Re: green roofs

**C* U* <c*@sbcglobal.net>**

There are 2 basic ways of doing a green roof--the German way, which  
is constructed with a series of layers and is the methodology on  
Chicago's City Hall--and the GreenGrid way, which consists of pre- 
grown "flats" of plants  either 6 inches or 12 inches deep. Many of  
these are sedums and other drought-tolerant plants. You bring in the  
flats, which already have emitters for irrigation, line them up next  
to each other, connect the irrigation, and bingo, it's done very  
quickly. The Apple Store on Chicago's Michigan Avenue has GreenGrid  
system. Go to www.greengridroofs.com. Construction according to the  
German way is more time-consuming.

I've heard presentations on the German roofs, which came into being  
about 40 years ago. It was stated that the German roofs hadn't leaked  
so far. In fact, a green roof is supposed to last longer than a  
conventional roof because it never comes in contact with rain or  
wind. It is, however, more expensive to install but because of  
longevity, pays for itself in the long run. Getting developers  
interested in this is a hard sell because they're not interested in  
the long run. Which is why the city of Chicago is putting the squeeze  
on. You want your building permit? Put on a green roof or do a roof  
garden or some significant street level planting. The percentage of  
green you have to provide hasn't been mandated in an ordnance as far  
as I know, but is no doubt something that you negotiate.

The Germans started doing green roofs as a way to control storm water  
runoff. In German cities, you're taxed for the amount of water that  
runs off your building. THerefore green roofs became a way of  
retaining water and reducing your taxes. In Chicago, Mayor Daley  
hasn't spoken much to this issue. He's more interested in reducing  
the heat island effect of cities and reducing air conditioning costs.  
Chicago's City Hall now has bee hives and the honey is being sold.
Carolyn Ulrich

On Jan 6, 2008, at 8:22 PM, Catriona Tudor Erler wrote:

> Does anyone have any information on the success rate of green roofs on
> commercial buildings in this country?  Through a friend who has just
> completed a green room on his garden shed, I heard of someone in a  
> condo
> in DC.  The association wants to redo the roof (which is in none too
> good condition) as a green roof. The person I heard about was voting
> "no" because he says the large commercial applications have a "high
> failure rate." That is, they leak, and plants die out and have to be
> constantly replaced at a great expense. My assumption is that they
> either didn't build them properly, or chose the wrong plants?   Any
> thoughts or information?  I know a huge percent of commercial  
> builidings
> in Germany have green roofs, but perhaps we are still far behind in  
> this
> country...
>     Thanks,
>     Catriona
>
>
>
> Does anyone have any information about the
>
>>
>>
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