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GSBN:re: Data on Living Roofs



On Sat, 18 Mar 2006 00:22:03 -0500, GSBN GSBN@...
wrote:

On Mar 17, 2006, at 10:05 AM, the Skillful Meany wrote:

Does anyone know of some hard data on the thermal qualities of living
roofs.
I've done some preliminary energy modeling, in Energy 10, and come out
with very little difference.

Is there some real data on this?


Mr. Meany;

In y2k, Dr. Karen Liu installed a living roof (she called it a Green Roof)
on half of a roof on a building at the Institute for Research in
Construction (IRC) on the grounds of the National Research Council (NRC)
here in Ottawa and then monitored the two roofs for thermal data and water
storage & runoff data for a number of years.

The first year, I think that there was minimal if any vegetation, just the
thin (100 or 150 mm ?) growing medium (not  straw). Subsequent years there
was a vegetative cover. I saw it the second year (grass)on a private tour.
The first year I think all she had were some widely-spaced sedums.

And as is the habit of research doctors, she published the data.
The link to one of her reports is in

-->the LINKS section at SB-r-us
---> MATERIALS AND METHODS folder
----> GREEN ROOFS sub-folder

There's a bunch of stuff in that folder that includes some links to
EuroSites that Chug (and others ?) put up. There may be more "real data"
in those as well.

The bottom (energy)line from Karen's monitoring is that green roofs could
reduce the daily space cooling energy load by an average of ~75% due to
reducing heat gain ... but it doesn't do much of anything to reduce heat
loss.

How real is Karen's data ?
It's Canadian (as in Ottawa climate). Eh ?

For the parts of Poppyland where the landscape gets so parched that it
jumps up and bites y'all in the arse with hell-fires and such on a regular
basis, I think that you'd be looking at the thermal benefits of just the
growing medium since I doubt that you'd be up on your roofs watering the
vegetation to keep it lush and green during periods of drought.

The non-thermal benefit may be that the growing medium might provide an
additional layer of fire protection for the waterproofing membrane and
framing below, or in the event of landscape infernos, maybe you flood the
growing medium (from a cistern dedicated to the purpose) in the hope that
that may discourage the roof from burning ?


=== * ===
Rob Tom
Kanata, Ontario, Canada
<ArchiLogic at chaffyahoo dot ca>
(winnow the chaff  from my edress in your reply)

Please visit   <a  target="_blank" href="http://www.mercycorps.org/";>http://www.mercycorps.org/</a>