“The design of The Leadenhall Building is the result of a powerful distillation of the key components of what makes a successful office building”
Rogers Stirk Harbour + Partners
The Leadenhall Building’s frontage is angled at 10 degrees. This distinctive, tapering shape is its defining characteristic. It was developed by architect RSH+P from the earliest design stage as a response to specific planning requirements: to protect views of major London landmarks, especially St Paul’s Cathedral in the City and the Palace of Westminster.
This is the reason why, when seen from the key vantage point of Fleet Street to the west, the building appears to ‘lean away’ from the dome of St Paul’s. The design also provides office space that can be configured in different ways.
The building’s tapered shape means that each office floor is ‘stepped back’ and 750 millimetres narrower than the one below it, providing office space in varied sizes to suit the needs of different businesses. With almost all the building’s service functions housed in the North Core, the offices have the additional advantage of fine unobstructed views across the City, the Thames and beyond.
The distinctive tapered shape (1) offers the best balance between preserving the view of St Paul’s dome from the west, providing flexible office space and fitting the City planners’ vision for the eastern cluster. The structure occupies the entire site and provides public space at the base rather than at the top (2, 3). The lifts, toilets and services that heat and cool the building are housed in the north core (4), where blocks of primary colour transform the building’s essential functions into a dynamic and eye-catching display. Steel K bracing (5) adds rigidity to the megaframe, which houses the unusually open-plan office floors (6). Every detail of the structure is clearly visible through the glazing (7), combining transparency and light with immense strength.
“I’m delighted by how well we converted theory into reality and I’m proud of having been involved with such a great building – I think we’ll all be looking back on this one for the rest of our lives”
Project Director Laing O’Rourke
Construction of The Leadenhall Building began in autumn 2011 using some of the most advanced technologies available at the time.
More than 80% of the components were prefabricated off-site, then delivered to the City of London site where they were assembled by a construction team led by Laing O’Rourke. Off-site manufacture makes the building process safer, less wasteful and more accurate, especially in such a constricted area. It also helps to minimise noise and disruption.
The megaframe was made at specialist steelworks in northern England, Scotland and Northern Ireland. It is divided into eight sections, each 28 metres high and comprising seven floors (apart from the first section, which contains five). The steel columns and beams are connected by nodes that transfer forces of up to 6,000 tonnes, while nearly 3,000 ‘megabolts’ (threaded steel rods) connect all the steel parts together.
These megabolts are stretched (‘pre-stressed’) before being installed, so that they create completely rigid joints. This type of construction is more commonly used for bridges and offshore oil rigs.
Lifting the steel frame sections into position required cranes that could lift up to 45 tonnes. The heaviest-duty crane available, however, had a maximum load of 32 tonnes, so two new ones were made especially to construct The Leadenhall Building.
Key to the building’s sustainability is its triple-layer glass ‘skin’. The outer layer of glass is separated from an inner layer of double-glazing by a cavity containing blinds that respond to the sun’s movement, keeping the office space comfortably cool throughout the working day.
The Leadenhall Building is designed and built to the guiding principle of its original owners (British Land and Oxford Properties) – that a sustainable approach is essential to create high-quality buildings. Each design and engineering element is chosen so as to use energy and resources efficiently.
At the heart of the building’s sustainability is its triple-layer glass ‘skin’. The outer layer of glass is separated from an inner layer of double-glazing by a cavity containing blinds that respond to the sun’s movement, keeping the office space comfortably cool throughout the working day.
The external glazing incorporates vents every seventh storey, allowing air to flow freely around the cavity. This minimises the need for artificial cooling – typically the highest single source of energy use in an office building.
Great time and detail has been taken to ensure the design of the building complements the surrounding
architecture, particularly with regard to London’s viewing corridors. Seen from the west looking towards St
Paul’s Cathedral, The Leadenhall Building will appear to ‘lean away’ from the historic