One Southwark Bridge

The refurbishment set out to modernise the building without losing its character or wasting what was already working. Commended by Southwark Council’s Director of Planning and Growth for its sustainable design approach, it delivers a ‘best in class’ workspace with a completely new façade and extension. In a site hemmed in by the river, Southwark Bridge and two scheduled monuments, and sitting on one of the largest archaeological sites in the world, the design had to work hard to add space, improve energy performance, and meet today’s workplace expectations while keeping disruption to a minimum.

We developed the civil and structural engineering designs with BDG and Squire & Partners. Most of the original frame was kept, avoiding unnecessary demolition. Careful checks of archive drawings and site investigations confirmed the structure could take more load, allowing for a new rooftop floor, extended façades, and reconfigured infills on all sides without heavy strengthening. The rooftop addition was chosen to minimise impact on nearby heritage assets, and extensions to the front and sides were planned with early archaeological works during the enabling stage.

Where new foundations were unavoidable, these were threaded in around archaeology and existing river wall anchors. An agreed strategy with Southwark Council and the archaeological team meant low-grade deposits were removed after investigation, while anything of note was encapsulated and protected so new structure could span over it. Pile locations were kept flexible to accommodate discoveries, giving the client and contractor greater cost and programme certainty. The east infill sits on a cantilevered ground beam, the south elevation spans a full-height truss over glazed frontage, and stability comes from the original concrete cores extended upwards. Civil works reused most of the existing drainage system and added green roofs and re-purposed underground tanks to cut rainwater discharge by about a third.

The building achieved a BREEAM ‘Outstanding’ rating, driven in large part by the 95% structural reuse strategy that significantly reduced embodied carbon, the integration of green roofs, and the repurposing of the former diesel tank as a sustainable urban drainage storage system. The performance-led façade design, developed alongside the architectural teams, also contributed to the rating by improving environmental control while maintaining the building’s riverside outlook.

The modern, high-performing building now forms part of WPP’s Southwark campus, sitting opposite our Rose Court project to create a cohesive workplace destination.