A double-skin facade with Cor-Ten panels
The building, a five-storey office block with an adjacent 16storey tower, is constructed of steel beams and columns with precast-concrete floor slabs.
The principal facades, of double-glazed fixed lights in birch frames, stainless-steel panels and Cor-Ten panels, are enclosed in an outer glass skin supported by a delicate framework of Cor-Ten members.
The metre-wide gap between the facade and the outer skin acts as a ventilation chimney, operated by adjustable louvres at the top, which modifies the effects of the climate on the inner facade and improves sound reduction.
The facades are cleaned and maintained by a cradle suspended from projecting CorTen brackets at the eaves.
Spandrels are clad with corrugated Cor-Ten steel panels bolted to Z-shaped Cor-Ten support frames. The architect designed the Cor-Ten components with the following features:
a 44mm vertical gap between each panel, lined with a Cor-Ten backing panel, ventilates components on both sides;
the edges of the panels allow rainwater to run off cleanly - otherwise residues of water would encourage corrosion;
neoprene gaskets and butyl strips to isolate components from each other.
The outer glass skin consists of a series of 6mm toughened glass sheets bolted to a Cor-Ten framework of vertical 100 x 25mm flats and horizontal 65 x 75 x 8mm angles.
The framework is suspended on 36mm diameter Cor-Ten steel support rods, with turnbuckles for adjustment on site, and is braced by 10mm diameter solid stainless-steel rods.
The glass panels are clamped with stainless steel brackets which are bolted to the Cor-Ten flats and angles; the connection is isolated using neoprene gaskets.