A glazed extension with a pitched roof supported by a steel spine beam The enclosure has a butterfly roof which rises to new and existing walls on both sides, supported by tapered 15mmthick steel fins springing from a central box-shaped spine beam. At the hall side the fins are pin-jointed to the wall of the first floor, which takes the form of an encased steel truss bridging a 14m space to link the hall to the glazed extension. At the church wall side, the fins are cut back to emphasise the transparency of the roof.
The spine beam, resting on 152 x 152mm UC columns clad with reconstructed stone, is the division line between the glazed enclosure to the main hall and the glazed link between hall and church. The spaces between the columns are glazed or have opening doors - the fixed glazing is toughened glass in stainless steel channels.
The spine beam consists of a pair of 260 x 90mm parallel flange channels welded together with 450 x 10mm steel side plates; the upper PFC provides the shape of a gutter and is filled with an insulated gutter liner.
Rainwater discharges into a downpipe set within the box beam and cladding. A gantry walkway for gutter and roof cleaning and maintenance runs above the gutter.
The tapered fins have welded back plates which are bolted to the spine beam.
Sliding U-shaped brackets with slotted holes to accommodate adjustment in two directions, are mounted on the fins to accept the glass.
The glass roof panels - doubleglazed toughened and laminated units - are fitted with combinations of Pilkingtons Planar 905 and 902 fittings. At the church wall side, the glass panels are bolted to anchor brackets, with a ventilation gap between the glass and the stone.