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Introduction

A green roof is as simple as it sounds; a green roof. Green roofs are the addition of agriculture onto the roof of a normal home. This can be as basic as a patch of grass to as extreme as a tree. There are many advantages to having a green roof on your home, both environmentally and financially for the home . It will greatly reduce heating and cooling costs, and also benefit the environment by adding more space for agriculture.While today in the 21st century, it's all about "going green" and being more environmentally friendly, green roofs have actually been around since as early as the 1960's in Germany, where they originated [1].


Benefits

Environmental

  • Reduces the amount of storm water runoff that could potentially effect drinking water and recreational activities such as swimming. 2
  • Adds Biodiversity 4
  • An increase in natural green space. 2
  • Natural Habitat creation 3
  • Filters CO2 levels and decreases risk for diseases such as asthma.
  • Reduces "Urban Heat island effect".
-"Urban Heat islant effect" is when buildings such as sky scrapers with lots of windows reflect the light from the sun, making the air temperature rise greatly.

Financial

  • In urban environments, it can greatly reduce the costs of heating. The green roof acts as insulation. 2
  • severe decrease in maintenance for the home owner 2
  • Increases the retail value of the home.
Comparing the rain water run off from a normal roof to a green roof. It is aparent that the green roof is significantly lower.
Comparing the rain water run off from a normal roof to a green roof. It is aparent that the green roof is significantly lower.



Basic structure of a green roof
Basic structure of a green roof
Structure

All green roofs start off as normal roofs, lined with a standard frame, weather it be metal, wood or tile. Most commonly used is a corrugated aluminum rooftop. On top of that is a waterproofing membrane, followed by a sheet of foam and a second waterproofing membrane. This is where the soil and plants are placed. Depending on the home owners desire, the average for standard plants is about 4" (10cm) thick. 5

Installing a basic green roof.




History

Church in Vidimyri, Iceland (Magnusson, 1987)
Church in Vidimyri, Iceland (Magnusson, 1987)
Even before being environmentally friendly was all people thought about, green roofs were around. In Iceland, people had to compromise for a lack of natural resources. They made the most of what they have, many roofs were covered in sod or turf that were piled on top of stone. Materials like wood were included if available.
Sod roofs on 18th century farm buildings in Heidal, Norway.
Sod roofs on 18th century farm buildings in Heidal, Norway.

Although the design for green roofs has not changed, the purpose of them has in a sense. In the 18th century, green roofs were part of using all available resources. Today, they are about having a cleaner environment, reducing heating costs as well as adding some eye candy to heavy urban areas.
Mountain Equipment Co-op store in Toronto, Canada.
Mountain Equipment Co-op store in Toronto, Canada.




A small green roof house in Mexico
A small green roof house in Mexico



References

1 http://www.infobeck.com/articles/2011/5/17/what-are-the-benefits-of-green-roofs.html
2 http://www.toronto.ca/greenroofs/findings.htm
3 http://www.roofgreening.ca/content/Habitat_Final.pdf
4 http://www.greenroofs.org/index.php/about-green-roofs/2577-aboutgrnroofs
5 http://www.youtube.com/watch?v=7zCyyF01CL4
6 http://www.greenroofs.com/Greenroofs101/history.htm