The Benefits of Green Roofs

By: Joanne Jones
Submitted: 2008-07-28 17:10:56
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Green roofs are basically when people grow plants on the top of a building, such as an office tower or a condo.  Green roofs can be developed from either modular units or directly installed on a roof.  Both methods involve creating a vapour proof layer between the plants and the roof of a building.  Thermal insulation is then installed over the vapour proof layer.  On top of this, a support panel is placed, with a water and root proof layer on top of the support panel.  Next, a layer of coarse gravel is placed, which will allow water to drain away from the roof.  Above this, you will find a filter membrane, such as a cloth.  Finally, soil and plants are placed on the top layer.  Due to the plants, green roofs are also called green spaces.

Green roofs have many environmental and economic benefits.  Some of the benefits of a green roof include reduced heating and cooling costs, reduced roof maintenance costs, improved air quality and improved sound insulation.  The exact amount of these benefits will vary with each building, as it depends on the type of building, the local climate and most importantly, the design of the green space.  Here is a closer look at the benefits that can be achieved once a green roof has been installed.

Environmental Benefits:

One of the most important benefits of green spaces is the moderation of temperatures in a city.  With a conventional roof, the roof absorbs and radiates heat back into the air.  With a green roof, the plants absorb the heat and use it to grow.  Since less heat is being given off, the surrounding air temperature is then lowered.

Green roofs provide sound insulation.  They can block outside noise sources such as machinery and traffic noise from cars, trains, transit and even airplanes.  Even if the combined layers of soil and coarse gravel are only 12 centimetres (4.7 inches) thick, they can still reduce the level of sound by 40 decibels.  The thicker the layers, the more sound they can block out.

The plants on a green roof also help to improve air quality.  Through photosynthesis, the plants remove carbon dioxide from the air and replace it with much needed oxygen.  As well, they remove pollution and other particles from the air, like a natural air filtration system.  As a result, smog levels are reduced. 

Green roofs can support more than just trees and shrubs; they can also be used as a source of local food production.  Locally grown food is fresher, tastier and more nutritious.  It also reduces the amount of fuel needed to transport the food to market.  As well, businesses, such as restaurants, that grow their own food can reduce the amount of money they spend on food.

Economic Benefits:

The green roof actually protects the structural roof beneath it and allows the structural roof to last approximately twice as long.  This prolonged life allows the owner of the building to save money due to lower maintenance needs and the reduced number of times the roof needs to be completely replaced. 

A green roof also reduces the heating costs during the winter months and cooling costs during the summer months.  Heating costs are reduced because less heat can escape from the building.  Cooling costs are reduced because the green roof acts as insulation and the plants provide shade.  Both of these factors prevent heat from entering the building through the roof. 

New developments that include a green roof are more likely to be well accepted by the surrounding community and receive quicker approval for building permits.  As well, people are willing to pay a premium for buildings with green spaces.  Therefore, units sell quicker and at a higher market value.

Article source: Expert Articles