The advantages are clear to see
Green roof landscapes look attractive and deliver many more advantages besides. Green roofs store water in a natural way, bind dust and barely heat up even in extremes of temperature. They protect the roof waterproofing even more effectively against environmental stresses than a layer of gravel, and serve to increase service life. In many municipalities discounts on surface water drainage charges are offered for green roofs. There is an increasing tendency for roof plantings to be required in urban development plans, or at the very least recognised as a means of ecological compensation. Valuable habitats are created for nature.The two charts illustrate the positive effects of roof plantings on rainwater drainage and temperatures.
Water retention
It rained in Burgdorf during the night of 2nd/3rd August. At the
college of engineering and architecture, the amount of run-off from extensive roof plantings in comparison with a gravel roof is recorded. Considerably more than half of the rainwater is stored long-term in the green roof structure. The run-off of excess water is greatly delayed and reduced. The gravel roof has no significant effect on run-off. The rain is channeled without delay directly into the drains. So the green roof is the clear winner here.
college of engineering and architecture, the amount of run-off from extensive roof plantings in comparison with a gravel roof is recorded. Considerably more than half of the rainwater is stored long-term in the green roof structure. The run-off of excess water is greatly delayed and reduced. The gravel roof has no significant effect on run-off. The rain is channeled without delay directly into the drains. So the green roof is the clear winner here.
Temperature pattern
A hot summer's day in August 1997 really highlighted the differences. Even on the surface of the substrate the rise in temperature is slight compared to gravel. But, as illustrated, the differences between the gravel and the underside of the substrate are greater still. The green roof heats up more slowly and to nowhere near the same degree. Green roofs thus offer much better protection against the sun's rays and extremes of temperature. That is good for the climate beneath the roof, and also extends the service life of the roof waterproofing.
At a glance
Roof plantings enhance a building because they- store rainwater and inhibit run-off
- reduce surface water drainage charges in some municipalities
- improve thermal protection and soundproofing
- protect the roof waterproofing from temperature extremes, UV rays and mechanical damage, thereby lengthening its life expectancy
- improve the microclimate by trapping dust, balancing temperature and regulating air humidity
- create ecologically valuable alternative habitats for fauna and flora
- improve aesthetics
- make roof areas more usable