Buildings with green roofs should be able to meet at least two of the following effects: Absorb 50-80% of the precipitation that falls on the roof.

Provide a cooling and insulating effect of the building and reduce reflection.

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2005: Through 2005, there were approximately 200 greenroof projects in Switzerland, totally about 10,000,000 - 15,000,000 m2.

The cities of Basel, Zrich, and Luzern, for example now require that every new flat roof be planted per building code. Stephan Brenneisen of the Zurich University of Applied Sciences says, "We work together with authorities to develop standards for green roofing according to their planning and construction laws." As of the end of 2005, approximately 20% of the flat roofs are green roofs within Basel in the city of Basel in a year there will be around 80.

Today about 200,000 m2 of the roofs in Copenhagen are flat and at least 30 buildings have grass on top.

Growth in new buildings with green roofs is presumably 5,000 m2 per year - but it is hard to predict a precise number as it depends on the cities' development.

Headquartered in Bonn, Germany, it has established a standardized method for investigating and determining the root penetration resistance of waterproofing products used throughout Europe.

Click here to link directly to see the recommended guidelines of the highly informative FLL German site. Were it not for specific conditions found in Germany, the higher costs associated with the initial construction of greenroofs may have precluded their widespread application (Charlie Miller publication, 1998).

According to the 2003 report by English Nature: Green Roofs: brown is the new green - "Green roofs: their existing status and potential for conserving biodiversity in urban areas - Report Number 498," 13.5 million square meters of greenroofs were installed in Germany in 2001.

One example of the German groups is the Deutscher Dachgartner-Verband (German Roof-Gardening Association), which has been advocating greenroofs since 1984 and provides up-to-date information on new developments in vegetated roof cover design in Europe to its many members.

Help make the city greener, reducing the urban heat island effect.

So counteract increased temperature rise in the cities.

Contribute to a visual and aesthetic architectural variation that has a positive effect on quality of life.