Canada's Condominium Magazine
Research being carried out at the University of Toronto’s school of architecture will almost certainly become standard reference material for future builders of green roofs, especially in northern climes. The research, which is studying in unprecedented detail the way plants behave in the relatively harsh micro-climate of a Toronto rooftop, has now been recognized by the American Society of Landscape Architects (ASLA). The ASLA Award of Excellence was given to the University of Toronto’s Green Roof Innovation Testing Laboratory, known as the GRIT Lab, part of the university’s Faculty of Architecture, Landscape and Design.
This latest ASLA recognition of Toronto projects (there have been several in recent years) could be the most significant yet. GRIT Lab is described as a state-of-the-art research facility and the only one of its kind in North America, studying the environmental performance of green roofs and solar photovoltaic technologies together. The award citation notes that while the results of the Toronto work may be specific to Southern Ontario, they will be transferable across regions, and will give landscape architects a better understanding of how green roofs actually work.
This is by far the most rigorous and comprehensive of all the test-roof research out there. In fact, it may be the only empirical study of a green roof. It’s particularly notable that it’s in a Northern climate.
2013 ASLA Professional Awards Jury
The rooftop lab comprises 33 test beds where different plants are grown in different types of soil, three green walls, and a weather station, all wired with 270 sensors. The sensors provide real-time data on soil moisture, flow rates of water, temperature, rainfall, humidity, solar activity and wind. All of these data are used in developing an understanding of the “water-energy-biology nexus” in the rooftop context, specific to Toronto. In other words, which plants thrive best on a Toronto rooftop, and what kind of care do they need to do so?
The GRIT Lab’s findings could affect future green roof construction in Toronto, and elsewhere where climate conditions can be harsh. As the ASLA awards jury noted, it is the most comprehensive test-roof research facility there is, and it is in a northern climate.
Green roofs are now mandatory in Toronto, and must be part of certain types of new construction, as regulated by the Green Roof Bylaw Construction Standard. GRIT Lab is evaluating and testing construction standards in the context of that bylaw, looking at four primary criteria: stormwater retention, evaporative cooling, biodiversity, and life cycle cost. Until now, the only data available to the city came from simulation models or metrics derived from elsewhere.
What makes the GRIT Lab unique is its multi-disciplinary approach. As the ASLA award description notes, green roof studies are typically conducted within the fields of biology, hydrology and building science and focus on individual components or functions pertaining to their specialized field of study. The GRIT Lab simultaneously studies plant growth, soil science, hydrology and energy to see how these factors together affect such phenomena as the urban heat island effect and water runoff.
The next phase of the project, which runs from 2013–2016, will look at the relationship between green roofs and photovoltaic (PV) arrays to see whether green roofs actually improve PV performance and lifetime as is now hypothesized. The researchers plan to test PVs at different heights above green and white roof surfaces.
A number of other Toronto sites have been honoured with awards by the American Society of Landscape Architects (ASLA) in the past few years: Sugar Beach, a delightfully named and designed city beach that used to be a desolate parking lot across from the Redpath sugar refinery on Queen’s Quay; Sherbourne Common, a sophisticated urban park that’s part of the redevelopment of the waterfront east; the park on Yorkville Avenue with the once-notorious but now popular multi-ton granite boulder at its centre.