Studio g+G, in collaboration with GBCA Architects, formed an integrated conservation team to restore the exterior of Mackenzie Hall—one of Canada’s most significant heritage assets. Originally constructed by the company of Canada’s second Prime Minister, called Mackenzie’s Builders,” the building had suffered from the effects of a previous restoration completed over three decades ago. That intervention used inappropriate mortar materials, leading to the accelerated deterioration of both the stone masonry and the replacement windows.

Our team provided comprehensive forensic testing, material analysis, restoration documentation, and general review services. The scope also included the restoration of the windows, scheduled for a future phase of the project. The original wood windows had been replaced during an earlier restoration by architect Carlos Ventin. Through archival research, analysis of early photographs and referencing local Victorian architectural precedents, we were able to accurately determine the original window detailing and muntin profiles.
Mackenzie Hall is a layered assembly of additions (1855, 1870s, 1930s and 1980s), each employing different techniques and historic materials. With the completion of this rehabilitation effort, the varying mortar types and construction methods now offer visitors a visible timeline—allowing them to distinguish between the original fabric of the building and subsequent additions.