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J UNE 2017 | 53 The Exchange RENDERINGS COURTESY IREDALE ARCHITECTURE The Exchange by ROBIN BRUNET H istoric structures, as well as the green building industry, could do with more friends like Franz Gehriger. For years, the CEO of SwissReal Group owned the old Vancouver Stock Exchange building and was intent on restoring it even before it received heritage status; he also wanted to augment the facility with a new tower in order to create Vancouver's first LEED Platinum heritage conversion and provide one of the most sustainable buildings in North America. His daughter, Nadja Gehriger, who is VP of SwissReal, says, "My father could have easily torn down the building and started fresh, but as a European he is extremely aware of the need for sustainability, as well as preserving old buildings – which aren't in abundance in western Canada." By partnering with Credit Suisse, Gehriger's grand vision has resulted in the impending completion of the $240-million The Exchange, which includes a complex retrofit of the original 1929 stock exchange building – out of which arises a 375- foot, 31-storey tower with seven levels of underground parking and 370,000 square feet of office space. To say that Gehriger and a small army of designers and builders were faced with numerous challenges would be an understatement. In 2012, when Vancouver City Council approved the stock exchange facelift, residents of the nearby Jameson House tower complained that their views would be spoiled if Gehriger built a tower that sat beside the stock exchange. "So early on in the design stages we considered either cantilevering the tower over the top of the exchange or placing it directly through the building," says Daniel Hawreluk, partner, Iredale Architecture. "We opted for the latter, and this pulled the tower further east and preserved the views for neighbours. This also allowed us to incorporate a roof deck on the top of the podium, which wouldn't have been possible with two separate buildings." While the stock exchange building was in relatively good shape, Read Jones Christoffersen Ltd. had to ensure that it was seismically upgraded – and on that score, bringing the new tower's foundation columns through the building would help enormously (10 columns in all, post tensioned slabs with big cantilevers). This left the brick and other masonry components of the stock exchange's gothic facade to be upgraded. "The idea was to restore the facade and the original lobby," says Hawreluk. "Beyond the lobby everything would be new, including a new six-storey Pender Street lobby. We designed very large and continuous floor plates for the lower levels in order for occupants to experience the old and new building elements – and after that would be the modern tower." Keri Briggs, Vintage Woodworks VP, says, "The Old Stock Exchange project included 235 windows; 179 of these windows were original historic wood windows that became a unique combination of restoration mixed with new thermal sash upgrades. Fifty-six units, both square head and segmented head, were manufactured as new high-efficiency replica units, because years ago those units had been replaced with aluminum windows that had failed." Briggs goes on to note, "Our restoration procedures exceeded some of the toughest safety standards we have ever been faced with, as we worked with both lead and asbestos abatement. The biggest challenge was working off of a hydro lift shared by masons and those managing the asbestos in the mortar. From the street, people may have seen large crate boxes moving from opening to opening. These boxes allowed us to work in all weather and all lighting, protecting the openings, the incredible trades people and containing the lead abatement area." Apart from safety, a major challenge of The Exchange project was that no underpinning agreement

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