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

Tuning a historic stone box

Friday, October 13
10:30 AM - 12:15 PM

From conception to completion, the Sir John A. Macdonald Building (SJAMB) Rehabilitation addressed multiple technical challenges to adaptively reuse the award-winning former Bank of Montreal (1929-31) in the Parliamentary Precinct, Ottawa, Canada. It is now a conference centre for the House of Commons.

One significant challenge was inverting the former banking hall's acoustic performance. Originally designed for high reverb for speech privacy, the new use instead required speech intelligibility to accommodate presentations, plus performance and music. At 18 metres wide, 40 metres long and 17 metres high, the Main Hall is an impressive volume. Adding to the space's scale, the inherent, heavily-ordered geometries and multiple noble hard surface materials (including marble, Benedict stone, large bronze and glass windows, terrazzo and a fine plaster coffered ceiling), essentially make the room a “stone box”. This palette was considered “untouchable” since it contributed to the space's heritage character. As the primary event space, the Main Hall had to adapt to challenging technical and performance requirements, while maintaining heritage value. Challenges and design evolution continued through construction.

To address these challenges, the integrated project team explored countless intervention options, eventually developing a multi-pronged hybrid approach that responded to existing design character and considered different approaches for different locations. Throughout development, the room's performance and the benefits associated with various intervention strategies were evaluated to tailor and maximize their contribution. To satisfy the functional requirements, the team employed a holistic design approach, beyond acoustics, including mechanical, lighting, daylight control, multimedia, security and sustainability requirements. Each of these considerations was evaluated by matrix throughout the process, with the evolving goals of employing multi-function interventions, maximizing reversibility and minimizing heritage impact.

Acoustic solutions affected almost all Main Hall surfaces. Ceiling interventions included acoustic panels that integrated concealed sprinklers and air returns suspended through existing holes, also returning visual solidity to the ceiling. Wall interventions included retractable banners, acoustic entry doors and acoustic curtains. To enhance sound dispersion, "speaker benches" with line array and bass speakers were designed. These also accommodate significant air delivery and in-floor heating manifolds. In the end, the final design required a bit of acoustic performance compromise, to balance protection of the heritage character, a key raison d'etre for the adaptive reuse.

This presentation will review the SJAMB Main Hall's heritage character, the challenges for the acoustic and other requirements, the design evolution for acoustical enhancement, the intervention integration, the importance of exploiting previous interventions, and the variable integrated solutions proposed and executed, including the successes and failures. The audience will learn the processes, approaches and solutions to the challenge of extensive interventions into high-heritage interiors. This will maximize relevance to other projects for this often underrepresented, but impactful area of historic preservation.

Learning Objectives:


Senior Associate Architect
MTBA Associates Inc

Chris Warden is Senior Associate at MTBA Associates Inc., an Architecture, Urbanism, Conservation firm, and has 12 years architectural and conservation experience. Serving as the heritage project manager for the award-winning Sir John A. Macdonald Building rehabilitation project, Chris has intimate knowledge of the work, participating from conception to completion. He is co-author of Building Resilience, national level practical guidelines for sustainably rehabilitating existing buildings. Other project experience includes the East Block Exterior Rehabilitation, multiple former National Printing Bureau projects and the Willson House Conservation Plan. He is a licensed architect, member of CAHP and is chair of docomomo Ontario.


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Tuning a historic stone box

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