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ASLA National Convention - San Diego 2011

Green Team at Green Roof Technology, - Saturday, November 05, 2011

By Kat Harrold GRP


Photo By Kat Harrold GRP

Sunny skies and cool autumn temperatures set the stage for Green Roof Technology's first exhibition at the  American Society for Landscape Architects national conference.  For a conference covering everything from urban planning to garden design, San Diego was setting a shining example and keeping it classy as always.  Will Ferrell's character Ron Burgundy would have been proud. 

Tours, seminars, and awards ceremonies took center stage this year covering everything from floating islands to ecoroofs.  Next to the Expo hall, the keynote address took place.  With the end of the closing statement the Beach Boys’ “Lets Go Surfing” resonated through the hall and a tidal wave of landscape architects flooded the Expo hall.  While many visitors were from California, professionals from all over the country, and in some cases the world, were present.  This was a great trade show for Green Roof Technology as we were eagerly received as a guiding mentor for green roof design and green roof implementation.

Curious professionals weren’t the only one’s visiting our booth.  Day one of the expo fell on Halloween.  Trick or treaters, most of which were teeter toddlers or stroller bound, roamed the expo hall in search of delectable treats.  The added sugar rush also helped maintain high spirits for the adults as they trick or treated for business cards and brochures.

Over all the trade show was a great success.  Even though the attendance in the hall was a little lower than expected, the contacts were high quality for Green Roof Technology.  Discussions and concerns about the industry were very thought provoking.  With concerns everywhere about mitigating heat island effect and stormwater management, the future of green roofs looks very bright indeed.

Run-Off Quality - Extensive Green Roofs

Green Team at Green Roof Technology, - Saturday, October 22, 2011

Green roofs are vegetated soil filter where the naturally loosened root zone creates an enhanced degradation and retention of pollutants. The older the green roof the better the performance - considering the green roof was designed, constructed and maintained according the worldwide accepted FLL Guideline. Based on higher temperatures in summer the release of nutrients can be higher but will be still far below the strictest German drinking water ordinance as different studies showed in long term studies between 1999 and 2003 in Germany (W. Kolb, G. Mann, M. Köhler). However most run-off is more or less stained by humic substances that are typically caused by organic matter including releasing substances of the plants.

Since this is just a visual issue (no overall quality problem) the run-off water can be easily stored in cisterns. The water can be used for toilet flushing, irrigation, car washing and other purposes. Colored water is not recommended for doing the laundry, it might stain white fabrics. Research from Köhler (1993) and Liesecke & Borgwardt (1995) also showed that green roof have the ability to filter airborne pollutants efficiently, like lead, copper, zinc and formaldehyde.

To minimize run-off water coloration the initial organic content of the growing media can be reduced. Ideal are green roof layers with high mineral content (drainage and green roof soil). Within the FLL guideline Green Roof Technology is able to enhance the removal of pollutants and run-off coloration at the same time. Specially engineered green roof growing media will perfectly customize for our clients need and based on leading research performed in Germany over the last 15 years. 

Since extensive monolithic green roofs retain as an average 50-75% the storage of the run-off (cistern size) has to be adjusted accordingly and is typical larger than without green roof.

Data from any Run-Off Quality research done in the United States or Canada can be just used as a rough speculation. We don't know any research performed with standardized components (e.g. growing media) and further more there is no uniform standard for compost or organic ingredients going into the growing media. Without uniform and standardize research all results are only speculation. Independent research (not sponsored by manufacturers) in Germany did consider these important facts and therefore the results are useful and easy to implement on real projects.

Any kind of plastics (drainage boards, chemical substances or modular systems) doesn’t support the cleaning power as much as perfectly engineered wall-to-wall green roof systems. More and more experts starting researching on how much chemicals are released by plastic components and water proofing materials since it well know that plastic components affect sea life  - where all run-off ends up.

On request Green Roof Technology will translate any information about leading green roof research done in Germany over the last 25 years. 

ABC Carpet Goes Green Week 1

Green Team at Green Roof Technology, - Tuesday, October 18, 2011

By Kat Harrold GRP


 Photo~ Jorg Breuning

After much anticipation and preparation, the ABC Carpet and Home green roof has officially begun construction!  We met with Construction Manager, Micheal Cluer, and Forewoman, Collen Loft, yesterday at ABC to check on the progress and to discuss project details.

The first few days consisted of meticulously cleaning the roof so as to remove all debris, such as nails and small stones, that might damage the waterproofing.  A thorough examination of existing roof conditions was also performed to check for any preventable trouble spots.  While the weather had called for only 10% chance of precipitation with sunny skies Monday, that 10% decided to make a visit early that morning which turned the sweeping into more of a mopping procedure.  On the bright side the roof will be squeaky clean and puddles were quick to evaporate.  

The next step after cleaning the roof will be to find the support beams and mark out where the green roof segments will go.  Once this is done, edging will be cut and assembled to frame the green roof planting areas.  Because of all the pipes present on the green roof there will be some areas that will be segmented so that they can be built around the pipes.  

Check in next week as we get into the dirty business blowing the growing media onto the roof.  For those of you not familiar with what that entails just think of a snow machine.....but one that blows dirt instead of snow.




ABC Carpet Goes Green

Green Team at Green Roof Technology, - Monday, October 10, 2011


 Photo courtesy of ~ ABC Home and Carpet

As the leaves begin to fall, a new roof is being raised as Green Roof Service and the Sustainable South Bronx prepare for the installation of ABC Carpet and Home's series of green roofs at its Bronx location.

Building a green roof on a warehouse can be a difficult task since the building is a wide open structure with little support for the roof.  To circumnavigate this issue, we designed green roof strips to go on every other support beam of the roof.  By keeping the green roofs on the strongest segments of the roof we were able to cover 10,000 square feet of the roof without over stressing the roof.

Green Build 2011

Green Team at Green Roof Technology, - Monday, October 10, 2011


Last week in Toronto Canada thousands of green minded people from all over North America gathered to discuss the latest in green innovations.  While classes and seminars took place, the trade show exhibit halls buzzed with energy.

As one might guess, there were green building vendors of every service and material imaginable.  A very exciting development this year was the amount of green roof oriented vendors.  Over a dozen vendors selling green roof products were present.  

For us, the trade show was a tremendous success with lots of great contacts established as well as an award for our booth! In addition to the typical displays of some key projects we have done, we also had a display showing the difference between storm water quality in a neighborhood with traditional roofs and ground surfaces versus one which utilizes green roofs, rain gardens and porous surfaces. 

We would like to thank all the wonderful people who stopped by our booth and the USGBC for organizing this event.  It would have been a very long and boring trip without you.  We hope you had a great time at Green Build and look forward to seeing you again in the near future!   


Green Roofs and Facades: A Habitat Template Approach

Green Team at Green Roof Technology, - Friday, September 30, 2011

by Jeremy T. Ludholm


Review by Kat Harrold GRP

Great article on using the potential our built environment presents for plant life rather than trying to turn it into an environment it simply is not.  This article explores how we can use plants adapted to rocky surfaces and windy areas to green our cities and our green roofs.   

Are there any rocky areas in a park near where you are?  What kind of plants do your find growing there and how might you be able to create a habitat for them in your built area?

Greenroofs & Walls of the World™ Virtual Summit 2011

Green Team at Green Roof Technology, - Tuesday, September 27, 2011

By Kat Harrold GRP

Photo courtesy of

Today was a long but exciting day in the green world.  At 7 am (est) the world of greenroofs and green walls just got a little greener as leaders in the eco minded community gathered together for a summit that no one had to drive to. Linda Velazquez started off the summit with a lovely introduction and welcomed key note speaker Charlie Miller of Roofsmeadow.

Charlies' opening broadcast was very informative perspective on the evolution of green roofs in the US and how there have been some misconceptions about the feasibility of these living structures.  One very interesting and key thing to remember from his talk was that while there may be a certain level of guilt about our built environment and the nature that it has displaced you simply can't "bring back" the landscape that originally occupied the city.  The geographic location may be the same as it once was but the micro-climate of a city roof on a windy street is drastically different from that of a deciduous forest floor.

Other presentations that followed were a very inspiring and entertaining discussion panel with Christine Thuring, Nathalie Baumann, Gary Grant, and Dusty Gedge.  Very excited to see so much research done on the older roofs and the long term ecological benefits and community's one can encourage.

Ralph Valazquez from Tremco gave a great presentation on corporate social responsibility.  I find that there are times where it seem that businesses and corporations have more power to change the quality of life in an area than the government.  Kudos to you Ralph for leading such a community and socially responsible organization and for encouraging others to do the same.

Chris Walk gave a refreshingly honest and informative presentation on Ranking Energy Benefits by Mission, Climate and Construction.  Through careful analysis of elements effecting a building's energy usage Chris examined several different types of buildings in various climates and how green roofs effected their energy usage.  In short far as the question "How much energy can I save with a green roof?" is concerned it's all relative.  In general green roofs can save energy for a building but that amount depends greatly on the construction of the building and location.

Nigel Dunnet gave a stunning presentation on options for designing ecologically diverse green roofs with a large visual impact.  Many times while the function of a green roof may be successful often it is visual boring or sterile.  Nigel also provided many wonderful approaches for maximizing seasonal and visual interest while still providing a richly diverse environment and functioning green roof.

The last presentation of the day was done by the Portland Ecoroof Program.  For anyone looking to start a green movement in their area this is a wonderful presentation for inspiration.  This presentation explored the history of green roofs in Portland and how the Portland Ecoroof Program grew from one green roof on a garage to over 30 acres of green roofs across the city.

Very nice presentations and much needed topics for the industry.  Tomorrow is sure to be equally as exciting!  I can't wait to see what green wall artist Patric Blanc has in store!

Harford Glen Recieves Donated Green Roof

Green Team at Green Roof Technology, - Tuesday, September 20, 2011
By Kat Harrold


Photo by ~ Kat Harrold

Despite flooding and hurricane winds Harford Glen Environmental Education Center completed it's demonstration green roof.  The demonstration green roof was donated by Green Roof Service LLC and features a regular black rubberized roof adjacent to an extensive green roof.  Designed at an angle, this green roof is set up to allow for visibility for students of all heights that visit Harford Glen.

Harford Glen is a critical resource in teaching school age children about the environment and the great out-doors.  Amanda Koss, one of the teachers at Harford Glen and lead advocate for this project, was a tremendous help with this project and so excited to finally have a green roof for the school.  This demonstration green roof will be a helpful hands on aid as part of their out-door class room lessons.  From this set up students can learn plant identification, stormwater management, heat island effect, green roof technologies, and ecology.  

The demonstration green roof sits on a "reclaimed wood" platform with an EPDM waterproofing membrane.  A protection fabric covers the green roof portion, followed by a drainage board, filter fabric, and extensive growing media.  The growing media was graciously donated by Skygarden.  Two drains are were also installed, one on the green roof side and one on the regular roof.  

The plants are a mix of sedums and herbaceous plants.  Some of the herbs consist of oregano, thyme, and chives.  A potential tasting addition to a school lunch!  



Photo by~ Jorg Breuning

Extensive Green Roof Maintenance

Green Team at Green Roof Technology, - Tuesday, September 13, 2011


Extensive green roof being planted - Kat Harrold 


By Kat Harrold GRP

A common misconception with green roofs, especially extensive ones, is that they require no maintenance.  While some green roofs may be fairly self-sustaining and require little maintenance there is still some regular maintenance required to keep the green roof as a system working to it’s fullest. The three main things to consider are the plants, media, and timing.

Plant selection is very important in determining when you need to fertilize and weed.  Also deciding what is a weed is very important.  A weed very often is as subjective as beauty; often it is simply within the eye of the beholder.  Newly planted green roofs will need more weeding than established roofs to cut down on competition of resources while they try to get a foot-hold.  

Green roof media blended properly should have very little organic matter.  While extensive green roofs generally don’t require much additional nutrients they do need a balanced low-level fertilizer with micro-nutrients applied twice a year.  Do NOT use an organic fertilizer such as manor or compost.  The organic material can break up into very fine particles, which over time could clog the filter fabric and cause drainage problems.  Specifics on fertilizer content for green roofs can be found in the translated German green roof guide the FLL.

Timing is very important in terms of preserving both plants and your sanity.  On an establishing extensive green roof be sure to weed once every 2 months for the first year.  You can cut back your weeding to 3-4 times a year once the plants have established.  Taking extra care in the springtime and after a heavy rain can save a lot of time weeding seedlings instead of full grown weeds.  Grasses should be cut back in late winter to early spring.  FLL specified fertilizer should be applied once in the spring and once in the fall for the first year.  Have a professional check your roof after that to advise how much is needed there after.  

The Sky is Falling: A Critique of Failed Sloped Extensive Green Roofs

Green Team at Green Roof Technology, - Tuesday, September 06, 2011

By Jorg Breuning

As of late we have been receiving more and more calls from building owners in distress about their green roofs.  The most serious of these complaints being erosion problems on their sloped roofs.  Sloped green roofs are a bit more complicated to design, install, and maintain than flat roofs and as a result people who disregard or don't know of the established FLL guidelines for sloped roofs, have created dangerous and costly situations ranging from mudslides to roof collapse.

One of the most infamous of these rooftop blunders was last winter in St. Charles, Illinois.  The project was designed to be the largest sloped roof in the US and during a heavy snow storm the roof collapsed.  Fortunately no one was hurt however the damage was devastating.  

Why did the roof collapse?  The problem lies in the drainage.  Snow is frozen water and where you have more water accumulating on a roof you will also have greater amounts of snow accumulate.  This insufficient or clogged drainage system and poor growing media is the most likely culprit in areas that held water or snow.  All this added weight during an extreme winter put the roof way beyond its capacity.

Sadly, this situation and others like it could have been avoid simply by hiring a true expert and checking their performance history for similar projects.  To read more about the dangers of improperly design sloped extensive green roofs and how to avoid them click here.

Below the renovated roof after it collapsed. Suddenly the green portion shrinked by at least 1/4.

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