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A Feast for Fauna - Creating Biodiversity for Pollinators

Green Team at Green Roof Technology, - Friday, May 11, 2012

By Kat Harrold


Photo - By Kat Harrold

Green roofs are more than just a lush tool for stormwater management.  Green roofs have other benefits such as the potential to bring forth a bountiful feast to pollinators.  Pollinators are critical to our survival making it possible for grow the crops that feed our hungry nation and aiding in the replication of vegetation which purify our air and bodies of water.  Pollinators include a variety of areal insects as well as a few birds and bats.  

A shining example of this style of green roof we have worked on is the Hamerschlag Hall at Carnegie Mellon.  Hamerschlag Hall features extensive and semi-intensive green roof areas with a variety of ground covers and tall grasses.  Herbaceous plants and sedums provide food while an array of evergreens creates opportunities for shelter.

On the rooftop of the Resource Conservation Technology Ice House we created a garden specifically for honey bees.  Fragrant drought tolerant herbs and bulbs bloom from February to November creating both seasonal interest and a consistent food source.  

Click here find out more about the specific plants used in the garden.



The Dirt on Urban Farming

Green Team at Green Roof Technology, - Tuesday, May 08, 2012

By Kat Harrold

Photo by - Jorg Breuning

For some the dream of farming on the roof is a mere extension of window box gardening while for others it can literally mean bringing the farm to the roof.  For those DIY farmers out there here are a few things to consider for your garden in the sky.

Whether you are creating an extensive or intensive green roof, always check to make sure the roof is strong enough for whatever weight load you might be adding to it.  The last thing you want is to wake up one morning feeling like a freshly planted spud.

Speaking of spuds, for the adventurous rooftop farmer looking to plant more than just a few herbs or the occasional tomato, consider creating raised planting beds.  When it comes to the health and safety of your green roof one of the most important things to keep in mind is proper drainage.    The organic material that is so good for your crops is a death sentence to the drainage system.  When the organic particles break down they get lodged in the filter fabric which can cause standing water and even bigger problems in the winter when it freezes.  To keep your roof happy and healthy, create a separate area, such as a planting bed with a bottom or container, for plants requiring deep rich soil like carrots and potatoes.  

Building raised planters can be advantageous for plant and farmer.  By having a set up allowing for the farmer to tend to the plants without crawling around the vegetation you protect the plants from accidental damage and compacting the soil.

Roof to Fork Menu

    Ratatouille (recipe courtesy of

    (all vegetative ingredients can be grown in a regular semi-intensive green roof set up with no additional organic matter needed)

        1 onion, sliced thin
        2 garlic cloves, minced
        5 tablespoons olive oil
        ¾ lb eggplant, cut into ½  inch pieces (about 3 cups)
        1 small zucchini, scrubbed, quartered lengthwise, and cut into thin slices
        ¾ lbs small ripe tomatoes, chopped coarse (about 1 ¼ cups)
        ¼ teaspoon dried oregano, crumbled
        ¼ teaspoon dried thyme, crumbled
        ¼ fennel seeds
        ¾ teaspoon salt

        ½ cup shredded fresh basil leaves

In a large skillet cook the onion and the garlic in 2 tablespoons of the oil over moderately low heat, stirring occasionally, until the onion is softened. Add the remaining 3 tablespoons oil and heat it over moderately high heat until it is hot but not smoking. Add the eggplant and cook the mixture, stirring occasionally, for 8 minutes, or until the eggplant is softened. Stir in the zucchini and the bell pepper and cook the mixture over the moderate heat, stirring occasionally, for 12 minutes. Stir in the tomatoes and cook the mixture, stirring occasionally, for 5 to 7 minutes, or until the vegetables are tender. Stir in the oregano, the thyme, the coriander, the fennel seeds, the salt, and pepper to taste and cook the mixture, stirring, for 1 minute. Stir in the basil and combine the mixture well. The ratatouille may be made 1 day in advance, kept covered and chilled, and reheated before serving.




Good News for EPDM Roofs!

Green Team at Green Roof Technology, - Thursday, May 03, 2012

By Kat Harrold

Photo courtesy of

Good News!  EPDM (ethylene propylene diene monomer) is a synthetic rubber waterproofing commonly used on roofs.  Once thought to be incompatible with (electric field vector mapping system), due to too much black carbon interference, now has compatible grey and white versions!  

What does this mean?  It means that if you want to use EPDM waterproofing under your green roof you can also have the piece of mind by having one of the most accurate leak detection systems installed as well!  In many cases the leak detection system is cheaper than the waterproofing warranty as well.

ABC Carpet Green Roof Environmental Monitoring

Green Team at Green Roof Technology, - Monday, April 30, 2012

By Andrew Yanders

Photo By Kat Harrold  -   Featuring Jorg Breuning (left) and Andrew Yanders (right) at ABC Carpet and Home

In 2010, the Bronx Overall Economic Development Corporation (BOEDC), in partnership with the Bronx Borough President’s Office, submitted a proposal to the Bronx River Watershed Initiative to fund a 10,000 square foot green roof on the ABC Carpet Bronx Outlet building at 1055 Bronx River Avenue, Bronx, NY.  Green Roof Technology worked with the BOEDC to manage the project, beginning with the design all the way through training and supervising a local workforce to install the green roof.  The installation at ABC Carpet was completed in early November of last year.

This past Friday, Jorg, Kat and Andrew traveled to the Bronx to check on the health of the green roof and to construct 4 environmental monitoring stations.  All 4 stations are approximately 1 m tall with a 1 m x 1 m x 0.15 m box integrated on top.  Two of of the top-mounted boxes are filled with an extensive green roof system and the other two are only lined with a waterproof membrane.  Each box is equipped with 3 temperature probes and a tipping bucket.  In the coming weeks, a stand alone weather station will be installed on the roof to monitor wind speed, relative humidity, air temperature, and sun intensity.  

Over the last decade Green Roof Technology has worked with numerous organizations and academic institutions to design and set up their green roof monitoring programs.  Beginning in the late 1990’s, GRT helped establish the first FLL green roof media testing laboratory at Pennsylvania State University and advised their leading researchers on how to set up their own green roof research center.  Since those early days in North American green roof research, Green Roof Technology has had the pleasure of establishing research programs at Carnegie Mellon University, Swarthmore College, the City Hall in Chicago, and Villanova University.  In 2007, Green Roof Technology worked with the BOEDC to design and install green roof research stations at the Bronx County Court House.  These stations were the first green roof boxes to be tested in North American according to the strict FLL guideline and the FLL’s standardized testing procedures.





What to Know When Working With TPO

Green Team at Green Roof Technology, - Thursday, April 26, 2012

By Kat Harrold


Photo - Jorg Breuning

Working with green roofs for quite some time we have come to appreciate the compatibility of the TPO waterproofing with the Electric Field Vector Mapping System (EFVM).  Something important to consider however is the relation between the insulation and the waterproofing in determining the type of EFVM system.  

A project using waterproofing adhered to the insulation requires a metal mesh EFVM system in between the waterproofing and insulation whereas the system that has the waterproofing mechanically fastened to the insulation requires only a wire perimeter on top of the waterproofing.   Aside from being more labor intensive to install and modify, some roofing manufacturers would not warrantee their TPO with the metal grid between their waterproofing and insulation.  Proceed with caution when roofers site incompatibilities with their TPO and an EFVM system.  You may want to consider another manufacturer. 

ASLA Tour Lancaster Green Roofs

Green Team at Green Roof Technology, - Monday, April 23, 2012

By Kat Harrold

Franklin and Marshall Schader Hall  -By Kat Harrold

This past Friday, our very own resident green roof guru, Jorg Breuning, acted as an impromptu green roof tour guide in the city of Lancaster, Pennsylvania.  They city was host to American Society of Landscape Architects’ Pennsylvania-Delaware chapter’s annual meeting.  The city of Lancaster boasts many thriving extensive green roofs and has recently announced its commitment to becoming a national role model for urban green infrastructure through its LIVE Green program.  Green Roof Technology has had the pleasure of designing several green roofs in Lancaster City.  Jorg led a group of 30 landscape architects around the city explaining the different green roof systems on display.  The tour group visited two green roof designed by our firm, located at Franklin & Marshall University and Tellus 360



Swarthmore's David Kemp Hall Reaches Tenure

Green Team at Green Roof Technology, - Wednesday, April 18, 2012
By Kat Harrold

Photo ~ By Green Roof Technology

For some, green roofs may seem a novel addition to a green minded institution but to Swarthmore College it was an essential and strategic move.  In 2008 when the college needed to add a dormitory to accommodate its growing student body, there were concerns about the increased run off from the new construction.  Sustainable architecture through green roofs offered a solution that minimized the building foot print making construction of the new dorm possible.  The green roof was spear headed by a few brave faculty, dedicated alumni and students, and Green Roof Technology.  To stay on budget the school chose to invest in a green roof instead of the costly LEED certificate while still building to LEED standards.  This dorm was recognized in 2010 with the American Institute of Architects Housing Award.

The 8,600 sf green roof is the home to many plant species including sedum album murale, sedum spurieum roseum, delosperma nubigerum, and some indigenous plantings.  The green roof also features a raised planting bed for experimental vegetation such as cacti.

The profile of the green roof is a shallow extensive system and has a total profile of 3.5 inches with the growing media depth composed of 2 inches.  While Swarthmore may have a reputation for having the best maintained green roofs in the area, the maintenance required on the roof is blissfully minimal.  To maintain its pristine state Gardener Lars Rasmussen weeds occasionally as needed and irrigates only when drought conditions exceed two weeks.  The roof is minimally fertilized and occasionally cutting back of the overly aggressive plants takes place to encourage more diversity on the roof.

Since its installation the green roof has reduced run off, air pollution, and saved energy on the top floor of the building by as much as 25%.  While the green roof is not available for students to congregate it is open for guided tours and classes and is visible to all from the third floor.

Mulch is Great for the Ground. Is it Good for the Roof?

Green Team at Green Roof Technology, - Thursday, April 12, 2012

By Kat Harrold

Photo By Jorg Breuning

Mulching season is upon us the air is ripe it's fragrance.  While the good gardener may protect their garden from unwanted weeds with a coat of mulch this can actually kill the functionality of a green roof. 

The fine organic matter produced from the decaying mulch creates a hotbed for weeds that take advantage of the added nutrients.  These same fine particles also clog the filter fabric and drains which result and standing water and roof load issues.

To protect your green roof from unwanted plants there are two main things you can do.  The first is if it is a sedum roof, don't irrigate unless extreme drought lasting more than a month.  The dry conditions often fry the seeds before they get a chance to germinate.  Use only a small amount of slow release fertilizer twice a year for the first 4 years.  Poor soils with a low level of nutrients are ideal for sedums.  Excessive fertilizer can actually be detrimental to sedum growth while simultaneously providing excellent conditions for weed growth.




NYC Botanical Garden : The Orchid and Green Wall Show

Green Team at Green Roof Technology, - Tuesday, April 10, 2012

By Kat Harrold

Photo ~ Kat Harrold

For those of you looking to escape the cold snap and visit the warm weather again try the NYC Botanical Orchid Show.  Not only will you get your warm weather fix but you will also be privy to an incredible display of living art featuring vertical gardens by french botanist Patrick Blanc.  

The show runs till the end of the month and features orchids of every color, shape, and species imaginable.  As an avid orchid fan I have spent countless hours admiring the orchid displays of Longwood Gardens and this might even trump their Orchid Extravaganza.  What makes this particular orchid display so amazing is the integration of so many varieties into several Patric Blanc designed green walls.

Like an artist carefully apply strokes of paint to a canvas, Patrick Blanc give sweeps of color to these green walls with dedrobiums, cymbidiums, cattelyas, and many more.  The use of ephiphytes, plants that absorb moisture and nutrients from the air or accumulating debris, are an excellent choice for maximizing water and nutrient resource conservation in green walls.






First American 'Sun-Root' Installation at NYC Parks Dept.

Green Team at Green Roof Technology, - Wednesday, April 04, 2012

 By Kat Harrold


Photo~ Jorg Breuning

It's official!  The 'Sun-Roots' have landed in America!   The first installation of 'Sun-Roots' took place on the NYC Department of Parks and Recreation at Randall's Island.  The 'Sun-Roots' are part of their on going green roof research program that tests over 25 different green roof systems. 

Check back soon for more information on this revolutionary system pending the installation of it's solar panels!




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"We sought Mr. Breuning as a lecturer because his company represents one of the most successful, technically advanced, and progressive businesses associated with green roof technology in the USA."

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