“We knew that there was more to gain by working with the existing fabric of a space instead of racing to the conclusion that it’s better to demolish and start over, so the scheme makes the existing structure work hard to allow for significant reconfiguration.
The building was completed long before Canary Wharf became what it is today and prior to the opening of the Jubilee line extension. The substantial changes in the area in the intervening decades mean that the orientation of the building, its entry points and the way it connects with the surrounding public realm had to be rethought for today’s use.”
Why does the building need to be upgraded?
The existing building was completed in 1991, long before Canary Wharf became what it is today and prior to the opening of the Jubilee line extension. The substantial changes in the area in the intervening decades mean that the orientation of the building, its entry points and the way it connects with the surrounding public realm, has to be rethought for today’s use.
Why did you decide to retain the existing building rather than demolish it?
First and foremost, the building sits over water and therefore is essentially built on stilts. This placed major constraints on adding further floors because it meant we couldn’t penetrate the slab without having to re-pile through the water. This technical restriction around adding height forced us to examine the building in its current state to look at how we could add floorspace without pulling it down and rebuilding it.
Our decision to re-clad the façade was in part driven by our internal reconfiguration. By shifting a stair core and filling in the multi-storey central atrium space, we’ve deepened the floor plate to achieve a considerable uplift in NIA. The new façade, with its expansive glazing, is necessary to introduce as much natural light as possible into the building, but it also provided an opportunity to introduce green terraces to every floor as secondary breakout spaces.
Articulating a façade which is designed to look like a new building, but is in reality a refurbishment, presented a challenge because we were working with the existing structural grids. The grids weren’t necessarily set out where we would have liked them, so each corner had to be treated individually to design around the existing column grid.
As a practice, we very rarely knock down a building and start again, we’re always looking to see what’s possible and how far we can take the existing structure. The building’s location over water is obviously a huge deterrent to demolition. Through design studies we identified that we were able to find an additional 25% NIA through internal reconfiguration and a three storey extension, so we were able to make the numbers add up for the client, Quadrant Estates. They were quick to appreciate the value-add, both from an environmental and viability perspective, in refurbishing the existing building, which ultimately promised a shorter programme and far less embodied carbon.
How did you work to minimise the whole-life carbon impact of the building?
Sustainability and well-being has been at the forefront of the design process. The building has been designed to minimise energy and water use, and provide a healthy, comfortable environment for tenants and visitors. Our energy assessments show that our proposals have reduced the overall energy demand of the building by 62%. The development has taken a fabric first approach, by improving the performance of the external façade; the thermal performance of the new glazing is much higher than the existing marble façade.
In addition to the proposed improvements to the facade, energy efficient measures have been incorporated into the design. For example: the building is all-electric, it utilises high-efficiency building services, photovoltaic panels on the roof, the use of an air source heat pump to provide free heating, and waste heat produced during cooling will be redirected to other areas in the building. We have also interrogated all products used within the building to try and use materials that can be recycled at the end of their life. As a measure of our commitment to sustainable design, the building has been designed to achieve a BREEAM 2018 Excellent rating.
What have been the main lessons from the project that you could apply on other developments?
We wanted to take the time to look beyond what may be a tired or unsightly façade and analyse what the possibilities are. We are no strangers to retrofitting buildings and believe that often there will be more to gain by working with the existing fabric of a space instead of racing to the conclusion that it’s better to demolish and start over.