One Undershaft

Sector

Office Building

Location

London, UK

Year

2023

Architects

Eric Parry Architects

Client

FMDC

3D Illustrations

Eric Parry Architects

Eric Parry Architects has submitted revised plans for the 74-story One Undershaft, set to become Western Europe’s joint-tallest building at 309.64m, matching The Shard. The City of London approved a previous 289m design in 2019, featuring a 73-story cuboid tower with 90,000m² of office space. The new proposal, developed with Stanhope, introduces an 11-story podium and three stepped glazed volumes with outdoor amenity spaces.

Our role was to inform the façade design team by supporting them with solar control and daylight performance assessments for two facade alternatives.

Our work aims to:

Assess solar performance(Peak Solar Gains) of the currently considered facade design and assess whether they meet the solar gains target
Compare daylight performance (sDA) between the considered facade designs
Assess the risk of increased visual discomfort of the currently considered design. As the bottom element of this design is located rather centrally within the field of view of occupants, it may redirect sun rays in a way that causes visual discomfort. We performed a simple raytracing exercise to assess the potential of direct sunlight to reach inside spaces after being reflected by this element.