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Green Roof Technology Blog

Green Roofs vs. Reflective Roofs

Green Team at Green Roof Technology, - Friday, January 06, 2012

By Kat Harrold

 

Photo Courtesy of A3C

There are a number of debates swirling around the roofing industry these days, possibly none more so than the green roof versus reflective white roofs debate.  Numerous factors go into the decision making process when deciding which roof best suits your needs.  Short term cost is a no-brainer discussion, but the environmentally friendliness and long-term investment debate is a bit more complex.

The environmentally friendliness debate is typically discussed within the context of energy savings and heat-island mitigation.  To accurately assess the differences in energy savings between the two roof types for a specific building a mechanical engineer, who is familiar with the thermodynamic properties of the various layers of green roofs and how they work together with the existing building, would need to be consulted.  However, to gain a general idea of what temperatures are at play, below are graphs showing the differences in temperature on various types of roofing surfaces.

   

 

The illustrations above show that the green roof is the most even keel choice out of the group, providing heat insulation during colder temperatures and cooling the roof during the warmer periods.  As shown above, a cool roof provides more cooling effects than a regular tar roof; however, it is still considerably warmer than the green roof during the warmest times of the day.   Conversely, the cool roof is the coolest of all the roof types when the temperature dips.  

You might say to yourself, “Well the cool roof may not be as effective temperature wise as a green roof but it’s cheaper.”  Wrong.  While the initial installation of a cool roof may be cheaper than that of a cool roof consider this; according to Greenroofs.com “Green Roofs vs. Cool Roofs” in March 2011, cool roofs may reflect up to 90% of the sunlight the first year however it quickly loses this capability to only about 70% from UV damage, pollution, dust, and exposure to the elements unless meticulously cared for.

The other price tag to examine is a cool roof like any other regular roof will need to be replaced after about 20 years.  A properly designed and maintained green roof should last 50 years or more.  Consider this the next time you need to re-roof.  

Green Washing

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

By Kat Harrold

IDS12: Toronto Interior Design Show 2012

Green Team at Green Roof Technology, - Monday, January 02, 2012
By Andrew Cole Yanders


Photo Courtesy of www.interiordesignshow.com

The party begins on January 26.   Toronto’s largest contemporary design fair kicks off with a party Thursday night with local DJ Karim Rashid spinning tracks.  The 4 day event will showcase the best and brightest from Canada’s flourishing design scene.  In addition, leading designers from all corners of the world will be exhibiting their newest creations.  Green Roof Technology has the special privilege of collaborating with Jill Greaves Design to create a stunning rendition on ‘How do you live’?  The exhibit will focus on the style of urban living.  Where green is the new black, green roof technologies will be taking center stage as the latest in eco-chic. 

Solar Living Roofs

Green Team at Green Roof Technology, - Thursday, December 15, 2011

By Kat Harrold


Photo courtesy of Optigrun

Roofs offer a variety of uses other than just keeping your house safe and dry.  If your not using your roof for open space or a place to watch fireworks on the 4th of July, one of the best ways to utilize this space is to add a green roof with solar panels.  While the green roof can provide excellent stormwater management, protect your roof, and keep you building cooler in the summer it can also host solar panels.  The cooling benefits that your building and surrounding environment enjoy also prevents the solar panels from overheating, allowing them to run more efficiently during summer's scorching months.

The main concerns about combing the two were damage to the green roof during installation of the solar panels as well as roof penetrations.  Fortunately there is a solution.  Using the latest in solar/green roof technology, this drainage board also acts as a stand for the solar panel.  Instead of punching a hole through your roof to secure the solar panel, it attaches to the drainage board which uses the green roof as ballast to keep it in place during high wind events.  

Similar to the set up of a regular extensive system, you have you protection mat over the waterproofing followed by the drainage board.  The combined drainage board captures water like a regular drainage board and has a gravel strip area underneath the drip area.  A filter fabric covers the top of the drainage board and a capillary mat moves excess water out of the gravel strip reservoir and into the rest of the drainage board where the vegetation can absorb it.

For more details and images on how this set up works visit our solar page.    

 

Upcoming Case Study Announcement: The Podium Roof Garden at Toronto City Hall

Green Team at Green Roof Technology, - Wednesday, December 14, 2011

By Andrew Cole Yanders

 

Photo by Jorg Breuning

The focus of this academic exercise will identify a few of the leading psychological tendencies that drive up the costs of green roof installations.  In a previous article we highlighted an impractical design that led to a “snowballing effect” of errors and costly mistakes.  During the course of a green roof design and green roof specifications, decisions are constantly made that affect the final installation cost as well as future maintenance expenses.  In any green roof design, it should be the goal to keep project costs for installation and green roof maintenance as low as possible without sacrificing the function.  Experience, practical designing and resourceful engineering can make a dramatic impact on reducing the average market cost of installing a green roof.

Instant green with pre-vegetated mats or tray systems are always much more expensive than built-in-place. Instant green requires much more maintenance to adapt the plants to the location or keep them in perfect conditions.

The City Hall in Toronto has already begun to loose the originally designed pattern of the tray system in the first year.  The main cause for this is due of the lack of experience in maintaining this system. Judging by the transformation that has already taken place, the green roof will convert to a meadow style green roof in the next two years even when maintenance efforts are drastically increased.

A monolithic or built-in-place, seamless semi-intensive / extensive green roof on the City Hall of Toronto could have been installed for approximately half of the costs of the current modular system and would have had the same visual aspect today but with much less maintenance, no irrigation and less fertilizer.

A fraction of the cost (approximately $1,000,000.00), more water retention and no irrigation needed an in-place system would be much more environmentally friendly.  A monolithic or built-in-place system would be a highly efficient extensive, semi-intensive green roof according modern green roof technology.   

Saving taxpayers money for the installation and the savings for required maintenance over the next decades should be the priority of responsible and experienced designers and planners.  With the saved money – just from the installation - the city could have installed another 40,000 ft² green roof and which could have retained additional 614,295 gal of rain water per year that doesn’t need to be processed expensively in a treatment plant.

As soon as the Case Study is complete it will announced on our blog and available for download on our Resources page.

Click here for an emailed copy the case study upon it's release 

A History of Green Roofs

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

By ~ Andrew Cole Yanders

One of the life’s great pleasures is the act of discovering an idea in a book that fundamentally changes the way you see the world.  This dynamic relationship between your life and the world of ideas is where creativity is sparked and dreams are made.   Often times you do not even understand what you are looking at but you recognize that it is different and fundamentally how things should be.  Today we are inundated with ontological debates, and possibly no more so than in how we view the structures we live and work in.  The image below of a classic Norwegian cabin speaks to my unconscious sense of how things should be.  Albeit a crude dwelling, it is awesome because of that fact.  Looking back into history for examples of how we used to strive to live in harmony with nature can provide the spark of inspiration we all need to find modern solutions to our most daunting challenges. 

  

The classic sod roofs of Scandinavian homes have many of the essential benefits modern green roofs have today such as insulation and stormwater control.  Well designed and constructed sod roofs have proven to last centuries.  We hope that 100+ years from now, our grandchildren and great-grandchildren will look upon our green roofs the same way we look at these awesome Norwegian sod roofs.

Here at Green Roof Technology we are proud to house the largest green roofs archives in the United States.  Because our history with green roofs began way back in the mid 1970’s in Stuttgart, Germany, we have had the privilege to collect government and trade publications for almost four decades.  We thought the rest of you would enjoy taking a peek back in history too.

In the early 1970’s, Germany was the epicenter of a revitalization of roof top gardening.  Technologies and techniques were created to waterproof large flat roofs and shield them from root penetration.  Intricate irrigation systems were devised to support large woody perennials.  Roof gardens became a status symbol of wealth and prosperity during an age of rapid urbanization.

The next evolution in green roofing began in the 1980’s when light-weight extensive roofs were developed.  Popularized by their low costs and huge environmental benefits, the bird’s eye view of many German cities quickly changed in the subsequent decades.

Pictured below are a few covers from our collection and one page from a 1984 publication by the Baden-Wurttemberg government outlining intensive and extensive green roof systems.

For more green roof information take a look at our Resources Page. 

 

 

Cities Alive - Philadelphia 2011

Green Team at Green Roof Technology, - Monday, December 12, 2011

By Kat Harrold

 

Photo ~ Kat Harrold

Last week the North American Green Roofs for Healthy Cities conference was held in the rapidly becoming emerald city of Philadelphia.  The conference was a very rich event in terms of contacts and the latest and greatest in developments in the green roof and green wall industry.

This year brought some new technology with us to show off one of the best solutions for combining solar and green roofs.  The black plastic component resembling as shark fin that took center stage at our booth is one of the latest developments in drainage boards world wide.  The drainage board feature a built stand for the solar panel allowing the weight of the green roof to ballast the solar panel stand.  By utilizing this set up one can take advantage of the stormwater benefits of the green roof as well as the energy producing benefits of the solar panel.  The other added benefit of this set up is that the green roof keeps the solar panel cooler preventing it from over heating and allowing it to produce energy more efficiently during the cooler months.  This new development was very popular this year and we look forward to the promotion of solar green roofs in the future.

Aside from the trade show there were also very high quality networking events and informative lectures taught by some of the industries finest.  One of my personal favorites was a lecture about green roof mapping in Germany by Professor Manfred Kohler.  By using ideas from this lecture, if we could map and stay current with green roofs being built in North America we could better monitor the health and performance of these roofs to truly document and take advantage of their stormwater benefits.  This could also be very useful in trying to create green ways for migratory birds.

Over all it was a wonderful conference and the solar drainage board made it back safely despite the wind's best efforts!

Can't wait to see everyone at the 10th Cities Alive conference in Chicago!

 

 

 

NY Green Infrastructure Symposium

Green Team at Green Roof Technology, - Tuesday, November 22, 2011

By Kat Harrold GRP

 

Last Thursday the Environmental Finance Center at Syracuse University and the State University of New York College of Environmental Sciences and Forestry hosted the 2011 Central New York Green Infrastructure Symposium.  The best and the brightest professionals, researchers, and government officials poured into the symposium to share ideas and learn about green infrastructure applications and regional workforce development.

Joining the discussion was our fearless leader Jorg Breuning.  As a guest lecturer Jorg presented a wealth of knowledge covering common mistakes to avoid with green roof design, construction and maintenance.  He also busted a few myths about green roofs as well.  A download of this presentation can be found on our Resources page under Modern Green Roof Technology.

Over all it was a very informative and productive symposium.  It was also a real treat being able to see old friend Charlie Miller who gave a wonderful opening keynote presentation.

Green Instance Magazine

Green Team at Green Roof Technology, - Monday, November 21, 2011

By Andrew Cole Yanders


 

 

It’s been another busy week at Green Roof Technology.  Earlier this week a Green Roof Evaluation Case Study was posted for download, highlighting the necessity of a diligent maintenance program and the damage that can occur when one is not administered. 

Today we are excited to announce the upcoming release of the first issue of our quarterly magazine: 

GREEN INSTANCE, The International Review of Living Infrastructure.

The magazine is hitting the press this week and will be delivered to leading architects, urban planners, landscape architects, building owners, general contractors and facility managers around the world.  The limited first printing will also be available at our booth at CitiesALIVE 2011, hosted in historic Philadelphia, Pennsylvania from November 30th to December 2rd

Following CitiesALIVE 2011, we will post GREEN INSTANCE for free download on our website.

If you wish to receive a hard copy of GREEN INSTANCE please email andrew@greenrooftechnology.com.  Availability is limited.    

Green Roof Time at Penn State

Green Team at Green Roof Technology, - Thursday, November 17, 2011
Green Roof Tech Rookie Recalls His Time at One of the Best Green Roof Research Programs in the US

Photo courtesy of Centre Daily Times

On a sunny but cold Tuesday morning I stepped into the Tyson Building for the first time.  I was returning to Penn State two years after completing my undergraduate degree.  The basement hallway was warm and inviting but in my palms was a cold sweat.  Re-entering the classroom was like walking into a strange country.  I crossed the threshold and took a seat next to the prettiest girl in class; some old habits never go away.  I relaxed into the typically first day pre-class conversation and waited for Professor Berghage to arrive.  A few minutes later in walked a tall, stalky man with a long grey ponytail wearing blue jeans, a vintage LL Bean shirt and of course a toothy smile.  Horticulture 497A: Green Roofs, Rain Gardens and Living Walls consisted of no more than 15 students, most of who were already familiar with Dr. Berghage and were all apt to calling him simply ‘Rob’.  I realized within minutes that this class, this time in space, was a foreign country from all the other class rooms I ever spent time in at Penn State.  Gone were the slightly awkward, poorly dressed but all too clean-cut professors from my days as an economics student. 


Photo Courtesy of Andrew Cole Yanders

After a period of introduction to green roofs the class moved to a nearby classroom in Headhouse l.  Rob continued to discuss the myriad components that go into a modern green roof and passed examples around for all of us to inspect.  This is a trend in Dr. Berghage’s teaching style I came to greatly appreciate, theoretical explanations then immediate tactile experience.  The following week we began discussions on media and our week’s lab time was spent creating and testing media with varying air-space porosities.   The varying medias the class created were then placed into experimental hanging boxes in the greenhouse and covered with sedum album cuttings.

University Park campus is lush with green roofs with more coming with each new building Graham Spanier is incapable of saying no to.  Stepping onto the roof of the Forestry Building, Penn State’s first green roof, was my first experience with a completed green roof.  It was hard to even call it spring yet, but the roof looked wonderful to me, vibrant and full of life.  We toured more roofs throughout the semester and charted installation progress on others.  Special interest was made to watch the the ground level intensive roof being built on top of the new nano-fabrication laboratories in the Millennium Science Building.               

As a class we spent considerable time evaluating the two major green roof systems on the market in the United States today, the modular system and the built-up system.  We constructed two experimental boxes for each system and fill with an FLL approved media.  The boxes were hung and fitted with lysimeters.  Naturally we determined evapotranspiration rates as well as time to peak flow rates at varying degrees of inclination.

Several weeks of the semester were also dedicated to the study of rain gardens.  Anyone who has spent any time at University Park during heavy rain storms knows to wear their wellies.  The Biggler River comes first to mind.  Suffice it to say Penn State has a problem with storm water.  Decreasing amounts of green space coupled with increasing roof areas are compounding the problems on an already over-stressed infrastructure.  The difficult job of trying to alleviate the problem falls on the shoulders of Lawrence Fennessey, Penn State’s Stormwater Systems Engineer.  Dr. Fennessey took the class on an afternoon long tour of the entire campus, which is mind-blowingly huge, pointing out all of the challenges that need to be met and the ingenious solutions that have been implemented.  Porous pavements, curb cuts, infiltration gardens and bioswales are only a few examples of the techniques Dr. Fennessey and the rest of OPP have used.

When I returned to university for the Spring Semester 2011 I wasn’t one hundred percent certain what wanted to study.  I knew I wanted to do something ‘green,’ to study biological systems.  I talked with department heads of both Agricultural Engineering and Molecular Biology expressing my desire to study algae and biofuels.  They set me up with a defined academic path, which I began to pursue, but time, money and ultimately my desire to remain at university became an issue.  With green roofs I found a perfect outlet for all my aspirations.  Today I could not be happier; I am working with biological systems and also fulfilling my artistic passion for landscape design.
        

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