Stiff + Trevillion reveals revamp of banking HQ in London’s Square Mile

The London-based practice has submitted an application to refurbish and extend the Woolgate Exchange at 25 Basinghall Street in the heart of the capital’s financial district.The plans for the nine-storey office building, designed by Sidell Gibson and completed in 2000, include a two-storey roof extension with a roof terrace on the north-west wing and a large new rooftop ‘pavilion’ with planters and seating.The building’s exterior will also get a green facelift with curved balconies cantilevered from the existing structure, and a portico created by the balconies above. The entrance will also include a double-height collonade.According to planning documents submitted to City of London, the retrofit project will retain 98 per cent of the existing building, avoiding the release of 13,814 tonnes of embodied carbon. The architect’s design statement describes the scheme as ‘an exemplar for green infrastructure’ which will ‘demonstrate best practice for urban greening’.It concludes: ‘The subtle modifications to the buildings design and massing, including greatly improved urban greening, will reposition the building and contribute to the wider context along both Coleman Street and Basinghall Street. The refurbishment of the building interior will provide contemporary, high-quality office space suitable for modern working practices with a focus on amenity and wellbeing.’Woolgate Exchange was developed by property investor MEPC in 2000 and leased to German bank West LB before being bought by Canadian investor Ivanhoe Cambridge in 2013 for a reported £265 million.According to the planning application, the building is currently empty, with the applicant listed as a trust owned by French bank BNP Paribas and Anley Trustees.