Having attended the always inspiring Pecha Kucha night at the Brisbane Powerhouse, I was intrigued by landscape architect, Sidonie Carpenter’s introduction to the concept of ‘green roofs.’ As the presentation time was limited, I was compelled to research the topic further and this is what I discovered…
Green roofs are a phenomenon that has taken off in many countries around the world and is recognised as an important response to climate change. A green roof system is an extension of a building’s existing roof which involves a high quality water proofing and root repellent system, a drainage system, filter cloth, a lightweight growing medium and plants.
There are two types of green roofs: ‘intensive roofs,’ which are thicker and heavier to support a wider variety of plants, and ‘extensive roofs,’ which are lighter, easier to maintain and covered in a light layer of vegetation.
Other than their aesthetic value, there are many proven benefits such as:
- Increasing air quality and helping lower air temperatures, which aids in the reduction of the “Urban Heat Island Effect” and helps combat climate change.
- Aiding in biodiversity in urban areas by providing refuges for wildlife.
- Saving water – green roofs can significantly reduce the volume of run off rainwater. They can also reduce the impact of flash flooding.
- Providing insulation which then reduces the energy consumption of a building, because the temperature inside is more constant and comfortable.
Millennium Park, in Chicago, is one of the largest green roofs in the world, at more than 24 acres. Fukuoka City in Japan have an amazing building called “ACROS Fukuoka” where one side looks like a conventional office building with glass walls, but on the other side there is a huge terraced roof that merges with a park.
In North America, the benefits of green roof technologies are being increasing understood as the green roof industry moves from novelty to common practice. In Europe green roof technologies have become very well established since the 1980s. This has been a result of government legislative and financial support. Perhaps it’s time for the cities of Australia to catch on?