Green Roof | WGIC Bangalore 2018

Green Roof



A Green Roof refers to a building roof that is designed to be covered with vegetation or other greenery, all planted over a waterproofing membrane in order to prevent seepages and erosion. Some Green Roofs include additional layers that are helpful to the growth of vegetation such as a root barrier, and drainage and irrigation systems, depending on the size of the Green Roof.

There are two types of Green Roofs: Extensive and Intensive. Extensive Green Roofs are six inches or shallower and are frequently designed to satisfy specific engineering and performance goals. Intensive Green Roofs have the capability to become quite deep and merge into large on-structure plaza landscapes with features such as promenades, lawns, large perennial plants, bushes and trees.

Benefits of a Green Roof:

Environmental benefits
- Reduces temperature
- Mitigates urban heat-island effect
- Reduces temperature of roof surface by up to 31°C
- Reduces ambient temperature by up to 4.2°C
- Improves air quality
- Vegetation filters airborne particles
- Green landscaping can contribute up to 80% reduction in dirt particles
- Improves rainwater retention
- “At source” technique for controlling run-off in urbanised areas
- Reduces surface contaminants, reduced occurrence of soil erosion into waterways
- Reduces CO2 and increase oxygen exchange
- Promotes natural carbon cycling and atmospheric gaseous exchange
- Enhances biodiversity in urbanised areas

Economic benefits
- Serves as insulation to reduce heat flux through the roof
- Reduces heating/cooling costs by up to 25%
- Reduces building cooling resources
- Achieves 15% net energy savings in a 5-storey building with roof garden
- Reduces peak cooling load by up to 80%
- Reduces Peak Roof Thermal Transfer Value (RTTV) by up to 80%

Property Benefits

- Increases the property value by:
- Lessening stress due to thermal expansion and contraction on the membrane, doubling the service life (Velazquez, 1999)
- Improving acoustic insulation
- Reducing noise levels of up to 50 dB (McMarlin, 1997)
- Enabling cultivation of vegetables and fruits
- Enhancing the company’s image and aesthetic appearance of the building
Social Benefits:

- Fosters community interaction
- Offers therapeutic effects and improved health to users