[WORKING DETAIL 29.01.09] Arcade roof
Herbert Museum and Art Gallery − The arcade roof is designed to provide a transitional environment with the following functions: a naturally ventilated
buffer zone between external temperatures and the exhibition galleries; solar shading to the gallery facades using a pattern of solid and glazed panels; natural lighting to the building’s interior; and thermal insulation.
The roof structure of the arcade is glulaminated timber in a diagrid form, supported continuously by the roof of the two-storey galleries along one side and raking timber columns on the other. The structural grid measures 3.75 x 9.6m.
Here, the structure transforms into a portalised post-and-beam structure covering the History Centre, using 295 x 170mm laminated timber beams that support 135mm-thick solid timber cross-laminated panels that curve at the transition point. The 270 x 142mm arcade roof beams are paired and connected to 250mm-diameter cast steel spherical nodes, with welded flitch plates that accommodate the differing angles and twist of the structural members.
The arcade roof consists of 1.8 x 1.8m solid and glazed roof panels. The solid elements are twin-skin aluminium insulated panels in thermally broken glazing sections, supported on timber purlins spanning between node points, covered with terne-coated stainless steel. The roof glazing is double-glazed toughened and laminated low-E glass with automatic opening lights. The roof covering of the History Centre is standing seam terne-coated stainless steel on thermal insulation.
John Pringle, director, Pringle Richards Sharratt Architects