Green roof at Palisades West
Several readers expressed interest in hearing more about the green roof atop the parking garage at Palisades West office complex that I visited last Friday. Developer Tim Hendricks of Cousins Properties came out to speak to a handful of visitors who’d jumped at the chance to see live oaks and other big flora growing on a rooftop that is generally off-limits to the public.
I neglected to take notes, but I remember some of the details Tim shared with us. Two feet of soil underlays most of the plants on the roof, but the trees are sitting in specially constructed pockets that are four feet deep. To understand the weight considerations in building a rooftop garden like this, he suggested an at-home experiment. Fill a bucket with soil, and lift it to test the weight. Now pour water in the bucket until the soil is completely saturated, and lift it again. Now imagine that weight spread across the top of a parking garage. I think we all got a little nervous at that point, wondering whether the engineers were up to snuff.
Tim explained that parking garages are normally made of pre-fab materials. To support the weight of the green roof, this one had to be specially designed and poured in place, doubling the cost. Why, then, would anyone bother to build such an expensive parking garage? “Ego,” he said matter-of-factly.
Normally green roofs are associated with reducing heating and cooling costs in the buildings they shelter. Obviously, with an open-air parking garage, that wasn’t a consideration. So why did he put a garden on the roof of the parking garage? He said he wanted to look down from the building pictured above and see something beautiful rather than the glare of parked cars. Obviously bragging rights are also involved, as well as good publicity in an environmentally minded city.
I expressed surprise at the plant selection. Usually green-roof plants grow in shallow trays and have a low profile, helping them to survive the extremes of temperature and wind dessication that occur on rooftops. This green roof, in contrast, stands tall with vertical plants like live oaks, Texas mountain laurels, and various other trees, and rows of boxwoods. Tim replied that he wanted this to be more than a green roof. He wanted it to be a garden.
The east side of the roof overlooks the Austin skyline.
When a vanity development project makes tree huggers happy, you know something unusual is happening. I don’t know whether we’re likely to see similar projects cropping up considering the expense, and I’m still curious about the long-term viability of these large, vertical plants growing in such extreme conditions. But the visit was interesting and educational. In a perfect world, perhaps we wouldn’t need the garage at all and could zip to work via convenient and efficient public transportation. Until then, Palisades West shows what a moneyed compromise might look like.
All material © 2006-2009 by Pam Penick for Digging. Unauthorized reproduction prohibited.
That is really remarkable. I wouldn’t mind parkng there just to sit in the garden.
I like your point about the odd collision between ego/vanity and eco considerations. In the short term it is certainly good–the key is to make the trendiness into a true culture change…
The rooftop gardens are amazing. I love the Austin skyline!
Hi Pam, thanks for continuing this story. How deep is the soil here, to be able to support trees? This is just amazing. I would imagine there would be tons of publicity about this once the word gets out. It is a marvel.
Frances
Wow. I just think of the garden that a person could make if one had the money to pursue the dream. Hopefully those plants will be watered and cared for well enough for them to live. How old is the garden? I think he won bragging rights.
Very cool! Thanks for sharing!
Pam, It’s perfect and how calming it must be for folks to look out their office windows and see a garden instead of cars. I would be thrilled if our city had simple roof gardens! Is there some type of watering system up there? Even Buffalo grass needs some water! gail
I like to see green innovation. And ingenuity. He shows both. I like this concept, and hope we see more of this in the future. Thanks for sharing.
Brenda
If ego is going to result in this kind of creation, who would complain? There is a green roof/rose garden on the University of British Columbia campus at Vancouver that has the same effect. It just becomes part of the larger environment and, the day we were there, was filled with students walking, sitting, enjoying.
That still amazes me! I want a roof top garden! lol
Thanks for your comments, everyone. Frances, the soil is two feet deep under most of the plants, and four feet under the trees. Lisa, he said the garden was planted last August—pretty much the worst time to plant in Austin’s heat and drought. I believe he said they lost 20% of the plants, which, considering the time of year and extreme conditions, doesn’t sound surprising. Gail, yes they have a watering system, but I didn’t get the details. —Pam
What a lovely garden! And I bet all the other office workers like looking out at the greenery — and knowing that their cars are in shade all day!
What a fantastic garden. To think about all the planning, execution and resources that went into it, makes me wonder what could have been done in a more traditionaly sited garden with the same amount of input.