A timber cruck frame structure
The conference centre is designed on environmentally responsible principles. The north-west wing houses the auditorium, which holds 200 people and is suitable for music or speech. The 16.8 x 11.8m single-storey space rises to 8.5m high at the ridge; it is naturally ventilated by means of dampers at the base of the walls and at the ridge.
The roof is clad with cedar shingles. The north-west wall is of 150mm insulated timber studs with a timber-boarded finish on the inside; the north-east wall is of 375mmthick rammed earth clad on the outside with 150mm insulated timber studs and Western Red cedar boards.
The pitched roof structure consists of four massive timber arched frames at 4.5m centres.
Based on the cruck frame principle, they rise from floor to ridge inside the auditorium.
Each cruck frame is formed of English Douglas fir members, bolted together at their ends with Douglas fir glulam splices. Unlike many green oak structures, the splice allows stresses to move through the timber rather than relying on bolted connections to transmit the load.
The same bolts are used to fix a fabricated steel shoe to each glulam splice; the shoes support 225 x 225mm Douglas fir purlins or, near the eaves, 125 x 125mm Douglas fir props, which rake upwards to support the purlins. Threaded rods, bolted to the purlins, were used to adjust their position precisely on site.
The eaves extends over the rammed earth wall and beyond, supported by 175 x 50mm eaves rafters that are fixed back to the roof rafters. The roof covering and gutter are formed by a single-layer roof membrane covering; the outer projection is edged with zinc.