Design competition winners Acanthus Lawrence and Wrightson Architects' concept uses the curved copper roof to envelop both the high level platform access and the lower street level areas with one cohesive structure.
The roof 'burrows' into an existing embankment while rising up from suburban street scale to form a platform canopy and enabling light to enter the lofty ticket hall. Secret gutters, bull-nose eaves and soffits, all in copper, reinforce the continuity of the smooth curved roof form.
The roof consists of a curved lamella structure using intersecting timber beams decked in plywood. Pre-patinated copper sheets were laid over the decking using the 'traditional method' which incorporates cross welts but with modern jointing and fixing techniques to ensure an extremely long, maintenance-free life.
Today, pre-and post-patination techniques are available to provide straightaway the distinctive green patina which otherwise takes several years to develop in the environment. The architects considered that copper addresses sustainability concerns with its low embodied energy, a long tradition of recycling and non-toxic characteristics.
The copper roof was also Highly Commended for craftsmanship in Copper Development Association's Copper in Architecture Awards 10.