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Swarthmore College's Little White Grub Problem

Green Team at Green Roof Technology, - Friday, October 26, 2012
A few months ago we were contacted by Swarthmore College to help identify the cause of a disturbance on the roof.  During a routine visit in August about 20% of a large, upper section of a green roof was completely torn up.  The disturbance occurred in areas where low-growing Sedums, such as S. sexangulare, S. album, and S. spurium dominate.  Areas where taller Sedums, such as S. takesimense, S. kamtschaticum grow were left undisturbed.  

Further investigation located the likely perpetrators.  Numerous white grubs were found in soil.  The likely cause of the Sedums being torn up is from birds scavenging for a snack.  The grubs feed off the roots of the Sedums, weakening their ability to resist the damage caused by the birds.  

Our article about the damage inflicted on the green roof and ways to remediate the problem continues in our Autumn 2012 issue of Green Instance.  The Scott Arboretum of Swarthmore College has also written a summary of the events, which can be seen here.

The Enclave

Green Team at Green Roof Technology, - Wednesday, September 05, 2012

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.   

Mid Atlantic Green Roof Symposium Highlight

Green Team at Green Roof Technology, - Wednesday, August 22, 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?

Mid Atlantic Green Roof Symposium Wrap Up

Green Team at Green Roof Technology, - Wednesday, August 22, 2012

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.  

Episcopal Academy Green Roof Check-up

Green Team at Green Roof Technology, - Monday, August 20, 2012

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.  

A brief stop at the Baltimore Convention Center Roof Garden

Green Team at Green Roof Technology, - Wednesday, July 25, 2012

by Ryan Miller

This past Friday I traveled into the heart of Baltimore City to visit the roof garden atop the Convention Center.  On the second floor huge floor to ceiling windows frame the roof garden and encourage visitors to take a step out into nature.  With benches and tables scattered throughout the garden, you can tell the owner's intent was to bring people outside, not only to look onto the city surrounding them, but to sit down and enjoy the unique natural environment.

The roof garden was completed in 2010.  Initially, the Convention Center was only going to receive a new waterproof membrane, but the roofing company, Barrett Company, suggested the owners go above and beyond the traditional upgrade and take part of a growing trend, bringing nature back to our urban areas.  I for one am glad the Convention Center owner had the foresight and courage to install a roof garden and did not succumb to the hesitance many property owners do when deciding to go with green roofs.  

Throughout the hundreds of Black Eyed Susan’s in the garden you will see numerous bees flying about.  No need to worry though, they have too big of a playground to concern themselves with visitors.

During my visit, the national Firemans & EMT convention brought in thousands of visitors to the Convention Center.  Many of them took time to eat their lunch and relax in this oasis just two stories up from busy Pratt steet, which you could almost hear none of. 

As I visit other cities I’m jealous of the green spaces they have for people to just relax and take in nature.  I’m glad I visited this roof garden as I now have a place to show off to visitors and colleagues alike.

I plan on adding this roof to our tour of Baltimore City green roofs on September 13th.  Please email me if you are interested in attending this tour, Ryan@hvccb.com.  

Heat Wave 2012

Green Team at Green Roof Technology, - Friday, July 06, 2012

 

The unceasing heatwave gripping the Northeast is quickly moving into the absurd.  With temperatures consistently hovering around 100º F there are few places outdoors you would consider pleasant.  Especially not a roof top smack in the middle of New York City, straddled by an interstate highway. Despite the Extreme Heat Advisory, we decided to send Andrew back to the Park & Rec Building to check up again on the Sun-Roots.  

Andrew was happy to report that the sweat pouring from his brow was more than enough to irrigate the sun-baked Sedums.  During conditions like these we continue to be amazed at the ability of Sedum to thrive in such extreme hot and dry conditions in minimal growth media.  Stressing times like these are good for the Sedums, it develops their hardiness.  It is important not to spoil your green roof plants by irrigating them.  They may suffer a little bit, but they will survive and reestablish themselves even stronger for the next heatwave.  

Biodiversity on Extensive Green Roofs

Green Team at Green Roof Technology, - Tuesday, July 03, 2012

By Kat Harrold


Photo by ~ Jorg Breuning

Despite issues of limited growing media depth and access an extensive green roof still offers a lot of potential for creating biodiversity.  The shallow system is capable of supporting a variety of drought tolerant herbaceous plants, succulents and grasses providing food and shelter year round.  Many insects and birds have found their way onto this type of green roof orchestrating ecological webs and food chains.  The limited accessibility of the green roof to terrestrial animals also offers sanctuary to ground nesting birds.  

 

 

 

Episcopal Academy Raises the Roof

Green Team at Green Roof Technology, - Thursday, June 28, 2012

By Kat Harrold

 

Photos by Jorg Breuning

As the procession of minivans dropped off their little darlings for another exciting day at summer camp the sound of heavy machinery and green roof construction joined the chorus.  Green Roof Technology and UrbanEcoforms with the help of the Episcopal Academy's green roof advocates Joe and John made record time with the installation of the Episcopal Academy's first two green roofs.

The already eco-minded school has an impressive collection of energy efficient buildings and outdoor learning opportunities.  The green roofs are an invaluable asset in expanding their commitment to the environment and hands on learning.

Both green roofs are visible from glass hallways providing excellent observation of seasonal changes.  The extensive green roofs feature a mix of sedum plugs and cuttings with a grass swale and picturesque clusters of allium. 

 

 

 

                                                                              

 

 

Biodiversity and Semi-Intensive Green Roofs

Green Team at Green Roof Technology, - Tuesday, June 26, 2012

By Kat Harrold

Photo by ~ Jorg Breuning

They say variety is the spice of life and this indeed tends to be the case when creating a green roof to promote biodiversity.  Green roofs with both intensive and extensive portions have been found to support the highest amount of biodiversity.  The combination of sedum meadow, grasses, and shrubs provides not just food but shelter for several species.  More information covering biodiversity on semi-intensive green roofs can be found on our case studies page in "Where the Beetles are Crawling and the Honey Bees are Humming." 

Visit us next week as we conclude our biodiversity segment with biodiversity on extensive green roofs!

 

 


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