The centre has been described as 'four drums connected by a glass-roofed foyer'. The drums have convex, nonsymmetrical walls, resembling a flattened orange in shape. They are set at the corners of the site and contain galleries. The foyer, at first-floor level, forms the centre and extends between the drum walls to form entrance canopies. On the ground floor are cafes, bars and a shop. Below, a basement contains ancillary accommodation.
The roof of each drum is fitted with a large wind-cowl. Fresh air is drawn through the 'mouth' of the cowl into the building and used air is discharged through the 'tail'. The 11mdiameter cowls rest on steel rails fixed to concrete roof slabs which are driven to face the prevailing wind.
The ground- and first-floor slabs are constructed of cast in-situ concrete resting on tapered, mushroom-headed concrete columns. Each drum is formed of 30 'ribs' - curved and faceted 406 x 176mm universal beams. Ten of these ribs extend to a hub to support the concrete roof deck.
The ribs are infilled with corrugated steel sheeting and covered with a vapour barrier and mineral-wool insulation. This system is overclad by a 'Brodscreen' cladding system of stainless-steel panels supported on an extruded aluminium carrier system fixed back to the steel ribs by an adjustable plate of U-shaped brackets.
The panel joints are silicone-sealed with the carrier forming a back-up drainage channel. Set inside the steel frame is a blockwork drum with the space between forming the supply air plenums feeding fresh air down to floor level .
The roof of the foyer is made of double-glazed laminated glass panels on an extruded aluminium carrier system, supported by a tubular steel framework. The junction between the glass roof and the faceted cladding is formed by a gutter of galvanised steel lined with Sarnafil.