Toronto's Financial District has been growing at a frenetic pace in recent years, and the growth continues with multiple office towers currently under construction in the area. One of the most high-profile projects underway at this time is Brookfield's Bay Adelaide East, a 44-storey, 980,000-square-foot office tower rising at Yonge and Adelaide. Heritage consultants ERA have been working with architects KPMB, Adamson Associates, and developer Brookfield Properties to preserve two façades of a four-storey stone and brick structure built in 1850, and a recent blog post on ERA's website helps to break down the process, which involves casting moulds from the heritage masonry's exterior and then recasting these surfaces in concrete to build new sections of historic façade.

Yonge and Adelaide as seen before construction began, image from Google Street View

Carrying years of grime in the Google Street View image above, the façade of of the heritage building was saved when the entire building was taken down. A modern glass podium will rise at this location, but the next building up the street, seen in the background above, is remaining in place. With the recently restored Dineen Building (wrapped in plastic in the image above) immediately to the north, the opportunity to strengthen the heritage aspects of that corner presented itself, so a plan was made to move the façade north, removing the PoMo cladding now fronting 132 Yonge. The east façade will stay on Yonge Street, moved about a hundred feet north, while the south façade will become the new north façade of 132.

The former location of retailer 'Addition Elle', 132 Yonge houses the mechanical facilities for the entire Bay Adelaide East site on its upper floors. While new retail will eventually open at ground level, the mechanical facilities will how be hidden by the reconstructed heritage façade. There has been a catch though; 132 Yonge has a longer frontage than the since-demolished building to the south, which would leave a void in the Yonge Street façade due to lack of masonry. This gap will be filled in with concrete castings made from the heritage façade, forming what ERA Architects describes a a "ghost wall". The wall will have an almost identical texture to the heritage sections, albeit with a slightly lighter and more uniform colour.

Heritage component including 'ghost wall' in the three southern bays along Yonge Street, image courtesy of KPMB Architects

In the project's early stages, crews disassembled the heritage façades into 34 pieces and transported selections to concrete fabricators where numerous silicon moulds were made from the sections. These sections were then used to cast a final product in glass-fibre reinforced concrete (GFRC), a light, strong, material capable of showing a high level of detail, including the pores and marks of age in heritage bricks. Unlike the heritage masonry, Bay Adelaide East's ghost wall will be monochromatic and lighter in tone, (seen in the three southern bays in the image above), hinting at the block's lost fabric as opposed to replacing it. Work continues on installing the heritage masonry and ghost wall; the upper cornice section is being reconstructed while the new GFRC façade is slated to be installed this summer.

132 Yonge Street as seen in October, image by Jack Landau

Masonry work on 132 Yonge as seen in October, image by Jack Landau

Detailed images of the ghost wall fabrication process can be found on ERA Architects' blog post, linked here.

For additional information about the Bay Adelaide Centre East, visit the dataBase file, linked below. Want to get involved in the discussion? Check out the associated Forum thread, or add your voice in the comments section provided at the bottom of this page.