Are there any (landscape) architects in here?

I've got quite a few questions about creating a large scale garden or green area on a rooftop the size of your average wal-mart.

First of all, what would be the approximate cost, assuming you wouldn't need any major structural changes to the building to support the project?

And secondly, and equally important, are there real environmental benefits do doing something like this?

Thoughts?

7/29/2009 11:51:16 AM

Apparently someone in the SoapBox gave me some answers before I posted here.

http://www.ediblebrooklyn.net/magazine/index.php/summer-2009/traceability.htm FYI

7/29/2009 11:56:27 AM

im glad I can help sometimes.

I have some herbs and stuff on my fire escape which is nice.

7/29/2009 12:10:35 PM

First, I'm not a landscape architect. i am a Structural Engineer and a LEED AP, though.

Quote :

"I've got quite a few questions about creating a large scale garden or green area on a rooftop the size of your average wal-mart. First of all, what would be the approximate cost, assuming you wouldn't need any major structural changes to the building to support the project? "

That would be a lot. A wal-mart is like 100,000 square feet. So you're talking a few million dollars at least. That's also a risky assumption, esp. if it really was an old Wal-mart. You'd need to renovate most regular buildings, I would think. I mean, a ballpark weight would be something like 15 pounds per square foot, and that's a significant percentage of the dead load of a regular roof that you're talking about adding.

Quote :

"And secondly, and equally important, are there real environmental benefits do doing something like this?"

Improved water quality, air quality, reduced heat island, better insulation, all sorts of stuff. Green roofs can score points in a lot of LEED catergories.

7/29/2009 12:14:34 PM

^ awesome, thanks. Do you mind if I send you a PM later with more questions, or do you have any online literature i could read? Thanks

7/29/2009 12:36:18 PM

Quote :

"are there real environmental benefits do doing something like this?"

Absolutely!
I've been thinking about building one of these.
You basically make a light-weight soil alternative, and construct a shallow bed with drainage in mind.
There's a lot online about it, I'm pretty sure -- you should post updates of your progress...

7/29/2009 12:42:41 PM

Quote :

"^ awesome, thanks. Do you mind if I send you a PM later with more questions, or do you have any online literature i could read? Thanks"

Naw, that's about all I got right there.

7/29/2009 1:39:50 PM

Soil unit weights(saturated)
Clays and Silts: 80 pcf - 100 pcf
Clayey/Silty Sands: 90 pcf - 135 pcf
Sand: 100 pcf - 130 pcf

These vary widely due to other factors (water content, % compaction, etc).

If you want the roof on a 1-story building to hold a 1-foot thick layer of soil, I usually hear that a good rule of thumb is to design the building to support two stories. There are probably more changes that need to be made to the roof framing system too.

7/29/2009 2:39:36 PM

can't say much about the topic myself, but the building I've been in for a few months has a green-roof (there are actually two). Can't wait til its actually grown in considerably.

http://www.onecoolblow.com/index.php

7/29/2009 9:22:20 PM

^Copper downspouts on that building??? Sheesh, that's money there.

7/30/2009 11:22:37 AM