Toronto Mandates Green Roofs

The Toronto City Council approved a measure mandating the use of green roofs on certain sized buildings. The measure is set to take effect in 2010.

According to Jennifer Lewington of "The Globe and Mail,":

The new rules kick in for new residential buildings constructed after Jan. 31, 2010, that are at least 2,000 square metres... and at least 20 metres high (six storeys), down from the 23 metres originally proposed.

Larger, commercial buildings will also be required to have between 20-50% green roof coverage. Although this measure was largely opposed by developers, there were some arguments owing to no Canadian building standards for green roofs. Air France offers free stopovers in Paris.

To mitigate higher costs for green roofs in renovation, greenroofs.com reports:

The latest move will provide cash incentives to commercial, industrial and institutional (ICI) property owners to install eco-roofs. Currently, the City is willing to provide incentives of $50 (Canadian) per square meter up to $100,000 for building owners who install green roofs, on a one-year pilot basis.

Although similar laws exist in Japan and Germany, consistent with both their compressed populations and issues surrounding storm water management, Canada has been successful with voluntary use of green roofs.

One major example is Vancouver. The Vancouver Convention Centre West is the largest green roof in all of Canada. It covers over six acres and has over 400,000 indigenous plants species. Taste the Purest Tea on the Planet – Organic and Fair Trade Certified Shop Numi Organic Tea

While tax paying citizens of Toronto can argue whether this measure should have passed and whether it is too stringent or not, the benefits of green roofs are undeniable. The buildings that have green roofs enjoy 20-30% reduced heating and cooling costs, as well as reduced storm water runoff. Additionally, the aesthetic benefits of green roofs create a positive environment in major cities.

Sky Farms and Green Roofs

2009 has been full of stories about sky farms and green roofs. While this blog focuses on green roofs, the concept of sky farms is very intriguing.

Inhabitat.com, treehugger.com, and verticalfarm.com have all been bringing new information to the scene about this growing concept.

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If one considers a city, it inhabitants, food requirements and the logistics to meet those needs, it becomes clear that urban farming can be an efficient way to both feed a growing populace and reduce environmental impact.

In three previous posts, "Food in the City," "New York's Dragonfly Concept," and "Dubai's Food City," I have explored different takes on urban farming. What I have found is that sustainable food production is possible, though start up costs are quite high.

What strikes me about the urban farming concept is the synthesis of green roofs, green walls, grey water purification systems, as well as the use of solar and wind power. This synthesis of existing technologies produces a product greater than the sum of its parts.

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One question that hasn't been answered is whether the urban farms should be open to environment or walled. With the inherent pollution of a city, it would seem the open farms would naturally concentrate the pollution in the vegetation. However, a hybrid approach, using large green roofs would help to reduce both the air pollution as well as filter the rain water.

As the urban farming concept continues to grow in cities such as Las Vegas, Vancouver, and Toronto, credit has to be given to Dr. Dickson Despommier, Ph.D., one of the leading scientists in the field.

As global urban population grows, the need to feed the population becomes more urgent. While green roofs can help reduce some of the problems of increased urban populations, urban farms can not only meet food needs, but also reduce the stress on existing farm lands.

Food in the City

Vancouver seeks to been one of the greenest and sustainable cities in the world. To help reach their goal, they held the FormShift Vancouver Competition, and Harvest Tower won an Honorable Mention.

Inhabitat.com reports that this new complex, a tower, green roofs, and grazing area, "... consists of interlocking tubes that grow various fruits and vegetables, house chickens and contain an aquaponic fish farm." Hydroponic garden

While this is more ambitious than Los Angeles's edible green roof, it is in the same league as Dubai's Food City. Vancouver also boasts Canada's largest green roof.

Other agricultural products include, "... a livestock grazing plain, as well as a bird habitat and boutique sheep and goat dairy facility." There will also be a restaurant, and grocery store.

Sustainability is also important in this project, through the use of wind turbines, photovalic glazing, and methane captured from composting. I think composting is a euphemism for manure. Water will be provided by a large rain cistern on the roof. Water Barrels and Storage The green roofs will also provide filtration, mitigate storm water runoff and reduce air pollution.

While vertical farming is being studied elsewhere by "...Dr. Dickson Despommier, an environmental health scientist at Columbia University, his work reveals that for every one acre of indoor farming, four to six acres of outdoor land can be saved." While farming in the city keeps the food local and reduces transport pollution, the once-farmed land can be returned to natural habitats.

Canada's Largest Green Roof is in Vancouver

World Architecture News reports:

...Vancouver Convention Centre West, ... with 6 acres of green roof it boasts the largest in Canada, and the largest non-industrial green roof in North America. This combined with many other eco-measures is set to help the project achieve LEED Canada Gold certification.

The green roof itself is a thing of great beauty and purpose. According to the article, there are "...400,000 indigenous plants and grasses,..." Additionally, a roof this size helps to control heating and cooling costs, as well as reducing air pollution. Discover Top Rated Mighty Leaf Herbal Tea. Tea lovers love our delicious herbal tea blends. You will too. Save 25% on your first order!

This is not a beautiful project, but also allows Vancouver's green roof credentials to take root. While the city boasts the Centre for Architectural Ecology - Collaborations in Green Roofs and Living Walls, the Convention Center will also create habitat for marine life, as well as improve the shoreline.

While the green roof is the most obvious "green" feature of the structure, it also uses the most advanced in green technologies. There is a significant waste water recycling. Heating and cooling is aided by using a heat pump system, "...that takes advantage of the constant temperature of adjacent seawater,..." and uses window placement for lighting. Water Barrels and Storage The Convention Centre's expansion was designed to be "...used as a hub to support 7,000 media during the XXI Olympic & Paralympic Winter Games."

The design and architectural work was done by Architects LMN and Vancouver-based Musson Cattell Mackey Partnership as well as DA Architects & Planners.

This beautiful new addition will also serve to provide Vancouver with the opportunity to compete with Toronto for the World Green Roof Congress in the years to come. Mountain House Freeze-Dried Food

Green Roofs Provide Benefits in Winter

Can green roofs provide benefits in climates with strong winters? According to Karen Liu of the National Research Council of Canada's Institute for Research in Construction, the answer is "Yes!"

In an article posted in EnviroZine, green roofs provided a 10% improvement in the heat loss of tested buildings in the winter. The results of the first round of testing were so significant the NRC-IRC began performing a multi-year study on green roofs to verify the results.

Once the benefits were confirmed, the article indicates that NRC-IRC designed green roofs specifically for winter climates. From the article:

"... green roofs are often planted with drought resistant plants ...which grow in a six-centimetre thick layer of a light weight growing medium (such as volcanic rock), the winter green roofs were composed of juniper shrubs... The purpose was to reduce the effect of wind speed (which draws heat from the building) and to increase the building's resistance to heat loss. Junipers were particularly well-suited for the experiment because they are evergreens and spread easily."

The research on both traditional home structures and homes built specifically for cold climates found that the juniper-based, winter green roofs increased heating efficiency by 10 and 8.5% respectively. Additionally, the winter green roofs helped to reduce the fluctuation in roof temperature, thus improving the life of the roof itself.

It would be very interesting to see if cities such as Chicago could benefit from the addition of junipers to their large number of green roofs.