Award

FEBRUA RY 2019 | 39 West Block Rehabilitation Although security considerations prevent the disclosure of how many tunnels and underground components were created, Heiber says, "We dug three-storeys down into bedrock in the courtyard area to accommodate a new mechanical room and other elements. Altogether, we blasted through the equivalent of 28 Olympic-sized swim- ming pools of bedrock – 70,000 cubic metres - to create the new underground levels and pedestrian and utility tun- nels. This alone took a year of work." The revamped West Block also had to be seismically upgraded, requiring additional steel and concrete work. The rehabilitation – which would be augmented with new elements such as 12 elevators, two large escalators, and 1,000 doors with complicated security hardware – included the replacement of 1,436 windows and what Heiber describes as "an extremely high level of finishes: wood, stone, and bronze. All the lighting fixtures were new but had to look like original heritage components." Unsurprisingly, creating the new mechanical elements was equally chal- lenging. "Ceilings being restored to their original heights and other archi- tectural considerations limited our ability to install ducts, so we located fan coils in perimeter rooms," says Clive Lacey, president and CEO of Crossey Engineering Ltd. "We also cre- ated a dedicated outdoor air system." Essentially, an intake was installed on the roof of Mackenzie Tower and ran all the way to the basement mechanical room. "Demand control ventilation was created in all areas, with displacement ventilation in the House chamber." Room-to-room acoustical consider- ations were of paramount importance. "Given that so many rooms had mutual ductwork, there had to be attenuation, and we wound up installing over 400 silencers for privacy's sake, as well as to keep the fan noise down," says Lacey. Arguably the jewel of the entire project is the new House chamber, which is showcased by light shining through a new glass "cloud" ceiling held aloft by tree-shaped steel columns. The impressive copper roofing was identified early on as needing repair, preservation and/or replacement and so Heather + Little Ltd. (fabricators of custom ornamental sheet metal and historic sheet metal, who went on to win the 2018 North American Copper in Architecture Award for the West Block Rehabilitation Project) worked closely alongside PCL Constructors and the architects to ensure the replace- ment was done in-kind, replicating the language of the original installation. This required the total removal and replacement of the old copper batten roofing, and restoration of the cop- per clad windows, tower finials, and copper cresting. All parts of the tower PHOTOGRAPHY COURTESY PUBLIC SERVICES AND PROCUREMENT CANADA Mariani Metal, proud fabricator and contributor to the West Block project. From engineering, fabrication, to fi nal delivery and assembly. Our philosophy is to make it real, using a methodology consisting of precision, innovation and excellence. www.marianimetal.com.

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