The single-storey building has a steel-framed wall and flatroofed perimeter structure which supports four timber gridshells. They are raised above the flat roof on canted kerto columns, set on steel shoes which are bolted to the main steel structure The columns also act as mullions to the canted aluminium-framed clerestories set between them. These have opening lights which are operated by the building management system.
Each curved gridshell is 13.2m long by 7.2m wide; in form it is a shallow barrel vault with a complex double curvature, the radius of which varies across the span. Each gridshell rises from a 3m-high ceiling to 5.5m above floor level at the corners; its highest point at the centre is 7.5m above floor level.
The gridshell is constructed of 200 x 63mm beams of LVL (laminated veneer lumber) at 1m centres. They are connected together in a lamellar sequence, ie the end of one beam is bolted at right angles to the mid-point of a second beam; a third beam is bolted to the mid-point of the second beam; and so on.
The beams were connected with a bolted Shearlock connector developed and patented by Cowley Structural Timber.
The connector, a sleeved bolt lined with epoxy resin, is hydraulically pressed into the end grain of the timber element; the bolt head can then be operated through a small oblique hole in the side.
The gridshell is covered with a deck of LVL boards, approximately 300mm x 27mm thick, with tongued and grooved edges and pre-sawn to 'petal'-shaped units, to ensure a close fit over the curved surfaces, and allowing the gridshell and deck to act as a stressed-skin structure.
The deck is covered with rigid insulation and a Sarnafil single-ply membrane.