Retrofit route chosen to reduce carbon impact

MATT Architecture parked its initial plans for a 44-storey tower on the site and opted instead for a “deep refurbishment” of the Grade II Listed 1920s City headquarters. This move to adapt and reuse an existing building and give it a new lease of life was taken with a view that a retrofit approach would enable both embodied and operational carbon reductions.

As is the case with listed buildings, how to improve performance without damaging the historic architectural features that underpin the listing was a significant undertaking. Active measures, like full electrification and replacement of the air handling gear, alongside more passive measures to improve the environmental performance, such as replacement windows and a general upgrading of the thermal envelope were employed.

Sir Edwin Cooper, the building’s original architect, was particularly celebrated for his facades so MATT Architecture opted to use a specialist insulating plaster on the internal face of the envelope to improve the overall U values while maintaining the external appearance of the solid masonry elevations.

Designing solutions for today’s workplace needs

Optima worked closely with the architects and contractors to achieve the prime design solution for the interior partitioning and doors where fire performance, guarding, and acoustic comfort was a priority. Here the vision was not only for high-performance systems, but solutions which both complimented the heritage building whilst offering a modern twist.

Work on the interior of the building involved changes to the building’s layout to create more spacious, flexible office accommodation, and to reintroduce natural light into the centre of the building.

MATT Architects’ designs added new projecting dormers to the roof and have created a new glazed “notch” between the St Mary Axe and Bury Court elevations of the building. The glazed “notch” also reintroduces natural light into the deepest part of the building plan and enables the creation of balconies on every floor of the building – providing external amenity space for the well-being of occupants.

Opting for glazed partitioning and doors echoed this design intent to help create light, bright interiors in this historic building. The building’s high ceilings, and large arched windows were also at the heart of design for the architects. Taking the aesthetic lead from the striking, tall, black external windows into the internal windows and doors, Optima 117 Plus Shoreditch edition was the solution to match with the external Crittall-framed windows, and was a key factor for the fitout. And offering high acoustic performance the systems support a comfortable working environment for today’s occupiers.

Fire performance meets heritage design

Optima’s Technishield partitions and doors were specified in key areas for fire performance compliance. Again, working as a team with the architects and contractors, we were able to resolve some of the key challenges presented in this unique site.

For example, within the main entrance 90-minute fire rated door sets needed to be incorporated within a heritage arch. We formed a design which utilised a mirror within the arch to give the illusion of the archway being open to the corridor. The result is striking, maintaining the building’s original feel but also managing the required fire performance.

The Baltic Exchange project is notable as it has been an opportunity to preserve and enhance what was desirable to sustain the character of this significant building, and to ensure its future viability and continued use as the home of The Baltic Exchange.

Located in the heart of the City of London tower cluster and overlooking The Gherkin (30 St Mary Axe) which stands on the sites of the former Baltic Exchange and Chamber of Shipping, which were extensively bomb damaged in 1992, this building has been restored to its former glory in a sensitive and high-quality repositioning to deliver best in class office accommodation.