The new corporate headquarters of Unilever, the world’s third-largest producer of foodstuffs, were built in the heart of London, and enjoy a clear view of Blackfriars Bridge and the Thames. On the Victoria Embankment, the London architects office Kohn Pedersen Fox Associates contrived to strike a delicate balance between historic architecture and modern façade technology. The original building was completely gutted and then underwent extensive interior-fitting work, including an integrated atrium, which soaks up the sunlight that permeates the roof glazing and the halo-glazed west façade.
Seamlessly interwoven shapes and line architecture determine Kohn Pederson’s draft design. Clamped onto the storey ceilings at the top and bottom, the atrium-glazing panels are placed close together; at the top, they are slide-mounted in order to absorb any movements in the ceilings. The panels are joined by the closely set, but barely discernible vertical joints to form an harmonious meandering glass sheet. Made of glass-fibre reinforced plastic (GRP), the intermeshed socle panelling appears to have been moulded from a single cast and accentuates the horizontally designed architecture. The interchange between transparency and physical existence is carried over onto the roof area, where the horizontal lines dissolve into a steel load-bearing structure composed of triangles and clad in GRP half-shells. Above the structure, light domes fuse into a seemingly uniform glass roof. Such sensual architecture in a continuous form could not have been fashioned to such a high degree of perfection without applying GRP techniques. Glass-fibre constructions provide a fitting response to today’s free-form, CAD-driven architecture. The free forms configured from polygonal lines in a computer program are transposed into softly rounded inverse shells using CNC millers. This method produces 3D shells which could not have otherwise been manufactured from sheet metal to this level of perfection.
The building-high, fully glazed west façade also boasts an extraordinary degree of transparency. An area of just under 1,000 square metres forms an almost seamless glass shield, interspersed solely by sporadic, horizontally set stainless-steel sheathings that spawn an overall horizontal pattern. The “non-material” effect was achieved by the selective use of glass as a static-like element. Tensile bars inserted behind the joints are joined to the force-fitted façade bolts using metal shoes and bear the vertical load of the glass panels. The façade is reinforced against wind loads using laminated-glass fins that create its slender profile. In addition, tension/compression rods connect each node to the ceiling behind in order to minimize façade oscillation. The reinforcing fins are made of three-ply glass, with a special inlaminated colour membrane that changes colour depending on the angle in view. The colour’s artistic aspect is set off against the glass façade’s technoid character; irrespective of whether onlookers gaze at or through the construction, the charm of the reduced effect and the ever-changing hues playing off the reinforcing glass fins animate the façade.
