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The Best Green Roof System

Green Team at Green Roof Technology, - Saturday, August 01, 2015

The main purpose of an extensive Green Roof is stormwater retention and delaying stormwater runoff amongst many other added values.

Above: An Irrigated thin layered Green Roof System – without irrigation it would be dead.

In the last decade in North America, we've seen many Green Roofs where the intended plants never really flourished. I estimate that in the US at least 50% of the green roofs are not performing to their fullest potential. This can be observed by simply looking at the most obvious of indicators, the plants themselves, regardless if they were planted on purpose or somehow found the space to take root. 

Most of these less healthy extensive Green Roofs are thin-layered systems, pre-planted boxes (often called modular systems or hybrid systems), Green Roof Systems from roofing manufacturers with ineffective components, single source warranty-systems, or design intents without consideration for the needs of plants. Typically these systems much more costly (whether thin or thicker) and the mid to long term results are often far below systems that are assembled in place with common sense.


Thin-Layered system with irrigation - doesn't work and doesn't retain much water

We all know that the transition from being a common nursery-grown plant (including pre-planted boxes) to the extreme environment of a rooftop poses severe challenges. Green roof plant nurseries typically have "great" advice and recommend the installation of temporary or permanent irrigation systems. In some areas this might be helpful when operated correctly but in all cases this advice is defeating the purpose of an extensive Green Roof (water retention). In almost all cases any type of irrigation caused a spiral of failures and it is wrong to irrigate extensive Green Roofs in areas with limited water for the cause of just having a green roof (Green Washing). Most company sponsored experts don’t see the entire picture or they only see the short term profit and commission (“Mow-Blow-Go”).

If a problem occurs and since many Green Roof system developer lack the proper and specific green roof horticultural knowledge, they may not be able to identify problems by simply looking at the indicators (the plants). This could cause the problem to gain momentum. In addition, the false conclusion that technology (Google search, Apps, synthetic growth media or sophisticated soil moisture control devices) can fix the problem supports my theory of hardly experienced or misinformed green roof professionals. They rely heavily on technology to fix any issues and miss the big picture.

Nature has the ability to take care of itself, as long as the appropriate design, materials and plants are used in addition to being familiar with the immediate location and climate.

Thin layered, super lightweight systems or systems with “innovative” components are just by physics not meant to retain “more” stormwater for the plants or they retain too much water for specific plants. As a matter of fact the costs for retaining stormwater in thin layered systems are extremely high comparing to a standardized extensive Green Roof with a thickness of 4-6 inch (depending on location). Besides the initial costs the lack of water retention (don’t forget all studies are done by the companies!) won’t support any significant bio diversity plus the operational costs (because of the required irrigation) are tremendous over time. Typically these Green Roofs never pay back with they are not utilized for “Green Washing” purposes in advertising.  

Irrigated extensive Green Roofs and/or thin layered, super lightweight systems (below 25 lbs/sf) will increase the nutrient pollution in runoff, require higher fertilization application, have hardly any tendency for self-healing, and may increase the pressure of unwanted plants and have a high risk for failure. Irrigated extensive Green Roofs are not environmentally friendly in most loactions!

Green roof designers and green roof professionals must understand that certain advertising, studies, White Papers or project references are all assembled by specific manufacturers and their goal is to make money – unfortunately on the back of a very advanced technology and on the back of their clients.

When we advise our clients they get the full picture because we have seem all solutions in the last 35 years, we have tested them and we are currently working millions of square feet where these systems require upgrades, reinstallation or massive repair (around 20 million in damage so far).

We also help our clients doing it as efficient as possible and to get their money back from prior failures through warranty claims and sophisticated lawsuits. This might help to standardize the function of Green Roofs and helps to get the black sheep out of the market. The building owner has a right that things are done right from the beginning.

Never irrigated in the last 10 years.

Leading Green Infrastructure since almost 150 Years!

Green Team at Green Roof Technology, - Friday, July 10, 2015
 Leading Green Infrastructure since almost 150 Years!

Stuttgarter Nachrichten

Picture: Stuttgarter Nachrichten

Living Green is not just an empty phrase for City of Stuttgart, Germany.  The history goes back almost 150 years as the “Stuttgarter Verschönerungs Verein” was founded. A powerful Association with an authority comparing to today’s City Department of Parks and Recreation. Even during the Nazi-Time the Association was entirely independent and was able to protect historical buildings, Parks and to increase living green with new parks and living green recreational areas.

Based on this history it was no accident that Stuttgart is the pioneer of an unmatched progressive Green Roof program in the 1980’s and the City of Stuttgart is still the leader with the most Green Roofs in the world.

Just recently the City revised the Building regulations for the entire State Baden-Württemberg that every building owner has to implement more living green. A controversial discussed item in politics because some people understood that as forcing Green Infrastructure – but it was meant to inspire building owners to value Green Infrastructure as an investment for the future with related high savings for operational costs.

In an newspaper article of Stuttgarter Nachrichten the new building requirements are explained including the benefits for the local infrastructure and the lasts high demand for well trained and educated Landscape people.

I was very excited to see that they used a current picture of a Green Roof project I installed in 1999/2000.

This Green Roof is a demonstrating project at a landscape company and covers their truck parking. The depth of the Green Roof reaches between 4 inch to 12 inch – from Sedums, perennials, shrubs to trees that grow over 15 feet. Since it is on a roof the reflecting pond is rather shallow, has a water feature and is lit up at night to create a private out door space for the company owner. The City of Stuttgart, Germany is a place where ecology and economy is closer together than in any other place on Earth I know.

2001all rights Jörg Breuning
Picture: Jorg Breuning taken one year after installation

15 Million Square Feet of Green Roofs in 2 days!

Green Team at Green Roof Technology, - Monday, April 06, 2015

Over 15 Million square feet of Green Roofs in 2 days!

In the World’s Green Roof capitol it isn’t a problem to walk over 15 million square feet of Green Roofs in two days.
Grinnell College Students, Architects and Professors joined me this year on a two day trip though out Stuttgart Germany.

Within the city limits and a population of around 700,000, Stuttgart can offer likely over 200 millions square feet of extensive and highly divers Green Roofs – more than the entire USA and probably Canada together.

The two days tour emphasized Green Roofs that are between 15 and 30 years old and that host over 40 different plants species. Remarkable is that not a single Green Roof was ever irrigated, nor fertilized in the last 10-15 years and most of them are maintained only once a year.

No Green Roof was ever replaced or fixed and the water proofing under all Green roofs never, ever leaked (in the US 50% of the green roof are getting fixed or replaced in the first 5 years). The average installation costs were at around $4-6/sf (in the US around $12-18/sf).

All Green Roofs have three major functions: stormwater retention, stormwater retention and stormwater retention.

Green Roofs in Stuttgart are part of a building like windows or doors. There is no necessity to make a big fuss out of it.
Being the World Champion in modern Green Roof technology is nothing to celebrate – it is the responsibility of sustainable and environmental conscious lifestyle combine with common sense.

The highlight of the tour was the Bosch Parking Garage with the world’s largest Solar Green Roof that was designed with extremely high diversity of plants that are found only in (local) native dry meadows.
While the Green Roof measures around ¼ Million square feet the PV is designed for 1 Megawatt.
Unmatched world record in this combination on building structure that is 100 feet above a 6 lane Highway.

First Garden Bridge for Pedestrians in North America.

Green Team at Green Roof Technology, - Friday, February 20, 2015

Modern Green Roof technology combined with a Blue Roof to minimize artificial irrigation, to maximize water retention and enable visitors to cross a busy four-lane highway without leaving the lush greening of a park.


The Garden Bridge at Universal Studios in Orlando is the first of its kind in Florida. Designed by Miles Architecture Group Inc., Libra Design Group and Green Roof Service LLC, the green bridge creates an innovative connection of Universal City developments. Selected ground covers, shrubs and trees escort pedestrians almost without notice that they are crossing over a busy highway. The distinctive landmark project is engineered with people in mind.

The Garden Bridge at Universal Studios Orlando project is approximately 3,000 sf (145' x between 18 and 25' wide). The bridge is designed to pond water in the granular drainage area to increase the water retention (a blue-green roof combination, Patent hold by Optigreen - 1978 and the first time introduced to North America by Jorg Breuning in 2001).

Unique projects require unique solutions. Keeping the costs for the structure low, the trees are located above the bridge's pillars. The walkway gently winds up to the bridge and over and is easy accessible for the handicapped or service carts.

The project was possible with an outstanding waterproofing solution by ALT Global. ALT Global meets the FLL requirements for root resitance.


This innovative green roof project is a master piece of teamwork between architects, structural engineers, landscape architects and green roof professionals with an open mind, environmental leadership and common sense.

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SRWA Conference 2014

Green Team at Green Roof Technology, - Sunday, October 19, 2014

Next Generation of Sustainable Buildings


Baltimore, MD / Hershey, PA --- The Sustainable Roofing and Waterproofing Alliance (SRWA) hosted its fifth annual fall conference from October 8-11, 2013 in Hershey, PA. The event brought together a global audience of architects, roof consultants, green roof experts, building design professionals, contracting firms, and building owners. This unique program featured in-depth educational courses and hands-on demonstrations designed to inform and advocate for advanced green building practices.

Enhanced moisture control of super insulated, high performance buildings envelopes in each climate zone on Earth is the key for long-lasting, low-impact and healthy buildings. Proper solutions will maximize the payback of investments for building owners and drastically reduce the environmental footprint of building structures at the same time.

The speakers at the SWRA Conference paired common sense with decades of scientific research and developed best management practices for any building envelope application.

“With over 200 attendees from 19 countries around the world the fifth SWRA conference set a new milestone for building professionals”, said Jorg Breuning, Green Roof Service LLC – Green Roof Technology, “vegetation on top of buildings are the ultimate transition from manmade structures to the natural environment.”

Effective, economic design and maintenance principals of modern Green Roof Technology was presented and discussed by Jorg Breuning. With over 34 years of experience, Jorg Breuning demonstrated that thinking outside the box or a ridged modular grid will separate the wheat from the chaff.

The SRWA team led by Samir Ibrahim, Director of Design Services at Carlisle did a phenomenal job to make this conference happen. 

Mineral Wool on Green Roofs

Green Team at Green Roof Technology, - Sunday, September 21, 2014

 Green Roof Innovation

 Mineral Wool on Green Roofs

 Green Roof Technology Reveals Latest Study about Mineral Wool on Living

Since their first commercial production in 1871 (Georgmarienhütte, Germany), mineral wool found its way in many applications like thermal insulation and soundproofing. Mineral wool, mineral fibers are typically referred to synthetic materials like fiber glass, ceramic fibers and stone or rock wool.

Two main types of mineral wools are on the market – water repellent (Hydrophobic) and water adsorbent (Hydrophilic). For horticultural purposes, only the hydrophilic type is useful. Many patents were granted for simple Hydroponic systems or the germination of seeds with mineral wool in the early 80’s.

In modern green roof technology the first green roof systems came on the market around 1985 in Germany at a time as the German green roof industry gained tremendous momentum. As a lightweight solution with high water retention, mineral wool seemed an ideal material. The higher costs and the higher carbon footprint - comparing to lightweight aggregates – were argued with easier installation and higher water retention.

Extensive research over more than 5 years at the University of Geisenheim and on numerous buildings confirmed the high water retention properties. However, in the mid-run these tests also revealed that the performance and the health of the vegetation were far below conventional green roof systems with standardize green roof components. Mineral wool manufacturers and green roof system suppliers stepped away from the idea of using mineral wool as a growing component for green roofs.

“Today we can see a revival of mineral wools in the green roof industry,” says Jorg Breuning, CEO, Green Roof Service LLC,” in countries with hardly any green roof experience, mineral wool is getting rather popular with potentially fatal results in the mid and long-run.” 

Especially in the United States, the market is growing rapidly for mineral wools on green roofs, disregarding existing studies and without extensive long-term tests. It isn’t even proven whether certain fibers can cause health problems, leach out chemicals or whether these components can be recycled when the green roof doesn’t perform anymore.

In 2012, the lack of performance of mineral wool as a vegetation carrier resulted in a major green roof restoration at Amsterdam International Airport. 90,000 square foot of green roof – built with mineral wool - had been taken off and replaced by a standardized green roof system. At this point, this was the largest green roof restoration in the history of mineral wool on green roofs. Costs that could have been avoided.

Doing it right in the first place.

Green Roof of the Year 2014

Green Team at Green Roof Technology, - Tuesday, September 09, 2014


Green Roof of the Year 2014 – 30 Years and Counting

The second oldest Green Roof Association* in the world, FBB (Fachvereinigung für Bauwerksbegrünung), awarded a prize for Green Roof of the Year 2014 to a 30 year old Green Roof on the Allianz Insurance Company in Stuttgart, Germany. Oldest Green Roof Association DDV (Deutscher Dachgärtner Verband).

The roof is one of the first projects where Jörg Breuning, CEO at Green Roof Service LLC / Green Roof Technology was substantially involved in the realization. Allianz Insurance Company decided in 1981 to build their local headquarters in the heart of Stuttgart. At that time the office building was already a big step forward for urban development in many regards. Along with very advanced, environmentally friendly technologies it was also one of the first buildings to achieve the split between living green working space and luxurious living in downtown of a large City. 

The Green Roof is generally assembled around the building and on different levels. Most people in the offices have a view into the green spaces.  Some areas of the Green Roof are accessible for coffee breaks and, on the highest floors there is usable garden space for the Condominium owners. The top floor even offers extensive lawn areas as playgrounds for kids.

All Green Roofs together measure over 21,000 sf. This inner city oasis utilized an advanced Optigreen Green Roof Systems with fully automatic high tide and low tide irrigation system in the mineral drainage layer. The plants “decide” when they need irrigation; no drop of water is wasted or can evaporate before reaching a plant. Neither a person nor electricity is needed to operate this fully mechanical system and it leaves enough room for precipitation to fill up the water storage under the plants. This green roof represents a smart combination of Blue Roof and Green Roof as Green Roof Service LLC / Green Roof Technology is still doing it on projects today. It is a foremost and 100% accurate irrigation system far beyond most irrigation systems that are operated by sensors, electricity, Apps, tubes, pipes or other highly vulnerable and expensive equipment  we see every day on projects in North America or around the world.  

The entire depth of this highly efficient Green Roof technology is approximately 18 inch and has allowed lawn, perennials, shrubs and small trees to grow for over 30 year without replacement or  changing out the growing media. 

Green Roof Service LLC / Green Roof Technology is proud of this Award and we are pleased to offer more information about it. We offer Green Roof tours for anyone interested in this kind of technology.

This has been a landmark project for more than 3 decades and we congratulate all who are part of this Award!

*Note: Oldest Green Roof Association in the world: DDV (Deutscher Dachgärtner Verband).

Green Roof of the year Green Roof of 2014 

30 years Green Roof / 2014  

 Picture 2013 Optigreen

Uneven Water Supply for West

Green Team at Green Roof Technology, - Tuesday, July 15, 2014


WASHINGTON, June 18, 2014 -- The final water supply forecast for this year shows the West divided into a wet north and dry south while snowpack has already melted in much of the region, according to data from the USDA National Water and Climate Center (NWCC).

Washington, most of Idaho, Montana, Wyoming and the northern parts of Colorado and Utah are expected to have near normal or above normal water supplies through the rest of summer, according to the forecasts. Far below normal streamflows are expected for the southern parts of Oregon and Utah, southwestern Idaho, California, Arizona, New Mexico and western Nevada.

Many of these areas are in the nearly 500 counties across the country experiencing drought, 57 of them in California alone, according to USDA disaster designations.

This year saw near-record low snowfall in parts of Nevada, California, Arizona, New Mexico and the southern parts of Utah and Oregon. Even with some May precipitation, those areas remain dry.  The biggest change this season was in the Washington Cascades. At the beginning of February the snowpack was about half of normal, but it recovered and most of Washington will have a near normal water supply from snowmelt, according to the Center. 

Spring snowmelt is well underway, according to NWCC hydrologist Cara McCarthy. “A lot of our SNOTEL sites have already melted out, especially those in the southern half of the West,” McCarthy said.

Colorado had mixed weather during May. “They had winter and summer all in one month: snowmelt, snowfall, snowmelt,” said McCarthy. Heavy precipitation combined with snowmelt, causing flooding in parts of the state.

Forecasters monitor conditions all year, but June is the final forecast of the season. “These are snow-based water supply forecasts,” McCarthy said. “Typically by July there won't be enough snow left on the ground (to measure).”

In Western states where snowmelt accounts for the majority of seasonal water supply, information about snowpack serves as an indicator of future water availability. Streamflow in the West consists largely of accumulated mountain snow that melts and flows into streams as temperatures warm into spring and summer. USDA scientists analyze the snowpack, air temperature, soil moisture and other measurements taken from remote sites to develop the water supply forecasts.

The NWCC water supply forecast is part of several USDA efforts to improve public awareness and mitigate the impacts of climate change, including drought and other extreme weather events. Through the creation of the National Drought Resilience Partnership, launched as part of the President’s Climate Action Plan, federal agencies are working closely with states, tribes and local government to develop a coordinated response to drought.

Since 1939, USDA has conducted snow surveys and issued regular water supply forecasts. View information by state.

Source: USDA

In dry years most Therophytes like
Asteriscus aquaticus are able to flower as very small plants and produce seeds that are able to survive evon more unfavourable seasons.

Leave Only Footprints, Take only Memories

Green Team at Green Roof Technology, - Wednesday, April 09, 2014

By: Samantha Yurek


Many people wouldn't think twice when gathering a lovely bouquet of flowers while out for a hike. But maybe this is a lesson we should all be practicing and passing down generations, when out enjoying the great outdoors. Transporting flowers for your own benefit is erroneous and punishable in certain situations. 

Although the United States doesn't have a specific law protecting wildflowers from being violently up-rooted, the Endangered Species Act of 1973 does cover all of the plants that are slowly vanishing.

Many states have specific laws regarding plants. For example, North Carolina's Plant Protection and Conservation Act states that it is unlawful "to possess any protected plant, or part thereof, which was obtained in violations of this Article or any rule adopted thereunder." If caught, fines can rise as high as $1000.

There are many reasons why you shouldn't pick wildflowers or take plants from the wild. Not only does it reduce the vibrancy of the location, but it also can be damaging to the environment. The USDA explains it perfectly, "We don't often realize it, but wildflowers support entire ecosystems for pollinators, birds, and small animals on a micro scale. Butterflies and other insects, small birds, and animals depend on seeds, nectar, and pollen for their food supply and life support system. In addition, some pollinators are not very mobile or have very small home ranges or depend on just one species of plant and die once their habitat has been destroyed."

In some cases, transporting flowers from the wild can also aid in the spread of invasive species.


It may not be your first reaction when someone goes to pick a few flowers, but just keep in mind that they are a living object as well, attempting to survive and reproduce just like the rest of us. And is it really worth picking these plants, only to have them wilt in a matter of hours or days? Especially when you could be enjoying them all spring and summer if you were to simply let them be.

So my advice to you is, instead of pocketing flowers from Mother Nature's garden, it is just as easy to take a short trip to your local nursery. Not only will there be a great selection on plants to choose from, you will directly be supporting your local community.

       Let me reiterate: 

Green Roofs, Green Infrastructure in Lancaster, PA

Green Team at Green Roof Technology, - Wednesday, March 05, 2014

Going Green Will Save Lancaster in Controlling Storm Water

Release Date: 03/04/2014
Contact Information: David Sternberg, 215-814-5548

-New EPA Report Documents Savings-

(LANCASTER, Pa. – March 4, 2014) The U.S. Environmental Protection Agency (EPA) released a report today that found green infrastructure can be a cost effective solution to controlling stormwater while providing numerous economic benefits. Using the City of Lancaster as a case study, EPA sought to quantify the economic benefits associated with utilizing green infrastructure for controlling wet weather pollution.

Mayor Rich Gray

“Cities like Lancaster are leading the way in creating cost-effective and innovative solutions to the stormwater challenges we face today,” said EPA Regional Administrator Shawn M. Garvin. “By keeping rain water from coming into contact with pollution in the first place, green infrastructure improves water quality while making communities more livable.”

The report estimated that within the combined sewer system (CSS) area, Lancaster’s green infrastructure plan will reduce gray infrastructure capital costs by $121.7 million and reduce wastewater pumping and treatment costs by $661,000 per year. It will also provide approximately $2.8 million in energy, air quality, and climate-related benefits annually.

These benefits exceed the costs of implementing green infrastructure, which were estimated to range from $51.6 million if green infrastructure projects were integrated into already planned improvements to $94.5 million if green infrastructure projects were implemented independently.

"The City has invested more than $25 million over the past decade in ‘gray infrastructure’ improvements to increase the capacity of the City’s wastewater system,” said Lancaster Mayor Richard Gray. “In spite of this investment, a significant amount of untreated combined sewage continues to overflow into the Conestoga River and eventually into the Chesapeake Bay. Green infrastructure will help reduce the volume of storm water entering our wastewater system and, at the same time, transform the City into a more sustainable, healthy community.”

Unlike single-purpose gray stormwater infrastructure, which uses pipes to dispose of rainwater, green infrastructure uses vegetation and soil to manage rainwater where it falls. By weaving natural processes into the built environment, green infrastructure provides not only stormwater management, but also flood mitigation, air quality management, and community revitalization.

In 2011, the City of Lancaster released its comprehensive green infrastructure plan. Developed with the assistance of city, county, and state agencies, the plan identified opportunities for adding green infrastructure throughout the city within 5-year and 25-year timeframes; estimated the water quality benefits and articulated a series of policy, outreach, and technical recommendations for implementing green infrastructure in the city.

Because of the plan and the city’s interest in understanding the added benefits of green infrastructure, EPA selected the City of Lancaster to serve as a case study for calculating the additional environmental, social, and economic benefits.

“Valuing multiple benefits of green infrastructure ensures water management investments by the City will help beautify, provide a safer, healthier and more prosperous community,” said Liz Deardorff, Clean Water Supply director at American Rivers.
“The results of this study affirm that green infrastructure has multiple benefits for both large and small cities needing to reduce pollution and ensure clean water.”


Lancaster, like hundreds of other cities across the country, has both a combined sewer system (CSS) and a municipal separate storm sewer system (MS4). While the CSS collects both sewage and stormwater and conveys flows to a wastewater treatment plant, the MS4 collects only stormwater runoff and discharges flow directly to receiving streams.

The report summarized how installing green infrastructure in the CSS area could reduce gray infrastructure capital investments and associated wastewater pumping and treatment costs; as well as how installing green infrastructure in both the CSS and MS4 areas could produce a range of environmental benefits across the city.

A copy of the report can be accessed at this link:

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