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Irrigation on Extensive Green Roofs

Green Team at Green Roof Technology, - Thursday, May 02, 2013

By: Jörg Breuning

The main purpose of an extensive green roof is stormwater retention and delaying stormwater runoff amongst many other added values.
 
Above: An Irrigated Green Roof 

In the last decade, I'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 pre-planted boxes, or commonly known as modular systems. Not only are these systems much more costly, the mid to long term results are often far below systems that are assembled in place and at the time of installation.

I 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 more permanent irrigation systems. This advice is defeating the purpose of an extensive green roof and shows that asking self-appointed experts can cause a spiral of failures. Since many green roof installers lack the proper 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 less experienced or misinformed green roof professionals. They rely heavily on technology to fix any issue 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 climate.

Green roof designers and green roof professionals must understand that less is often more when it comes to extensive green roofs. No building owner wants to irrigate their roof in short, mid or long terms. There is no need to make a green roof more complicated by using multiple synthetic or plastic layers. LEED™ certification supports using gray (recycled) water for green roof irrigation; but what is the point of watering an extensive system when it's main purpose is to retain stormwater? Common sense and experience are the only two things that will aid in planning the perfect green roof.


Above: An Unirrigated Green Roof

Implementing irrigation on an extensive green roof is a clear sign of not understanding the basic principles of horticultural techniques or the laws of nature. Irrigation reduces the water retention, increases the nutrient pollution in runoff and requires higher fertilization application. Irrigated extensive green roofs are not environmentally friendly, not economically feasible and have hardly any payback for the building owner.

I tell my clients if they have an offer or design for an extensive green roof that includes irrigation - be cautious!

 

First Steps to Planning a Green Roof

Green Team at Green Roof Technology, - Tuesday, April 23, 2013

 By: Samantha Yurek

Happy Earth Week! Hopefully everyone has taken some time out of their busy lives to lend a hand to our beautiful planet we inhabit. Whether it is picking up some litter, planting a tree or deciding to go all out and look into acquiring a green roof! Here are a few things you should have a good idea of before you leap into the planning process.

1. How sturdy is your roof?  Adding growing media and plants to your rooftop adds weight to your structure. Make sure your roof can handle some extra weight first. Find out the materials and structure of your building.

2. Is your roof sloped?  A slight slope is perfectly fine, but anything steeper than 15 degrees, the roof might become a slide for the plants without additional constructive design.

3. How much are you willing to spend?  Implementing a green roof is an investment for the future. Simple extensive vegetated roofs usually cost around $10-$15 a square foot (pre-grown planter boxes or modular systems are more expensive). Many local programs will help pay for green infrastructure, based on the environmental benefits. 

4. What type of green roof are you looking for?  A simple meadow-like area, not accessible and mainly for the environmental benefits (extensive) or an intensive roof, complete with recreational room and the potential for larger plants such as trees.

5. How are the sunlight conditions?  The majority of green roof plants enjoy direct sunlight to flourish. If the building is situated in a heavily shade area, the green roof plant selection becomes limited.

6. Do you want an integrated solar green roof?  The Sun-Root™ System is the newest of technologies, a fully integrated system and an ideal symbiosis of PV panels and an extensive green roof. It is easy to install and will not penetrate the roof. The entire system has the potential to pay back within 5 years and also meets stormwater requirements in all cities of North America.

 

Do your homework first before deciding on a green roof, our website is a great starting point to increase your green roof knowledge. If you're interested in a green roof or have any questions, please don't hesitate to contact us, we would be happy to help you get started today!

University of Maryland to Install More Green Roofs

Green Team at Green Roof Technology, - Monday, March 11, 2013

By: Samantha Yurek

The University of Maryland installed their first extensive green roof back in the fall if 2008 on Cumberland Hall.  Approximately 6,000 square feet of the rooftop is covered in vegetation.  The Adele H. Stamp Union building also completed renovations which involves yet another two new green roofs in 2009.

 

Picture courtesy of UMD

Summer of 2010 brought a Rooftop Food Garden on top of the South Campus Dining Hall. Planters made from salvaged wooden pallets hold all sorts of food including cucumbers, peppers, potatoes, tomatoes, mint and lavender, to name a few. In addition, the space is available for individual gardening projects and other student research or coursework. In the fall of 2011, the Denton Dining Hall followed suit, when the re-opened building integrated green and cool roof systems.

Although this makes up very few of the many buildings at the University of Maryland, each green roof helps to alleviate storm water runoff, the heat island effect, and each building's heating or cooling costs. 

The University of Maryland's Council on the Environment recently rewarded a grant to two graduate students, to extend on their solar energy and vegetated roof research.  Read the full story by the Diamondback here. 

In the future, it wouldn't be surprising to see more building constructed or renovated complete with green roof systems. The technology is available and the industry has definitely grown in the past few years.  

Aquascape Sues over Collapsed Green Roof

Green Team at Green Roof Technology, - Thursday, March 07, 2013

 

By Jörg Breuning Picture: Daily Harrald

Back in February of 2011, the lower end of Aquascape's headquarters collapsed after a heavy snow event that blanketed Chicago with 2 feet of snow in 24 hours.  The building once held the title as the "largest sloping green roof in North America," covering over 256,000 square feet. 

In a blog post, Green Roof Technology covered the roof collapse back in 2011, blaming the failure of the green roof on poor engineering regarding the drainage of the system. Blog post 09/06/2011

We also wrote a Case study about the dilettantism and ignorance of so-called experts that are designers, engineers and construction companies when it comes to modern green roof technology (download PDF: Fixer Upper or Lawsuit? Sloped Extensive Green Roof Critique).

Since we've collected even more examples that are not mentioned in the press, that are fixed “quietly” or where the client has been convinced that certain problems are “normal” for a green roof. We estimate the potential of law suits on existing green roofs over 80 million Dollars, which is probably more than the entire Grant money  spent so far for the implementation of green roofs.   

Many of these self-promoted experts are still playing an important role in the American green roof education system (GRP) and within the North American industry. It is interesting to mention that in other countries where green roofs have been established over decades and where there are 10 times as many built annually, that there were never such incidents reported. These countries not even have a “highly developed” green roof professional education system. What they have is called Common Sense; the understanding of how small indicators could cause huge problems and they understand their responsibility to the industry even when they are not directly involved. There is no ignorance, dilettantism or vanity – just pure professionalism based on solid education.

Now two years later, Aquascape has sued 9 different contractors, construction companies, engineers and architects for $13 million in damages.  These companies include Artisan Design Build LLC, Senekteks, Tricon Construction, Olsson Roofing, Tecza Environmental Group, Applied Ecological Services, Metallic Building Company, Area Erectors and Dewberry Architects (Read the Daily Herald Article) and we still have the cart in front of the horse.

At Green Roof Service LLC/Green Roof Technology we obviously can't change the system, but we will continue to support owners of green roofs to get what they deserve and what they are paid for. 


Green Roofs & Solar: Double Your Benefits!

Green Team at Green Roof Technology, - Monday, March 04, 2013

Green Roofs & Walls of the World - Virtual Summit 2013 is striving to inform, share and create a global social media experience for learning and networking around green roofs and living walls.  

 

Join Jörg Breuning & Ryan Miller on Thursday March 7th at 1pm Eastern time as they discuss the benefits of combining solar power and vegetated roofs!

Immediately after Green Roof Technology's video, a 15 minute live Q&A will take place with Jörg and Ryan.  The video will touch on the benefits of a solar green roof, cost-benefit analysis, two interviews with the president of Solar Gaines, Hans Wittich and Artie Rollins, the assistant commissioner for city-wide services with the NYC Parks & Rec Building, along with much more. 

If you're interested, tune into the video and Q&A session, you may register on the Summit Website

 

FBB Green Roof Symposium 2013

Green Team at Green Roof Technology, - Wednesday, February 27, 2013


Photo: Jorg Breuning

The German FBB (Fachvereinigung Bauwerksbegrunung e.V.) is the oldest Green Roof Association in the world and with around 120 members, probably one of the smallest. However, most FBB members are considered leaders in modern green roof technology and their average green roof experience is far over 20 years. It is an elite group that has seen everything you can imagine related to vegetation on impervious areas.

As the father of all green roof associations, this year's event was again filled with innovations, information and trends.The FBB president, Dr. Gunter Mann, pointed out that there is a huge potential for the industry to increase the annual green roof construction. In 2012, the 120 FBB members reported over 40,000,000 square feet of new construction, a significant addition compared to the previous years. The true annual new green roof construction in Germany might be doubled compared to the rest of the world. However, Germans are modest and not interested in quantity, but specifically in quality. Quality of installation, intelligent research and decent public relations are the foundation of the FBB.

In partnerships with other associations (Landscape Association, Concrete Association, Roofing Association, Association for Water Protection, along with many more) it is impressing to hear about the successful public awareness on green roofs.

The elite group at the FBB does a great, inexpensive and super-efficient job for a better and sustainable environment, mainly throughout Germany and reaching out into the world. For many decades they have been setting milestones for a growing, global industry and it is always a blessing to mingle with the biggest, most experienced and best-educated green roof professionals in the world.

Bravo!

 

First International Bird Airport on Intensive Green Roof

Green Team at Green Roof Technology, - Monday, February 18, 2013

 Ornithoport in Bonn

Picture: Bundeskunsthalle

Airports are plentiful in our world, but a unique concept involves creating airports specifically for birds.  An exhibition on the roof of the Art and Exhibition Hall over the summer of 2012, highlights this common area as a destination point for birds.  To aid this bird airport (ornithoport), nesting boxes and feeders were installed, as well as approach and departure structures, complete with flashing airport signals and safety announcements.  All together this presentation is not only an awesome art piece, but probably the best landing facility for birds from all around the world.  The curator of this project, Professor Res Ingold explains, "In our case, it is an artistic project with scientific backing."

Founded in 1992, the Art and Exhibition Hall of the Federal Republic of Germany has played an important role in the community of Bonn, Germany.  Designed by the architect, Gustar Peichl, the building displays various exhibitions in fields of art, archeology, cultural history, science, and technology.  Aside from exhibitions, the community center frequently hosts symposiums, conferences, performances and concerts.  One of the more attractive aspects of the building is the intensive rooftop garden, which is often site for sculpture displays.  This vegetated rooftop is a nice addition for relaxing with a fantastic view of the surrounding city.  In the summer refreshments are served at the beer garden, wildflowers brighten the landscape and the air is busy with buzzing honeybees.  Multiple honey bee colonies call this rooftop garden home.  In 2012 these little magnificent creatures produced 1,200 pounds of honey!  Accurate daily monitoring of the productivity of the honey bees is accessible online in German, French and English. 

Stormwater Retention and Green Roofs

Green Team at Green Roof Technology, - Thursday, February 07, 2013

By Jörg Breuning

Any impervious area of urban development prevents precipitation from infiltrating into the ground.  Instead of soaking up the water, it redirects it to another area. By redirecting the stromwater into other areas, the run-off will accumulate elements that are on this impervious area and pollute the run-off water.

Looking for Stormwater Retention (direct contact of humans with water)

Over the last 5 decades multiple studies show that these pollutants have a measurable negative impact to the watersheds and ultimately the lakes, bays or oceans. Since humans are in direct or indirect contact with these bodies of water (through swimming, potable water, irrigation of land grown food, aquatic or seafood) these pollutants have great impact on our health and causes billions of dollars to be spent on health care. The majority of pollutants in our water sheds are caused by chemicals of farmland, substances from vehicles (antifreeze, oil rubber) or simple trash that is carelessly discarded.  For example, in many areas people are advised to reduce the consumption of local fish to less than one time a week because this food source is too polluted. It is questionable whether vegetables from farms (including rooftop farms in polluted cities) or other meat from mass husbandry are a good alternative.

With smart stormwater best management practices (BMPs), pollution can be controlled effectively. It can't be diminished to a value that equals the natural environment previously - before the location was populated. Decreasing polluted stormwater run-off is a responsibility of everybody (not only the government) and it will pay-off by creating a livable environment for humans. If we don't make this investment and make it mandatory, our living quality will decrease and the value of our environment will drop over time. People will eventually move to healthier places, but these places are limited. We only have one earth.

Considering that an extensive green roofs with a 4 inch depth can retain 50% or more of the annual rainfall, they are the most efficient “direct on source” solution. If these extensive green roofs are engineered, installed and maintained properly, there is no pollution in the reduced, delayed or remaining run-off and for sure substantially less comparing to an impervious area on the ground. Comparing to other on-source stromwater BMP’s (e.g. pervious pavements) the costs of extensive green roofs are minimal – although still an investment for the building owner. Green roofs can be perfectly combined with any other stormwater BMP what increases the efficiency.

Official numbers show that the imperiousness of residential properties is around 30% and commercial land at around 65%. The implementation of extensive green roofs on commercial properties is typically cheaper because the roof areas are bigger and easier accessible.  Green roofs on large scale commercial buildings (warehouse belts around cities) will reduce the run-off dramatically and in addition will reduce the heat island effect by lowering the air temperature that is transported to the surrounded city.

If these commercial owners would choose integrated vegetation and solar (PV) systems, the costs of the green roof installation and maintenance could be off-set in less than 10 years and there would be no additional costs that increase the product of this company.  Since this environmental step is an investment, these eco-conscious companies would also reduce their tax on profits in the short term. However, reducing short term profits doesn't seem popular in the current economic environment and as long as there is no eco-rating of these companies. In this case LEED is counterproductive.

Water is the number one source for life on earth and any on-source reduction of run-off from the production process of goods or impervious areas will increase the living conditions tremendously, avoid expensive battles for clean water, and allow the human population to grow healthy and protect the native environment.




Spotlight on the Sun-Root™ System

Green Team at Green Roof Technology, - Monday, January 28, 2013

Back in 2012, Green Roof Technology installed our first Sun-Root™ System in New York City.  The vegetation’s ability to cool the air increases the efficiency of the solar panels perched atop the green roof. 

Learn more about combining solar and vegetated
roofs with our Sun-Root™ System

This week the Sun-Root™ System has been highlighted in “Under Cover: Solar Vegetated Roofs Take Root,” a recent online article by Green Manufacturer.  The Sun-Root™ will also be in the spotlight in their January/February issue of the Green Manufacturer Magazine.     

Chicago, one of America's green roof leaders, is slowly falling behind in the technological race. Numerous studies have proven solar energy integrated with vegetated roofs are more efficient than either practice by itself. Chicago has yet to offer any incentives that include integrated solar green roof systems.

Northwestern University: 
What Chicago Green Roofs Are Missing Out On 




Cool Roofs are not Green Roofs

Green Team at Green Roof Technology, - Thursday, January 17, 2013

By: Jörg Breuning

 

In Physics class we learned basics about thermodynamics and about thermodynamic equilibrium. In simple words the content of a black coffee mug “adjusts” faster to the surrounding temperature than in a white coffee mug assuming the material and material thickness of the mugs are the same.

Exposing these mugs to the sun light the black mug will convert the electronic energy (sun light) into heat faster and no light or shade cools it faster assuming the ambient temperature is lower. The physics behind converting light into heat is called radiation-less transition. White (or bright) colors reflect the (sun) light more effective than black. 

Any macroscopic or microscopic body on our earth is exposed to these physics properties including all particles in the air of which can be plentiful in polluted cities. While the sun light enters in to the earth's atmosphere, all bodies (particles in the air) receive portions of the sun's electronic energy and convert them in to heat. For example, on a high mountain we experience much more sunlight, or electronic energy, because the air is "thinner" or has less particles in which the light has to travel through. On a beach the light intention is also very high and this is caused by the reflection of the light off the the water and sand. Sunburns on the beach are of high risk because of the consistent wind, we don't experience the transition from light into heat on our skin as fast. No living organisms can reflect the light 100% effectively, but they can actively reduce the consequences (heat) by using techniques such as evapotranspiration.

Roof Surface Temperatures
(a sunny day in May, air temperature around 72ºF)

Reflective roofs can't reflect 100% of the light either, but they are good to a certain degree (see roof temps above). However while reflecting the light back in to the atmosphere, this reflected light will meet all the particles (bodies) again and substantially increase their temperature. It is well proven that less than 5% of sunlight is reflected back into space once it's in our atmosphere.

White roofs relocate the transition point of light into heat from the roof into the atmosphere or surrounding bodies (e.g. buildings). They simply don't eliminate the problem of increasing temperatures (heat island effect) caused by human settlements and they don't decrease the environmental foot print of structures. In addition, the white surface has a slow thermodynamic equilibrium. It takes a long time to to heat up in the winter (when heat is necessary) and cools down slower during summer nights.

The kingdom of plants were the only organisms over millions of year who developed a super-efficient mechanism to reduce the heat transitioned from the sun light. It is called evapotranspiration - powerful, miniature AC units powered simply by solar energy. These super little AC units are found naturally on Earth, but can be practically placed anywhere.  By using this naturally occurring phenomenon and installing green roofs, the outcome will go further beyond any man-made machine or material.

In many countries where insulation requirements are more intense than in North America, it is questionable whether reflecting roof material makes sense to start with. From a global environmental perspective and understanding the basic science of physics, reflective roofs are just relocating the heat issue caused by human development. It is similar to building a chimney higher at a coal power plant so not to pollute the air, when in fact the wind will just carry the pollution toward a different city.

Sometimes I wish all LEED™ professionals would have more common sense and follow these laws of nature and their own environmental gut feeling - it is simply better living under a tree canopy rather than under a polar glacier. 


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