Zurich House North Sydney

Constructed in 1984, the facade consisted of continuous ribbons of windows supported by concrete spandrel panels cast In situ between the external structural concrete columns. The window system contained an alternating arrangement of pivot sashes and fixed glazing, common in its day to allow easy cleaning of the glass from the inside of the building. A cold joint had been formed between the columns and the cast in situ spandrel panels, effectively creating a vertical crack together with a horizontal crack along the poorly placed concrete base. These junctures had not been sealed properly and did not link up with the window framing seals. These breaches in the air seal allowed air and water to enter the window system and manifest at the base of the wall with wet carpets being a constant nuisance for many years. The window system had not been installed correctly to achieve pressure equalisation and with the pivot sash gaskets being in poor condition, water freely entered the windows at many locations. Prior to our prototype repair a sirowet test was carried out which demonstrated that under cyclone condition a typical bay of 5 windows leaked at 12 locations. Repair of the windows included replacement of all of the glazing seals, modification of the sub framing and reinstallation of seals to the cold joints between the columns and cast in situ spandrel panels. A repeat test confirmed the success of the repair. Other work included a major refurbishment of the balcony doors located on the numerous terraces around the building.