Proposals for the 1920s office building include a new roof garden and more workspace
Henning Larsen has submitted plans to redevelop a 1920s office building at 43-45 Portman Square in London. The proposal, created in collaboration with BentallGreenOak (BGO) on behalf of the Welput Fund, has been submitted to Westminster City Council for approval.
The proposed redevelopment includes a comprehensive retrofit of the existing building, incorporating ground-floor retail spaces, communal workspaces, and a new atrium.
“It is a true privilege to reimagine an iconic 1920’s building into an inviting, collaborative workspace that meets contemporary standards. We are proud to partner with our ambitious client, BGO, on this project, which we hope will show a vision that both honors the history and embraces the future of the Portman Estate Conservation Area in London,” said Jacob Kurek, global market director, Henning Larsen.
The building is designed to operate with net zero carbon emissions and is anticipated to deliver a 72% reduction in energy intensity compared to current levels.
Portman Square, situated in Marylebone, serves as a link between Oxford Street’s shopping district and the residential Portman Estate. The site sits within the Portman Estate Conservation Area.
The building, originally designed by Messrs Joseph Architects in 1928, underwent partial reconstruction in 1996. The latest redevelopment will retain the historic façades while replacing the existing windows to improve the building’s thermal performance.
“With 70% of Westminster within a conservation area, the redevelopment of 43-45 Portman Square balances the core values of retrofit first”, said Alexander Morris, managing director of BGO.
The project includes the removal of the current roof to allow for additional office space and outdoor terraces. The proposed mansard-style roof extension will replicate the form and pitch of the existing roof.
A new roof garden is designed to support local biodiversity policies and create a biophilic working environment, featuring a rainwater retention system, birdhouses, gathering spaces, and a pavilion.
The interior of the building will also undergo significant refurbishment, with several floors of the eight-storey atrium being infilled to create more office space.
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