Green roof

A green roof or living roof is a roof of a building that is partially or totally covered with plants. It may also include layers such as a root barrier and drainage and irrigation systems.Rodriguez Droguett, B. (2011). Sustainability assessment of green infrastructure practices for stormwater management: A comparative emergy analysis (M.S.). Retrieved from https://www.proquest.com/docview/900864997 Container gardens on roofs, where plants are in pots, are not generally true green roofs. Although, this is debated. Rooftop  ponds are another kind of green roof which are used to treat greywater.Özyavuz, Murat, B. Karakaya, and D. G. Ertin. "The Effects of Green Roofs on Urban Ecosystems." GreenAge Symposium 2015. Vegetation, soil, drainage layer, roof barrier and irrigation system make up a green roof.EPA (2017) Green Roofs. U.S. EPA. Available from: http://www.epa.gov/heatisland/strategies/greenroofs.html

There are reasons why a building may have a green roof. The reasons include absorbing rainwater, providing insulation, creating a habitat for wildlife, increasing benevolence and decreasing stress of the people around the roof, and helping to lower urban air temperatures and go against the heat island effect. Green roofs are able to be added on old buildings as well as new buildings. They can be put on small garages or larger industrial, commercial and municipal buildings. They effectively use the natural abilities of plants to filter water and treat air in urban and suburban areas.

There are two types of green roof:
 intensive roofs: thicker, with a minimum depth of . They can support many different kinds of plants, but they are heavier and require more maintenance.
 extensive roofs: shallow, ranging in depth from  to . They are lighter than intensive green roofs, and they don't need as much maintenance.

References

Category:Roofs
Category:Energy conservation
Category:Gardening
Category:Renewable energy
Category:Sustainable development
Category:Urban planning