The Leadenhall Building

PROJECT
SUMMARY

The Leadenhall Building is a 51-storey tower located in the heart of the City of London, bounded by Leadenhall Street to the South and St Helen’s Square to the east. It provides space of the very highest quality for commercial, retail and restaurant use, which reflects the demands of the modern City of London occupiers.  Additionally, it provides two levels of trading floors and a high-quality public realm at Ground level.

The building comprises a number of distinct architectural elements that provide a legible expression of its constituent parts. These elements include the primary stability structure, the ladder frame, the office floor plates and the northern support core.

The scope of our work is the complete external envelope, and internal lift lobbies, totalling some 70,000m2 of glazed and louvred facades.

Key
Facts

• 51 floors

• 70,000m2 of bespoke facade

• Around the clock work on site, Challenging programme and complex logistics

• 16 facade types

• Challenging set of movement and tolerances due to the geometry of the tower and the build sequence

SCOPE

Fully glazed double-skin, externally ventilated facade to the office floor plates, with motorised blinds, and walkway grilles at each floor for access.
Fully glazed double-skin, externally ventilated facade to the office floor plates, with motorised blinds, and walkway grilles at each floor for access
Steel and glass stick systems to the lower Galleria floors
Structural silicone-glazed unitised facade to the North Core.
Glazed entrance systems, with powered doors
Single and double glazed external facades to the north core (lift enclosures).

Facing
challenges

The design intent for the Office Floors necessitated a prefabricated double glazed inner skin, supported at each floor level. The outer skin comprised a single glazed system, suspended from a steel mega-grid via steel mullions, at 7-floor intervals. This created the externally ventilated cavity, 600mm wide, with aluminium walkway grilles and motorised Venetian blinds, connected to the BMS. The structural glazing system to the North Core comprised prefabricated curtain wall panels of typically 2.8m wide x 4.0m high, fixed directly to the feature architectural steel frame of the Lift Enclosure. The facade jointing systems necessary to accommodate panels with totally different support systems are entirely bespoke and complex.
The result is one of the most stunning Office Buildings in the City, made possible by a close and proactive working relationship with the Design and Engineering Consultants, RSHP and ARUP Structures.

Off-site
prefabrication

The facade design maximised the use of prefabricated facade systems,  manufactured off-site in China, and shipped wherever possible as completed assemblies. This significantly improves site installation times and interfaces, whilst maximising the quality associated with off-site fabrication.

Site
challenges

The aggressive construction programme was achieved by maximising the use of prefabrication across the entire project. This approach is key to achieving consistent quality within such a programme, and to ensure that safety of the site operatives remains paramount. The Office facade panels were installed from the floor plates, whilst the large North Core panels were installed from a multi-function monorail system designed to follow the irregular shape of the North Core. Logistics and deliveries to the tightly constrained site required considerable coordination with the Main Contractor, including deliveries during the night. At peak, some 5 shipping containers per day were being delivered to site.