Leading law firm Howes Percival is on track to open its new £3m three-story office by the spring.
A topping-out ceremony, which marks the stage when a building reaches its highest point, was held to celebrate the completion of the main part of the Cathedral Close building.
The new St Martin's House will be on a 15-year lease and will feature an open-plan layout, with conference and meeting rooms. The original features and façade of the building will be kept.
Chairman Tessa Haskey said: 'Moving in to a new, modern, purpose-built complex, right in the historic heart of the city, will completely transform our working environment and we are very much looking forward to moving offices next year.
'Creating a contemporary new office space while preserving the character and architectural heritage of the Grade II-listed building has been a tough challenge, but it looks fantastic.'
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