The building enclosure is formed of curved storey-height panels of concrete sprayed onto expanded metal lath and curved reinforcing rods.The floors are steel frame and concrete slab construction.The 6m-high concrete panels are suspended from the steel frame;
generous movement joints are set laterally and continuously between the top and bottom edges of the concrete panels.
The panels are lined on the outside with 75mm mineral fibre insulation and an acrylic render finish, overlaid with a series of 660mm-diameter anodised aluminium discs.The discs - about 15,000 of them - are fixed back to the concrete with stainless steel threaded rods set in cast-in sockets and nylon washer spacers.They were polished to a mirror finish before being naturally anodised.
Rainwater is collected by inset aluminium gutters, which run laterally between the top and bottom edges of the wall panels;
it is discharged via gullies into internal drainpipes.
A plinth of 4mm mirrorfinished stainless steel panels runs at the base of the curved wall, separated from the pavement by a recess lined with black anodised aluminium.
The plinth upstand houses a U-shaped gutter and rainwater gully.
Glazed openings in the wall are detailed so that the glass stands proud of the aluminium discs.The overlap, obscured with a fritted pattern and a mirror backing, creates a concealed 500mm-wide gutter, which drains the wall above.
The glazing consists of frameless cold-resin-laminated glass panels braced with toughened glass fins.Each fin is clamped between a pair of 80 x 80 RSAs, which in turn are bolted to the extended leg of an RHS set at the base of the concrete panel.