Earthwatch – Green Roofs For Beauty and Environmental Benefits

Green Roofs Add Natural Beauty and Environmental Benefits to Urban Buildings 

By Lisa Boushy

Downtown Toronto has often been referred to as a concrete jungle – it can be difficult to spot anything “green” while walking along the financial district among the glass and steel skyscrapers. Although originally built for functionality, nowadays tall buildings are primarily for architectural self-promotion and ego inflation (think Donald Trump). Most skyscrapers have not only reached their expected lifespan, but are now becoming energy-inefficient in just two or three decades.
With the advent of emails and blackberries, telecommuting is becoming more attractive, but for those still making the trek to work everyday, the concept of seeing nature in the downtown core is not only desired, but also sorely needed to combat the stresses of the workplace. While some office towers have been converted to condos and others have been stripped and rebuilt, the hottest trend to hit North America is the construction of green roofs – which serve to beautify the surroundings and make the buildings more eco-friendly.

A green roof can be defined as any system where a vegetated area becomes a part of the building’s roof. This can include vegetation, a filter layer, a drainage layer, a root resistance layer and a waterproof membrane. Most green roofs are classified as either Intensive or Extensive.
An Intensive roof system consists of a deep growing medium that supports a variety of components and growth like plants, flowers, shrubs, trees, and even fruits and vegetables. The landscape design can encompass anything from paved stones to waterfalls and these roofs are accessible to the public. One example is Manulife Centre’s 25-year-old green roof, located at 44 Charles St. West, which has three story high mature trees. Another example is 401 Richmond, a converted warehouse building containing multiple companies (photo below).

According to Beth Anne Currie, Environment, Health and Safety Coordinator of Urbanspace Property Group, their retrofitted rooftop provides a green oasis in the center of the city. “In hot weather, employees have lunch hour yoga classes, conduct wireless media meetings, or just go up for a breath of fresh air and a break from work.”

On the other hand, an Extensive roof system is a shallow growing medium, usually pre-grown (and pre-assembled into one component) or planted in place, and consists of panels, which create layers. All of this is positioned above the existing roof, thereby making it an “extension” of the original. Now Magazine’s building at 189 Church St. is a good example (see photo top of page). Planted with a mixture of sedum species (a low-maintenance, succulent plant tolerant of extreme temperatures and able to survive with little irrigation), this roof was designed by Elevated Landscape Technologies. Made of interlocking green roof tile to maximize water retention, it took a year to make!

While Intensive roofs have an aesthetic appeal and are accessible to the public, Extensive roofs are not, but have more environmental benefits.

Environmental Benefits of Roof Tops

Apart from adding lush green spaces to cities, green roofs extend the life of the roof and can provide a place for local food production and even habitat for birds. Perhaps more importantly, green roofs help manage storm water (it helps reduce runoff which can cause floods and water pollution from sewage). They also significantly add to a building’s energy efficiency – especially during peak times – so in the summer, the largest impact on energy savings is reflected in lower air conditioning costs, and in the winter green roofs retain a larger layer of insulation which conserves energy. Green roofs also improve air quality and decrease urban air temperatures (called Heat Island Effect – defined as an urban area that is significantly warmer than its surroundings).

In fact, in a study conducted by Ryerson students for The City of Toronto, titled Environmental Benefits and Costs of Green Roof Technology, the following benefits were backed up by some interesting statistics:
•Citywide savings from reduced energy for cooling is $22 million, equivalent to 4.15KWh/m2 per year
• Reduced cost avoided due to reduced demand at peak times is $68 million
• Reduced Urban Heat Island Effect by lowering the city's temperature (from 0.5 to 2 degrees Celsius) and reduced cooling costs of 12 million
•Green roofs last up to twice as long as regular roofs

To test the study, the City of Toronto decided to launch the Green Roof Pilot Program this past spring. According to Ilze Andzans, Senior Environmental Specialist at Toronto Water, the mandate “was to provide property owners in the City of Toronto with a financial incentive to construct green roofs, thereby fitting it within the broader context of Toronto Water's storm water management strategy.”

Criteria for viable candidates included only heated buildings above ground level (excluding roof top garages), new or retrofitted roof tops, and primarily flat roof tops (maximum 10% slope). The program was also limited to Extensive roof types, which from an environmental perspective as stated above, is the most beneficial in energy conservation because “the larger the green area, the better,” said Andzans.

Although $200,000 was initially allocated from Toronto Water’s budget, only about a quarter of that was spent due to a few factors; it was a tight timeline of only four months and there weren’t enough applicants – only 18 applied with 16 receiving the incentive. In fact, not one applicant came from an industrial building, which typically is a much larger per square foot area and therefore would require more money.

“We got a great response from residential homeowners, but we were hoping for the big industrial buildings because their flat roofs create a bigger impact on the storm water system,” said Andzans. And although the lack of applications from industrial building owners was a disappointment to them, the successful applications included a representative mix of residential, institutional, commercial and mixed use buildings in the central part of the city (south of 401 between High Park and the Beaches).

Toronto Hydro was initially supposed to contribute money to the pilot program but pulled out. “The city’s incentive, in terms of a dollar value, was just not high enough. It worked out to $1/square foot. We were hoping Toronto Hydro would give some money, but they didn’t because it’s more difficult to quantify energy savings but easier to quantify water savings”. If Toronto Hydro had not pulled out, the program could have paid two to three times more than what they ended up paying. In the end, the program gave away roughly $30,000 which translated to 3000 square metres of green roof among the 16 applicants ($10/per square metre).

With Canada’s current energy and air-quality crisis (and the federal government’s reluctance to enforce laws on big industry) it doesn’t come as much of a shock that Toronto Hydro would pull out or that industrial buildings didn’t think of applying for an incentive. But where does all of this leave us?

After gathering their analysis and evaluating the results of the program Toronto Water’s recommendation to city council will be to establish a permanent green roof incentive program with no deadline and a higher per metre financial incentive. Andzans would like to see the program modeled after Chicago’s, which offers larger lump sums (up to $5,000 per residential owner). Chicago also separates their program between residential and commercial budgets and Montreal’s Gaz Metro gives $50/square metre.

There are other programs in place, like the Down Spout Program and the Canada Green Building Council, a broad-based coalition of representatives from the design and building industry, which accelerates the design and construction of green buildings. Elevated Landscape Technologies, as mentioned earlier, is a sustainable technology company which offers ways to get funding for your green roof (Ontario Trillium Foundation is one supporter). And there are numerous other landscape and design companies within the city that are on board – even private owners are now looking for leed-certified buildings when buying.

It seems like Canada is still behind cities like Tokyo or countries like Germany and it is obvious we need to get past the money issue because all roofs will need replacement within 25 years.

Now Magazine was one of the successful applicants to the Green Roof Pilot Program. Indeed, Editor and CEO, Alice Klein, is one of the few business owners to put her money where her mouth is. Judging from her deep commitment to other environmental causes, the cost of the construction and the lack of funding did not deter her.

“We started work on our green roof before the pilot program, and then we got accepted, but frankly it’s not a lot of money. Compared to the cost of the roof, which was expensive, it was a very limited dollar amount. The fact is, if you have to repair your roof, which people do every 25 years or so, and if you are looking at costing, you do have the support of that little bit of reduction and given the rising cost of energy, we think it will be worthwhile...plus, we were interested in being pioneers,” said Klein.

And that, precisely, is the attitude and leadership that is required if we are going to make a dent in the energy and water crisis that Toronto is currently in.

Resources

•City of Toronto Green Roof Pilot Program, www.toronto.ca/greenroofs (you can find the complete Ryerson study here)
•Elevated Landscape Technologies, www.eltgreenroofs.com
•Canada Green Building Council, www.cagbc.org