Office annexe, North Wraxall, Wiltshire Montrésor Partnership working details
Steel roof and wall supporting panels in aluminium frames The shape and roof pitch of the single-storey building were determined by its former use.Three walls are of cavity blockwork.The steel roof and west wall structure is arranged in three primary and four secondary bays.
Four prefabricated cranked steel frames of paired 160 x 80mm RHS beams run above the servant spaces and are bolted to a cast in-situ concrete beam set in the rear wall.The purlins of the major bays run between the beams and were site-welded to them.The steelwork was not required to have fire protection and is finished with a highly UV-resistant alkyd zinc phosphate primer/ silicone alkyd top coat combination.
The bays support silver anodised extruded aluminium glazing bars.A series of transparent, translucent and opaque, fixed and opening glass panels is fixed to the glazing bars with extruded aluminium pressure plates.
The opaque panels are insulated; the transparent and translucent panels have super low-E coatings and 20mm argon-filled cavities.
Solar radiation is controlled externally by motorised louvres set above the glazed roof, and internally by manually operated horizontal roof and wall blinds.
An elastomeric membrane runs under the blockwork wall coping, along the back of the wall, down behind the aluminium pressing and into the transom, where it is clamped by a pressure plate.
The membrane continues along the tops of the side walls to the eaves; it runs vertically down the jambs of the front wall to seal the blockwork/glazing junction, then turns to form a horizontal seal to the sill.The joints were finished with silicone sealant.