Green Roof at the University of California, Davis - Teaching Green

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Green Roof at the University of California, Davis - Teaching Green

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Green Roof at the University of California, Davis - Teaching Green

  1. 1. Teaching Green
  2. 2. Teaching Green Environmental, Economical, and Educational Benefits:Proposal for a Green Roof at the University of California, Davis University of California, Davis Department of Environmental Sciences Landscape Architecture Program Senior Project: June 2007 Yanet Martinez
  3. 3. Teaching Green Environmental, Economical, and Educational Benefits:Proposal for a Green Roof at the University of California, Davis Acceptance and Approval by: A Senior Project presented to the faculty of the program of Landscape Architecture at the University of California, Davis Professor Mark Francis, Senior Project Advisor in partial fulfillment of the requirements for the degree of Bachelors of Science of Landscape Architecture. Assistant Professor Stephen Wheeler, Committee Member Presented by Yanet Martinez Adjunct Assistant Professor Jeff Loux, Committee Member at University of California, Davis on Steve McNeil, Committee Member the Fiftheenth day of June, 2007
  4. 4. The overall purpose of this paper is to provide the students, faculty, and administration at the University of California, Da- vis with a general understanding of green roofs, as well as the potential benefits that a green roof would have on the campus. As new information arises and people become more conscious of global environmental issues, the need to design with envi- ronmentally friendly techniques has increased along with the de- mand for knowledgeable individuals capable of executing them. To fulfill this demand, it is crucial to educate individuals proper- ly on these issues and their potential solutions. Although green roofs alone are not enough to solve all environmental issues, re- cent research and improved technology have demonstrated the importance and positive impact that they have, especially in ur-Abstract banized regions where solutions for reducing pollution and heat islands, as well as expanding the use of vegetation are of prior- ity. Implementing a green roof at the University of California, Davis, would provide not only the environmental benefits that green roofs typically provide, but also a site for students and faculty to learn and conduct research. Through the information obtained from text and highly valuable web sources, as well as through the overview of campuses that have already applied a similar idea and through information gathered from case studies of successful green roofs, a general understanding of this long- standing yet recently improved technology has been provided. I formulated a conceptual design for Hunt Hall, the proposed site for this project, fromthe information collected. The de- sign is based on the integration of intensive and extensive roof gardens as well as the more recently developing semi-intensive roof garden. Suggested layering techniques to satisfy the roof of Hunt Hall will be reviewed as well as a suggested plant list that would serve as most functional for this region.
  5. 5. Yanet Martinez, a 2007 Landscape Architecture graduatingBiographical Sketch senior from the University of California, Davis, was born and raised in southern California in the city of Carson, where she attended school up through high school, while also helping her parents part-time in the family business, a wholesale nursery. Prior to transferring to the University of California, Davis, Yanet, attended El Camino College in Torrance where she completed her general requirements and was a writer for “The Union,” campus newspaper, and an active officer/member for the Rotoract Club. While still in Southern California, her interest in landscape architecture grew as she became more involved in the family business and dealt with different professionals in the related field. ii
  6. 6. Since her arrival at the UC Davis campus in 2004, Yanet was Upon her return to Davis, Yanet continued her internship withintrigued by the community, diversity and environment of the the County of Sacramento Department of Regional Parks, ascampus, which led to her membership to Kappa Kappa Gamma she completed her final courses. After graduation, Yanet will bewhere she participated in philanthropic and community events. traveling to South America to see more of the world. UltimatelyIn early 2005, Yanet was admitted to the Landscape Architecture Yanet will work to build a professional career in the field ofProgram. That same year, she traveled to Japan, where she landscape architecture.participated in a study abroad program offered by the UC Davislandscape architecture program. There she traveled to Osaka,Kyoto, and Nara, among other places, as she studied the history,tradition, and techniques of Japanese gardens. Upon her return,Yanet remained an active student of the landscape architectureprogram and also participated in ASLA functions. In the summer of 2006, she began an internship with theCounty of Sacramento Department of Regional Parks, whereshe assisted in various projects. She continued to work untilshe once again departed Davis for a study abroad landscapearchitecture program led by California State PolytechnicUniversity, Pomona in Italy. During her studies in Italy shetraveled to cities like Rome, Florence, Arezzo, and Venice whereshe studied architecture, gardens, and history. iii
  7. 7. To my loving family that just never stop giving of themselves in countless ways, both direct and indirect.Dedications A mi familia quierida que nunca para de dar de ellos mismos en maneras innumerables, ambos directo e indirecto. Dad.Mom.Nin.Gordo.Johanna.Jordan. I luv u much! iv
  8. 8. I would like to express sincere thanks to the entire faculty, staff, and students of the Landscape Architecture program for teaching me all that I know and helping me to become the individual that I am. Mark Francis, for the many conversations that helped clarify my thinking upon deciding for a topic, thanks. Stephen Wheeler, Jeff Loux, Jim Harding, Steve McNeil, your collaboration to this project meant a great deal to me.Acknowledgements Celine Livengood and Guy Kolling thanks for your support. To all the “fantabulous” LDA class of 2007 who made my time at Davis as memorable as I could’ve wished, thanks! Mooney, Micah, Eddie, and Jaime…you all are wonderful friends. Thanks for all your help! To my dearest friends that helped me through my journey and kept me sane through the senior project process, Tereza and Justin, thanks, luv u!
  9. 9. Abstract ............................................................................................ii Biographical Sketch .......................................................................iv Dedications .....................................................................................iv Acknowledgements ........................................................................v List of Illustrations Photographs ..........................................vii Introduction ....................................................................................1 What is a Green Roof ? ..................................................................4 History of Green Roofs ................................................................6 Green Roof Layers ......................................................................11 Intensive Green Roofs .................................................................15 Extensive Green Roofs ................................................................18Table of Contents Semi-Intensive Green Roofs .......................................................21 Benefits of Green Roofs .............................................................24 Disadvantages of Green Roofs ..................................................31 Universities and Green Roofs ....................................................32 Case Study: Yerba Buena Gardens ............................................38 Case Study: Union Square ...........................................................43 Case Study: YMCA ......................................................................48 Hunt Hall Site Analysis ................................................................53 Designing a Green Roof .............................................................58 Hunt Hall Conceptual Design ....................................................62 Plant List ........................................................................................65 Bibliography/References .............................................................67 vi
  10. 10. 1.1. Green Roof ...............................................................................1 1.2. Installation of green roof at UC of Florida .......................2 1.3. Hunt Hall ..................................................................................3 2.1. Depiction of the Hanging Gardens of Babylonia ..............7 2.2. Roof garden at Palazzo Piccolomini ....................................8 2.3. Traditional Scandinavian green roofs in Norway ...............9 3.1. Green Roof Layers ...............................................................11 3.2. Intensive green roof. Layer section ...................................16 3.3. Rockerfeller Center ...............................................................17 3.4. Millennium Park ....................................................................17 3.5. ACROS Prefectural International Hall ..............................17 3.6. Extensive green roof. Layer section ..................................19 3.7. Ocean Houses at Post Ranch Inn ......................................20List of Figures 3.8. Heinz 57 Center ....................................................................20 3.9. Minneapolis Central Library ................................................20 3.10. Semi-instensive green roof. Layer section ......................22 3.111. The Calhoun School .........................................................23 3.12. The Culver House Residences ..........................................23 3.13. Library Square Building .....................................................23 4.1. Storm Water ...........................................................................25 4.2. Heat Island Profile ................................................................26 4.3. Green roof benefits chart ....................................................27 4.4. Vegetable roof garden at Trent University .......................28 4.5. Green roofs create ecological habitats (1) .........................28 4.6. Green roofs create ecological habitats (2) .........................28 4.7. Solaire building ......................................................................29 5.1. David Beattie and student at Penn State green roof (1) ......33 5.2. David Beattie and student at Penn State green roof (2) ......33 5.3. Ford Motor Company green roof ......................................34 5.4. U of Arkansa students on green roof (1) .........................34 vii
  11. 11. 5.5. U of Arkansa students on green roof (2) .........................34 9.3. Hunt Hall existing site photographs 2 ...............................555.6. Rooftops at UC Davis ..........................................................35 9.4. Hunt Hall proposed site .......................................................595.7. Green roofs across America ................................................376.1. Yerba Buena Gardens. Plan view. ......................................386.2. Yerba Buena Gardens ...........................................................396.3. YBG. Site Analysis Photograph 1 ......................................406.4. YBG. Site Analysis Photograph 2 ......................................406.5. YBG. Site Analysis Photograph 3 ......................................406.6. YBG. Site Analysis Photograph 4 ......................................406.7. Vegetation at YBG .................................................................416.8. YBG. Site Analysis Diagram ..............................................427.1. Union Square Park. Plan view. ...........................................437.2. US. Site Analysis Photograph 1 .........................................447.3. US. Site Analysis Photograph 2 .........................................457.4. US. Site Analysis Photograph 3 .........................................457.5. US. Site Analysis Photograph 4 .........................................457.6. Vegetation at US ....................................................................467.8. US. Site Analysis Diagram ..................................................478.1. YMCA building .....................................................................488.2. YMCA. Site Analysis Photograph 1 ..................................498.3. YMCA. Site Analysis Photograph 2 ..................................508.4. YMCA. Site Analysis Photograph 3 ..................................508.5. YMCA. Vegetation at YMCA ............................................518.6. YMCA. Site Analysis Diagram ..........................................529.1. Hunt Hall vicinity map .........................................................539.2. Hunt Hall existing site photographs 1 ...............................54 viii
  12. 12. 1.1. Green Roof.Introduction Green roofs are a practice that within the later part of this century has risen in popularity. Although it may appear that it is a concept of recent emergence, green roofs actually date back as far as B.C. (Osmundson 1999). The term green roof is defined as any man-made structure, most notably roofs, whose traditional material have been replaced with vegetation (Green Roof 2007). Their unique ability to produce a space for plants, which would normally not grow vegetation naturally, is the result of continuously developing technology which consist of roof layering. Two major types of green roofs exist: intensive and extensive. However recent
  13. 13. developments have produced a hybrid referred to as a semi- and agricultural issues, that the University of California, Davisintensive green roof. Although these green roofs can be would consider the idea for a proposal of a green roof for thebeneficial environmentally, economically, and educationally, campus. The addition of such a project to the campus wouldeach has qualities, which make them distinct from one another. assist in upholding Davis as one of the top universities andEach type of green roof mentioned will be discussed in further research facilities in the nation and may perhaps even lead todetail within the following sections. the development of other projects that share similar objectives. Development of a green roof would also demonstrate the concern of the university to address issues and educate students on the issues that are currently of major importance such as going green, environmental sustainability and global warming. Through the exploration of green roof sources an overview of the benefits said to be produced by green roofs will be covered in this paper. Of the many benefits said to be produced by1.2. Installation of a green roof at the University of Central Florida. the construction of green roofs, those that address possible solutions for air and water pollution, heat island reductions,As many universities throughout the nation, as well as abroad, additional recreational areas, ecological areas, insulation, andare already endeavoring into the integration of green roofs as a increase roof life expectancy will all be discussed. A brieflearning tool for students and faculty, it seems only appropriate overview of possible economical benefits will also be covered.that as a university that is largely dedicated to addressing, Possible disadvantages that may result from green roofs willeducating, and conducting research on environmental, ecological, also be reviewed.
  14. 14. Green roofs, sometimes referred to as roof gardens, werealso analyzed by visiting the sites in order to achieve a betterunderstanding of the components that make a successful greenroof. Case studies were conducted on the Yerba Buena Gardens,Union Square and the roof garden atop the Central YMCAlocated in San Francisco. Although there were limitations onthe information gathered about each case study, they still presentcertain elements that could be integrated into the proposedgreen roof for the university campus. 1.3. Hunt Hall. Furture location for the Landscape Architecture Program.As a result of the data obtained, enough information was By the end of this paper it is intended that the reader gain angathered to provide a suggested preliminary conceptual design overall general understanding of green roofs. They should befor Hunt Hall at the University of California, Davis. The able to define what a green roof is, understand its layers, knowconceptual design consist of the three types of of green roofs, the different types of green roofs, and list the benefits andin an effort to familiarize possible users with all three. As Hunt possible disadvantages that come with building a green roof.Hall is proposed to undergo renovation in the next couple It should be noted that the intention of this paper is to getyears and serve as the home for the Department of Landscape the reader acquainted with the concept of green roofs and toArchitecture, it seemed as the ideal location. Aside from a propose the possibility of the University of California, Davisconceptual design, a suggested plant list for each green roof implementing a green roof on campus. This paper is not totype was also formulated. The plants selected were based on serve as a primary guide for the construction of green roofs.what would might possibly be suitable for the site.
  15. 15. A green roof is the concept of growing vegetation on a man- made surface, generally the roof of a building (Green Roof 2007). Green roofs usually consist of different layers that make the growth of vegetation on these otherwise non-vegetative surfaces, possible. Generally green roofs consist of a vegetation layer, growing medium layer, filter layer, drainage layer, protection layer, and a waterproofing layer (Dunnett 2004). Green roofs can be divided into two categories known asWhat is a Green Roof ? intensive and extensive. Recently a third type of green roof known as the semi-intensive green roof has emerged. When distinguishing between green roofs, important factors to look for include, soil thickness, vegetation selection, accessibility, and weight. Intensive green roofs are typically the more elaborate of the two green roofs and share the qualities of most gardens that come to mind. Extensive green roofs on the other hand are usually inaccessible, are composed of limited vegetation, and usually designed with some of the ecological and environmental benefits in mind. The emerging semi-intensive green roof can be seen as a hybrid of the two established green roof types. This recently emerging type of green roof integrates more of the
  16. 16. qualities that are found in extensive green roofs, however theyprovide for accessibility and occasional interaction of people tothe garden (Dunnett 2004).Green roofs should be looked upon as more than just plantson a roof, as they have demonstrated environmental andeconomical benefits. They have been applied as solutions forair and water pollution, heat reductions, alternative recreationaland ecological space and more. Thus far, they have also beencredited with providing insulation to buildings, reducing energycost and increasing property values (Green Roofs for HealthyCities 2007).The benefits that green roofs are credited with seem immense,however additional research and for creating and understandingnew solutions, materials, and methods in the construction ofthis new technology is still a essential. As with anything else, thebetter we understand this technology the more beneficial it willbe to communities and the nation.
  17. 17. The concept of green roofs may seem like a moderately innovative idea, however green roofs have actually been linked back to ancient historic times. Throughout the historic evolution of green roofs the role of these gardens seem to have shifted from simply aesthetics purposes to adaptation for survival and recently onto environmental purposes. The information gathered in this section on the history of green roofs will give an overview on the use of this garden system throughout its history and throughout its role amongst different cultures. ItHistory of Green Roofs is only by studying the history of green roofs that a better understanding and appreciation of the different gardens, i.e. intensive, extensive, and semi-intensive, can be achieved. It should be noted that throughout this section the terms, roof garden, intensive, extensive, and semi-intensive may be used in place of green roof, if considered more appropriate. Throughout time, the mention of green roofs has come about in many literary documents with the first recorded reference toward the Hanging Gardens of Babylonia, which existed since before B.C.. Although no physical evidence seems to have ever been discovered of these gardens existence, the mentioning by
  18. 18. creditable individuals such as Strabo and Diodorus Siculus has Early depictions described the construction of these gardenslead to the belief of their existence. The majestic description upon “stone beams some sixteen feet long and over these wereof these gardens has even listed them as being one of the seven laid first a layer of reed set in thick tar, then two courses oforiginal World Wonders (Hanging Gardens 2007). baked clay brick bonded by cement, and finally a covering of lead to prevent the moisture in the soil penetrating the roofThe story behind the creation of these gardens is said to be the (Osmundson 1999).” Plants were then situated on top andresult of king Nebuchadrezzar II, as a way of consoling his wife irrigation was made possible through pumping of the river.Amytis in her longing for the landscape of her homeland, which As the gardens of Babylonia were described as being elaborateis described as abundant in vegetations and green hills. These and mainly for aesthetic pleasures it can be said that the firstgardens are said to have been built upon Babylonian ziggurats, historical recorded green roofs were what we refer to today aspyramid like buildings with large landings that allowed for intensive.placement of these gardens (Osmundson 1999). The preservation of the town of Pompeii in Italy, as the result of the infamous Mount Vesuvius eruption in A.D., lead to the uncovering of a roof garden atop the roof of Villa of Mysteries. Similar to the Hanging Gardens of Babylonian, the gardens uncovered in Pompeii were situated atop a building that had arched walls for ventilation. As a result of the volcanic eruption, the garden was preserved rather well so that archaeologist have been able to identify the type of vegetation that was used, by2.1. Depiction of the Hanging Gardens of Babylonia. casting molds of their roots (Osmundson 1999).
  19. 19. Pompeii wasn’t the only Italian town to have gardens growing purpose of this roof garden was entertainment purposes, thisatop its roofs; Pienza, Lucca and Careggi are towns that had garden was most definitely held intensive qualities. Similar to theroof gardens as well. In Pienza, a garden constructed atop the garden at Palazzo Piccolomini, this garden was built atop of thePalazzo Piccolomini during the 1460s, by orders of Pope Pius roof of the building, covered in a layer of soil and vegetation.II, is one of the most well preserved roof gardens to this date(Osmundson 1999). The garden is built atop a masonry building On the other side of the world in the island city of Tenochititianand composed of primarily small manicured plants, making this Mexico, during the same time roof gardens were emerging inan intensive roof garden. Europe, a completely different civilization had also developed this similar technology of creating roof gardens. As the Spanish conquerer Hernan Cortez described in a letter to Charles V, 1520, “numerous wealthy citizens who also possess fine houses… in addition to the large and spacious apartments for ordinary purposes, have others, both upper and lower, that contain conservatories of flowers (Modern History Source Book 1998).” The description in this letter led to the indication that roof garden in Tenochititian existed around 1520, before2.2. Roof garden at Palazzo Piccolomini. the invasion by the Spaniards.In Careggi, the well-known Medici Family also had a roofgarden. The garden was composed primarily of a collection In the 1600s even more roof gardens emerged throughout Europeof exotic plants that the Medici family collected and served as a and other parts of the world. Like most gardens documentedrepresentation of their wealth (Osmundson 1999). As the main up to this period, roof gardens built in this era were quite similar.
  20. 20. Today we would describe these roof gardens as intensive, as These new versions of roof gardens were usually consisted ofthey were quite elaborate and primarily designed for aesthetics a layer of soil, which served as the base for grasses and lowand entertainment. Two gardens in Russia, the Kremlin Palace growing vegetation, to grow. Because these gardens werein Moscow and the Hermitage in Saint Petersburg are examples generally planted atop smaller dwellings, they weren’t intendedof the gardens built in this era (Osmundson 1999). for larger vegetation or as being accessible hence maintaining them was less necessary (Dunnett 2004).Prior to the 1800s the notion of a roof garden was usuallyassociated with wealth, power, aesthetics and entertainment,and were what we may now refer to as intensive gardens. Inthe early 1800s however gardens atop roofs started to developin Germany that were unlike any of the gardens that had beencreated before. Whereas before gardens were created primarilyfor the aesthetic pleasures of the wealthy, in Germany a transitionshad begun that evolved these gardens into a functional buildingmaterial. Middle class people in German adopted the idea of 2.3. Traditional Scandinavian green roofs in Norway.growing vegetation on the roof of their homes as a method ofinsulation for their homes during harsh seasons. During the Middle class in the United States also seemed to have adaptedcooler seasons the vegetation and soil layer helped retain heat this method of insulations, as homes, schools, and other buildingin the building and to cool it during warmer seasons. These were being constructed with extensive roofs. Towns within thenew types of roof gardens seemed to share similar building states of Dakota and Nebraska especially demonstrated a likingapproaches as those found in the roof gardens before them. for this technique (Dunnett 2004).
  21. 21. After a project demonstrating the functions of this new roof extensive roof gardens has made it the leader on extensivetechnology was revealed at the World Exhibition of 1868 in gardens. Along with Germany, regions in Scandinavia andParis, the international launch of the extensive roof garden Kurdistan also developed this technology. Similar to the originalseemed to have taken place as people became fascinated with extensive gardens of the 1800s, the gardens of the twentieththe concept (Dunnett 2004). At the same time, however, the century were designed for the benefits that they provided to theintensive roof gardens began to emerge once again, as they buildings and their dwellers. Insulation, extended roof life, andbecame a popular entertainment asset especially for theatre and aesthetics were the purposes of the emerging extensive roofhotels. Again it seemed as if gardens where returning to the gardens (Dunnett 2004).intensive type gardens. In large developing cities such as NewYork, the luxury of open space was limited and so the idea of From the 1950s to today, a stronger emphasis has been put onconverting roofs into an open space began to sprout yet again. studying roof gardens and distinguishing between the two mainThe gardens that developed during this era were much like the types, intensive and extensive. As more research is conductedfirst roof gardens wherein they were being built for the pleasure on the subject matter, it is becoming apparent that these gardensof the wealthy (Osmundson 1999). are beneficial to societies on many levels, especially when dealing with the latter of the two types, the extensive green roof. AsDuring the twentieth century, technological advancements a result of these recent findings, a third type of roof gardenallowed for improved construction of roof gardens in general. referred to as semi-intensive, which is a mix of intensive andRoof gardens such as those at the Kensington, Rockefeller Center, extensive, has emerged.and Union Square of San Francisco, which have inspired manyof today’s roof gardens, were built during this era (Osmundson1999). In Germany, the development of technology for 10
  22. 22. I.1. Green Roof Layers.Green Roof Layers The production of a green roof is more than simply the placement of vegetation on a rooftop. Green roofs consist of multiple layers that make the establishment of such vegetation possible. Whether its an intensive, extensive, or semi-intensive green roof, all green roof types usually consist of six main layers. These layers are commonly identified as the vegetation, growing medium, filter, drainage, protection and waterproofing layers (Living Green Roofs). Although layers vary according to the type of green roof, the overall objectives of these layers is the same in for all green roof types. For the purpose of this project, a general overview of green roof layers will be provided. An overview explaining the purpose of each layer and how each 11
  23. 23. functions will be given. Specific information for each green it is important to study the type of plants which are appropriateroof type are within Intensive Green Roofs, Extensive Green for a particular type of green roof. Extensive green roofs, forRoofs, and Semi-Intensive Green Roofs sections. example are designed to support the lightest weight possible, which limits the plant selections to mainly ground covers,1. The Vegetation Layer particularly sedum, which are not only light, but whose rootsThe vegetation layer, is the part of a green roof individuals are don’t require much depth in the growing medium layer. Intensivemost familiar with as it is the layer that adds the “green” to the green roofs on the other hand, are design to accommodate largerroof. Depending on the type of green roof and the climatic plants, providing a larger plant selection for this type of greenregion where a green roof project is located, the material used roof (Dunnett 2004). In the end, when selecting plant materialwithin this layer is bound to vary highly, in comparison to for ay green roof, “it is necessary to choose plants suitable forthe other layers. The main objective in creating a successful each climate, whether the conditions are periodically very dry,vegetation layer for any green roof type, is to use plant material very hot, very cold, or very variable (Living Green Roofs).”which is typically drought tolerant, able to withstand hightemperatures and wind (Dunnett 2004). Selecting plants with 2. The Growing Medium Layerthese characteristics will help ensure their longevity and the The growing medium or substrate layer is located directedsuccess of the green roof. Also when selecting plants size and beneath the vegetation layer and above the filter layer. Unlikeroot depth of the plants need to be considered especially when most gardens, green roofs can not be planted with the typicaldesigning an extensive green roof (GR-Cooling L.A. 2006). For “garden soil or topsoil... because it is too heavy and too fertilethese reasons some of the most commonly used vegetation in (Dunnett 2004).” When selecting a growing medium for a greengreen roofs include succulents and ground covers. Each green roof it is important to consider weight, especially with extensiveroof type is designed to support particular type of vegetation, green roofs. Instensive green roof may usually use typical garden 12
  24. 24. soils, but using a growing medium specialized for green roofs 4. The Drainage Layeris ideal. A major concern when selecting a growing medium The drainage layer located below the filter and above thehas to do with safety as “soil containing a lot of peat or other protection layer, is one of the most important layer in theorganic substances is liable to shrinking, and can be a fire hazard construction of a green roof. The drainage layer is essential(Living Green Roofs).” Companies specializing in green roof in determining where water directer toward after it has reachedmaterial often carry specialty growing mediums or substrates. the green roof. “If drainage is inadequate on a flat greenThese growing mediums are usually lightweight and contain roof, then damage to the roof membrane may ensue (Dunnettnatural minerals, however artificial soils are also available which 2004).” Other issues that may result from a faulty drainageusually include “vermiculite and perlite (Dunnett 2004).” “A system include puddles, erosion of growth medium, rotting ofgood roof soil is therefore mainly a mineral soil, not containing plants, and unwanted plants (Living Green Roofs). In orderclay, which is too impervious. To make the soil lighter, crushed to achieve a green roof which will be beneficial especially inbrick or lava can be mixed in (Living Green Roofs).” treating storm water it is necessary to install a drainage system, appropriate for the specific roof type. The drainage layer should3. The Filter Layer provide the function to store some water which is available toThe filter layer is located between the growing medium and the vegetation layer (Dunnett 2004). The material typically usedthe drainage layer. Typically a fabric material is used and is in the drainage layer, is available from all nature to manufactured.neccessary “to stop the substrate from disturbing the drainage Materials commonly include gravel or crushed rock, crushedfunction.” Use of this layer prevents the blockage to the lava, crush leca or crushed bricks, rockwool, foam material, anddrainage layer, which may be caused by possible debris from plastic sheets (Living Green Roofs).the growing medium and also serves as “an erosion control thatholds the substrate in place (Living Green Roofs).” 13
  25. 25. 5. The Protection Layer “Unless the roof memebrane is damaged while laying the greenLocated under the drainage layer, most green roofs typically roof, the soil and vegetation cover will protect the membraneinclude a protection layer. The main purpose of the protection from these types of injuries later (Living Green Roofs).” Threelayer is to create a barrier between the roots of the plants and types of materials which are typically used for this layer includethe waterproofing layer. This layer essential prevent damage the built-up roof, the single-ply membrane, and the fluid-appliedto the roof structure which may result from root penetration. membrane (Osmundson 1999). Each type consist of the“Root protection membranes are usually composed of rolls of following: built-up roofs consist of “bitumen/asphalt roofingPVC and laid out over the weatherproofed roof deck or suface felt or bitumized fabrics,” single-ply membranes are “sheets of(Dunnett 2004).” Other root repellant alternatives also include inorganic plastic or synthetic rubber material” sealed heat orchemicals, copper sheets, and rubber seals (Living Green Roofs). adhesive, and fluid-applied membranes are liquid “sprayed orIn some cases, especially with extensive green roofs, this layer is painted on the surface of the roof and forms a complete sealleft out as it is believed that the roots of ground covers, such as (Dunnett 2004).”sedum, will not damage the roof. However each potential greenroof project should consider installation of the protection layerunless otherwise specified by a professional.6. The Waterproofing LayerThe waterproofing layer, essentially the first layer to be appliedto any green roof, is important in sealing the building fromwater. This layer is important in order to keep the building fromany damage which may result as a excessive water or moist soil. 14
  26. 26. Defined The idea most people get when they think of a green roof is what is referred to as an intensive green roof. Intensive green roofs can be considered of higher popularity because they are generally aesthetically appealing, have garden-like features and are accessibility. As Snodgrass describes, intensive green roofs are the combination of “deeper, more organic substrates and rely on irrigation system to recreate full-scale gardens above ground (Snodgrass 2006).” Because intensive green roofs are a moreIntensive Green Roofs elaborate garden, they sometimes require more components or more of each component, than either an extensive or semi- intensive green roof would require. Due to the large-scale intensity of this green roof, the structure of the building should be able to support additional weight “typically from 80 to 150 lb/sq ft,” to be able to support the various layers, additional soil which may exceed 12 inches, and the vegetation of moderate size, not to mention the weight added by the activity of individuals that access the site (GR-Cooling L.A. 2006). Intensive green roofs are often also referred to as roof gardens. Intensive green roofs are typically the more elaborate of the two green roofs and share the qualities of most gardens that come to mind. 15
  27. 27. Advantages and Disadvantages exceed over 1 foot in depth, will help determine that a greenThe following is a list of the positive and negative factors that roof is indeed intensive (Dunnett). Plant material used is usuallymay result from an intensive green roof. enough, however to identify the type of green roof. Instensive green roofs are the only capable of supporting trees and largePros Cons shrubs in it vegetation layer, and contains the largest plantAccessibility High maintenanceGood use of otherwise non Heavy weight load selection of all three types, and as a result bear more weight.used space The figure below shows two sections illustrating the layers of anAllows for recreational uses High cost/Expensiveand multi-purpose activities intensive green roof. Intensive green roofs may also require anWider vegetative selection May require additional structural support additional irrigation layer, not shown in the figure below.Provides the best insulation Usually requires profes- sional installation Intensive Green Roof LayersAesthetically appealing Requires irrigation 1. WaterproofingComponents LayerGreen roofs of all types usually consist of similar layers. The 2. Protection Layerdifference for each usually seen in the thickness of each layer, 3. Drainage Layerplant selection, and weight. Because intensive green roofs are 4. Filter Layermore elaborate and require more support its layers are thicker 5. Growing Mediumthan extensive are semi-intensive. According to the specific Layerproject, the layer thickness will vary. Often the thickness of 6. Vegetation Layerthe growing medium layer, which is minimally 6 inches and can 3.2. Intensive green roof. Example of two layer types. 16
  28. 28. ExamplesThe following are examples of Intensive Green Roofs: 1. Rockefeller Center, New York, New York (3.3.) 3. ACROS Prefectural Int’l Hall, Fukuoka, Japan (3.5.) 2. Millennium Park, Chicago, Illinois (3.4.) 4. Fairmont Hotel and Tower, San Francisco, California 5. The Hilton Palacio de Rio, San Antonio, Texas 6. Equitable Plaza, Pittsburgh, Pennsylvania 7. Pershing Square, Los Angeles, California 8. Union Square, San Francisco, California 9. University Green, Cambridge, Massachusetts 10. Theodore Hall, Davis, California 17
  29. 29. Defined Unlike intensive green roofs, extensive green roofs have qualities that make the better choice for achieving greater ecological and environmental benefits (Dunnett 2004). Originally, the function of these gardens was to provide insulation for primarily residential homes in regions such as Germany, Ireland, and the Scandinavian countries. As the Scandinavian Green Roof Institute defines, extensive green roofs consist of “very thin layers, drought tolerant plants and require littlerExtensive Green Roofs or no maintenance (Living Green Roofs).” Because the main functions of extensive green roofs are typically for insulating and ecological reasons, the accessibility of this type of green roof is limited to maintenance, which usually requires only seasonal or yearly access. For the same reason, extensive green roofs are not necessarily designed to be aesthetically pleasing, as intensive green roofs are, but the replacement of typical roof surfacing with live vegetation usually still provide improved scenery. Extensive green roofs may commonly also be referred as turf green roofs, or eco-roofs. 18
  30. 30. Advantages and Disadvantages layer is limited to mostly low growing grasses and groudcovers,The following is a list of the positives and negatives factors that such as sedum. Extensive green roofs are not designed tomay result from an extensive green roof. support shrubs or larger plants. Finally the combined system of an extensive green roof typically has a “saturated weight of Pros Cons 15-30 lbs/sq ft (Green Roof Types 2005).” Light weight Limited plant selection Low maintenance Inaccessible Yields high percentage of Less aesthetically pleasing Extensive Green Roof Layers ecological benefits Less expensive 1. Waterproofing Layer Can be placed on smaller 2. Protection Layer structures 3. Drainage Layer 4. Filter LayerComponents 5. Growing Medium LayerExtensive green roofs are composed of the similar layers as the 6. Vegetation Layerother two green roofs mentioned. Because extensive green roofsare the least complex, its has the thinnest layers and in somecases some layers, such as the protection layer, are not used atall. The plant material used in the vegetation layer, as well as theroof itself, will usually help determine if it is possible to leave outlayers. The growing medium layer in an extensive green roof hasa minimum of 3 inches and maximum of 6 inches. As a result ofthe growing medium layer, the plant selection for the vegetation 3.6. Extensive green roof. Exampe of two layer types. 19
  31. 31. ExamplesThe following are examples of Extensive Green Roofs: 1. Ocean Houses at Post Ranch Inn, Big Sur, California (3.7.) 3. Minneapolis Central Library, Minneapolis, Minnesota (3.9.) 2. Heinz 57 Center, Pittsburgh, Pennsylvania (3.8.) 4. Premier Automotive North American Headquarters, Irvine, California 5. California Academy of Sciences, San Francisco, California 6. School of the Future, New York, New York 7. Cornell University Dept. of Horticulture, Ithaca, NY 8. Carnegie Mellon University, Hamerschlag Hall, Pittsburgh, Pennsylvania 9. Life Expression Wellness Center, Sugar Loaf, Pennsylvania 10. Mashantucket Pequot Museum, Mashantucket, Connecticut 20
  32. 32. Defined The most recent type of green roof to emerge, is known as a semi-intensive green roof. A semi-intensive green roof can be described as having characteristics of both intensive and extensive green roofs. As with extensive and intensive green roofs, the main factor in distinguishing a semi-intensive green roof usually has to do with vegetation type, soil thickness and weight. Semi-intensive green roofs are determined to be “usually 6-12 inches deep with a saturated weight of 30-50 lb/Semi-Intensive Green Roofs sq ft (Green Roof Types 2005).” For this type of green roof, vegetation that can be used rangings from ground covers to herbs, shrubs and grasses. Since the vegetation for this type of green roof is larger than that found in extensive green roofs, maintenance is required on a regular basis, even though it’s not as intense as intensive green roofs. Semi-intensive green roofs are designed for occasional or low impact use (Green Roof Types 2005). Advantages and Disadvantages Since the semi-intensive green roof can be seen as somewhat of a hybrid of extensive and intensive green roofs, most of its 21
  33. 33. qualities are moderate. When studying all three green roof types roof system has a “saturated weight of 30-50 lb/square feet.together, factors such as cost, maintenance, weight, all appear (Green Roof Types 2005).” Because semi-intensive green roofsto be moderate for semi-intensive green roofs. Advantages combine the benefits of extensive and intensive green roofs,and disadvantages for this green roof can be made only when they are becoming more appealing.compared one-on-one with another type. The following is a listof some of the more obvious positives and negatives that may Semi-Intensive Green Roof Layersresult from semi-intensive green roofs: 1. Waterproofing Layer 2. Protection Layer Pros Cons 3. Drainage Layer Accessible Partly limited plant selection Aesthetically pleasing May require irrigation 4. Filter Layer Provides moderate recre- Require regular mainte- 5. Growing Medium Layer ational space nance 6. Vegetation LayerComponentsSince semi-intensive green roofs share qualities of both extensiveand intensive green roofs the components are a mean of the twogreen roofs. As mentioned earlier, the vegetative layer for thesemi-intensive green roofs consist of primarily “grass, herbs,and shrubs,” which require little to moderate maintenance (Int’lGreen Roof Association 2007). The growing medium layer istypically 6 inches to 12 inches in depth. The semi-intensive 3.10. Semi-instensive green roof. Example of two layer types. 22
  34. 34. green ExamplesThe following are examples of Semi-Intensive Green Roofs: 1. The Calhoun School, New York, New York (3.11.) 3. Library Square Building, Vancouver, British Colombia (3.13.) 2. Culver House Residences, Chicago, Illinois (3.12.) 4. Bell Museum of Natural History, Minneapolis, Minnesota 5. Bamboo Holding Shed, Asia Trail - Smithsonian National Zoo, Washington, DC 6. University of Michigan Cyclotron Building Addition, Ann Arbor, Michigan 7. Earth Pledge Foundation, New York City, New York 8. Museum Place Lofts, Portland, Oregon 9. HSBC Bank Green Roof, Mexico City, Mexico 10. Inter Continental Resort, Berchtesgaden, Germany 23
  35. 35. Through the recent research that has been dedicated to green roofs, it has been demonstrated that the application of this technology has resulted in a range of benefits. “Green roof technologies not only provide the owners of buildings with a proven return on investment, but also represent opportunities for significant social, economic and environmental benefits, particularly in cities (Green Roofs for Healthy Cities 2007).” Socially, they have been credited with providing recreational and open space for communities, as well as making them moreBenefits of Green Roofs aesthetically appealing and even a widely recognized attraction (Noyes 2006). Economically they reduce cost by improving building insulation, extending the longevity of roofs, and increasing property value. Environmentally, green roofs are said to improve air and water quality, and reduce heat islands (Dunnett 2004). The information in this section provides a general understanding of some of the major benefits that green roofs have been credited with. 24
  36. 36. Storm Water PollutionWithin recent years, the importance of addressing waterquality issues has become the priority of many city and stategovernments. As cities become more and more urbanized andman made structures and surfaces out number square footageof natural vegetative areas, the problem of storm water run offand pollution will increase. Because these man made surfacesare not permeable, rainwater is unable to penetrate into soil ornatural substances, which would otherwise filter out pollutants.In fact, materials such as concrete and asphalt that are usedin large on roads, parking lots, and buildings, collect manycontaminates that collect in a city like “oil and other synthetichydrocarbons, heavy metals, road salt, pesticides, and animalwaste,” which hence pollutes the storm water (Dunnett 2004). 4.1. Storm water from residential and urban areas collect pollutants that eventually make their way into natural bodies of water.Green roofs would not only be beneficial in reducing the to around 5 percent for a forested area.” This extra surfaceamount of pollutants that storm water collects, but also in the runoff is water that eventually finds its way to natural bodiesprevention of storm water flow in sewage systems and natural of water and sewage systems. Natural bodies of waters such asbodies of water, in erosion, and in lowing temperatures by rivers and lakes are effected “not only by the quality of runoffretention of water. As Dunnett states, “75 percent of rainfall but also by its quantity, as a high volume of flow contributes toon towns and cities is lost directly as surface runoff compared erosion and sedimentation, and impacts aquatic habitats (Storm 25
  37. 37. Water Pollution Prevention 2006).” In a similar way, sewage is made up of this material. “In the United States, buildingssystems and water treatment facilities become overloaded when consume six times as much energy and produce six times asdealing with large amounts of surface runoff. much greenhouse gas emissions as all cars and trucks combined (Hall 2006).” Green roofs work as a solution in reducing thisBy installing green roofs on building especially in large urban problem as they convert some of the surface causing thiscities, storm water pollution would be reduced, as water problem into green vegetative spaces.absorption would take place from the vegetative and soil layers.The soil would hold and release water as needed, while plantprocessed the water through the transpiration process (Dunnett2004). This not only decreases the percentage of surface runoffbut also helps cool the area down.Reduced Heat Island EffectAs cities grow, vegetative spaces are being replaced by man-made surfaces, resulting in a regional heat increase. As defined 4.2. Profile of urban heat temperatures.by the Environmental Protection Agency, “’heat island’ refersto urban temperatures that are higher than nearby rural areas Vegetation important in achieving cooler temperatures. “If all(Chang 2000).” Heat islands result from surfaces such as asphalt, the roofs in a major city were ‘greened,’ urban temperaturesconcrete, and roof materials that absorb the heat radiated could be reduced by as much as 12 degrees (Noyes 2006).” Thisfrom the sun, which causes this temperature increase. This is is because vegetation naturally cool regions and also providesa problem in larger urbanized cities as much of their surface shade and evapotranspiration. This is created as “heat energy 26
  38. 38. is drawn from the surrounding air to convert the water to watervapor, which produce a cooling effect (GR-Cooling LA 2006).”Regions that lack vegetation obviously have higher temperatures,as illustrated in the Urban Heat Island Profile figure. As largercities are lack the space for vegetation, green roofs are now thealternative. But in order to achieve higher results in temperaturereduction more green roofs need to be constructed.Air PollutionThe cooling effect that is created as a result of vegetation notonly helps to reduce the heat island effect, but it also helps 4.3. Green roofs benefit chart.decrease pollution in the air which is often a result of hightemperatures. As stated by Green Roofs for Healthy Cities, “1 Recreational, Vegetative, and Meditative Spacesquare meter (10.76 sq ft) of grass roof can remove between 0.2 In areas where space is limited, green roofs serve as alternativekg of airborne particulates from the air every year (Green Roofs places for recreation, vegetation, and meditation. Recreationalfor Healthy Cities 2007).” Some of these air pollutants include green roofs provide an opportunity for open space in adust and smog. Cities like Los Angeles where air pollution is a location that would not otherwise exist. Whether these spacesproblem could reduce by green roofs are built. Currently Los are public or private, the individuals frequenting the site willAngeles and many other cities, are following Chicago, the green benefit highly as, “green natural environments are places whereroof leader in the United States, by promoting green roofs and humans can recover (Living Green Roofs).” Green roofs canencouraging individuals (GR-Cooling LA 2006). also help build stronger communities as they provided a space 27
  39. 39. for neighbors that would typically not have a place to interact, Studies have shown that people who live in large cities oftento interact. In some cases, green roofs have been utilized for suffer from more health issues as opposed to individuals whogrowing vegetables, herbs, and fruits. Growing food on green reside in greener environments with more open space. Greenroofs is very beneficial as it could produce “fresher produce, roofs provide a natural environment for individuals to relax anddecreased travel time to the market and related environmental escape from the city, without having to travel very far. Thecost, and control soil, fertilizer and pesticides, (Green Roofs “therapeutic benefits that result from caring for plants,” as wellfor Healthy Cities 2007).” Using a roof to grow food would as the “restorative effect of a natural view holds the viewers’provide economical benefit, as well. An example of this is Trent attention, diverts their awareness from themselves and fromUniversity in Canada, whose green roof serves as the growing worrisome thoughts, thereby improving health (Green Roof forgrounds that provides the vegetables used by various campus Healthy Cities 2007).”cafes (Blyth 2006). Reconstruction of Ecological Habitats The decline of natural areas as a result of urbanization has displaced and interrupted ecological habitat for many creatures. As society becomes more environmentally conscious, the importance of these creatures and their habitats will have many organizations throughout the country trying to develop solutions, in order to fix these problems. For many species that migrate, like birds, the need for rest-stops may be limited. The installation of green roofs would build an environment where4.4. Vegetable roof garden at Trent University. these species could create a temporary habitat. In itself, a green 28
  40. 40. roof could also serve as a habitat for smaller species, such as Economical Savingsbutterflies and invertebrates. The extent of how ecologicallysensitive a green roof will be depends on the design andmaterials used. For example, ecological benefits are likely to behigher in extensive and semi-intensive green roofs, as they areinaccessible, limiting human interaction. Green roofs designedto be ecologically beneficial differ as they integrate more naturaland organic materials. In Switzerland, for example, often timesto recreate an ecological habitat they “use no particular drainagelayer, but allow the water to drain through the soil, or even be 4.7. Solaire Building, New York. (photo gallery)left standing in puddles, as in nature (Living Green Roofs).” Initially, a green roof may seem to be costly, but the long-term savings that result from having a green roof are greater than the cost. Some of the initial cost that goes into a green roof project may qualify under “grants related to energy efficiency and/or green roofs” depending on the project itself (Green Roof for Healthy Cities 2007). Although green roofs can be initially costly, costing twice as much as traditional roofs, in the long term the savings are greater. Green roofs have shown to last twice as long as traditional roofs as it “protects the waterproofing from4.5. 4.6. Green roofs can provide ecological habitats for various creatures. both the uv-light and the temperature extremes, increasing the 29
  41. 41. life expectancy of the membrane to at least 60 years, accordingto studies (Living Green Roofs).”Green roofs also help cut cost as they serve as insulation forbuildings, which reduces the use of materials, and the useof heating and cooling systems. Buildings require less airconditioning during the summer because of their natural wayto retain moisture and cool temperatures. In winter months thereverse happens as they retain heat, reducing heating cost. Thisis especially true with intensive green roofs as they have thickerlayers. Cooling and heating insulation may vary according to thebuilding size.Green roofs can also provide other benefits as they allow forLEED points, the use of recycled material, improved health,solar panels, and noise reduction among other things. 30
  42. 42. Although the benefits from a green roof are much greater, disadvantages exist which need considerations prior to starting any project. The primary disadvantages to constructing a green roof are almost all directly linked to expenses. Green roofs can be very expensive, depending on the size of the project. Often times the cost of installing a green roof can be twice the cost of traditional roofing. As reported by USA Today, in 2006 the “cost of green roofs is about $14 to $25 square foot (Holladay 2006).” Additional expenses may also arise ifDisadvantages structural reinforcement of the building is required. This is especially true in older building and with intensive green roofs of as intensive green roofs can weigh anywhere between 80 to 150Green Roofs lbs a square foot (GR-Cooling L.A. 2006). It is important that the project site be thoroughly studied prior to construction for potential issues as there have been cases where major repairs have been required after completion of projects due to things that may have been fixable during the building stages, such as cracks and leaks. Disadvantages particular to each green roof type also exist. For disadvantage on specific green roof types see the Intensive Green Roofs, Extensive Green Roofs, or the Semi-Extensive Green Roofs section. 31
  43. 43. As an educational institution, the University of California, Davis, can expect a great outcome from installing a green roof as it could join other notable campuses that are leading the way for environmental awareness. By installing a green roof at the campus, not only would UC Davis be recognized as contributing to the research of green roof technology, but the entire University of California system as well. Investing in a project of this type would help place the Davis campus amongst some of the most elite universities currently leading the way inUniversities Green Roofs the research of green roof technology. As of now, some of the most recognized universities with green roofs on campus include, Harvard, Carnegie-Melon, Massachusetts Institute of Technology, University of Georgia, North Carolina-Chapel Hill, Pennsylvania State, and Michigan State (Colwell 2007). Despite the fact that green roofs have been around for many years and countries in Europe and Asia are leaders with its recent technology, the United States has only recently acknowledged the potential of green roofs. Currently, government agencies, businesses, and universities are leaders in the paving the way for green roofs, but because there is not sufficient knowledge about 32
  44. 44. this technology, the people capable of installating green roofs Educational institutions, especially universities, have the potentialare limited and the cost for green roofs are high. As Dr. David J. to expand the field of green roofs as we know it within the UnitedBeattie and Dr. Robert D. Berghage, who have been advocates for States by developing research which can be applied to projectsgreen roofs at the Pennsylvania State University stated, although and educate individuals in the proper science of green roofs.information is abundant in Germany, it is limited and “not In North America alone, “there is potential for a green roofbeing directed to those who really need it,” in the United States. industry worth several trillion dollars (Beattie 2004).” Because“Even landscape architects, the professionals most frequently of the benefits that have already been associated to green roofs,called to design a green roof, have little knowledge of soils and nationwide and abroad, investing in a green roof as a learningplants. As a result, several projects have been compromised or facility would benefit, educators, students and communities.have failed (Beattie 2004).” Many of the universities which have installed green roofs on their campuses are already using them to conduct research or as learning classrooms. Research and topics being discussed vary from university to university, but one of the main things that each campus is studying is how green roofs hold up in their regions and how they may respond differently in different climate situations. As of now most of the universities conducting this research are focused primarily in the Northeast, Midwest, and Southern U.S. states. These part of the nation also have the more green roofs as shown in the Green Roofs Across America5.1. 5.2. David Beattie and student tending green roof vegetation. map. By proposing a green roof for the UC Davis campus, it 33
  45. 45. would serve as one of the first universities on the west cost to roof at the “Dearborn, Michigan assembly plant, a 10.4 acrehave a green roof. Since the temperatures on the west coast are project (Colwell 2007).” While the Ford Motor Company didvery distinct from other parts in the country, the collection of install their extensive green roofs, the research at Michiganinformation applicable to green roofs in this region is needed if State University still continues with the objectives “to evaluatethey are to be successful in this area. By installing a green roof, plant species, propagation and establishment methods, plantplants, soil, and alternative material can be studied by individuals succession, water and nutrient requirements, water quality andand communities. quantity of storm water runoff, and energy consumption (The green roof research).” At the Penn State Center for Green Roof Research, Dr. Beattie, director of the program, leads the program in “green roof research, education, and technology transfer in the Northeastern US (Penn State Center for GR Research 2006).” Some of the main objectives for the center include gathering data on storm water runoff, determining green roof effects on storm water, and comparison of green roofs vs. traditional roofs.5.3. Ford Motor Company Green RoofOne of the more well-known green roof research programs is At the University of Arkansas, professor of landscapelocated at Michigan State University and was originally initiated architecture, Mark Boyer, has been in charge of a couple of greenby Ford Motor Company. This was started in an effort to better roofs located atop campus building since their construction inprepare the company with the installation of their own green October 2006. As Boyer states, the purpose of the project at the 34
  46. 46. University of Arkansas was “to determine what type of plants Currently many universities are proposing the adoption of aand soil – if any - will survive the Northwest Arkansas climate green roof for their campus either for educational purposes,(Harris 2007).” Since the installation of the green roofs, Boyer or simply for the benefits that come with installing a greenhas stated the success of the green roofs. Their popularity on roof. More recently universities such as Duke University andcampus has resulted in various departments approaching Boye Stanford University have joined the other green roof campusesrequesting a green roofs of their own (Harris 2007). as they prepare for installation of their own green roof. These universities along with Massachusetts Institute of Technology, Virginia Wesleyan and the University of Virginia are among the few campus to receive grants from the Environmental Protection Agency to develop and maintain a green roof (The Leaves are Changing 2005). Finally the opportunities that can be gained through the installation of a green roof at the UC Davis campus are immense. From recognition for the campus, to better-prepared students in the field, to development of better spaces, green roofs have much to offer. As Beattie stated, “as educators, one of our biggest opportunities is to educate those involved in the extensive green roof industry. Knowledge of plant culture and the fundamentals of soil science related to green roof media are5.4. 5.5. University of Arkansa students helping with installation of green roof of critical importance (Beattie 2004).” 35
  47. 47. Rooftops at the UC Davis CampusThis aerial illustrates the percentage of the campus that rooftop current make up. The main buildings have been highlighted in greento show the visual impact green roofs create. Hunt Hall, the proposed site for this project is with the orange outline. (5.6.) 36
  48. 48. Green Roofs Across AmericaCurrently the majority of green roofs in the United States are being built in the east coast. As a result, most green roof informationfound is applicable to these regions. In an effort to increase the number of green roofs in the west coast, education and research ofgreen roofs in this region is needed. (5.7.) 37
  49. 49. “The Yerba Buena Garden is based on the idea that construction of new cultural facilities and public open space can transform a blighted district and bring economic development (boston). “Yerba Buena Gardens 6.1. Yerba Buena Garden off Mission and Howe streets. Plan view. Yerba Buena Gardens is located in the Central East side of San Francisco, within the South of Market District. The site is situated atop the George Moscone Convention Center, covering 5.5 acres on 2-blocks worth of San Francisco real estate. Surrounded by Mission, Folsom, 3rd, and 4th streets, Yerba Buena Gardens, marks the center of the larger redevelopment project 38
  50. 50. that transformed this area of San Francisco into one of the city’s effort to minimize the weight on the Moscone’s roof structuremain attractions. Since the beginning of the redevelopment (Osmundson 1999). Applying similar techniques for theproject, led by the San Francisco Redevelopment Agency proposed site would help reduce weight, should it be required.(Yerba Buena Center), back in the 1960s, the project site wasa controversial issue as stadiums and high-rise buildings were Site User Analysisthe argued reason for driving low and middle-income residents Yerba Buena Gardensout of the area (Osmundson 1999). Actual construction for has a unique atmospherethe Yerba Buena Gardens did not begin until the 1970s when for a fast pace city likethe construction of the underground convention center began. San Francisco. EnteringIt wasn’t until over twenty years after construction on the site the gardens, one canbegan that the lower portion bounded by Mission and Howe escape from the city.streets opened to the public in October 11, 1993 (Yerba Buena While observing theGardens). In 1998, the upper portion of the garden referred to Yerba Buena Gardensas the children’s garden opened (Yerba Buena Gardens-Wiki). on a Sunday afternoon, 6.2. Yerba Buena Gardens. it rapidly became clearYerba Buena Gardens, much like any public garden, is composed what the demographics for visitors to the site were. Perhaps,of a variety of garden elements such a multi-purpose lawn as the result of the children’s garden on the southern blockarea, amphitheater seats, children’s playground, and more. The of the gardens, most of the people frequenting the site wereEsplanade area of the Yerba Buena Gardens serves as the adults with young children 8 years and younger. Areas of highlargest open space and is unique as its “grassy slopes” were user impact versus low user impact are identified in the Yerbaconstructed with of 2-feet of Styrofoam and 2-feet soil in an Buena Gardens - Site Analysis. 39
  51. 51. The northern block of the gardens in the areas referred to departments for the purpose of education and research, inputas The Esplanade and the Sister City Gardens, were also well from these departments is ideal in developing a site that would beoccupied, although the demographics differed much from those suitable to all. Spaces should also be designed to serve multiplefound in the block located just south of it. Here you will find functions suitable for an array of events such as lectures, labs,young adults relaxing and lost in there own world, senior citizens and special exhibits. Elements such as amphitheater seatingpracticing yoga, and business people glancing at the daily news. and shade structure could possibly be integrated into the site, in order to accommodate all uses.6.3. 6.4. Yerba Buena Gardens. Users on the amphitheatre seating arealocated in the children’s garden.General Features LessonsGeneral elements that can be borrowed from the Yerba BuenaGardens include community planning, multi-purpose open 6.5. 6.6. Yerba Buena Garden. Users on the Esplanade side of the gar- den. View toward Mission Street and of the stage.space, amphitheater style seating, shade structures, art sculptures,walkways and materials. Lessons learned from the Yerba BuenaGardens will allow for a more successful design for the proposeduniversity site. If this green roof is to shared amongst different 40
  52. 52. Vegetation Plant PalettePlants at the Yerba Buena Gardens included, but were notlimited to, the following plants: • Agapanthus spp. – Lily of the Nile • Lagerstroemia indica – Crape Myrtle • Leptospermum spp. – New Zealand Tea Plant • Liriope muscari – Liriope • Loropetalum chinese – Chinese Fringe Bush • Nandina domestica – Heavenly Bamboo • Pelargonium spp. – Geranium • Prunus cerasifera – Purple Cherry Plum Tree • Rhaphiolepis indica – Indian Hawthorn • Rhododendron spp. – Azalea • Sultera corda. – Bacopa 6.7. Vegetation at Yerba Buena Gardens. 41
  53. 53. Yerba Buena Gardens - Site Analysis Building/ Structure High Impact Area Green Roof Limit Low Impact Area Open Space/ Multi-Purpose Vegetation/ Planting Area Seating Area Water Feature Roof Limit Entry Access(6.8.) 42

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