Bacon's Rebellion

Democracy Thrives in Sunlight

Green Roofs Take Root in Virginia

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by

James A. Bacon
in

The green roof movement in Virginia is spreading. Plant-covered roofs are popping up in Richmond, Charlottesville, Norfolk and Northern Virginia, reports Carlos Santos for the Times-Dispatch. Virginia is hardly in the forefront of the international trend, but at least it’s taking part in it.

Green roofs seem to be a case where marketplace economics and environmental sensitivities dovetail nicely. Green roofs generally cost twice as much as conventional roofs to install: They require additional layers of root barrier, gravel, topsoil and, of course, the ground cover. But they do provide a financial payback. The roofs last twice as long, and they reduce roof temperatures as much as 40 degrees from the ambient air temperature, which eases the strain on air conditioners and cuts electric bills. As a side benefit, the roofs help insulate against outside noise.

The social benefits are significant, too. Green roofs don’t just mean cooler rooftops, they also help reduce the urban “heat island” effect. In effect, each green roof makes a tiny contribution to lower temperatures for everyone. Even more meaningful, the plants and topsoil help manage storm water run-off by absorbing thousands of gallons of rainwater. Water that filters through plants and soil tends to be cleaner than water that runs off normal roofs, down downspouts and across parking lots. Water filtered through green roofs also is cooler, with less disruptive impact on aquatic life in streams.

How can Virginia accelerate the building and retro-fitting of green roofs? I’m not a big believer in income tax credits — our tax code is riddled with too many holes as it is. But I do think that buildings with green roofs should receive some kind of credit on its water-sewer bill to reflect their beneficial impact on storm water drainage. Perhaps the General Assembly could pass enabling legislation that allows municipalities to extend such a credit.

(Photo credit: Richmond Times-Dispatch. Photo shows a lower-level roof top of the SunTrust Bank building in downtown Richmond.)

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13 responses to “Green Roofs Take Root in Virginia”

  1. The Richmond Democrat Avatar
    The Richmond Democrat

    I used to live in the building across the way and watched them plant this roof over the course of a weekend about two years ago.

    Good to see that it is flourishing.

  2. Charles Avatar
    Charles

    I wonder how much they are paying to water that thing. 🙂

    I do agree with the concept though.

  3. Larry Gross Avatar
    Larry Gross

    geeze.. all I can think about.. is what happens if that roof starts to leak…

    I understand the sentiment.. but does this really make sense?

    it seems like at some point.. all of that stuff has to be pulled up and removed… wrong?

  4. Anonymous Avatar
    Anonymous

    IF

    all of this is true

    THEN it would seem that this might be an environmental initiative that actually does make both economic and environmental sense. It would even seem to be that unusual circumstance wherein the user gets enough benefits to cover his own costs – and there are extra benefits left over.

    Larry asks a good question.

    How do we know these things last twice as long? Who has had one in operation for 50 years? How much does it cost to water/maintain? Who is going to mow it?

    Does the building need special engineering to support the weight? If so, is retrofitting a realistic option? Does it only work on flat roofs, which are the ones most prone to leak?

    When maintenance is needed, how much additionl cost does this cause?

    My observation of plants is that their roots will drill through darn near anything. Why not the roof?

    After the water goes through the soil doesn’t it still go across the underlying roof, down downspouts, across parking lots etc.? Once it gets there is it still cooler?

    The heat island argument does make sense, but only if you have a lot of green roofs, otherwise the effect of one green roof is lost in the noise.

    Overall, if I put on my ROM environmental economics hat this looks like it makes sense. But if I put on my “Let’s go fix the roof hat” I hear a little voice screaming “Are you freaking nuts”.

    It looks like a good idea, but the mechanics of all the way things, especially new things, can go wrong just raises all kinds of flags to me.

    Still, it does look good……

  5. Larry Gross Avatar
    Larry Gross

    In our locality.. just in recent years have they gone to green/red metal roofs with a pitch on them vice the old flat tops with gravel and it was the repairs that caused the change.

    The roofing companies put the rubber membrane down.. then put goop and gravel on it – and a year later there are leaks…

    they finally got tired of this and went with the much more initially expensive metal roofs.

    I can just see suggesting to to them that they not only go back to the flat design but then dump dirt on top of it and plant stuff…to boot.

    Perhaps the technology has improved…..but it just seems to be that flat roofs and leaks go together.

  6. Anonymous Avatar
    Anonymous

    If the green roofs work and are maintainable then just phase them into the building code over time; simple as that. We’ve done that with plenty of other things and things like green roofs, solar power heaters, solar power can be done just as easily.

    ZS

  7. Anonymous Avatar
    Anonymous

    Solar power and green roofs might wind up competing for space.

    How will we choose?

    Hint: ROI.

    RH

  8. Anonymous Avatar
    Anonymous

    Not the building code. It should be for safety and health only. Mandate performance, if you must, and then leave it up to the engineers how to meet the requirements.

  9. Anonymous Avatar
    Anonymous

    “Not the building code. It should be for safety and health only. Mandate performance, if you must, and then leave it up to the engineers how to meet the requirements.”

    The building code is used for far more than safety and health. It is used for implementing best building practices.
    e.g. Why were low flow toilets mandated years ago? From an ROI standpoint it made sense for communities to mandate less water usage than to build larger sewer lines and water treatment plants.

    Well it’s the same thing with green roofs, solar panels, and other emerging technologies. We use incentives to get the early adopters to try out the technology and see how it works, then if it viable and makes economic sense it gets integrated into the codes.
    For the green roof if the payback period is 10 years and the building has a 50 year life, then it makes perfect sense to look into adopting it in all new buildings.

    ZS

  10. Anonymous Avatar
    Anonymous

    Here we disagree.

    The building code implements minimum practices, mostly. If it is used for more than safety and health, it shouldn’t be. Ont he other hand, if someone tells you “it meets code”, you should ask if it exceeds code. The Titanic met the code.

    The low flow toilets were a bad idea. Sewage drain lines were built with a certain slope premised on the amount of flush water. So now you are more likely to have back ups. And, because they frequently don’t flush properly, there is a black market in Canadian toilets, and a lot of toilets being flushed twice.

    In other countries, rather than mandating low flow toilets they have dual option toilets for a small flush or a big one as needed.

    What really happens with the codes is that industry lobbies to get its products incorporated so that they have an advantage over competitors. If you had the patent on low flow toilets, what would you like to see?

    I believe the argument was made that low flow toilets would postpone more and larger sewer service, but I’m not sure the public was ever sold on the idea. So, if you can’t sell it, mandate it and paer it over with what may very well be a lie.

    I can remember a battle royal between industrial incinerator operators and industrial dump site operators, each lobbying to get rules passed that crippled the other. In fact, the right answer was probabbly some of both.

    To make matters worse they lobbied under disingenuoous names like the environmental action council for clean water, which was really the lobbying group for incinerators, naturally , the environmental action council for clean air was composed of the waste dump operators.

    According to the code, there are only two basic ways to build a house. If you depart from those methods, then you usually must hire an engineer to ensure your structure is sound, even if it is a commonly used type. So the code is the full employment act for engineers.

    Likewise, you may be required to use graded lumber. This does very little to ensure that sound lumber is used and a lot to ensure employment for the lumber graders. In New York, when this one hit the hooper, private sawyers threw an effective campaign to have it killed.

    Really, if you are going to take the time and trouble to saw your own lumber, would you put bad lumber in your house or other structure??

    Granted, we got into this mess because builders screwed up. But then we have the instances where silt fence and other requirements are made and followed blindly when there is no need for them.

    If I don’t want a green roof, solar panels or $400 argon filled windows, I shouldn’t have to have them. At most, I should have to sign a waiver saying that the benefits have been explained to me and I chose not to avail myself.

    Maybe if I’m building a retirement cottage I figure I don’t need to invest in a 100 year building.

    What the building code really is and what it gets presented as are far different things, as many builders will tell you.

    RH

  11. Anonymous Avatar
    Anonymous

    This is a great article and discussion. Green roofs become more important in larger cities such as New York and Chicago where storm water runoff is taxed. Green roofs hold about 1/2 of the water in a half inch rain, as well as filtering out the fine particulate matter found in that water.

    I have read about the green roofs in Virginia and those around world at Clean Air Through Green Roofs (http://www.cleanerairforcities.blogspot.com)

  12. Richard Avatar
    Richard

    It's totally awesome to make a green roof out of your empty roof, not only it's environmentally-friendly, it also makes your house looks fantastic. Prior to reading this post, I had a friend that has a rooftop garden, with the first layer being an existing waterproof flat roofing in Miami, FL to prevent moisture from seeping in.

  13. Brendan Gertner Avatar
    Brendan Gertner

    The green roofing system sure is a cool thing to have, especially when you want to have your own greenhouse or garden on your roof, and I am usually seeing some of those whenever I am having a stroll around Richmond or at the top floor of our office. But in my case, I would prioritize having a slate roof installed by the roofers (Vancouver, BC) due to me being frantic about the storm.

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