Green Roof Technology Blog

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!

Picture: Stuttgarter Nachrichten

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.

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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Thank you for all the comments on the blog post:

Irrigation on Extensive Green Roofs

 

We believe a lot of people in North America agree with the comment that in some areas Green Roofs can't thrive without irrigation. We at Green Roof Technology don’t disagree nor agree. Allow us to bring the discussion into a fundamental perspective:  

Before you built a structure, you have to remove nature or simpler living plants that nobody watered before. Modern green roof technology is able to mimic this type of environment and allows to promote exactly this drought tolerant and hardy vegetation. With a little more understanding of this technology, it is even possible to increase the plant varieties or the plants density.

Nevertheless  the attractivity might not meet the expectations of us (humans). Our picture in mind of a roof garden is a lush green vegetation form that is created with plants that please us (humans), that are not poison or dangerous. In some areas we can achieve this goal by utilizing resources that haven’t been available at this location before the structure was built.

By using natural resources (and water is the most valuable) we start changing our environment (we take water away from somewhere – from plants somewhere) just for our own comfort. Understanding that and the value of water should create an awareness to green roof professionals or engineers to design modern green roof technology in a way that no water or super highly restricted amounts of water are utilized.

Unfortunately, the irrigation industry and most of the green roof designers grew up in an environment where resources are endless. With that said the current waste of water on green roofs is simply not acceptable to me and in these cases green roofs are an environmental nightmare - just for our pleasure (and cash) and that things look “nice and green”.   

When I drive around in neighborhoods in San Francisco in the morning, my car is being washed by all the sprinklers and nobody has a problem with that…..

Simple and efficient technology is here since many decades but not in the interest of the industry, nor “re-invented” in the US or there is a lack of common sense – maybe it is a combination of all.

Most issues I am confronted with, are a result of high tech irrigation that is just not doing what it is supposed to do, there is not the right app, poorly designed and installed, too complicated for facility people etc. or simply drains the budget of building owners over time this water costs are going up.

Let’s discuss further and email us directly: info@greenroofservice.com

 

Comment by Jure Šumi ((LinkedIn):

 
Interesting input Jorg. Yes, extensive roofs should be self-sufficient where they can be. But in my mind this is not possible in really arid areas like Jim is saying. With our partners in Abu Dhabi we are now investigating what plants should be used there, where top temperatures are regularly reaching 120 F in summer months (with no rain for years). If you use local plants that are surviving in desert than they are surviving only due to the fact that the roots are extremely long and go deep in to the ground to find some moisture (not possible on the roof). Limited irrigation is still needed but the roof needs design with minimised ET, so also irrigation is as low as possible.

Maybe another thing to consider. Yes or no irrigation is also a question of what someone wants from green roof. Nice look is one aspect, stormwater managment is another. We should not forget Energy efficiency. According to our investigation and perfromance tests, evaporation has big effect on energy efficiency in the summer due to cooling effect. If moisture in the green roof system drops below certain level, the cooling effect is limited. So to have best energy perfromance of the roof, than you need irrigation.

 

Response Jörg Breuning:

Thank you Jure.

My starting point of thoughts about irrigation on extensive green roofs goes back to a fundamental point and only a handful people make these considerations.

Humans are capable to replace nature with a manmade structure on any location on Earth and they make it suitable for people to live there. In these fundamental thoughts, I expect that humans are also able to create this lost part of nature on top of these structures.

I agree this is not always cheap and not everybody is blessed with creativity or experience. Nevertheless, it is possible and it is our responsibility if we respect nature.

The rooting depth of plants is certainly a key element - it isn’t a road block. It seems it is the preferred excuse that we don’t need to feel responsible in what we re doing and that we don’t feel guilty.

I also think it using water for cooling buildings in an open system (what any green roof is) is considered - in my world - using elementary, limited and precious resources for our convenience. In the case that producing water (in dessert states) for the wasteful irrigation of plants (to make our close environment nice) might be a problem to justify to more than 100 million people that have no access to dependable water resources.

What I am saying is, that growing plants even in areas where plants would hardly grow can be done with extremely low impact on natural, precious resources at costs that are lower in the short or long term. The current hype for green roofs can create significant drawbacks in 15 or 20 years from now to building owners if the costs of water continue to rise. Keep in mind a 20 year old green roof is not even the half of the life span of a green roof (at least that is what I know from experience).

Professionals need to start thinking long term and not for quick profit, they should disregard fancy fashions or get away from desperate LEED point collecting terms if they seriously respect nature. 

Jörg Breuning

 

Picture: Deep rooting plant on roof with hardly any soil and never intentially planted (in Texas at the border to Mexico).

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. 

 Green Roof Innovation

 

 Green Roof Technology Reveals Latest Study about Mineral Wool on Living

 

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).

  

 

 Picture 2013 Optigreen

 

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.