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An Interview with Wolfgang Ansel


Ecoroof Portland is next week! Make sure to check out the participants, program, and the coverage of presentations and tours throughout the month. Please spread the word!





An Interview with Wolfgang Ansel

We are very excited to welcome green roof expert Wolfgang Ansel to Portland this week. Mr. Ansel will be the first of two keynote speakers at Ecoroof Portland on Friday, March 18th. As the Director of the International Green Roof Association, Mr. Ansel brings a great deal of expertise and knowledge of green roof policies and programs from throughout the world.

His presentation, titled "A comparison of Green Roof Policies in Europe, Asia and the US: Requirements for the Successful Development of a Green Roof Market" will begin at 1pm on Friday, March 18th at Ecoroof Portland Exhibit Hall B Classrooms. In advance of Mr. Ansel's visit, we asked him to answer a few questions, and the interview is posted below.



Portland Ecoroofs (PR): What are the long and short-term benefits of green roofs for building owners? Why are they a better option than a conventional roof?

Wolfgang Ansel (WA): Green roofs offer a wide range of positive effects for buildings, inhabitants, and the environment. As a natural “coat”, landscaped roofs can lead to marked improvements in a building’s energy balance. House owners choosing to incorporate green roof systems will have lower energy bills due to the thermally insulation effect. During the summer months, residents will also profit from the cooling effects of the green rooftop. In addition, the vegetation layer protects the waterproofing from harsh weather conditions and other environmental effects.


Apart from the economic benefits we have ecological advantages, which no conventional roof can deliver. Green roofs act as “stepping stone biotopes” and give plants and animals a replacement for their natural habitat. Landscaped rooftops also make a key contribution to flood protection. Depending on the type of construction, between 50 and 90% of the precipitation that falls on these rooftops is retained and returned directly to the water cycle via the process of evaporation. This leads to reduced stress on the sewer system during the year and at peak flow periods. The process of water storage and transpiration also helps to reduce the “urban heat island effect”. At the same time dust and toxic particles are filtered out, leading to massive improvements in the air quality. And last but not least the view over landscaped roofs and parks on underground garages increases the quality of life.

PR: Why do we need international standards for green roof building best practices? How would they positively impact construction of green roofs that are appropriate for their local environments?

WA: In Germany, the FLL Guideline for the Planning, Execution and Upkeep of Green Roof Sites was published already in 1990, and they are constantly revised –most recently in 2008- to keep up with technical progress. Most European countries as well as the USA and Singapore are following the German guidelines, although a 1:1 transfer is not possible. The regional conditions, like climatic factors, building tradition, local flora, as well as legal and planning aspects must always be taken into consideration. An internationally acknowledged standard like the FLL Guideline is very important as a reference for countries where the green roof market is just beginning. For example, it could point to best practices in green roof technology like multilayer green roof systems. But it can not compensate for the creation of national standards.

PR: What could mainstream adoption of green roofs do for American cities and communities?

WA: The answer is quite easy: It would increase the quality of the urban environment, it would help to counteract the urban heat island effect and stormwater management problems, it would reduce the prices for green roof systems and it would create a lot of new jobs in the environmental sector (e.g. for local landscape contractors). And apart from that it would show future generations that we listen to the signs of time.


PR: Are there any US cities that are good bets for adoption of policy requiring green roofs, and is this kind of government support for the movement necessary to bring it into the mainstream?

WA: Well, without any exaggeration, Portland is really doing an amazing job. I´m very impressed by the combination of regulations, incentives and public relation work. I know about initiatives in Seattle, New York, Boston, Chicago, Washington D.C. Philadelphia and Minneapolis but I think the approach in Portland is the most comprehensive one. The answer to the second question is YES. As long as investment in environmental goods like clean air, water, biodiversity and urban climate is considered inadequate by the investors, the public authorities must take on the responsibility to guarantee a healthy environment. In some way green roofs work like catalytic converters. They are improving the urban environment. And the success story of catalytic converters also started with regulations and tax incentives by the government.

PR: What are the biggest barriers to mainstream adoption of green roofs? What is being done to circumvent these challenges?

WA: Very often people are not aware of the advantages of green roofs. And sometimes they have cut-and-dry opinions about the costs of a green roof and the reliability of green roof technology. Public relation work is very important to overcome these prejudices. But it is very important to provide home owners, investors, architects and developers with adjusted information.

PA: What are some of the most innovative approaches or projects you’ve seen involving green roofs? What have they revealed about the benefits of this concept?

WA: At present we can see a lot of innovative approaches at the interface with other green technologies. Green roofs can be combined with photovoltaics and increase their efficiency. Other concepts use green roofs as module within sustainable stormwater management. If we look at the High Line Project in New York even an elevated park can be created with modern green roof technology. The green roof approach is very flexible and can be modified according to the changing environmental conditions and the special requirements of a project. Nature is the key to solve a large number of problems that accompany our modern way of living.

PR: What would you tell someone considering a green roof, but who is concerned about the upfront cost?

WA: First I need to find out, which of the various green roof advantages is most important for them. Are they more interested in the ecological benefits or are the economic benefits decisive? As soon as I know the “selling point” it is much easier to talk with them about the upfront cost. 




If you're interested in learning how green roofs have helped cities in Europe and the US become more sustainable, and how cities have developed policies to help the green roof industry flourish, you'll want to make sure to attend the presentation!

Ecoroof Portland

Keynote Addresses: Wolfgang Ansel and Paul Kephart (preview next week) 

1pm - March 18th, 2011

Oregon Convention Center - Exhibit Hall B

Hope you can attend!


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