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View Full Version : Greenroofs? Seems like a bad idea to me.


FIMCO-MEISTER
03-03-2009, 09:41 AM
saw this article in The Coloradoan.
http://greenroof.agsci.colostate.edu/

i don't care how hardy a plant is on a 110 degree roof it is going to need water. I think a great business opportunity is the green roof removal business.

Here are the plant choices.

EPA GREEN ROOF PLANTING PLAN
The green roof will have 4” deep modules randomly planted at 8” on center with the following mix of
several species of Sedum:
*Sedum cauticola 'Lidakense' - blue/gray foliage, pink flower, bloom August-Sept, height 4 and 6 inches
*Sedum floriferum 'Weihenstaphaner Gold' - green foliage, orange/yellow flower, bloom July-
August, height 4"
*Sedum hybridum 'Immergrauch' - green foliage, yellow flower, bloom July-August, height 6"
*Sedum kamtschaticum - green foliage, yellow flower, bloom June-July, height 6"
*Sedum reflexum - blue foliage, yellow flower, bloom June-July, height 6"
*Sedum sexangular - green foliage, yellow flower, bloom June-July, height 4"
*Sedum spurium 'Fuldaglut' - Red foliage, Red flower, bloom Fall, height 6"
*Sedum ternatum - Dark green foliage, White flower, bloom May-June, height 2"
These species were chosen by the green roof subcontractor, Green Grid, as selections that are
well-suited to the Denver climate in terms of drought tolerance and cold hardiness. This selection
is per the intentions that the green roof be a dry land tapestry that will change its appearance
seasonally, looking very dormant and lifeless at times.

JeffY
03-03-2009, 10:30 AM
We have installed some green roofs that are accessible for homeowners to go out and water the plants during extended drought seasons. I think we tend to think of green roofs that go on houses that have steep inclines and inaccessible to supplementing watering if it's needed. Here's an example of a green roof I saw that I wish architects in the US would design.
http://www.lawnsite.com/picture.php?albumid=145&pictureid=995
That building is in Singapore.
Another picture of a green roof in Europe, http://www.lawnsite.com/picture.php?albumid=145&pictureid=996

In fact, Europe has been in the green roof movement for over 10 years. Tokyo also requires that its medium and large buildings allocate at least 20% of their roofs to be green roof.

Some people resist change and some people embrace it. I am involved in green roofs because a member of the company I work for is involved in the green movement such as permeable pavers, water-harvesting, green roofs, rain gardens, etc. He initially wanted to use water-harvesting to water an entire yard and I had to shoot that idea done because it was impractical. The tank would run dry after 1 cycle. I convinced him to use the water-harvesting tank to run drip for the landscape beds and know the tank can last for 21 cycles before it needs to be refilled again.

FIMCO-MEISTER
03-03-2009, 10:37 AM
Thanks Jeffy. I'll be more open minded in my research. Talking to a well respected commercial roofer it just seems fraught with problems. How do you find a leak if one develops? A roof designed for greenroofing seems doable. Changing an existing roof seems problematic.

DanaMac
03-03-2009, 10:46 AM
I've never seen one first hand for a home. But in Snowmass Village they have some condos that have them for the carports.

gusbuster
03-03-2009, 11:00 AM
Don't know if you guys have ever heard of the "GAP" Jeans store, but their corporate headquarters here in San Bruno is and was one of the first "green roofs" in this country. Still going strong, been through a few earthquakes, though have not heard of any significant problems. However, the roof is planted with native grasses from our area. The only time though you can see it if you are looking for it and know where to look as you transition from I 280 to I 380.

JeffY
03-03-2009, 11:19 AM
I agree that retrofitting a roof into a green roof would be complicated and costly. It is easier to incorporate the green roof into a new design. Typically in the greenroof that you shown where they use native plants and water-tolerant plants such as sedum, there is a rubber liner similar to the ones they use for water features and ponds that they lay down on the roof. Just like ponds can have leaks, I'm sure these greenroofs can have leaks as well. I'm not aware how one would discover where the leak is because I have not run into that yet. The greenroofs we install are the modular type where we just lay the trays down and if there was a leak, I'm sure we could just pull the trays up to inspect the liner if it was needed.

mitchgo
03-03-2009, 11:42 AM
Meh,

Just put a bunch of Vinca up there it'll do fine.

Wet_Boots
03-03-2009, 11:51 AM
"Green" driveways would make more sense, and be a lot simpler.

Mike Leary
03-03-2009, 12:13 PM
"Green" driveways would make more sense, and be a lot simpler.

They are now code in new contruction up north.

EagleLandscape
03-03-2009, 04:36 PM
I don't know Peter.

I don't know how much temp different there really would be if the entire roof was landscaped. You are only talking a few feet, or few hundred feet higher in elevation. Is the solar radiation just that much more intense?

If the garden is only a little corner of the roof, then yes, temps would be high. if the whole thing is landscaped, i don't think temps would be that big of a deal. There is alot of aeration underneath the materials in a green roof. areas for roots to grow deeper, thus need less water.

here is a roof top garden in downtown. We do the maintenance on the ground level around the building, not sure who does the roof top though.

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=1401+elm+st+dallas+tx&sll=32.78156,-96.799985&sspn=0.001312,0.002843&g=1404+elm+st+dallas+tx&ie=UTF8&ll=32.781484,-96.800373&spn=0.001312,0.002843&t=h&z=19&iwloc=addr

EagleLandscape
03-03-2009, 04:41 PM
ASLA Green Roof: http://www.greenroofs.com/projects/pview.php?id=158

this should also help: http://www.usatoday.com/tech/graphics/green_roofs/flash.htm

irrigationgrl
03-03-2009, 11:10 PM
Quote from the ASLA,
I would have added pic's but seems does not want me to manage attachments at this time.

Last year the American Society of Landscape Architects (ASLA) replaced the conventional roof on its downtown Washington, DC headquarters with a green roof. Even more interesting is that in addition to the roof, they installed equipment to monitor the benefits of the roof and after a year of monitoring, the results are in!

The new green roof was found to have retained thousands of gallons of stormwater, reduced building energy costs by hundreds of dollars a month, and lowered outdoor air temperatures. These striking results extend the benefits to the entire area and shows other area companies that installing green architectural elements is not only environmentally friendly, but cost friendly as well.

FIMCO-MEISTER
03-04-2009, 07:21 AM
What is the oldest greenroof going? My commercial roofer friend says a roof needs to last 20+ years. UV is the killer of roofs. This obviously prevents that. Servicing roof equipment could be an issue. Like irrigation roofs constantly have newfangled ideas but the bottom line is that none have consistently lasted 20+ years which is why the tried and true methods keep hanging on.

DanaMac
03-04-2009, 08:19 AM
How much "green" material is on a roof? in terms of depth. We get some wicked hail storms here, which cause entire zip codes to get new roofs. I would think a green roof might prevent the hail damage.

Tom Tom
03-04-2009, 08:46 AM
Quote from Petes article:

"The primary objective of EPA's green roof is to absorb the precipitation which contacts the roof surfaces and release it at a reduced and measured pace. The green roof is expected to reduce peak flow and runoff volumes from rain and snowmelt events to mimic a more natural landscape. Reducing the peak flow will minimize deleterious impacts to the South Platte River from concentrated stormwater runoff."

I say paint the damn roofs white and collect the water to flush toilets or something

Waterit
03-04-2009, 08:47 AM
Retro-fitting for a green roof would be expensive - have to account for the "live-load" weight of the new materials AND the rain/snow it will retain. Don't see many going this route.

Anyone have Carraba's restaurants near them? They have a semi-green roof, but have found that it has to be changed out every few years due to root growth and sediment accumulation.

DanaMac
03-04-2009, 10:15 AM
Retro-fitting for a green roof would be expensive - have to account for the "live-load" weight of the new materials AND the rain/snow it will retain. Don't see many going this route.

Anyone have Carraba's restaurants near them? They have a semi-green roof, but have found that it has to be changed out every few years due to root growth and sediment accumulation.

We have 2-3 Carrabas here in town. But I don't know if they are the green roofs. Good chicken marsala

JeffY
03-04-2009, 10:29 AM
Used to have one just down the street that I went to all the time until I moved to a different part of the city. The "green" roof did appear to be changed out every few years, mostly because of lack of upkeep maintaining them.

I went for the chicken bryan most of the time. Nothing like a heaping of goat cheese on top of the chicken.

irrigationgrl
03-05-2009, 01:08 AM
Well they seem to have quite a few benifits. Of course Dana it would have to be in the plans for new buildings and not a retrofit kinda decision.

mitchgo
03-05-2009, 01:19 AM
Near Seattle. In mercer Island they built a bridge over a freeway just for a park and plants. I love driving by it seeing all the plants on the freeway .

hoskm01
03-05-2009, 09:32 AM
Near Seattle. In mercer Island they built a bridge over a freeway just for a park and plants. I love driving by it seeing all the plants on the freeway .



Similar to Phoenix. Pretty much the only tunnel in AZ. About 3/4 mi long. Parks and even a lake over top.

http://www.lawnlogistics.com/Storage/PhxTunnel.JPG