BNP Paribas’ new London headquarters by Marylebone station was designed by The Whinney Mackay-Lewis Partnership to include state-of-the-art dealing floors for its UK investment banking operations.
With leases due to expire on its other London offices, there was a critical need for the new building to be completed and operational before the end of 1997. This constraint was significant to the choice of the site in Harewood Avenue, with its existing planning permission for a 45,000m2 office development, and the decision to use precast cladding panels to ensure that its modelled façades were efficiently achieved to the highest standards of quality with programme certainty.
The early appointment of the precast cladding and window specialist trade contractors not only facilitated their contribution to the design and construction processes but also allowed the opportunity to carry out an extensive programme of static and dynamic testing of a mock-up of the external façade.
The colour of the precast cladding panels was chosen to respect the adjacent Marylebone station and hotel and therefore included red terracotta. The terracotta tiles, supplied by Shaws of Darwen, were incorporated as bands during the casting of the reconstructed stone finished spandrel panels. On the Harewood Road elevation, the precast spandrel panels with three courses of terracotta tiles are typically 3m wide. They form the feature oriel bays and include curved-on-plan units. The similar spandrel panels to the other elevations are typically 6m wide with one band of terracotta and weigh up to 5.5T each. The fluted semi-circular column units, up to 7.5m high, and parapet panels at 5th floor level are also reconstructed stone finished precast concrete units, each individually supported and fixed using stainless steel fittings to the structural concrete floor slabs and steel columns. The reconstructed stone was produced as a grade 45 mix using a blend of red and buff coloured aggregates without the need for any pigmenting of the cement. The finish was achieved by the rubbing and controlled acid washing the surface.
Incidentally, the flamed textured Rochebelle Rose limestone walls that flank the entrance and turn the external corners of the building were also supplied and fixed by The Marble Mosaic Co Ltd.