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The distinctive form of the 225-meter Leadenhall Building is part of London’s ‘City cluster’. As well as a bold addition to London’s skyline, it soon added to the City’s language too, being affectionately dubbed the ‘Cheese Grater’. Designed by Rogers Stirk Harbour + Partners, it sits directly opposite another of our collaborations with Sir Richard Rogers, the iconic Lloyd’s building, as well as St Mary Axe (the ‘Gherkin’), Heron Tower, Tower 42 and the Pinnacle.
Together with Rogers Stirk Harbour + Partners, we won the 2001 competition to redevelop the site for British Land with an approach that met both of their main objectives: speed and space.
Project Summary
42 floors
82%fabricated offsite
56,000m2 office space
Challenging timelines
• Speed, as the businesses in the City’s financial heart know, is a competitive advantage. From demolition of the existing P&O building to construction of the new tower, rapid construction was a critical factor.
• The efficiency of a building can be seen it its net-to-gross ratio – how much of the building’s space is lettable. In this high rent location, the design needed to create the maximum net space.
• Though smaller in scale than many of its newer neighbours, St Paul’s remains the icon of the City. In this sensitive location, the building would have to preserve views of the Cathedral from Fleet Street
“ We are led to seek overall quality, fitness for purpose, as well as satisfying, or significant, forms and economy of construction. To this must be added harmony with the surroundings and the overall plan. ”Learn more about our valuesSir Ove Arup Founder
Demolishing norms
Traditionally, the replacement of one building with another is a linear process. The old building is demolished. The site is cleared. Foundations for the new building are laid. We were able to save months on the Leadenhall Building’s construction programme by challenging this process. Our demolition strategy for the old P&O building allowed for new perimeter foundations to be installed in parallel with the removal of the substructure. Effectively, our strategy allowed for demolition from the bottom up, allowing for removal of higher floors in parallel with foundation works.
Structure as architecture
Our founder, Ove Arup, championed the close collaboration of architect and engineer for the elegance and efficiency of the design it produced. For the Leadenhall Building, this partnership allowed for structural steelwork and building services to become an integral part of the architectural concept. The steel megaframe forms part of the detailed architecture as well as carrying many services. Critically, it greatly reduces the need for columns that interfere with lettable space. The huge office floors are virtually column-free. Even the largest floors needed only six columns.
As well as adding lettable space, the megaframe allowed for an ambitious construction schedule. Being able to rely on accurate machining of the steelwork meant large sections could be prefabricated, greatly reducing the time needed for shimming on site. Accurate fabrication also meant each floor’s table structures could be lifted into position with their services and floors already attached. In all, 85% of the finished building was prefabricated off-site.
Respecting the neighbours
The distinctive triangular form that earned the ‘Cheese Grater’ its nickname is a sensitive response to the building’s location behind St Paul’s Cathedral. Its profile leans respectfully away from Wren’s masterpiece. Its unobtrusive silhouette in fact allowed for a much taller building, with more lettable space, than would normally be acceptable is such a sensitive location.
Shaping a better world
Founded by Sir Ove Arup, we are firm of designers, planners, engineers, architects, consultants and technical specialists all focused – like our work at 52 Lime Street – on shaping a better world.
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