engineering.
Located on a prominent triangular island site at Holborn Circus, the redevelopment of 40 Holborn Viaduct transforms an existing 180,000 sq ft office building into a highly sustainable, all-electric workplace.
Unlocking new potential through structural adaptation, vertical extension and the sustainable reinvention of existing buildings.
Originally completed in 2008, the building comprises a steel frame with composite metal deck floors, nine storeys above ground and three basement levels. By retaining approximately 70% of the existing structure, the scheme significantly reduces embodied carbon while extending the building’s lifespan and enhancing its commercial value.
The redevelopment introduces three additional storeys above the existing roof level, alongside extensions to the western floorplates and new landscaped terraces offering panoramic views across London. A high-performance façade incorporates suspended balconies with integrated planting, contributing to biodiversity while improving the building’s environmental performance and its relationship with the surrounding public realm.
Our structural approach prioritises the reuse and adaptation of the existing building, with targeted interventions to accommodate the increased floor area and revised architectural arrangement. These include the introduction of new structural framing to support the vertical extension and suspended balconies, internal modifications to facilitate reconfigured spaces and selective strengthening of existing columns, beams and connections to accommodate additional loads. The proposals also seek to maximise the reuse of existing foundations, minimising the need for new substructure works.
Together with the comprehensive replacement of building services and enhancement of tenant amenities, these interventions create a flexible, contemporary workplace aligned with the client’s sustainability, wellbeing and environmental, social and governance (ESG) aspirations. The project demonstrates how a considered, retrofit-led engineering strategy can unlock significant environmental and commercial value while preserving the embodied resources of an existing building.
2024 WAFX Award – Reuse
