Green rooftops have several benefits that help to improve urban spaces. Green rooftops transform flat, black roofs into aesthetically pleasing garden areas. Each green rooftop is unique and specifically designed for the loadbearing characteristics of the roof, the space available, and other attributes that must be taken into consideration in the engineering (GRHC, 2016). Green roof tops have several advantages in that they provide better stormwater management, moderate the urban heat island effect, improve air quality, improve energy efficiency, reduce noise, and create usable space out of roofs (GRHC, 2016). Rooftop agriculture extends the idea of the green roof to include food production (Whittinghill & Rowe, 2012). This research will explore the benefits of green roof tops as a potential solution to expanding the area available for agricultural production.
One of the primary benefits of green roofs, regardless of the design or purpose, is that it can help to eliminate the negative effects of pollution (Rowe, 2011). Green roofs provide many chances to improve pollution in several different ways. Green roofs can reduce carbon dioxide emissions, as it increases the number of plants in an urban area that help to remove harmful emissions from the air. Green roofs also provide habitat for animals and wildlife (Rowe, 2011). Green roofs also improve the longevity of roofing membranes by protecting them from UV light and other damage (Rowe, 2011). This means that they will not contribute as significantly to the amount of roofing materials in landfills. Green roofs also improve the quality of stormwater runoff and provide a use for grey water (Rowe, 2011).
The second most important benefit of green roofs is that they help to reduce the energy efficiency of the building. Green roofs eliminate sunlight striking the black rubber roof of the building causing elevated temperatures. In warmer climates, green roofs can significantly reduce the costs of cooling the building (GSA, 2011). Aside from blocking heat producing sunlight from reaching the roof, the plants must be watered regularly. Watering the plants also helps to cool the roof and provides a source of evaporative cooling also. A green roof can lead to a reduced need for air conditioning (GSA, 2011). Green roofs reduce peak and daily summer cooling demand by creating cooler ambient air directly above the building (GSA, 2011).
In both winter and summer, green roofs serve as insulation. In the summer, green roofs help to protect the building from sunlight and provide evaporative cooling. This helps the building to maintain a more constant temperature, while depending less on building cooling systems. The green roof provides thermal mass and shading to the roof area (GSA, 2011). In the winter, the energy efficiency is reduced somewhat, but green roofs still provide some insulation factor. The green roof protects the building from exposure to cold winter air and also prevents heat loss through the roof (GSA, 2011).
The two main benefits of green roofs are air pollution reduction and savings in energy efficiency. These benefits make green roofs cost-effective over the long-term. Regardless of the type of green space that is planned for a building, the building will operate more efficiently both in summer and in winter due to the effects of the thermal mass of the roof. Green rooftops provide many human benefits aside from these two main benefits. It makes the space useful for human activities beyond simply providing protection from the elements. There are many different ways in which green roofs can be utilized for the benefit of the public.
They can be used to provide recreational space, space for cafes and restaurants, or playgrounds for children. Rooftop agriculture is only an extension of the green roof concept that makes it not only a potentially profitable endeavor, but also helps to provide a locally grown food source, and helps to provide increased space for agriculture.
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Green Roofs for Healthy Cities (GRHC) (2016). Green Roof Benefits. Retrieved from
http://www.greenroofs.org/index.php/about/greenroofbenefits - Rowe, D. (2011). Green roofs as a means of pollution abatement. Environmental Pollution 159
(8-9):2100-2110. - United States General Services Administration (GSA). (2011). The Benefits and Challenges of
Green Roofs on Public and Commercial Buildings. Retrieved from
https://www.gsa.gov/ - Whittinghill, L. & Rowe, D. (2012). The Role of Green Roof Technology in Urban
Agriculture. Renewable Agriculture and Food Systems 27(4):314-322.
