London Stock Exchange, 10 Paternoster Square
Contractor Bovis Lend Lease Ltd/ Stanhope PLC
Photos: N. Kane/ Charlotte Wood
This challenging project for the new home of the London Stock Exchange has been built on one of the most prestigious squares in the world.
This new building, which has been designed and developed by Eric Parry Architects and Sheppard Robson Architects with technical consultancy from Arup Façade, is situated at one of the most attractive architectural locations in London, adjacent to St. Paul’s Cathedral,
The building has an essentially clean architectural solution, which blends in with the texture of this important area. This was achieved by the use of Portland stone in conjunction with Focchi’s curtain walling technology.
2. Suspended structural silicone glazing acting as sun shading
3. Specialist pressure plate system for ground floor and Atrium Roof areas.
4. Structural silicone glazing for the internal light wells and balustrades.
1. Unitised curtain walling
The sobriety of a site such as Paternoster Square has been preserved by using non-reflective glazing with thermally broken Polyester Powder Coated (RAL 7030) profiles, which are harmoniously inserted into a grid of Portland stone.
The perimeter curtain walling consists of 2 different types of units:
Units inserted into the vertical strips formed between the Portland stone clad columns from floors 1 to 5.
A continuous zone of curtain walling crowning the upper floors of the building (the 5th – 6th and 7th ) with sunshading formed by feature glazed panels.
A total nr. of 1100 curtain walling units were used, the largest dimension used was 1600mm x 5100mm.
A strict testing regime totalling 15 no. tests were carried out to ensure the integrity of the design of the system:
3 no. weathertightness test sequences to a mock up of 6000mm x 4000mm 1 no. safety test to an ultimate pressure of 4 Kpa. (to simulate bomb blast pressure)
2 no. frontal acoustic tests
2 no. flanking acoustic tests
2 no. bomb blast tests using a TNT charge of 500 Kg.
2 no. impact tests to the suspended structural silicone laminated glazing
3 no. on site watertightness tests during the installation process.
Every individual unit, including those used at the corners, was prefabricated in our factory and then delivered to site, ready for the installation. This allowed for thorough quality control procedures to be carried out “in-house” and minimise on-site operations.
A particularly interesting feature is the arrangement of the curved façades where the use of curved fascia, stone and coping elements permitted the use of facetted glass units without interrupting the radial aesthetic of the façade.
2. Suspended structural silicone glazing acting as sunshading The 220 no. laminated glazed panels (15mm, 1.52pvb, 12mm, average dimension 900mm x 4800mm, weight 300 Kg), were formed using heat soak tested toughened glass panes and have been purposefully “randomly” arranged.
The fixing of the glazing was by a structural silicone bonded channel to a continuous stainless steel rail. This silicone is screened from view externally by a satin polished stainless steel fascia.
A sequence of impact tests was carried out to ensure the reliability and security of this innovative fixing method of the glazing. It was demonstrated that the period of at least 24 hours would elapse from the initial fracture of either one or both panes forming the laminated pane until complete failure of the glazed panel. Though it is important to note that the test panel collapsed from it’s frame only after it had been inclined at an angle, not when it remained vertical.
3. Pressure plate stick system
The importance of the Stock Market as an institution and the particular location of this building encouraged the Client to request bomb blast tests which would guarantee the ability of the curtain walling system to absorb the dynamic pressure caused by an explosion.
The installation of double glazed units (4500mm x 1500mm) at roof level required a detailed method study. Though this also helped to provide a suitable glass replacement strategy in the event of failure.
A concealed fixing system and non-slip glazing allow for both normal cleaning operations and also the extraordinary maintenance.
4. Structural glazing
The need for natural light inside the building has been realized successfully by the use of a succession of heat soak tested toughened and laminated glazed panels (both panes 8mm with 1.52mm pvb) 4300mm x 1500mm, at the open areas. These panels continue along the line of the external decorative stainless steel strip at the floor slabs, but blend in effortlessly both internally and externally due to the application of a bespoke ceramic frit.
The appearance of the circulation areas has been enhanced by the use of a structurally glazed balustrades in order to minimise visual impact and provide an inbuilt elegance to these zones.
Eric Parry Architects
Eric Parry Architects was established in 1983, the year Eric Parry was appointed as a lecturer in architecture at the University of Cambridge, where he taught until 1997. In 2006 Eric Parry was elected Royal Academician (RA), one of the highest accolades for a practising architect or artist in the UK. In addition to his work in architectural practice, Eric Parry has held a number of eminent posts including President of the Architectural Association. He also currently serves on the Royal Academy Architecture Committee, the RIBA Library Committee, the Kettles Yard Committee and the Mayor’s Design Advisory Panel. He has in the past served on the Arts Council of England’s Visual Arts and Architecture panel and the RIBA Awards Group. Eric Parry Architects is an established and award-winning practice with a portfolio of notable work. In 2012, AJ100 Award win for Eric Parry Architects. The practice won the award for Fastest Growing Practice and was highly commended for both Building of the Year and Practice of the Year at the annual awards held in London.
In the practice’s 75-year history, Sheppard Robson has designed award-winning architecture, interior design and masterplanning projects around the world, building a strong reputation across numerous typologies – including office, education, residential, healthcare, science and retail projects. From their head office in London and studios in Manchester, Glasgow and Abu Dhabi, the founding principles of innovation and sustainability continue to shape the work of the practice and its interior design group (ID:SR), reinterpreted and enlivened by the creative talent of their designers. The work of the practice benefits from an ability to have a constructive dialogue with clients and end-users, as well as collaborating closely with other members of the project team throughout the design and delivery of a project.