment requirements while maintaining accessibility and long-term maintainability. We also introduced new electric hot water generation systems to provide sufficient capacity for the expanded shower facilities within constrained plant spaces.
Ventilation systems were reconfigured and extended to serve the new facilities and retained basement uses, while existing smoke ventilation systems were adapted and recommissioned to suit the revised layout.
Design for People
The new end-of-journey facilities encourage more sustainable commuting choices, while the refurbished office floors provide contemporary, adaptable workspaces designed to meet the needs of modern occupiers.
Close collaboration between Hilson Moran and JRA Architects ensured the successful integration of exposed services, lighting, air distribution and architectural finishes. Occupant comfort was further enhanced through upgrades to building systems, including the replacement of manual trench heaters within the reception with fan-assisted units and the installation of energy-efficient LED lighting throughout refurbished areas.
Delivering these improvements within a live, multi-tenanted building required close coordination across the entire project team to maintain uninterrupted services for existing occupiers throughout construction.
Design for Planet
The project demonstrates how refurbishment can extend the lifespan of existing commercial assets while reducing the environmental impacts associated with demolition and new construction.
By retaining and adapting existing building infrastructure wherever possible, the scheme maximised the value of embodied carbon already invested in the asset. Existing systems were upgraded and repurposed to support new occupier requirements, while energy-efficient LED lighting and modern building services improve operational performance.
Through thoughtful retrofit and adaptive reuse, the project team has successfully repositioned 20 Gresham Street for the next generation of occupiers while supporting a more sustainable approach to commercial real estate.
