BAU 2019: case study facades

London: New White City Campus of Imperial College - Prefabricated high-class facade elements made in Germany

Prefabrication is and always has been a key issue in construction on account of the advantages associated with it: components can be manufactured under ideal conditions independent of weather and then mounted or assembled efficiently so as to save time and money. For example this way, it is now possible to mount prefabricated houses within a single day. Prefabricated elements also play a key role in the safety-relevant area of facades. Apart from the goal of saving time and money as referred to above, there is yet another advantage in densely-populated cities: in many cases, there simply is not enough space to store semi-finished products on construction sites in terms of safety and logistics. A perfect example of where these aspects applied was realized in London in 2018 and involved competent collaboration by the renowned German companies Lindner Fassaden GmbH (Arnstorf) and Agrob Buchtal GmbH (Schwarzenfeld).

A portrait of the building owner
The “Imperial College of Science, Technology and Medicine” (Imperial College) is a university and technical college of applied sciences in London. Founded in 1907, it is among the leading international institutions of its kind. In 2013, the facility acquired a site spanning 46,500 square metres in the London suburb of White City, with plans to erect a building housing research, teaching, companies, and apartments. This saw the entire campus area double to 93,000 square metres. These impressive figures are an indication of the sheer size and significance of Imperial College. Since then, lots has happened on the new site referred to as White City Campus (aka Technology Campus): the “Translation & Innovation Hub” opened in 2016; 2017 saw the “Invention Rooms” go into operation and ground was broken for the “Michael Uren Biomedical Engineering Research Hub”; the “Molecular Sciences Research Hub” (MSRH) opened in 2018. The so-called Block F was also built during this period. Completed in 2018, it accommodates around 200 apartments for key college personnel.

Block F: high-end facade elements
This formulation certainly has a double meaning: it relates to the high technical demands and the fact that the residential tower is approximately 140 metres high. With its 35 floors and its distinctive sculptural architecture, it is a firm landmark of West London. The building shell comprises about 2,400 prefabricated facade elements cladded with glass, ceramics or a combination of these two materials. The elements were realised by a successful interplay of competencies exhibited by the two renowned specialists Lindner Fassaden GmbH, D-Arnstorf (in co-operation with its local partner Lindner Facades, London) and Agrob Buchtal GmbH, D-Schwarzenfeld (in co-operation with its local partner EH Smith, GB-Solihull and GB-Brasted).

Details on the prefabricated elements (part of Lindner Fassaden GmbH)
The warm facade largely comprises elements which are 1.5 metres wide and 3.25 metres high, whereby the Lindner CW85 system permitted a certain level of standardisation and therefore improved feasibility. At the same time, the building’s distinctive silhouette also demanded individual special solutions. One example is represented by the staggered eastern side where every second floor forms a step offering patios for its residents. Furthermore steel balconies were created elsewhere. This required the use of thermally separated “wing elements” 2.25 metres wide which not only clad the cold area but also serve as wind and visual protection. The southwest side is marked by another typical feature in the form of an elevator shaft which is visible from afar and where all-glass elements measuring 3.05 by 3.25 metres ensure optimum transparency.
All elements were manufactured by Lindner Fassaden GmbH in Arnstorf in Lower Bavaria. Before that, the elements and composite system were inspected in detail in terms of the requisite properties such as sealing against air and water or noise protection. The standardised versions were then manufactured within the framework of sophisticated line production while special versions such as wing or corner elements were manufactured in a so-called island production process. In optimising the material flow, the distinctive experience offered by the company in areas of lean production and the Kanban system paid off in practice.

Details on the ceramic cladding (part of Agrob Buchtal GmbH)
The architects PLP Architecture, London, desired a salmon-coloured terracotta shade in three differentiated nuances and two surface finishes (smooth and grooved) for the ceramic-clad elements. Agrob Buchtal complied with these explicit specifications using specially-manufactured facade tiles in three lengths of up to almost 150 cm and a height of 29.7 cm (a perfect fit for the element grid) as well as other special formats - yet more evidence of the fact that tailored project-specific solutions are among the proven strengths of this architectural ceramics brand. This is also shown by some further aspects: in line with the specifications, the tiles feature a mesh glued to the back which serves as fall protection in the event of intentional mechanical damage. To secure the facade ceramics to the elements manufactured by Lindner, a special variant of the “Omega” profile for the modern KeraTwin K20 fastening system was developed and used. One relevant issue in terms of the statics of a building concerns the weight of the facade cladding. Agrob Buchtal scores well with around 32 kg per square metre as this value is comparably low for a ceramic variant but does not compromise stability: the thickness of the tiles is tared exactly, and supplemented by high-quality raw materials as well as special expertise in the areas of moulding, drying and firing.

Sophisticated logistics
Prefabrication does not end once the products leave the plant but is in fact a comprehensive process as indicated by this project. The prefabricated components were loaded in accordance with a special system onto steel pallets at the Lindner Fassaden GmbH plant in Arnstorf, whereby a truck load comprised 18 standard elements. For around 2,400 elements, this corresponds with well over 100 trucks which needed to safeguard the carefully timed material flow as there were no possibilities to store components on a large scale on site in densely-populated London. Accordingly, Lindner Facades Ltd. co-ordinated the sophisticated site logistics: on arrival, the pallets were forklifted from the truck and transported to a so-called buffer area where the elements were inspected and cleaned before being transferred to the building’s designated safety zone. From there, the prefabricated components were lifted by crane into a vertical position, hoisted to their respective spots on one of the 35 floors, and fastened by qualified fitters from RF Fixing Ltd.

Block F on the new White City Campus of Imperial College is a perfect example of the advantages offered by prefabricated facade elements. Smooth co-operation by everyone involved literally gave rise to an outstanding and widely-visible result with an architectural brilliance and power. / /

Werner Ziegelmeier (Head of Public Relations)
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