The British Columbia Institute of technology [BCIT] is home of the “Center for Architectural Ecology”. The Center studies green roof and living wall technology.
On October 15, I had the opportunity to attend a green roof workshop at the center in Vancouver. The workshop was led by Jonathan Hays, the technology transfer coordinator for the Center.
Although green roof technologies are relatively new in North America, the concept has been successfully implemented in Europe for many years. The advantages of green roofs include:
- Storm water managemeny
- Urban heat island reduction
- Energy efficiency
- Economic
- Air quality and acoustic
- Health and quality of life
- Habitat and biodiversity
There are two types of green roof designs:
- extensive green roofs use a vegetation layer between 2 to 6 inches deep. This shallow planting medium reduces costs but restricts the type of vegetation that can be planted.
- Intensive green roofs have a much thicker vegetation layer. This design is much costlier but allows for unique designs and public access.
Construction techniques have been well tested through experience in Europe. The diagram above [taken from CMHC’s “Green Roofs - a Resource Manual for Municipal Policy Makers”] shows the multiple layers required for the proper construction of a green roof.
The Center at BCIT has an extensive green roof with one third of the roof using a 3 inch vegetation layer, one third using a six-inch vegetation layer and the remaining one third left open as a control area. The center also tests a number of other roof types in several roof emulation modules [REM].
My conclusion after visiting the center is that green roof technology should be considered for any flat roof commercial buildings but that is not yet ready for residential use in Canada.
For more information on green roofs, check out www.BCIT.ca/greenroof
1 Comment
March 13th, 2010 at 3:09 pm
Now this is a great idea. I would like to see more green roofs. The cost however, can be prohibitive.
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