How illuminating

When North East Worcestershire College decided it was time to revamp its campus in Redditch,
it was keen to stamp its identity on the town. The buildings making up the campus were a hotchpotch of uninspiring structures dating largely from the 1960s. Esentially, they were a blot on the townscape, and the college wanted to replace them with a landmark building that would attract the local community.
Birmingham practice D5 Architects was given the task of designing a learning and resource centre, but the tight budget meant that a really eye-catching design would be tricky. What is more, D5 had to retain a dull three-storey building opposite the campus building.
D5, however, had a bright idea that was cost-effective and striking to look at. It decided to link the new building and the uninspiring block with an enormous bow-truss steel and glass roof. The visual impact of such a large roof spanning the space between two relatively small buildings is dramatic. The fact that the resulting plaza is open to the elements at one end gives even more emphasis to the soaring sense of space.
The roof is in the shape of a shallow asymmetric V, rather like a tick. The aluminium frame supporting the glass is in turn supported by steel columns positioned at the angle of the tick, and five large steel bow trusses.
At the north-west end is a restaurant, which bridges the space on the second and third floors and provides an internal circulation route between the two buildings.
A covered square was not in the brief but Ben Jepson, associate architect at D5, says that once the college saw the concept it was keen for it to be built. Jepson was able to push for a decent specification so he stipulated glass over cheaper alternatives such as polycarbonate or Teflon.
“Glass was such a fundamental part of the scheme, that it could not be compromised,” says Jepson. He says that Teflon would have diffused too much light, and polycarbonate would have presented the college with maintenance issues as it has a tendency to attract dirt.
The lopsided tick shape came about because of the need to limit the span of the roof. “If the span was any wider then the steel elements would have been deeper and chunkier,” says Jepson. The use of bow trusses also meant that the thickness of the steel could be minimised. “It was the slenderest option.”

As well as providing an unusually shaped roof, the pitch of the smaller span also has a practical function – to clear rainwater from the flat roof of the old building. The rainwater collects in the gulley between the two roof sections and is taken off the roof via a siphonic rainwater drainage system from Geberit.
The impressive roof will make the students feel good about their college. Townspeople should also take pride in their covered plaza. The space is currently popular with skateboarders, who make the most of the steps and handrails, but once there is seating in place the square should become a popular stop-off point for shoppers on their way back from the high street.

• For more details on the roof of the new building, see “Appraising the roof”