Green Roof Research in North America By Jörg Breuning
I am always amazed how much funds, intellectual energy and resources are put into research of extensive green roofs without the consideration of feasibility and without considering the demands of the plants. Especially in research common sense should be the starting point of any qualified discussion. This raises also the questions, why are extensive green roofs in Europe –in particular Germany – are so successful?
It is solely successful because extensive green roofs according modern green roof technology are a cost efficient (and beautiful) tool to manage stromwater issues. Period. All other highly market benefits or positive “side effects” are generated by the system for free because these are only consequences of successful implemented nature. Focusing on the side effects and improving them will compromise and eventually reduce the main purpose of an extensive green roof by increasing costs for designing, engineering, implementing and maintenance.
In the academic world Liebig’s law of the Minimum should be applied in any step of the discussion and research. However understanding the limiting factors – including limiting economic factors – requires a tremendous amount of experience, historical data and common sense. The lack of these factors and the lack of time seem the limiting elements but justified by many unique human properties like vanity, self-promotion and economic restrains. On the other side (consumer side) the humans are also part of nature and it is natural that any of their decisions are made accordingly. If an idea doesn’t fit into this process (controlled by the scarcest or limiting resource) we walk away from it, like plants will “walk away” if their minimum requirements are not met. With the disappearance of plants on an extensive green roof we lose the purpose and the investment.
It is common sense that plants cannot walk away as fast as humans so their disappearance might take 2 decades or more which is still much less than the lifespan of extensive green roofs – the lifespan we promote.
For example measuring and promoting building insulation properties of a thermal mass or heat sinks like extensive green roofs was developed as a selling instrument of the industry (like reflective roofs). Trying to improve that will consequently compromise the main purpose to the negative. The end of this research will find out that it is most efficient and probably 10 times cheaper just to increase the buildings insulation on any surface of the building. It will also perfectly benefit when energy prices will continue to super-proportional increase or when we like to build our settlements that they last longer than just two decades – or when we want that the building has the same lifespan as an extensive green roof.
As I brought modern green roof technology to North America from Europe I expected a higher understanding of common sense and of Liebig’s law since it seemed to work in the social and financial world. Investing the research funds in actual extensive green roofs according proven modern green roof technology (e.g. not pre-planted boxes) would benefit the environment, industry and building owner much more and would help to start an entirely new research generation in 10-15 years from now.
When it comes to living technologies going back to the roots sometimes helps or simply is a necessity.
On Friday, November 16th Jorg and Ryan will be in Washington DC to give a presentation on Solar Green Roofs.
The event is hosted by the Anacostia Watershed Society and will focus on 3 important issues: a) the benefits and design of solar green roofs, b) the design and plant selection for green roofs, and c) methods to reduce the installation and life-cycle costs of green roofs.
If you wish to join us on Friday, please RSVP to email@example.com Space is very limited, as we expect a full house.
We have exciting news. Green Roof Technology is looking for the right individual to join our team. You can see more details about the position here.
But suffice it to say, we're looking for an experienced and enthusiastic person to help with all our social media needs and office organization.
We have been sorely needing someone to help us out with this work for some time now, and with the upcoming year looking busier than ever, this winter is the best time to add to our ranks.
If you're interested in the position, please email firstname.lastname@example.org, subject Social Media Position. Be sure to include your resume and cover sheet.
The Enclave Gets a Lawn
Last week Green Roof Technology, with the help from some friends from Highview Creations, spent 3 days installing a 4300 sf. sod lawn at The Enclave in College Park, Maryland. The project was a huge success. Every step of the way went nearly as smoothly as we had imagined.
Here's a succession of photos taken over the course of the install. Enjoy!
Just a note to everyone out there: Rolling out 4300 sf of sod in 100 degree heat is HARD work. I spent most of the day soaking myself down under the sprinklers.
Some decades ago Patrick Blanc, French botanist working at the French National Centre for Scientific Research and specialized in plants from tropical forests created and introduced a unique design for a vertical garden with real plants (Vertical Garden, Green Wall or Mur Végétal). His simple system or other much more sophisticated systems are based on a consistent water and nutrient supply comparable to horizontal high tide/ low tide (Ebbe/Flut) systems in super-efficient nurseries. These systems often include artificial light and heat/cooling for sustainable growth.
Without being a horticultural expert Patrick Blanc was able to start a new trend utilizing horizontal plant propagating systems applied to the vertical as living art. Maintenance and operational costs of all these wall planted systems are very high and so the environmental benefit is certainly questionable. Typically in less than 10 years costs for maintenance and replanting increase the cost for installation without considering the high consumption of energy and water.
Today when you fly in to Paris Airport Charles de Gaulle you will see multiple, small green walls - very attractive, lush green with an appealing biodiversity. Closer investigations discovered that these walls the next step of green walls that are super-efficient and extremely low cost for installation and maintenance. The systems at Charles de Gaulle Airport in Paris don’t need any artificial lights, they are completely disconnected from any power and water source and they are very efficient dust collectors. The amazing biodiversity has potential for the highest LEED rating.
Here are a few plants identified:
Good art reinvented.
Dr. Phil O. Dendron, Bel Air, August 26th 2012,
One topic on discussion during the symposium I believe is in need of even more discussion is the implementation of a requirement to monitor the long-term performance of green roofs.
The need for annual green roof monitoring is essential. Too often we encounter failing green roofs. The green roof ecosystem is fragile, especially in its early establishment years, and can fail for many reasons. They can fail due to poor design, poor installation, wrong material choices or negligent maintenance, and none are mutually exclusive. The effect this has on the performance of a green roof is dramatic. A complete failure of a green roof system can occur rapidly and it is a huge liability, both economically and for safety reasons. Let us also not forget that a bad green roof is an image problem for all of us and reflects badly on the entire industry. Each green roof that fails to support its vegetation or leaks is one more stigma the entire industry has to overcome.
A mandatory green roof monitoring system, whether operated by a government agency or an independent 3rd party, would be able to identify failing green roofs and require whatever is necessary to restore the green roof to a proper level of performance. We believe any green roof that is supporting a healthy ecosystem, complete with year-round vegetation cover, is more likely than not properly functioning and meeting leading performance metrics.
Recently, buried within Maryland’s Stormwater Management – Watershed Protection and Restoration Program was a clause that requires annual monitoring of stormwater bmp’s:
(III) PROCEDURES FOR MONITORING AND
ANNUALLY VERIFYING THE EFFECTIVENESS OF THE ON–SITE SYSTEMS, FACILITIES, SERVICES, OR ACTIVITIES IN REDUCING THE QUANTITY OR IMPROVING THE QUALITY OF STORMWATER DISCHARGED FROM THE PROPERTY.
Striking ‘annually’ from the clause is disappointing and the legislators have essentially gutted this clause of its ability to secure long-term performance effectiveness. Once again we believe a mandatory monitoring system is essential and it is only a matter of time until one is implemented. Who will be the first?
by Andrew Yanders
Mr. Toad doesn't care to reinvent the wheel.
Last Thursday and Friday Jorg and I subjected ourselves to the horrendous Baltimore - DC traffic and attended the The First Annual Mid-Atlantic Green Roof Science & Technology Symposium at the University of Maryland. The title of the symposium was "Redefining Green Roof Science" and the mission statement clearly states why:
Standards for green roof performance have not been established. The MGRST symposium is dedicated to disseminating results of scientific research that will lead to the establishment of green roof performance standards for the Mid-Atlantic region.
Year after year we attended similar academic conferences and each year we are confronted with the same experiments and the same conclusions, all of which we know have been done and confirmed a decade ago in Germany. For us, the researchers are only confirming what we believe to already be ‘common sense.’ We are certainly not disparaging the work of researchers who are attempting to better understand the green roof field they have recently entered. What we truly regret is the inability of academic researchers to acquire and process the information already available rather than attempting to reinvent the wheel.
What the green roof industry needs from its academic partners is a strict methodology and process to assess all the green roof components / complete systems available on the market. Nearly a decade ago, the Green Roof Media Testing Laboratory was successfully implemented at Penn State University and has undoubtedly beneficially impacted the green roof industry. A similar manufacture’s test for all other green roof components would best serve the entire green roof industry by setting minimum requirements and disabling inferior products from being dumped on the market.
By Andrew Yanders
Last Friday I drove up to Newtown Square, PA to check-up on two green roofs we installed earlier this summer at the Episcopal Academy. I was joined by two of our Philly friends from Urban Ecoforms, Zach and Jared.
July was a remarkable month. The extreme heat coupled with the lack of precipitation made the first days of establishment especially stressful. We placed the roofs on a strict regime of water - beginning with the first week and gradually reducing the amount of water week by week until irrigation ceased after 4 weeks.
As expected, many of the plants did exceptionally well. Notably, Delosperma cooperi and Allium schoenoprasum had no problem handling the conditions. Our Sedum cuttings did not fare so well. The surface of the growing media dried too quickly and became too hot for roots to adequately form.
This hot area on the roof where the cuttings did not establish well was planted with a couple of trays of Sedum sexangulare and Sedum reflexum and a five gallon buckets worth of assorted Sedum cuttings was again spread. The weather has cooled significantly in August and we feel the Sedum cuttings should establish nicely this time.
Planting a green roof is not a precise science. Trial and error is the only way to find out if a species is going to work or not in a specific location. We are finding out on the Academy roof that shading is creating two distinct zones on the small 700 sf roof. The temperature and exposure difference between the two zones is dramatically impacting the growing habits of the plants on the roof.