Sustainability considerations used to get a bye during heritage rehabilitation efforts but that's a thing of the past, architects were told at a seminar held at the recent Royal Architectural Institute of Canada (RAIC) conference in Ottawa.
Seminar leaders Mark Thompson Brandt and Christopher Warden, two conservation architecture specialists with the Ottawa firm MTBA Associates, are co-authors with others of a new manual titled Building Resilience: Practical Guidelines for the Sustainable Rehabilitation of Buildings in Canada. Brandt and Warden split their afternoon session on May 26 into a run-through of principles and then a workshop in which four groups were asked to consider the renovation of a recently completed Ottawa project, the Beaux-Arts/Art Deco styled Sir John A. Macdonald Building on Wellington Street.
"The two efforts, the sustainable, the natural conservation, and the cultural conservation, are one," Brandt said during a break in the workshop.
According to Brandt, who is a principal conservation architect and urbanist with MTBA, the guiding spirit of the manual comes from a policy statement adopted by the Federal Provincial Territorial Historic Places Collaboration: "Heritage conservation contributes to creating a sustainable built environment and resilient communities."
"It starts with this policy statement," Brandt explained. "We were hired by the senior levels of government, and they all agreed on this policy statement, so it started as a purely heritage document, saying, the act of heritage conservation is an act of resilience, it is an act of sustainability — landmarks not landfills, right?
"Then we say, how do we make it perform better, from all the aspects of sustainability, wellness and health and all of those good things, basically that's the guts of what we are talking about."
Potential clients such as Infrastructure Ontario, with its huge portfolio of government real estate and dozens of heritage buildings requiring upgrades, are fully on board with the new focus, said Brandt. Owners realize that the existing building stock with its inefficiencies is a huge source of carbon emissions and energy waste — thus offering significantly more potential for reaching climate change targets than through new builds, the presenters said.
It's a point reinforced by a statement from the Intergovernmental Panel on Climate Change, quoted by Brandt: "The largest potential of carbon savings by 2030 is in retrofitting existing buildings and replacing energy-using equipment...an energy savings of 50 to 75 per cent can be achieved in commercial buildings that make smart use of energy efficiency."
With all levels of government insisting on the new philosophy of combining heritage conservation with sustainability, Brandt told the architects, it requires firms with a heavy conservation focus to completely regenerate their practices.
For architects embarking on a heritage project, Brandt commented, "The first and most important thing is heightened awareness of an existing building's characteristics and behaviour."
Architects need to understand building evolution, where the cavities are and how the systems are failing, he said. The whole "building ecology" must be understood, he said, including how all systems interact and affect each other.
"It is really a shift in mindset from building first to maintain and augment first," said Brandt.
A value-based approach includes such steps as assembling an integrated design and rehabilitation construction team; determining the value- and character-defining elements of the project, with values found in design/cultural, environmental and economic aspects; thoroughly investigating and documenting all existing conditions, past interventions, design intent and construction methods; and mapping out conflicts and balancing project objectives, said the presenters.
Turning to the workshop component of the session, the MTBA colleagues were able to showcase a project that was completed in 2015, earning them five globes in Green Globes certification. The $99.5-million, three-and-a-half-year renovation of a former Bank of Montreal branch featuring a 60-foot-high vaulted ceiling and ornate tiled floor came in on time and on budget. The building, designed by Montreal architect Ernest Barott and built in 1932, is now owned by the federal government and is used for public functions.
After the workshop groups offered their comments, Brandt and Warden revealed their work plan. All windows and doors were rehabbed off site. Existing principal windows and fixed storm-window configurations were retained, new seals and sweeps added, glazing was replaced and new glazing tape installed, and operative acoustic curtains were installed at all windows that also enhance the thermal performance of openings.
Additionally, there was the rehabilitation of all heritage materials, including cleaning of the Benedict Stone interior to lighten spaces, and a gentle air trickle was introduced in the basement to aid the stack effect within cavities.
MTBA is up for a national Green Upgrade award for its work on the Macdonald building.