Sturgis Associates has lodged this scheme in London's West End with Westminster City Council's planning department.
The £20 million scheme - on New Cavendish Street - will 'substantially upgrade' an H-shaped office and residential building that covers an entire city block.
The Sturgis designs - for Greycoat Estates and City Offices - will completely rewrap the building, increasing the office space and creating nine new apartments.
It will create a new entrance for the office and will also make use of terracotta panelling in a bid to echo local Victorian architecture.
Simon Sturgis, of Sturgis Associates, said: 'Architects have a huge responsibility towards improving the urban landscape in which residents work and live.
'The area immediately surrounding New Cavendish Street is worn down and in need of regeneration,' he added. 'Our approach ensures that the design of the building contributes to the repair of the immediate environment and local streetscape.'
Construction is scheduled to begin in the spring of this year, if planning is granted.by Ed Dorrell