Track 2: DESIGN - PLANNING THE CONSERVATION OF HISTORIC PLACES / Volet 2 : Conception - Planifier la conservation de lieux historiques

Sourcing Stone for Union Station Toronto

Saturday, October 14
1:30 PM - 3:00 PM

Toronto’s Union Station, a National Historic Site, was constructed between 1914 and 1918. Its Beaux-Arts interiors are considered the grandest in Canada. It continues to be the central and most important rail hub in the country, and will have by 2020 a projected usage of 120 million passengers a year. A major $550M rehabilitation project is currently underway and the restoration of the heritage fabric is a significant component of it. Work in the Station is bound by a heritage easement agreement between the City of Toronto and Parks Canada. The Standards and Guidelines are the reference document governing reviews. EVOQ Architecture (FGMDA) are the heritage conservation architects.
This presentation will discuss issues around stone sourcing for heritage buildings, when the original sources have disappeared or become difficult to match. Strategies for procurement and solutions to a wide range of possible issues will be explored. The Union Station project provides examples of both situations. The stonework is a character-defining element.
The station’s Great Hall is clad in Zumbro and artificial stone. Procurement of new stone was needed for repairs and new areas. Initial sourcing was challenging due to spotty archival information. Given the clue in its name, the team began with the region of the Zumbro River in Minnesota. A summary of the next few months’ works reads like an adventure novel, involving detective work, geological hunts, visits to abandoned quarries and last-minute betrayals. The team had to negotiate through numerous challenges including procurement contracts, stone quality control, gaining difficulties, delivery, and tooling reproduction before the stone was finally installed.
The grey and grey-green Missisquoi wall marble in the lower level promenade presented a different challenge. The quarry was well known and in operation, but only its upper black benches were being gained. The blocks matching the Station had been quarried several years prior and were of variable quality. The unusual steep bed angle creates additional challenges with colour consistency when slabbing the blocks. The small quantity needed for the first stage of construction and pre-purchasing constraints meant that each slab of marble had to be inspected, rated, assigned for use by area, and approved prior to shipping to site. As a result of this initial phase, a pre-purchase strategy was enacted for the subsequent phases and this decision allowed the quarry to proactively determine which beds would best be gained from the lower grey and grey-green benches. However, the design team still had to make decisions about the disposition of the marble, to achieve uniformity of appearance in both the historic and new areas of the building. The final result provides tangible demonstration of the value of passionate and intelligent detective work and comprehensive planning in conservation projects.

Learning Objectives:


Senior Associate, Architect
EVOQ Architecture Inc.

Dima Cook has extensive experience in heritage conservation, construction and project management. She is recognized for her ability to manage large, complex projects from early design to contract administration. As a Senior Associate of EVOQ Architecture (FGMDA), Dima is responsible for directing the firm’s Toronto office. A graduate of the McGill School of Architecture, she is LEED AP accredited and serves as the firm’s sustainability advisor. She has served as the co-chair of the APT Sustainable Preservation Sub-Committee on Climate Change. In 2014, Dima was appointed to the City of Toronto Design Review Panel as its Heritage Representative.


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Keith Blades

Keith Blades Consultant in the Conservation of Historic Buildings Incorporated

Keith Blades Biography

Keith Blades commenced his career in the United Kingdom working with the Directorate of Ancient Monuments and Historic Buildings. [Now Historic England]

In over 40 years of practice in conservation he has worked with architectural firms and the Canadian Federal Government, where he set up a team of conservation masons for work on the Parliament Buildings.

He obtained an MA in Conservation Studies from the University of York and for the past 25 years has based his practice on a mix of consulting, teaching and practical work in the field of masonry conservation.


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Sourcing Stone for Union Station Toronto

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