Centre for Green Cities at Evergreen Brick Works
Reimagining an Industrial Relic: Evergreen, an environmental organization dedicated to making cities more livable, breathes new life into a defunct manufacturing complex in the heart of Toronto.
North American cities are littered with abandoned factory buildings, warehouses, and obsolete infrastructure. Occasionally, these relics are repurposed for the postindustrial age, getting a new lease on life. Such is the case with the Don Valley Brick Works, a deteriorating brick-making facility in the heart of Toronto closed since the late 1980s, but recently transformed into an environmental center for Evergreen—a Canadian non-profit organization focused on bringing nature into urban environments to make them more livable.
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Working with a multidisciplinary team of architects, landscape architects, engineers, preservation consultants, and other experts, Evergreen and the site’s owner, the Toronto and Region Conservation Authority, remade the complex of 16 masonry structures and sheds, built in the first half of the last century, into a setting for events and ongoing programs such as a farmers’ market, a native plant nursery, crafts workshops, bike repair clinics, and a children’s summer camp. The designers retained much of the gritty feel of the brick works, which the city designated a heritage site in 2002, but have reintroduced natural elements. For example, from the complex’s almost completely paved and impermeable 12-acre industrial pad, a system of greenways was “teased open,” says Bryce Miranda, an associate with du Toit Allsopp Hillier, one of two landscape firms on the brick works team—a team led by sister firm du Toit Architects.
The new marshlike channels feed a storm-water management pond at the southwest corner of the former industrial pad and connect to watercourses that are part of a lush, 40-acre garden completed in the 1990s on the site of the brick-making operation’s quarry. This network, along with 15 cisterns that collect rainwater from the roofs for irrigation, help combat flooding that has long plagued the low-lying site.
The only substantially new structure in the complex is the Centre for Green Cities, designed by Diamond and Schmitt Architects. Opened in September 2010, the 5-story, steel-framed and precast concrete slab office building is clad in corrugated metal panels sympathetic to the industrial character of the site. The building provides workspace for Evergreen and like-minded tenants. But even this new structure incorporates historic fabric: Its first floor is defined by a set of masonry walls that once housed part of the brickmaking process, as did the attached welcome center, or multi-purpose hall, sheltered under a new shed roof supported by original steel trusses. Two of the welcome center’s four enclosing brick walls are original.
Retaining existing elements provided one of the project’s key challenges, made more complex by Evergreen’s ambitious goals (the organization wanted a highly efficient, LEED Platinum facility). “We needed to fulfill performance objectives while retaining as much of the heritage character as possible,” says Michael Leckman, a Diamond and Schmitt principal. Although the historic double-wythe masonry walls offered little thermal resistance, the project team elected to leave them uninsulated—a decision motivated by concerns that moisture would become trapped, causing freeze-thaw damage. To compensate, designers heavily insulated new portions of the envelope, with R-values for the wall and roof assemblies at 35 and 50, respectively.
In addition to the superinsulated envelope assemblies, the HVAC strategy also plays a significant energy-saving role. Inside the Centre for Green Cities, heat is delivered through an in-floor radiant system on the ground level and perimeter radiators on upper floors, rather than through the ventilation system. The team expects this decoupling of ventilation and heating, along with a high-performance heat-recovery system, to reduce heating loads associated with ventilation by more than 40 percent. The approach should also prove effective for reducing overall energy consumption, since in a code-compliant office building in Toronto’s climate, “heating ventilation air can consume almost twice as much energy as is expended as a result of envelope losses,” explains Doug Webber, green building practice leader at Halsall Associates, the project’s sustainability consultant.
During cooling season, operable windows, along with three fan-assisted solar chimneys, help purge warm air, reducing dependence on conventional cooling. By relying on these primarily passive means, Evergreen was able to stall turning on the air-conditioning until late June, says Robert Plitt, the organization’s senior manager for sustainability.
The most unusual aspect of the cooling strategy may well be the air-conditioning system’s size: At peak, it has capacity to condition either the multipurpose space, or the offices, but not both. Instead of maintaining all of the rooms at the same temperature year-round, Evergreen deploys “demand management” techniques, such as scheduling of events during hours when the offices are typically unoccupied. Given the low likelihood of programming overlap, “is investing in systems that would be rarely used the best use of resources?” asks Webber.
Several elements of the design have yet to be implemented, including a biomass boiler, roof-mounted solar-thermal panels, and exterior shading devices. Nevertheless, say team members, the building is on track for Platinum and provides an excellent interior environment. It is thermally comfortable, has good air quality, and due to its narrow floor plate, is full of daylight, according to Plitt. “From an experiential perspective,” he says, “the building is phenomenal.”