In this blog I want to give some general
information about Green Roofs and their considerable effect on reducing the
energy consumption of buildings in Green Building industry. As we know, using
green roofs in our structures has some positive effects on it such as reducing
storm water runoff, attenuating roof temperature, reducing heat island effect,
optimizing energy performance, etc. Nowadays, green roofs are going to be more
widely used in different structures, but still it has to be improved in
different aspects. (e.g. 20% of commercial roofs in Germany are green.)
Although it seems that green roof construction
need a set of skills and takes a lot of time, effort and money (comparing to
conventional roof construction), It can considerably reduce the amount of
energy usage in a building. Generally, green roofs are made of some typical
layers such as waterproofing membrane, insulation, protection fabric, drainage
and filter layers, soil media and vegetation. The typical layering of the green roof systems can be seen in the picture below. Also, beside reducing the Heat Island effect, this system can effectively be used for reducing of the water
consumption of a building as well.
As some of the good examples of green roof users in United states,
I should mention Ford Motor Company (Dearborn, Michigan), Ballard Library in
Seattle, the new California Academy of Sciences building (Golden Gate park, San
Francisco), United States Postal Service's Morgan Processing and distribution
Center (New York City), Zeckendorf Towers (New York City), etc which are shown
in the pictures below.
Ford Motor Company (Dearborn, Michigan)
Billard Library, Seattle
New California Academy of Sciences building (Golden Gate park, San Francisco)
United States Postal Service's Morgan Processing and distribution Center (New York City)
Zeckendorf Towers (New York City)
Using this technology in the state of Florida
has some issues such as intense rainfall, long drought conditions, hurricanes,
wind uplift and scour resistance, viability of plants, biodiversity, fire resistance
concerns, etc. After a lot of investigations in this field, researchers came to
that the cultivation of Florida green roof must take some points into
consideration such as heat flow, moisture residence, plant selection, depth of
roots, weed suppression and wind uplift. Among these, wind uplift seemed to
more critical in using green roofs which some useful researches had been done
for obtaining better criteria in use of green roofs considering the wind uplift
issue (“Wind resistance of green roof systems” David Prevatt, Glenn Acomb).
Here, I should mention the Perry construction yard green roof on top of the
Rinker school of building construction at the University of Florida, which was
used as a case study for this research.
Rinker school of building construction, University of Florida
In conclusion, I think although cultivation of
green roofs in Florida has some issues, it can be really helpful for structures
in this region to be more sustainable. Investing time and effort in researching
in new ways of using this industry can lead us to a more sustainable future.
Tough, there are a lot of new research topics in this field that should be
taken into consideration.
With all of the positive effects that green roofs bring to the building and the environment as a whole, it seems they are rarely seen applied to new construction. In your research, did you come across any studies that that speified that certain vegetation may be better to others? Also, after reading this and seeing your illustration of the necessary material required for a green roof, does different vegetation or different green roof orientations alter the layering, or is the layering a standard practice that remains the same in all applications? Either way, this is an interesting topic, and appears to have become common practice in Germany.
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