Mortimer Street is smack in the heart of London, just off Oxford Circus in the swanky Fitzrovia district. It could not be a more desirable address but if you're a contractor renovating 4,000 sq ft, there it could be a major headache.

But thanks to G-Frame Structures and their smart application of an easy-to-build Sylva™ building kit by Stora Enso, this renovation was a success on a number of levels.

To give you the backstory, the building was originally a dress-making co-op: Hamilton and Co. The storefront was often the talk of London as long ago as the 1880s for its less restrictive clothing, including ingenious cyclewear, making it easier for women to ride bikes and, with that, gain more independence — a piece of herstory we can all tip our bike hats to.

Today, 27 Mortimer is still the talk of the town, but now it's for its incredibly small climate footprints and much sought-after office space.

Barr Gazeta Architects' design heightened the building, creating a new fifth floor and an additional 4,000 sq ft/1,219 m² workspace. They also created new communal areas, elevators and a five-foot living wall for a biophilic effect. What is particularly clever is that from the outside, you can hardly tell the difference.

The roof extension is concealed behind a shallow pitch traditional 'mansard roof profile' (two slopes on each side). This is why, from the street, you cannot see the additional space. The extension also acts as a second roof terrace, providing a peaceful escape from the street noise in a cosy timber-clad green sanctuary.

Lightweight but robust, made-to-measure Sylva™ CLT Walls and Floors enabled installation that had to be done on weekends only to not disrupt the workers. We cannot think of another material that would have worked in such exacting limitations in this very tight infill space.

What you are looking at now is a highly desirable 13,500 sq ft of Category A and B workspace.

Extending and improving an existing structure with timber not only provides a feel-good glow that heritage is preserved. The construction carbon footprint is a fraction of what it would have been to demolish and build new.

From an economic standpoint, the renovation was also a sound investment, offering leasing agents a sustainable differentiating factor. As the next generation of consumer awareness and feeling about climate change rises, businesses increasingly see their workplace or HQ as a brand extension that reflects their corporate sustainability goals. 27 Mortimer provides just that with lots of its own character and cycling-short-charms.

Awards

BREEAM Excellent Refurbishment and Fit-out ratings

WELL Gold enabled (even the air filters were installed to ensure superior levels of fresh, clean air, which are now delivering 30% more fresh air than minimum CIBSE guidelines).