The Mathers and Haldenby-designed Imperial Plaza Building at 111 St. Clair Avenue West is a 21-storey Modernist building constructed in 1957 as the executive offices for the Imperial Oil Company with landscape design by Dunington-Grubb. When it opened, it had a 20th floor observation level that was the highest point in Toronto. The property is designated under Part IV of the Ontario Heritage Act for its cultural heritage value and is subject to a Heritage Easement Agreement with the City of Toronto.
The project includes the rehabilitation of the two-storey entrance hall to accommodate modern retail tenants and the upper floors of the building have been converted to residential condominium units.
Two significant R. York Wilson murals depicting “The Story of Oil” have been conserved as part of the project and remain visible within the tenanted spaces on the ground floor. The entrance hall remains publicly accessible during business hours, and visible at all hours.
Alterations to the building were completed using materials and finishes to match existing, so that changes in appearance are minimal and subtle when viewed from the street and comply with the Standards and Guidelines for the Conservation of Historic Places in Canada.