In late May of this year, the City Council of Toronto passed a law mandating that all new development above 2,000m² of Gross Floor Area be equipped with a green roof. The law will apply to new building permit applications submitted after January 31st, 2010 for residential, commercial, and institutional buildings, whereas the cut off is January 31st, 2011 for industrial development. This mandate is the first of its kind in North America, and will likely serve as a precedent for more to come. The issue is important and relevant because it is an example of government using its direct regulatory power to instate environmental improvement as opposed to market based approaches.
Toronto’s Green Roof Bylaw specifies a certain percentage of the rooftop required to be “green” in relation to the size of the building. For a building with a Gross Floor Area of 2,000 – 4,999 m2, the amount of available roof space should be 20% covered by greenery. Similarly, a GFA of 5,000-9,999 m2 constitutes a green coverage of 30%, and so on. Not surprisingly, developers are unhappy about this law because estimates show that this requirement has the potential to add upwards of $150,000 to building projects. Nevertheless, the long term monetary and environmental benefits outweigh this one time cost, making it fairly cost-effective.
This mandate is a great step in the right direction for two important reasons. First, green roofs offer many benefits to the environment, such as reducing rainwater runoff, filtering heavy metals out of rainwater, and vast energy savings. Green roofs reduce heating needs by adding mass and thermal resistance value, as well as cooling needs by evaporative cooling. In addition, if they are glassed in, green roofs can act as passive solar heat reservoirs and can reduce the city’s average temperature during the summer. Second, this mandate shows to the public governmental efforts to move towards more sustainable living. The idea of living sustainably should be solidified into the minds of the public so that we can learn to incorporate environmental consciousness into our lifestyles. In this regard, the green roof mandate is a step in the right direction as it will increase awareness of environmental issues as well as what is being done to address them.
I feel like making green roofs mandatory is a bit extreme due to the costs of constructing and maintaining them. This will only hurt Toronto economically because the high costs will scare away potential businesses. Maybe Toronto can make it more of an incentive program than a mandatory one.
ReplyDeleteI think Toronto's requirement for solar panels on buildings is a great way to incorporate environmental amenities into an urbanized lifestyle. Using regulations requiring developers shows other leaders that this is possible. Aaron, I agree that the cost is going to be extreme in the first place. However, the efficiency of the new buildings will increase eventually paying off the initial costs. I believe the 20%, 30%, etc. solar panel area is a good ratio for building contractors to accomplish. Noor, I like the other benefits you stated like pollution control. Are the statistics very strong for the reduction in urban runoff?
ReplyDeleteActually, a green roof is a roof that is equipped with a bed of vegetation, not solar panels. Sorry for not making this distinction clear in my blog post. The vegetation incorporated in green roofs is very productive in reducing urban runoff because it absorbs and utilizes rainwater that would otherwise fall on streets and sidewalks. On average, 75% of the water that falls on green roofs is used by the plants and recycled back into the water cycle. If green roofs are installed on a vast scale on city roofs, this would put a large dent in the amount of runoff coming from them--in turn easing the need for expensive storm water management techniques.
ReplyDeleteMy apologizes, I misunderstood what the term 'green roof' referred to. Even so, those are some awesome statistics to reduce run off pollution. 75%!?! Adding green roofs to all new buildings in Toronto is a great jump off point for other cities to follow. I also like the idea of adding 'color' to cities, I think this is a good way even to promote a better psychological state of mind for the people working in the cities. I also love the idea that the plants c an act as an insulator, so as not to lose heat! Rather than re-insulating theentire building adding a green roof could be more efficient. Now, I know that Canada is a quite a bit colder than the US; Do you think the green roofs will prosper (grow large) enough to make a big impact on energy savings?
ReplyDeleteI definitely agree that it is a good way to add some greenery to the city, and cultivating green roofs on homes and buildings could bring city dwellers a little closer in touch with nature. I do think that green roofs would collectively make a huge impact on energy savings and use; however, I am not sure if their implementation will spread that much in the United States. I feel as though Americans in particular are very resistant to being told they have to do something, so who knows if something like this could happen here. About the heat/cold issue, green roofs are actually really cool because while in the cold, they provide good insulation, and in the heat they also provide cooling by reducing the amount of sun's rays hitting and being absorbed by the building. It is known that the top floors of apartment buildings are warmer because heat rises, and having a cool layer of moist soil and plants counteracts this.
ReplyDeleteI think that's great, the addition of green roofs in a city along with all the benefits you mentioned is extremely neat to see and productive for residence, whether they live or work in the building having a green roof and proper planning will allow a place for someone to relax and enjoy. green roofs on housing units could even be used for small scale gardening. and if the whole city has it imagine the view from one roof too all the other greened roofs surrounding you. sounds like the perfect plan to me
ReplyDeleteThis mandate in Toronto is a great initiative to start moving towards more green roof technology. Hopefully the United States will follow suit soon. Although it creates extra costs for developers initially, the benefits for the environment and heating and cooling energy costs alone will help to have the green roof pay for itself. Germany and a few other European countries have passed legislation similar to this and it has not shown a decline in development or hurt the building economy.
ReplyDelete-Amanda Hamilton