Green Roofs not only provide a natural escape in an urban environment, but complement man-made “grey” infrastructure by absorbing harmful runoff and countering the ‘urban heat island’ effect. Green roofs bring nature to urban roof tops while also absorbing rain water and cooling the air.
About Green Roofs
Green roofs are contained areas of vegetation – such as trees, shrubs, crops or grasses – planted on top of a human-made structure. Green roofs can be found anywhere: on public structures such as government-owned buildings, schools, libraries or community centres, and on private structures such as residential houses, apartment buildings and commercial buildings.
A green roof typically incorporates a high quality water-proofing and root repellent system, a drainage system, filter cloth, a lightweight growing medium, and the plants themselves. There are three major types of green roof:
- Extensive green roofs are shallow in depth, require no irrigation, and have small plants.
- Semi-Intensive green roofs are deeper, require some irrigation, and have larger plants.
- Intensive green roofs are the deepest type of green roof, have a high capacity for irrigation, and can hold the largest plants.
What are the Benefits of Green Roofs?
Mitigation:The vegetation on green roofs absorbs carbon dioxide.
Adaptation: The vegetation on green roofs can help lower temperature in cities during the summer.
Stormwater Management: Green roofs are permeable surfaces that absorb stormwater and filter runoff.
Temperature: Green roofs provide insulation that moderates a building’s temperature, which reduces energy costs.
Habitat: Green roofs provide habitat for local species which helps increase biodiversity.
Food: Green roofs can be an important food source for pollinating insects and birds, especially in urban areas.
Clean Air: The trees and vegetation on green roofs sequester pollutants and improve air quality by removing health impacting pollutants such as ground level ozone and particulate matter.
Aesthetics: The trees and plants on a green roof provide a pleasing natural setting in an urban environment.
Food: Green roofs offer a prime location for urban agriculture. Local food production helps address issues of food security.
Social Well Being: Green roofs provide spaces for community interactions.
Jobs: Urban agriculture on green roofs can generate revenue and provide long-term employment.
Lifecycle savings: Green roofs can extend the underlying roof’s lifespan by shielding the roof from the effects of ultraviolet radiation, temperature extremes and mechanical damage.