Green Roofs are they worth it?
GS1200 Natural History of Illinois
September 29, 2008
Dr. Linda Vick
Green Roofs, Why Bother? When we think of a roof we think of something that protects and covers the top of a building or structure. But now days, there is more possibilities for the use and function of a roof top. It is called a Green Roof. A green roof is creating a rooftop that is covered with plants, grasses or small shrubs, trees, and soil. Green roofs help save energy, retain rain water, and can add beauty to any building. There are other possibilities such as producing food on rooftops. This could be the next step in organic food production. The use of green roofs can improve urban environments by providing benefits that may last for years to come. Here in Chicago, Mayor Daley, after visiting Europe was inspired by all the green roofs. He had been investigating urban heat islands, which is the way temperatures in urban areas stay consistently higher than the surrounding rural areas. Several dozen elderly Chicago residents had died during a heat wave and Mayor Daley wanted to do something to prevent this from happening again. In collaboration with the U.S. Environmental Protection Agency and Mayor Daley, Chicago became one of five cities to begin the urban heat island pilot project. The EPA evaluated and chose Chicago because of the ozone problems and by how much the city would benefit from a reduction in heat islands, the availability of data, and how much the community and local government were willing to help the project (EPA, 2008) According to The World Green Roof association, green roofs may provide such benefits as: - Protecting local watersheds through storm water management - Reducing the urban heat island effect - Promoting biodiversity within built up areas - Improving air quality by trapping and removing particulate matter - Increasing the local agricultural capacity of built up areas - Reducing the energy requirements of a building’s environmental systems - Making urban spaces more beautiful and inviting for humans that live in them - reduction in peak load (lower energy costs) for the building with the green roof - longer roof life - considerable insulation from noise pollution Part of having a green roof is just the beauty of it. A green roof can be aesthetically pleasing; adding color and variety to an otherwise black and gray view from above. Rooftops can become gardens that provide an environment of relaxation and leisure activities. Plants provide bio-physical benefits by absorbing greenhouse gases, retaining storm water, and creating fire retardant protection. According to the EPA, “Green roofs also filter pollution from rainwater. This is achieved by the root systems ' bacteria and fungi, which utilize the natural filtering processes of bioremediation and phytoremediation [pic]. As a result, the non-point source pollutants, [pic]nitrogen and phosphorus, are broken down and detoxified. This beneficial process increases over time as rooftop plants and root systems mature, (EPA, 2008).” During the flooding that we had a few weeks ago, green roofs could have helped soak up some of the rain water by acting like a sponge, soaking up moisture as it falls. It may not have been enough, but every little bit helps. The EPA suggests that three to five inches of soil or growing medium absorbs 75% of rain events that are one-half inch or less (EPA, 2008). When rain falls a green roof captures and evaporates it, which reduces the amount of storm water runoff. This helps protect rivers and streams and prevents sewer overflowing. In areas like Chicago that is mainly concrete and asphalt rainwater has few places to soak into soil during storms, therefore flooding can occur. Green roofs would help give the rainwater a place to go. Here is a comparison from the EPA website that shows the difference in a green roof versus a traditional or common rooftop construction (EPA, 2008).
[pic]
The costs to build a green roof can be double what it costs to build a traditional roof. The benefits can be great especially in an urban area like Chicago. The best time to build a green roof is when a building is being constructed. In this case it will double the life of the roof membrane and reduce energy costs for the building owner. The other time is when a roof needs to be repaired or replaced. The cost also depends on the type of green roof you will have, the climate and choice of plants and paving you use. There are two types of green roofs: • Extensive: Lighter than intensive green roofs. Soil is 1-6 inches deep and weighs 15-50 pads per sq. foot. • Intensive: Heavier than extensive green roofs. Soil is 6-24 inches deep and can weigh 80-150 pads per sq. foot. It depends on the structure of the building, how much weight it can hold, how the existing roof membrane is, and whether the roof has adequate accessibility for maintenance and care (Great Lakes Water Institute, 2008). Green roofs have to have an irrigation system. There is either a drip system which is permanently installed or a sprinkler and drainage system. Green roofs also need maintenance, but an extensive roof only needs maintenance the first 6-12 months as the plants are being established then only seasonally as necessary. Other costs include the growing medium, plants, and fertilizers. Green roof planting requires considerations such as what the space is being used for, budget, maintenance costs, how long the green roof will last, location, exposure, humidity, dryness, climate, what type of medium will be used, and irrigation system. Green roof plants need to be tough and less nutrient-reliant compared to those found in ground gardens. It can take many months to construct a green roof because of the complex layers that have to be installed. These layers copy the conditions found in nature. As seen in the picture above, the layers have to be placed on top of each other starting with the insulation layer, moisture barrier to protect the building from leaks, next a drainage layer that would be made of gravel, clay or plastic. The drainage layer is what keeps the soil aerated and helps retain moisture. The top layer is the growing media and plants. Depending on the size of the plants used, plants may be planted in pots to establish size and health then planted in the media. (Snodgrass, E. & Snodgrass, L., 2006 pg. 43). The US Environmental Agency gives some examples of green roofs in the United States: • The Gap Headquarters in San Bruno, CA installed a 69,000 square foot extensive green roof in 1997. • Ford Motor Company has installed green roofs on its corporate headquarters. • The Church of Jesus Christ of Latter-Day Saints Conference Center in Salt Lake City, Utah installed a 348,480 square foot extensive and intensive green roof in 2000. • Contractors recently completed a 30,000 square foot extensive green roof project on the Montgomery Park Business Center in Baltimore, Maryland. • Ducks Unlimited, a nonprofit organization dedicated to the conservation of waterfowl, included two green roofs totaling 28,190 square feet on its national headquarters. • Private and public interests in the City of Chicago and the City of Portland have installed or are planning to install over 43 and 42 green roof projects, respectively. The urban heat island pilot project helped bring about the green roof over City Hall. The green roof was designed to test its cooling effects. Results show that the roof surface temperature has been 7 degrees cooler on average than surrounding rooftops. Summer temperature has been shown to have dropped 30 degrees cooler than surrounding building. Chicago offered 20 residents and small business owners the City of Chicago Green Roof Grant, of $5000 towards a green roof project. The True Nature Foods company took advantage of this project and converted a former automotive shop into a “Victory Garden”. They have taken it a step further and have made it a vegetated roof. The roof will serve an additional purpose of supplimenting their current local farms and vendors with their own vegetables and herbs grown overhead (Pilotin, ¶3). Chicago is one of the leading “green” cities in America and is paving the way by example. Besides City Hall, Chicago now has green roofs on Chicago Center for Green Technology, Millennium Park and the Peggy Notebaert Nature Museum, not to mention some 200 residents. Green roofs have many benefits but for Chicago the most important ones are the reduction of higher temperatures in the city, called urban heat islands, noise reduction, energy savings from reducing heat loss in the buildings, and reduction of air pollution.
References
U.S. Environmental Protection Agency, (2008, April 8). Urban Heat Island Pilot Program. Retrieved September 28, 2008. http://www.epa.gov/hiri/pilot/index.html
University of Wisconsin (2008) Great Lakes Water Institute Green Roof Project. Retrieved September 27, 2008. http://www.glwi.uwm.edu/research/genomics/ecoli/greenroof/index.php
Snodgrass, E.C. & Snodgrass, L.L., (2006) Green Roof Plants: a resource and planting guide. New York: Timber Press, Inc.
Pilotin, E. (2006, Aug 1). Inhabitat: Chicago green roof project. Retrieved September 27, 2008. http://www.inhabitat.com/2006/08/01/chicago- green-roof-program/
FOR BROC:
http://www.timeforkids.com/TFK/election08/issue-environment.html[pic][pic][pic]
References: U.S. Environmental Protection Agency, (2008, April 8). Urban Heat Island Pilot Program http://www.epa.gov/hiri/pilot/index.html University of Wisconsin (2008) Great Lakes Water Institute Green Roof Project. Retrieved September 27, 2008. Pilotin, E. (2006, Aug 1). Inhabitat: Chicago green roof project. Retrieved September 27, 2008
You May Also Find These Documents Helpful
-
‘The radical environmentalists don’t care about anyone but themselves.’ The writer attacks the environmentalist on their selfishness and careless behaviour towards the residents of Greenville. Sure they are concerned about the environment, but they should also focus on the rights of the Greenville residents, Furthermore, Greenville is only responsible for a tiny fraction of household commissions, so how can one suburb’s actions affect the world’s overall carbon output? This evidence is backed up by an expert on this topic, Australian Greenhouse Office (AGO), as they clarify that hot water systems are only responsible for about 30% of household commissions, proving that one small suburb would have little to no impact on the environment in the future. From expert studies it is…
- 576 Words
- 3 Pages
Good Essays -
A Matterhorn Metal Roof- is also environmentally friendly! The metal roof is 100% recyclable, works to reduce the possibility of landfill waste, & comes recommended for rainwater harvesting!…
- 194 Words
- 1 Page
Satisfactory Essays -
Duneier, M., 'Etnography, the Ecological Fallacy, and the 1995 Chicago Heat Wave ', Princeton University and CUNY Graduate Center, 2006.…
- 1745 Words
- 7 Pages
Better Essays -
The author, Eric Klinenburg, uses multiple aspects such as meteorological, sociological, political, ethnographic, political, and journalistic aspects to explain the Heat Wave of 1995 in Chicago. My preliminary diagnoses of the cause of the high death rate would be that the heat wave worsened the health of Chicagoans who were already diagnosed with serious health conditions. The author poses a question that the heat wave may have affected the individuals who were already stricken with a disease. These individuals include African Americans and the elderly. Poverty levels could also be a reason as to why the death rates were so high because people living within poverty would have poor living conditions and unclean areas which could harbor pathogens…
- 276 Words
- 2 Pages
Good Essays -
In Livia Dugo resilience reflection essay she shows how green rooftops are known to reduce energy heating and cooling costs. She furthermore explains how this conceptions creat jobs such as suppliers and manufactures or roofing membranes and root repellent layers, Suppliers and manufactures of substrate, light weight soils and…
- 649 Words
- 3 Pages
Good Essays -
With alcohol advertisements filled with half naked women selling sex, their target market is limited to testosterone driven men looking for a good time. With this limited market beer companies are stained with a lackluster name. With men being the target for most advertising, appealing to women is a challenge, one that most beer companies tried to answer with light beers. Along with not appealing to women, most light beers have been given the reputation of being cheap and lacking quality. Budweiser came up with a beer that not only tackles the weight issue, but was given a superior standing among light beers. Budweiser opened many doors to different markets with the creation of Budweiser Select, a low calorie premium beer, along with creating a new lifestyle to beer drinkers.…
- 1715 Words
- 7 Pages
Powerful Essays -
Klinenberg, Eric. Heat Wave: A Social Autopsy of Disaster in Chicago. Chicago: The University of Chicago Press, 2002.…
- 1727 Words
- 7 Pages
Powerful Essays -
In this article, Buffam discusses the potential risks that green roof runoff can have on downstream ecosystems. Though beneficial in some areas, storm water runoff from these roofs have been found to seep harmful chemicals that can contaminate water quality. Sources of phosphorous, carbon, copper and iron have all been identified as a part of the hazardous runoff. It has been anticipated that these green roof ecosystems have fluctuating runoff concentrations depending on plant production, microscopic organismal activity within, and other temperature or light processes due to seasonal weather. By discovering the varying patterns of this fluctuating water quality from these predicted issues, green roof design and production can be improved and better understood. This would reduce the risk of runoff contamination and increase knowledge of how green roofs adapt to different climate changes. This study looks to first discover any possibility of noticeable seasonal variation in the amount of dissolved chemicals in green roofs along with any other events or measurable qualities that correlate and possibly explain these variations. It also looks into which factor is…
- 665 Words
- 3 Pages
Good Essays -
The first article “Grass roots green roof”¹ explains how a nature lover and her volunteer community install and maintain a low-cost green roof system on the roof of a 36-year-old residential building to implement storm water management. In the beginning, community disagreements, safety concerns, and structural issues prevent the progress of the green roof project, but based on the correct engineering assessments about the load capacity of, and other details about, the building, the green roof is perceived to be a better idea than the existing flat roof, and the project moves ahead. In the end, the builders of this low-cost green roof are happy about the progress, and hope that every community installs these low-cost green roofs on their residential buildings. This effort is a good example of a successful low-cost green development by a community group, which over time can make an important impact on the local…
- 505 Words
- 3 Pages
Good Essays -
The video, “Greening the Ghetto”, which featured speaker Majora Carter an example of the theoretical perspective known as conflict theory. She discusses how and why she has directed her time and energy toward sustainability power in rural areas, beginning with where she was born and grew up.…
- 497 Words
- 2 Pages
Good Essays -
(-- removed HTML --) Asphalt Pavement Can Help Reduce Urban Heat Islands (-- removed HTML…
- 616 Words
- 3 Pages
Good Essays -
Early asphalt roofing systems were applied in strips with a felt backing and granulated rocks implanted within the material. A few decades ago, fiberglass choices were manufactured to improve fire resistance and improve safety. Currently, asphalt shingles have utilitarian benefits as they have built in granules in different colors than can help improve the lifespan of the roof by protecting the shingles from the growth of algae. We now see granules in the shingles that actually reflect the sunlight and lower energy costs as well. You can also pick from a huge array of colors, textures and sizes that were not available even ten years ago.…
- 413 Words
- 2 Pages
Good Essays -
My original research was on the Tucson Garbage Project, which was a study done in 1973 by Dr.…
- 625 Words
- 3 Pages
Good Essays -
It then simulated what these conditions exactly are and later came to realize that they are most likely have a direct relation with rising outdoor temperature which are due to climate change effects. The study used Energyplus and Radiance to examine the effects using morphed probabilistic data from National Oceanic and Atmospheric Administration, (NOAA). There has been a positive response to these studies that involve reducing carbon emissions in order to mitigate climate change. This had been done through the design and construction of more energy-efficient buildings. However, there have been concerns that buildings like these can potentially overheat due to the increasing levels of thermal insulation and the airtightness of the design reducing the potential to reject heat gains from. As a result, it is important to look at the potential of these energy efficient building to become hotter and the effects of these instances on ones health. As stated earlier, air conditioning will be ones first line of defence in order to maintain the indoor temperature to that of ones thermal comfort level and as a result, preserve the indoor health and well-being of the population. Although one may think that building energy-efficient structures will reduce carbon emissions, the airtight spaces that are a direct outcome of these design will most likely…
- 1584 Words
- 7 Pages
Better Essays -
For my project my classmate, Marie, and I worked together to beautify a part of the school. We chose to focus on the small nook near the English trailers and the art room. Here we found bushes being choked by vines and weeds, no budding flowers, dead branches, trash, and lots of nasty mulch. We knew we had a lot of work ahead of ourselves and not a lot of time (well, for me anyways!).…
- 614 Words
- 2 Pages
Satisfactory Essays