There has been an exploding interest in green roofs of late. During the recent Vision Vancouver fundraiser I was introduced to Erika Richmond who designed and built my friend Toby B.’s greenroof in the downtown east side. Walking away from the conversation I suddenly realized I may actually live on a green roof.
The building I live in has 4 floors of commercial real estate and a rooftop townhouse development built around a 20,000 sq ft garden and sidewalks. The “sidewalks” have ceders and trees planted along them, the main garden is a grass field and with over 14 decently sized wood garden plots.
Is it technically a green roof? I don’t know. But it does create a beautiful and relatively peaceful living space 25 meters above street in an increasingly busy part of town.
(I realize the photos do not look particularly green but you we are in the midst of what passes for winter here in Vancouver. I’ll try posting some new ones come spring/summer.)
But it turns out the beauty is the least important part of green roofs. For a policy geek like me there is a fascinating and increasing amount of research into the benefits of green roofs – some of the most interesting of which has been commissioned by the City of Toronto and available in a report it published in late 2005.
Savings to the city of Toronto, based the assumption that 100% of available green roof areas over 350 sq m. were retrofitted and that 75% of the roof area was made green, were: 
Those are some large numbers.
What an enormous opportunity green roofs would have been for the federal budget. Buildings account for a significant amount of GHG emissions and the financial savings generated by such a plan are obviously enormous. Better still the greening of the aforementioned roofs would not require the equivalent planning of say building a highway, bridge or building and so could be undertaken relatively quickly. In short, they are shovel ready. Equally important, green roofs are probably more labour intensive (as opposed to capital intensive) than many of types of infrastructure projects. This means green roof projects might be better positioned to generate jobs and help lower our rising unemployment numbers. Massive year on year savings? Significant employment? Instant initial savings? An increase in property values? Sounds like a stimulus package winner to me.
Sadly, the trend appears to be catching on more in the United States than in Canada. A cursory exploration of the web reveals that New York City recently passed a city by-law that rewards building-owners who cover 50 percent of available rooftop space with a green roof with “a one-year property tax credit of up to $100,000. The credit would be equal to $4.50 per square-foot of roof area that is planted with vegetation, or approximately 25 percent of the typical costs associated with the materials, labor, installation and design of the green roof.” Philadelphia also has a tax credit (although it appears to be little used). Chicago however is an emerging capital of green roofs with over 200!
It is unclear whether Vancouver or Toronto have such a tax credit (it didn’t appear so, but please let me know if I’m wrong). That said, a growing number of Toronto public buildings now have green roofs and Vancouver will soon be host to Canada’s largest green roof. It’s a start, but given the size of the opportunity, we could be doing so much more.
eaves.ca 
Good post for discussion: Not to be a skeptic, but the cost savings above in Toronto would require in the neighborhood of a $10 billion investment to install green roofs (5,000 hectares * 10,000 sq m per hectare * $200/sq m) as a very basic calculation. The payoff is therefore a long long time in economic terms.Also the stormwater savings quoted above (the largest part of the savings) actually had a $40m or so range in the report, and they chose the top end of that range. I would also say from reading the report that they were very liberal with the potential benefits in economic terms, rather than being cautious.So, should public policy move in that direction? Is the benefit great enough? Why has it moved so fast in the other large cities? Is their cost of dealing with the stormwater/heat island problems higher?Any ideas?
George, not a buzz kill at all… the right question and it deserves a good answer. I'm working on it, but hope someone else might chime in as well.
I'm just psyched you have your own place ;-)
Great post David! There's definitely a lot of growing interest around green roofs and roof gardens. New York's green roof tax credit is both progressive and impressive and it surprises me that more cities aren't taking this initiative. As you've pointed out, green building retrofits and building green roofs are a tremendous opportunity to create employment while also investing in useful infrastructure and reducing energy consumption.As far as the numbers go, there are others better suited to answer that. From my experience, green roofs offer a lot of different benefits, many of which cannot be translated into dollars. Some of the more measurable benefits include reduced heating and cooling costs due to the additional insulation the green roof provides. The cooling benefit we received during the summer was truly amazing. Green roofs can also extend the life of your roof membrane by protecting it from UV rays. A lot of people get excited by how green roofs can mitigate your stormwater runoff…to me this isn't a great advantage, but on a citywide scale it's effects could be significant. Urban agriculture, or growing food on green rooftops is another potential benefit. Can you imagine if we greened all of the rooftops in Vancouver's Downtown Eastside and then used to those green spaces to grow vegetables while providing employment opportunities and teaching gardening skills to the local residents? We don't need to go far to see the potential for green roofs to affect the way we live.More important though, are some of the intangibles that green roofs provide: green spaces for birds, bugs and people to enjoy, a potential source of food, a possible area for urban composting, a unique staff amenity and a space for fun or contemplation. Green roofs can also be used as powerful marketing tools and strong company differentiators. Most importantly, green roofs inspire people and help them dream of a better world. They are tangible steps towards living in harmony with nature and that resonates with people.The world of business is changing quickly and consumers can control the direction it goes. My hope is that people will start to reward companies that invest in meaningful and substantial projects like building a green roof or community garden. Marketing dollars should be spent on these kinds of initiatives, rather than on traditional marketing campaigns which are often unsuccesful and at times wasteful. Are green roofs worth it? It's all a matter of what we decide to prioritize and value.
Its a very nice post. and I liked the comments posted by Toby Barazzuol as well. Thanks Toby Barazzuol for sharing your valuable comments with us.
This looks fantastic. I would love to live an apartment like this. Not only is it great for the environment and energy saving its also a great place to relax. I was speaking to a local Nashville roofers salesperson the other day about installing a solar panel on my roof :) Hopefully that will cut back on the energy bills a bit.
Indeed a good post! I leave under a green roof and i am proud of it! I just remodelled my house this summer. Tried to get it as green as possible. For the room I had to hire though a Minneapolis roofing contractor. They did a wonderful job with it!
Indeed a good post! I leave under a green roof and i am proud of it! I just remodelled my house this summer. Tried to get it as green as possible. For the room I had to hire though a Minneapolis roofing contractor. They did a wonderful job with it!
Indeed a good post! I leave under a green roof and i am proud of it! I just remodelled my house this summer. Tried to get it as green as possible. For the room I had to hire though a Minneapolis roofing contractor. They did a wonderful job with it!
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