green roof at the university of california, davis - teaching green

82
Teaching Green

Post on 14-Sep-2014

5.868 views

Category:

Education


2 download

DESCRIPTION

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

TRANSCRIPT

Page 1: Green Roof at the University of California, Davis - Teaching Green

Teaching Green

Page 2: Green Roof at the University of California, Davis - Teaching Green

Environmental, Economical, and Educational Benefits: Proposal for a Green Roof at the University of California, Davis

University of California, DavisDepartment of Environmental Sciences

Landscape Architecture ProgramSenior Project: June 2007

Yanet Martinez

Teaching Green

Page 3: Green Roof at the University of California, Davis - Teaching Green

Environmental, Economical, and Educational Benefits:Proposal for a Green Roof at the University of California, Davis

A Senior Project presented to the faculty of the program of

Landscape Architecture at the University of California, Davis

in partial fulfillment of the requirements for the degree of

Bachelors of Science of Landscape Architecture.

Presented by

Yanet Martinez

at

University of California, Davis

on

the Fiftheenth day of June, 2007

Acceptance and Approval by:

Professor Mark Francis, Senior Project Advisor

Assistant Professor Stephen Wheeler, Committee Member

Adjunct Assistant Professor Jeff Loux, Committee Member

Steve McNeil, Committee Member

Teaching Green

Page 4: Green Roof at the University of California, Davis - Teaching Green

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-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.

Abstract

Page 5: Green Roof at the University of California, Davis - Teaching Green

ii

Yanet Martinez, a 2007 Landscape Architecture graduating

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.

Biographical Sketch

Page 6: Green Roof at the University of California, Davis - Teaching Green

iii

Since her arrival at the UC Davis campus in 2004, Yanet was

intrigued by the community, diversity and environment of the

campus, which led to her membership to Kappa Kappa Gamma

where she participated in philanthropic and community events.

In early 2005, Yanet was admitted to the Landscape Architecture

Program. That same year, she traveled to Japan, where she

participated in a study abroad program offered by the UC Davis

landscape 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 architecture

program and also participated in ASLA functions.

In the summer of 2006, she began an internship with the

County of Sacramento Department of Regional Parks, where

she assisted in various projects. She continued to work until

she once again departed Davis for a study abroad landscape

architecture program led by California State Polytechnic

University, Pomona in Italy. During her studies in Italy she

traveled to cities like Rome, Florence, Arezzo, and Venice where

she studied architecture, gardens, and history.

Upon her return to Davis, Yanet continued her internship with

the County of Sacramento Department of Regional Parks, as

she completed her final courses. After graduation, Yanet will be

traveling to South America to see more of the world. Ultimately

Yanet will work to build a professional career in the field of

landscape architecture.

Page 7: Green Roof at the University of California, Davis - Teaching Green

iv

To my loving family that just never stop giving of themselves in

countless ways, both direct and indirect.

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!

Dedications

Page 8: Green Roof at the University of California, Davis - Teaching Green

v

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.

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!

Acknowledgements

Page 9: Green Roof at the University of California, Davis - Teaching Green

vi

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 ................................................................18

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

Table of Contents

Page 10: Green Roof at the University of California, Davis - Teaching Green

vii

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 ..............72.2. Roof garden at Palazzo Piccolomini ....................................82.3. Traditional Scandinavian green roofs in Norway ...............9

3.1. Green Roof Layers ...............................................................113.2. Intensive green roof. Layer section ...................................163.3. Rockerfeller Center ...............................................................173.4. Millennium Park ....................................................................173.5. ACROS Prefectural International Hall ..............................173.6. Extensive green roof. Layer section ..................................193.7. Ocean Houses at Post Ranch Inn ......................................203.8. Heinz 57 Center ....................................................................203.9. Minneapolis Central Library ................................................203.10. Semi-instensive green roof. Layer section ......................223.111. The Calhoun School .........................................................233.12. The Culver House Residences ..........................................233.13. Library Square Building .....................................................23

4.1. Storm Water ...........................................................................254.2. Heat Island Profile ................................................................264.3. Green roof benefits chart ....................................................274.4. Vegetable roof garden at Trent University .......................284.5. Green roofs create ecological habitats (1) .........................284.6. Green roofs create ecological habitats (2) .........................284.7. Solaire building ......................................................................29

5.1. David Beattie and student at Penn State green roof (1) ......335.2. David Beattie and student at Penn State green roof (2) ......335.3. Ford Motor Company green roof ......................................345.4. U of Arkansa students on green roof (1) .........................34

List of Figures

Page 11: Green Roof at the University of California, Davis - Teaching Green

viii

5.5. U of Arkansa students on green roof (2) .........................345.6. Rooftops at UC Davis ..........................................................355.7. Green roofs across America ................................................37

6.1. Yerba Buena Gardens. Plan view. ......................................386.2. Yerba Buena Gardens ...........................................................39 6.3. YBG. Site Analysis Photograph 1 ......................................406.4. YBG. Site Analysis Photograph 2 ......................................40 6.5. YBG. Site Analysis Photograph 3 ......................................406.6. YBG. Site Analysis Photograph 4 ......................................406.7. Vegetation at YBG .................................................................416.8. YBG. Site Analysis Diagram ..............................................42

7.1. 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 ..................................................47

8.1. 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 ..........................................52

9.1. Hunt Hall vicinity map .........................................................539.2. Hunt Hall existing site photographs 1 ...............................54

9.3. Hunt Hall existing site photographs 2 ...............................55 9.4. Hunt Hall proposed site .......................................................59

Page 12: Green Roof at the University of California, Davis - Teaching Green

1

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

Introduction

1.1. Green Roof.

Page 13: Green Roof at the University of California, Davis - Teaching Green

2

developments have produced a hybrid referred to as a semi-

intensive green roof. Although these green roofs can be

beneficial environmentally, economically, and educationally,

each has qualities, which make them distinct from one another.

Each type of green roof mentioned will be discussed in further

detail within the following sections.

As many universities throughout the nation, as well as abroad,

are already endeavoring into the integration of green roofs as a

learning tool for students and faculty, it seems only appropriate

that as a university that is largely dedicated to addressing,

educating, and conducting research on environmental, ecological,

and agricultural issues, that the University of California, Davis

would consider the idea for a proposal of a green roof for the

campus. The addition of such a project to the campus would

assist in upholding Davis as one of the top universities and

research facilities in the nation and may perhaps even lead to

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 by

the construction of green roofs, those that address possible

solutions for air and water pollution, heat island reductions,

additional recreational areas, ecological areas, insulation, and

increase roof life expectancy will all be discussed. A brief

overview of possible economical benefits will also be covered.

Possible disadvantages that may result from green roofs will

also be reviewed.

1.2. Installation of a green roof at the University of Central Florida.

Page 14: Green Roof at the University of California, Davis - Teaching Green

3

Green roofs, sometimes referred to as roof gardens, were

also analyzed by visiting the sites in order to achieve a better

understanding of the components that make a successful green

roof. Case studies were conducted on the Yerba Buena Gardens,

Union Square and the roof garden atop the Central YMCA

located in San Francisco. Although there were limitations on

the information gathered about each case study, they still present

certain elements that could be integrated into the proposed

green roof for the university campus.

As a result of the data obtained, enough information was

gathered to provide a suggested preliminary conceptual design

for Hunt Hall at the University of California, Davis. The

conceptual design consist of the three types of of green roofs,

in an effort to familiarize possible users with all three. As Hunt

Hall is proposed to undergo renovation in the next couple

years and serve as the home for the Department of Landscape

Architecture, it seemed as the ideal location. Aside from a

conceptual design, a suggested plant list for each green roof

type was also formulated. The plants selected were based on

what would might possibly be suitable for the site.

By the end of this paper it is intended that the reader gain an

overall general understanding of green roofs. They should be

able to define what a green roof is, understand its layers, know

the different types of green roofs, and list the benefits and

possible disadvantages that come with building a green roof.

It should be noted that the intention of this paper is to get

the reader acquainted with the concept of green roofs and to

propose the possibility of the University of California, Davis

implementing a green roof on campus. This paper is not to

serve as a primary guide for the construction of green roofs.

1.3. Hunt Hall. Furture location for the Landscape Architecture Program.

Page 15: Green Roof at the University of California, Davis - Teaching Green

4

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 as

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

What is a Green Roof?

Page 16: Green Roof at the University of California, Davis - Teaching Green

5

qualities that are found in extensive green roofs, however they

provide for accessibility and occasional interaction of people to

the garden (Dunnett 2004).

Green roofs should be looked upon as more than just plants

on a roof, as they have demonstrated environmental and

economical benefits. They have been applied as solutions for

air and water pollution, heat reductions, alternative recreational

and ecological space and more. Thus far, they have also been

credited with providing insulation to buildings, reducing energy

cost and increasing property values (Green Roofs for Healthy

Cities 2007).

The benefits that green roofs are credited with seem immense,

however additional research and for creating and understanding

new solutions, materials, and methods in the construction of

this new technology is still a essential. As with anything else, the

better we understand this technology the more beneficial it will

be to communities and the nation.

Page 17: Green Roof at the University of California, Davis - Teaching Green

6

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. It

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

History of Green Roofs

Page 18: Green Roof at the University of California, Davis - Teaching Green

7

creditable individuals such as Strabo and Diodorus Siculus has

lead to the belief of their existence. The majestic description

of these gardens has even listed them as being one of the seven

original World Wonders (Hanging Gardens 2007).

The story behind the creation of these gardens is said to be the

result of king Nebuchadrezzar II, as a way of consoling his wife

Amytis in her longing for the landscape of her homeland, which

is described as abundant in vegetations and green hills. These

gardens are said to have been built upon Babylonian ziggurats,

pyramid like buildings with large landings that allowed for

placement of these gardens (Osmundson 1999).

Early depictions described the construction of these gardens

upon “stone beams some sixteen feet long and over these were

laid first a layer of reed set in thick tar, then two courses of

baked clay brick bonded by cement, and finally a covering of

lead to prevent the moisture in the soil penetrating the roof

(Osmundson 1999).” Plants were then situated on top and

irrigation was made possible through pumping of the river.

As the gardens of Babylonia were described as being elaborate

and mainly for aesthetic pleasures it can be said that the first

historical recorded green roofs were what we refer to today as

intensive.

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, by

casting molds of their roots (Osmundson 1999). 2.1. Depiction of the Hanging Gardens of Babylonia.

Page 19: Green Roof at the University of California, Davis - Teaching Green

8

Pompeii wasn’t the only Italian town to have gardens growing

atop its roofs; Pienza, Lucca and Careggi are towns that had

roof gardens as well. In Pienza, a garden constructed atop the

Palazzo Piccolomini during the 1460s, by orders of Pope Pius

II, is one of the most well preserved roof gardens to this date

(Osmundson 1999). The garden is built atop a masonry building

and composed of primarily small manicured plants, making this

an intensive roof garden.

In Careggi, the well-known Medici Family also had a roof

garden. The garden was composed primarily of a collection

of exotic plants that the Medici family collected and served as a

representation of their wealth (Osmundson 1999). As the main

purpose of this roof garden was entertainment purposes, this

garden was most definitely held intensive qualities. Similar to the

garden at Palazzo Piccolomini, this garden was built atop of the

roof of the building, covered in a layer of soil and vegetation.

On the other side of the world in the island city of Tenochititian

Mexico, during the same time roof gardens were emerging in

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, before

the invasion by the Spaniards.

In the 1600s even more roof gardens emerged throughout Europe

and other parts of the world. Like most gardens documented

up to this period, roof gardens built in this era were quite similar.

2.2. Roof garden at Palazzo Piccolomini.

Page 20: Green Roof at the University of California, Davis - Teaching Green

9

Today we would describe these roof gardens as intensive, as

they were quite elaborate and primarily designed for aesthetics

and entertainment. Two gardens in Russia, the Kremlin Palace

in Moscow and the Hermitage in Saint Petersburg are examples

of the gardens built in this era (Osmundson 1999).

Prior to the 1800s the notion of a roof garden was usually

associated with wealth, power, aesthetics and entertainment,

and were what we may now refer to as intensive gardens. In

the early 1800s however gardens atop roofs started to develop

in Germany that were unlike any of the gardens that had been

created before. Whereas before gardens were created primarily

for the aesthetic pleasures of the wealthy, in Germany a transitions

had begun that evolved these gardens into a functional building

material. Middle class people in German adopted the idea of

growing vegetation on the roof of their homes as a method of

insulation for their homes during harsh seasons. During the

cooler seasons the vegetation and soil layer helped retain heat

in the building and to cool it during warmer seasons. These

new types of roof gardens seemed to share similar building

approaches as those found in the roof gardens before them.

These new versions of roof gardens were usually consisted of

a layer of soil, which served as the base for grasses and low

growing vegetation, to grow. Because these gardens were

generally planted atop smaller dwellings, they weren’t intended

for larger vegetation or as being accessible hence maintaining

them was less necessary (Dunnett 2004).

Middle class in the United States also seemed to have adapted

this method of insulations, as homes, schools, and other building

were being constructed with extensive roofs. Towns within the

states of Dakota and Nebraska especially demonstrated a liking

for this technique (Dunnett 2004).

2.3. Traditional Scandinavian green roofs in Norway.

Page 21: Green Roof at the University of California, Davis - Teaching Green

10

After a project demonstrating the functions of this new roof

technology was revealed at the World Exhibition of 1868 in

Paris, the international launch of the extensive roof garden

seemed to have taken place as people became fascinated with

the concept (Dunnett 2004). At the same time, however, the

intensive roof gardens began to emerge once again, as they

became a popular entertainment asset especially for theatre and

hotels. Again it seemed as if gardens where returning to the

intensive type gardens. In large developing cities such as New

York, the luxury of open space was limited and so the idea of

converting roofs into an open space began to sprout yet again.

The gardens that developed during this era were much like the

first roof gardens wherein they were being built for the pleasure

of the wealthy (Osmundson 1999).

During the twentieth century, technological advancements

allowed for improved construction of roof gardens in general.

Roof gardens such as those at the Kensington, Rockefeller Center,

and Union Square of San Francisco, which have inspired many

of today’s roof gardens, were built during this era (Osmundson

1999). In Germany, the development of technology for

extensive roof gardens has made it the leader on extensive

gardens. Along with Germany, regions in Scandinavia and

Kurdistan also developed this technology. Similar to the original

extensive gardens of the 1800s, the gardens of the twentieth

century were designed for the benefits that they provided to the

buildings and their dwellers. Insulation, extended roof life, and

aesthetics were the purposes of the emerging extensive roof

gardens (Dunnett 2004).

From the 1950s to today, a stronger emphasis has been put on

studying roof gardens and distinguishing between the two main

types, intensive and extensive. As more research is conducted

on the subject matter, it is becoming apparent that these gardens

are beneficial to societies on many levels, especially when dealing

with the latter of the two types, the extensive green roof. As

a result of these recent findings, a third type of roof garden

referred to as semi-intensive, which is a mix of intensive and

extensive, has emerged.

Page 22: Green Roof at the University of California, Davis - Teaching Green

11

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

Green Roof Layers

I.1. Green Roof Layers.

Page 23: Green Roof at the University of California, Davis - Teaching Green

12

functions will be given. Specific information for each green

roof type are within Intensive Green Roofs, Extensive Green

Roofs, and Semi-Intensive Green Roofs sections.

1. The VegeTaTion Layer

The vegetation layer, is the part of a green roof individuals are

most familiar with as it is the layer that adds the “green” to the

roof. Depending on the type of green roof and the climatic

region where a green roof project is located, the material used

within this layer is bound to vary highly, in comparison to

the other layers. The main objective in creating a successful

vegetation layer for any green roof type, is to use plant material

which is typically drought tolerant, able to withstand high

temperatures and wind (Dunnett 2004). Selecting plants with

these characteristics will help ensure their longevity and the

success of the green roof. Also when selecting plants size and

root depth of the plants need to be considered especially when

designing an extensive green roof (GR-Cooling L.A. 2006). For

these reasons some of the most commonly used vegetation in

green roofs include succulents and ground covers. Each green

roof type is designed to support particular type of vegetation,

it is important to study the type of plants which are appropriate

for a particular type of green roof. Extensive green roofs, for

example are designed to support the lightest weight possible,

which limits the plant selections to mainly ground covers,

particularly sedum, which are not only light, but whose roots

don’t require much depth in the growing medium layer. Intensive

green roofs on the other hand, are design to accommodate larger

plants, providing a larger plant selection for this type of green

roof (Dunnett 2004). In the end, when selecting plant material

for ay green roof, “it is necessary to choose plants suitable for

each climate, whether the conditions are periodically very dry,

very hot, very cold, or very variable (Living Green Roofs).”

2. The growing MediuM Layer

The growing medium or substrate layer is located directed

beneath the vegetation layer and above the filter layer. Unlike

most gardens, green roofs can not be planted with the typical

“garden soil or topsoil... because it is too heavy and too fertile

(Dunnett 2004).” When selecting a growing medium for a green

roof it is important to consider weight, especially with extensive

green roofs. Instensive green roof may usually use typical garden

Page 24: Green Roof at the University of California, Davis - Teaching Green

13

soils, but using a growing medium specialized for green roofs

is ideal. A major concern when selecting a growing medium

has to do with safety as “soil containing a lot of peat or other

organic substances is liable to shrinking, and can be a fire hazard

(Living Green Roofs).” Companies specializing in green roof

material often carry specialty growing mediums or substrates.

These growing mediums are usually lightweight and contain

natural minerals, however artificial soils are also available which

usually include “vermiculite and perlite (Dunnett 2004).” “A

good roof soil is therefore mainly a mineral soil, not containing

clay, which is too impervious. To make the soil lighter, crushed

brick or lava can be mixed in (Living Green Roofs).”

3. The FiLTer Layer

The filter layer is located between the growing medium and

the drainage layer. Typically a fabric material is used and is

neccessary “to stop the substrate from disturbing the drainage

function.” Use of this layer prevents the blockage to the

drainage layer, which may be caused by possible debris from

the growing medium and also serves as “an erosion control that

holds the substrate in place (Living Green Roofs).”

4. The drainage Layer

The drainage layer located below the filter and above the

protection layer, is one of the most important layer in the

construction of a green roof. The drainage layer is essential

in determining where water directer toward after it has reached

the green roof. “If drainage is inadequate on a flat green

roof, then damage to the roof membrane may ensue (Dunnett

2004).” Other issues that may result from a faulty drainage

system include puddles, erosion of growth medium, rotting of

plants, and unwanted plants (Living Green Roofs). In order

to achieve a green roof which will be beneficial especially in

treating storm water it is necessary to install a drainage system,

appropriate for the specific roof type. The drainage layer should

provide the function to store some water which is available to

the vegetation layer (Dunnett 2004). The material typically used

in the drainage layer, is available from all nature to manufactured.

Materials commonly include gravel or crushed rock, crushed

lava, crush leca or crushed bricks, rockwool, foam material, and

plastic sheets (Living Green Roofs).

Page 25: Green Roof at the University of California, Davis - Teaching Green

14

5. The ProTecTion Layer

Located under the drainage layer, most green roofs typically

include a protection layer. The main purpose of the protection

layer is to create a barrier between the roots of the plants and

the waterproofing layer. This layer essential prevent damage

to the roof structure which may result from root penetration.

“Root protection membranes are usually composed of rolls of

PVC and laid out over the weatherproofed roof deck or suface

(Dunnett 2004).” Other root repellant alternatives also include

chemicals, copper sheets, and rubber seals (Living Green Roofs).

In some cases, especially with extensive green roofs, this layer is

left out as it is believed that the roots of ground covers, such as

sedum, will not damage the roof. However each potential green

roof project should consider installation of the protection layer

unless otherwise specified by a professional.

6. The waTerProoFing Layer

The waterproofing layer, essentially the first layer to be applied

to any green roof, is important in sealing the building from

water. This layer is important in order to keep the building from

any damage which may result as a excessive water or moist soil.

“Unless the roof memebrane is damaged while laying the green

roof, the soil and vegetation cover will protect the membrane

from these types of injuries later (Living Green Roofs).” Three

types of materials which are typically used for this layer include

the built-up roof, the single-ply membrane, and the fluid-applied

membrane (Osmundson 1999). Each type consist of the

following: built-up roofs consist of “bitumen/asphalt roofing

felt or bitumized fabrics,” single-ply membranes are “sheets of

inorganic plastic or synthetic rubber material” sealed heat or

adhesive, and fluid-applied membranes are liquid “sprayed or

painted on the surface of the roof and forms a complete seal

(Dunnett 2004).”

Page 26: Green Roof at the University of California, Davis - Teaching Green

15

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 more

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.

Intensive Green Roofs

Page 27: Green Roof at the University of California, Davis - Teaching Green

16

adVanTages and disadVanTages

The following is a list of the positive and negative factors that

may result from an intensive green roof.

Pros cons

Accessibility High maintenanceGood use of otherwise non used space

Heavy weight load

Allows for recreational uses and multi-purpose activities

High cost/Expensive

Wider vegetative selection May require additional structural support

Provides the best insulation Usually requires profes-sional installation

Aesthetically appealing Requires irrigation

coMPonenTs

Green roofs of all types usually consist of similar layers. The

difference for each usually seen in the thickness of each layer,

plant selection, and weight. Because intensive green roofs are

more elaborate and require more support its layers are thicker

than extensive are semi-intensive. According to the specific

project, the layer thickness will vary. Often the thickness of

the growing medium layer, which is minimally 6 inches and can

exceed over 1 foot in depth, will help determine that a green

roof is indeed intensive (Dunnett). Plant material used is usually

enough, however to identify the type of green roof. Instensive

green roofs are the only capable of supporting trees and large

shrubs in it vegetation layer, and contains the largest plant

selection of all three types, and as a result bear more weight.

The figure below shows two sections illustrating the layers of an

intensive green roof. Intensive green roofs may also require an

additional irrigation layer, not shown in the figure below.

1. Waterproofing Layer

2. Protection Layer

3. Drainage Layer

4. Filter Layer

5. Growing Medium Layer

6. Vegetation Layer

3.2. Intensive green roof. Example of two layer types.

inTensiVe green rooF Layers

Page 28: Green Roof at the University of California, Davis - Teaching Green

17

exaMPLes

The following are examples of Intensive Green Roofs:

1. Rockefeller Center, New York, New York

2. Millennium Park, Chicago, Illinois

3. ACROS Prefectural Int’l Hall, Fukuoka, Japan

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

(3.4.)

(3.3.) (3.5.)

Page 29: Green Roof at the University of California, Davis - Teaching Green

18

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 littler

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.

Extensive Green Roofs

Page 30: Green Roof at the University of California, Davis - Teaching Green

19

adVanTages and disadVanTages

The following is a list of the positives and negatives factors that

may result from an extensive green roof.

Pros cons

Light weight Limited plant selectionLow maintenance InaccessibleYields high percentage of ecological benefits

Less aesthetically pleasing

Less expensiveCan be placed on smaller structures

coMPonenTs

Extensive green roofs are composed of the similar layers as the

other two green roofs mentioned. Because extensive green roofs

are the least complex, its has the thinnest layers and in some

cases some layers, such as the protection layer, are not used at

all. The plant material used in the vegetation layer, as well as the

roof itself, will usually help determine if it is possible to leave out

layers. The growing medium layer in an extensive green roof has

a minimum of 3 inches and maximum of 6 inches. As a result of

the growing medium layer, the plant selection for the vegetation

layer is limited to mostly low growing grasses and groudcovers,

such as sedum. Extensive green roofs are not designed to

support shrubs or larger plants. Finally the combined system

of an extensive green roof typically has a “saturated weight of

15-30 lbs/sq ft (Green Roof Types 2005).”

1. Waterproofing Layer

2. Protection Layer

3. Drainage Layer

4. Filter Layer

5. Growing Medium Layer

6. Vegetation Layer

3.6. Extensive green roof. Exampe of two layer types.

exTensiVe green rooF Layers

Page 31: Green Roof at the University of California, Davis - Teaching Green

20

exaMPLes

The following are examples of Extensive Green Roofs:

1. Ocean Houses at Post Ranch Inn, Big Sur, California

2. Heinz 57 Center, Pittsburgh, Pennsylvania

3. Minneapolis Central Library, Minneapolis, Minnesota

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

(3.8.)

(3.7.) (3.9.)

Page 32: Green Roof at the University of California, Davis - Teaching Green

21

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/

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

Semi-Intensive Green Roofs

Page 33: Green Roof at the University of California, Davis - Teaching Green

22

qualities are moderate. When studying all three green roof types

together, factors such as cost, maintenance, weight, all appear

to be moderate for semi-intensive green roofs. Advantages

and disadvantages for this green roof can be made only when

compared one-on-one with another type. The following is a list

of some of the more obvious positives and negatives that may

result from semi-intensive green roofs:

Pros cons

Accessible Partly limited plant selectionAesthetically pleasing May require irrigationProvides moderate recre-ational space

Require regular mainte-nance

coMPonenTs

Since semi-intensive green roofs share qualities of both extensive

and intensive green roofs the components are a mean of the two

green roofs. As mentioned earlier, the vegetative layer for the

semi-intensive green roofs consist of primarily “grass, herbs,

and shrubs,” which require little to moderate maintenance (Int’l

Green Roof Association 2007). The growing medium layer is

typically 6 inches to 12 inches in depth. The semi-intensive 3.10. Semi-instensive green roof. Example of two layer types.

roof system has a “saturated weight of 30-50 lb/square feet.

(Green Roof Types 2005).” Because semi-intensive green roofs

combine the benefits of extensive and intensive green roofs,

they are becoming more appealing.

1. Waterproofing Layer

2. Protection Layer

3. Drainage Layer

4. Filter Layer

5. Growing Medium Layer

6. Vegetation Layer

seMi-inTensiVe green rooF Layers

Page 34: Green Roof at the University of California, Davis - Teaching Green

23

green exaMPLes

The following are examples of Semi-Intensive Green Roofs:

1. The Calhoun School, New York, New York

2. Culver House Residences, Chicago, Illinois

3. Library Square Building, Vancouver, British Colombia (3.13.)(3.11.)

(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

Page 35: Green Roof at the University of California, Davis - Teaching Green

24

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 more

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.

Benefits of Green Roofs

Page 36: Green Roof at the University of California, Davis - Teaching Green

25

to around 5 percent for a forested area.” This extra surface

runoff is water that eventually finds its way to natural bodies

of water and sewage systems. Natural bodies of waters such as

rivers and lakes are effected “not only by the quality of runoff

but also by its quantity, as a high volume of flow contributes to

erosion and sedimentation, and impacts aquatic habitats (Storm

sTorM waTer PoLLuTion

Within recent years, the importance of addressing water

quality issues has become the priority of many city and state

governments. As cities become more and more urbanized and

man made structures and surfaces out number square footage

of natural vegetative areas, the problem of storm water run off

and pollution will increase. Because these man made surfaces

are not permeable, rainwater is unable to penetrate into soil or

natural substances, which would otherwise filter out pollutants.

In fact, materials such as concrete and asphalt that are used

in large on roads, parking lots, and buildings, collect many

contaminates that collect in a city like “oil and other synthetic

hydrocarbons, heavy metals, road salt, pesticides, and animal

waste,” which hence pollutes the storm water (Dunnett 2004).

Green roofs would not only be beneficial in reducing the

amount of pollutants that storm water collects, but also in the

prevention of storm water flow in sewage systems and natural

bodies of water, in erosion, and in lowing temperatures by

retention of water. As Dunnett states, “75 percent of rainfall

on towns and cities is lost directly as surface runoff compared

4.1. Storm water from residential and urban areas collect pollutants that eventually make their way into natural bodies of water.

Page 37: Green Roof at the University of California, Davis - Teaching Green

26

Water Pollution Prevention 2006).” In a similar way, sewage

systems and water treatment facilities become overloaded when

dealing with large amounts of surface runoff.

By installing green roofs on building especially in large urban

cities, storm water pollution would be reduced, as water

absorption would take place from the vegetative and soil layers.

The soil would hold and release water as needed, while plant

processed the water through the transpiration process (Dunnett

2004). This not only decreases the percentage of surface runoff

but also helps cool the area down.

reduced heaT isLand eFFecT

As cities grow, vegetative spaces are being replaced by man-

made surfaces, resulting in a regional heat increase. As defined

by the Environmental Protection Agency, “’heat island’ refers

to urban temperatures that are higher than nearby rural areas

(Chang 2000).” Heat islands result from surfaces such as asphalt,

concrete, and roof materials that absorb the heat radiated

from the sun, which causes this temperature increase. This is

a problem in larger urbanized cities as much of their surface

is made up of this material. “In the United States, buildings

consume six times as much energy and produce six times as

much greenhouse gas emissions as all cars and trucks combined

(Hall 2006).” Green roofs work as a solution in reducing this

problem as they convert some of the surface causing this

problem into green vegetative spaces.

Vegetation important in achieving cooler temperatures. “If all

the roofs in a major city were ‘greened,’ urban temperatures

could be reduced by as much as 12 degrees (Noyes 2006).” This

is because vegetation naturally cool regions and also provides

shade and evapotranspiration. This is created as “heat energy

4.2. Profile of urban heat temperatures.

Page 38: Green Roof at the University of California, Davis - Teaching Green

27

is drawn from the surrounding air to convert the water to water

vapor, 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 larger

cities are lack the space for vegetation, green roofs are now the

alternative. But in order to achieve higher results in temperature

reduction more green roofs need to be constructed.

air PoLLuTion

The cooling effect that is created as a result of vegetation not

only helps to reduce the heat island effect, but it also helps

decrease pollution in the air which is often a result of high

temperatures. As stated by Green Roofs for Healthy Cities, “1

square meter (10.76 sq ft) of grass roof can remove between 0.2

kg of airborne particulates from the air every year (Green Roofs

for Healthy Cities 2007).” Some of these air pollutants include

dust and smog. Cities like Los Angeles where air pollution is a

problem could reduce by green roofs are built. Currently Los

Angeles and many other cities, are following Chicago, the green

roof leader in the United States, by promoting green roofs and

encouraging individuals (GR-Cooling LA 2006).

recreaTionaL, VegeTaTiVe, and MediTaTiVe sPace

In areas where space is limited, green roofs serve as alternative

places for recreation, vegetation, and meditation. Recreational

green roofs provide an opportunity for open space in a

location that would not otherwise exist. Whether these spaces

are public or private, the individuals frequenting the site will

benefit highly as, “green natural environments are places where

humans can recover (Living Green Roofs).” Green roofs can

also help build stronger communities as they provided a space

4.3. Green roofs benefit chart.

Page 39: Green Roof at the University of California, Davis - Teaching Green

28

for neighbors that would typically not have a place to interact,

to interact. In some cases, green roofs have been utilized for

growing vegetables, herbs, and fruits. Growing food on green

roofs is very beneficial as it could produce “fresher produce,

decreased travel time to the market and related environmental

cost, and control soil, fertilizer and pesticides, (Green Roofs

for Healthy Cities 2007).” Using a roof to grow food would

provide economical benefit, as well. An example of this is Trent

University in Canada, whose green roof serves as the growing

grounds that provides the vegetables used by various campus

cafes (Blyth 2006).

Studies have shown that people who live in large cities often

suffer from more health issues as opposed to individuals who

reside in greener environments with more open space. Green

roofs provide a natural environment for individuals to relax and

escape from the city, without having to travel very far. The

“therapeutic benefits that result from caring for plants,” as well

as the “restorative effect of a natural view holds the viewers’

attention, diverts their awareness from themselves and from

worrisome thoughts, thereby improving health (Green Roof for

Healthy Cities 2007).”

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 where

these species could create a temporary habitat. In itself, a green 4.4. Vegetable roof garden at Trent University.

Page 40: Green Roof at the University of California, Davis - Teaching Green

29

econoMicaL saVings

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 from

both the uv-light and the temperature extremes, increasing the

roof could also serve as a habitat for smaller species, such as

butterflies and invertebrates. The extent of how ecologically

sensitive a green roof will be depends on the design and

materials used. For example, ecological benefits are likely to be

higher in extensive and semi-intensive green roofs, as they are

inaccessible, limiting human interaction. Green roofs designed

to be ecologically beneficial differ as they integrate more natural

and organic materials. In Switzerland, for example, often times

to recreate an ecological habitat they “use no particular drainage

layer, but allow the water to drain through the soil, or even be

left standing in puddles, as in nature (Living Green Roofs).”

4.5. & 4.6. Green roofs can provide ecological habitats for various creatures.

4.7. Solaire Building, New York. (photo gallery)

Page 41: Green Roof at the University of California, Davis - Teaching Green

30

life expectancy of the membrane to at least 60 years, according

to studies (Living Green Roofs).”

Green roofs also help cut cost as they serve as insulation for

buildings, which reduces the use of materials, and the use

of heating and cooling systems. Buildings require less air

conditioning during the summer because of their natural way

to retain moisture and cool temperatures. In winter months the

reverse happens as they retain heat, reducing heating cost. This

is especially true with intensive green roofs as they have thicker

layers. Cooling and heating insulation may vary according to the

building size.

Green roofs can also provide other benefits as they allow for

LEED points, the use of recycled material, improved health,

solar panels, and noise reduction among other things.

Page 42: Green Roof at the University of California, Davis - Teaching Green

31

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 if

structural reinforcement of the building is required. This is

especially true in older building and with intensive green roofs

as intensive green roofs can weigh anywhere between 80 to 150

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.

Disadvantages of

Green Roofs

Page 43: Green Roof at the University of California, Davis - Teaching Green

32

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 in

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

Universities & Green Roofs

Page 44: Green Roof at the University of California, Davis - Teaching Green

33

this technology, the people capable of installating green roofs

are limited and the cost for green roofs are high. As Dr. David J.

Beattie and Dr. Robert D. Berghage, who have been advocates for

green roofs at the Pennsylvania State University stated, although

information is abundant in Germany, it is limited and “not

being directed to those who really need it,” in the United States.

“Even landscape architects, the professionals most frequently

called to design a green roof, have little knowledge of soils and

plants. As a result, several projects have been compromised or

have failed (Beattie 2004).”

Educational institutions, especially universities, have the potential

to expand the field of green roofs as we know it within the United

States by developing research which can be applied to projects

and educate individuals in the proper science of green roofs.

In North America alone, “there is potential for a green roof

industry worth several trillion dollars (Beattie 2004).” Because

of the benefits that have already been associated to green roofs,

nationwide and abroad, investing in a green roof as a learning

facility would benefit, educators, students and communities.

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 America

map. By proposing a green roof for the UC Davis campus, it 5.1. & 5.2. David Beattie and student tending green roof vegetation.

Page 45: Green Roof at the University of California, Davis - Teaching Green

34

would serve as one of the first universities on the west cost to

have a green roof. Since the temperatures on the west coast are

very distinct from other parts in the country, the collection of

information applicable to green roofs in this region is needed if

they are to be successful in this area. By installing a green roof,

plants, soil, and alternative material can be studied by individuals

and communities.

One of the more well-known green roof research programs is

located at Michigan State University and was originally initiated

by Ford Motor Company. This was started in an effort to better

prepare the company with the installation of their own green

roof at the “Dearborn, Michigan assembly plant, a 10.4 acre

project (Colwell 2007).” While the Ford Motor Company did

install their extensive green roofs, the research at Michigan

State University still continues with the objectives “to evaluate

plant species, propagation and establishment methods, plant

succession, water and nutrient requirements, water quality and

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.

At the University of Arkansas, professor of landscape

architecture, Mark Boyer, has been in charge of a couple of green

roofs located atop campus building since their construction in

October 2006. As Boyer states, the purpose of the project at the

5.3. Ford Motor Company Green Roof

Page 46: Green Roof at the University of California, Davis - Teaching Green

35

Currently many universities are proposing the adoption of a

green roof for their campus either for educational purposes,

or simply for the benefits that come with installing a green

roof. More recently universities such as Duke University and

Stanford University have joined the other green roof campuses

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 are

of critical importance (Beattie 2004).”

University of Arkansas was “to determine what type of plants

and soil – if any - will survive the Northwest Arkansas climate

(Harris 2007).” Since the installation of the green roofs, Boyer

has stated the success of the green roofs. Their popularity on

campus has resulted in various departments approaching Boye

requesting a green roofs of their own (Harris 2007).

5.4. & 5.5. University of Arkansa students helping with installation of green roof

Page 47: Green Roof at the University of California, Davis - Teaching Green

36

Rooftops at the UC Davis Campus

This aerial illustrates the percentage of the campus that rooftop current make up. The main buildings have been highlighted in green

to show the visual impact green roofs create. Hunt Hall, the proposed site for this project is with the orange outline. (5.6.)

Page 48: Green Roof at the University of California, Davis - Teaching Green

37

Green Roofs Across America

Currently the majority of green roofs in the United States are being built in the east coast. As a result, most green roof information

found is applicable to these regions. In an effort to increase the number of green roofs in the west coast, education and research of

green roofs in this region is needed. (5.7.)

Page 49: Green Roof at the University of California, Davis - Teaching Green

38

“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 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

Yerba Buena Gardens

6.1. Yerba Buena Garden off Mission and Howe streets. Plan view.

Page 50: Green Roof at the University of California, Davis - Teaching Green

39

effort to minimize the weight on the Moscone’s roof structure

(Osmundson 1999). Applying similar techniques for the

proposed site would help reduce weight, should it be required.

siTe & user anaLysis

Yerba Buena Gardens

has a unique atmosphere

for a fast pace city like

San Francisco. Entering

the gardens, one can

escape from the city.

While observing the

Yerba Buena Gardens

on a Sunday afternoon,

it rapidly became clear

what the demographics for visitors to the site were. Perhaps,

as the result of the children’s garden on the southern block

of the gardens, most of the people frequenting the site were

adults with young children 8 years and younger. Areas of high

user impact versus low user impact are identified in the Yerba

Buena Gardens - Site Analysis.

that transformed this area of San Francisco into one of the city’s

main attractions. Since the beginning of the redevelopment

project, led by the San Francisco Redevelopment Agency

(Yerba Buena Center), back in the 1960s, the project site was

a controversial issue as stadiums and high-rise buildings were

the argued reason for driving low and middle-income residents

out of the area (Osmundson 1999). Actual construction for

the Yerba Buena Gardens did not begin until the 1970s when

the construction of the underground convention center began.

It wasn’t until over twenty years after construction on the site

began that the lower portion bounded by Mission and Howe

streets opened to the public in October 11, 1993 (Yerba Buena

Gardens). In 1998, the upper portion of the garden referred to

as the children’s garden opened (Yerba Buena Gardens-Wiki).

Yerba Buena Gardens, much like any public garden, is composed

of a variety of garden elements such a multi-purpose lawn

area, amphitheater seats, children’s playground, and more. The

Esplanade area of the Yerba Buena Gardens serves as the

largest open space and is unique as its “grassy slopes” were

constructed with of 2-feet of Styrofoam and 2-feet soil in an

6.2. Yerba Buena Gardens.

Page 51: Green Roof at the University of California, Davis - Teaching Green

40

departments for the purpose of education and research, input

from these departments is ideal in developing a site that would be

suitable to all. Spaces should also be designed to serve multiple

functions suitable for an array of events such as lectures, labs,

and special exhibits. Elements such as amphitheater seating

and shade structure could possibly be integrated into the site, in

order to accommodate all uses.

The northern block of the gardens in the areas referred to

as The Esplanade and the Sister City Gardens, were also well

occupied, although the demographics differed much from those

found in the block located just south of it. Here you will find

young adults relaxing and lost in there own world, senior citizens

practicing yoga, and business people glancing at the daily news.

generaL FeaTures & Lessons

General elements that can be borrowed from the Yerba Buena

Gardens include community planning, multi-purpose open

space, amphitheater style seating, shade structures, art sculptures,

walkways and materials. Lessons learned from the Yerba Buena

Gardens will allow for a more successful design for the proposed

university site. If this green roof is to shared amongst different

6.5. & 6.6. Yerba Buena Garden. Users on the Esplanade side of the gar-den. View toward Mission Street and of the stage.

6.3. & 6.4. Yerba Buena Gardens. Users on the amphitheatre seating area located in the children’s garden.

Page 52: Green Roof at the University of California, Davis - Teaching Green

41

VegeTaTion

Plants at the Yerba Buena Gardens included, but were not

limited 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

PLanT PaLeTTe

6.7. Vegetation at Yerba Buena Gardens.

Page 53: Green Roof at the University of California, Davis - Teaching Green

42

Building/Structure

High Impact Area

Low Impact Area

Open Space/Multi-Purpose

Vegetation/ Planting Area

Seating Area

Water Feature

Entry Access

Roof Limit

yerba buena gardens - siTe anaLysis

Green Roof Limit

(6.8.)

Page 54: Green Roof at the University of California, Davis - Teaching Green

43

“Planted rooftops are still a rarity in the central downtown areas of our cities. That must change, or our cities will continue to become more crowded, sterile, and unattractive places to live and work (osmundson).”

Union Square Park is located in the North East side of San

Francisco, within the Union Square District. The site is situated

atop an underground parking garage, surrounded by Powell,

Post, Geary, and Stockton streets.

The history of this park dates back to 1850 when this land was

first contributed and reserved by John Geary, San Francisco’s

first mayor, for the development of a park (Osmundson 1999).

Union Square Park

7.1. Union Square Park. Plan view.

Page 55: Green Roof at the University of California, Davis - Teaching Green

44

The park was given its name as a result of the demonstrations for

troop support during the Civil War (Union Square). No official

park planning was done during this time, other than community

contributions. It wasn’t until the 1940s that the development

of the underground parking structure came about to become

the first of its kind in the United States. In the 1990s, not

long after its first official design, Union Square, was redesigned

after complaints that the original design was no longer up to

standards (US, San Francisco 2007). In 2000, the new design,

which had been the result of a design competition was selected.

In 2002, Union Sqaure as we now know it, was completed (US

Past & Present).

As a result of its redesign, Union Square Park gained attributes

which make it a popular place for all types of visitors that frequent

the site. It is composed largely of granite pavement, which

allows for accessibility of multi-purpose uses, easy maintenance,

and control of the site. Terracing lawn areas were also added as

a new design feature, which are in the direction of Geary Street,

giving viewers a front row seat to observe shoppers.

siTe & user anaLysis

As the center of the major shopping district, Union Square Park

serves as a place to sit and take a break. Like the district to which

it is a part of, Union Square Park is constantly busy with people

moving in and out. While visiting the site, it accommodated a

variety of people each engaging in very distinct activities. The

eastern side of the site was utilized as an art gallery where local

artists and art enthusiasts mingled. A café located in the park

accommodated the espresso and cappuccino lovers. On the

northern and southern ends of the site, individuals relax on

lawn areas, while a few sun bathed, napped, walked their dogs.

7.2. Union Square Park provides people with a place to relax and people watch.

Page 56: Green Roof at the University of California, Davis - Teaching Green

45

generaL FeaTures & Lessons

General elements that can be borrowed from Union Square

Park include multi-purpose open space, seating, and planters.

Lessons learned form Union Square Park will allow for a more

successful development at the proposed university site. One

of the main ideas that Union Square inspired was the idea

of allowing other departments to access the facility for their

uses. For example, the art department could use the site for

7.3. Union Square. Art gallery of local artist held in the center of the park.

7.4. Union Square. High rise buildings surround this park.

7.5. Union Square. People enjoying terrace seating, which also funtions as access way into the park.

Page 57: Green Roof at the University of California, Davis - Teaching Green

46

art exhibits. Asking for donations from events could help with

upholding the green roof. Providing some sort of informal

seating would also be a good idea so people could feel engaged

with the site.

VegeTaTion

A list of plants located at the site was developed. Plants at Union

Square Park included, but were not limited to the following

plants:

• Agapanthus spp. – Lily of the Nile

• Brugmansia versicolor – Angel’s Trumpet

• Penstemon spp. – Penstemon

• Phoenix canariensis – Canary Island Date Palm

• Phormium tenax – New Zealand Flax

• Prunus spp.

• Rhododendron spp. – Azalea

PLanT PaLeTTe

7.6. Vegetation at Union Square Park.

Page 58: Green Roof at the University of California, Davis - Teaching Green

47

Building/Structure

High Impact Area

Low Impact Area

Open Space/Multi-Purpose

Vegetation/ Planting Area

Seating Area

Storage

Entry Access

Roof Limit

yMca rooFToP garden - siTe anaLysis

No Access

(7.7.)

Page 59: Green Roof at the University of California, Davis - Teaching Green

48

“Perhaps the best part of this old building is its rooftop garden, where members can sunbathe in a quiet, serene and sheltered environment. Up there, high above the Tenderloin streets, you can close our eyes and pretend you’re in your own backyard without worrying about what your neighbor thinks (Tenderloin).“

The rooftop garden atop the Central YMCA is located in the

North East side of San Francisco within the Tenderloin District.

The roof garden is located atop the eastern most side of the

building that looks over Leavenworth Street and Golden Gate

Avenue.

Central YMCA Rooftop

8.1. YMCA building located on the corner of Leavenworth and Golden Gate streets.

Page 60: Green Roof at the University of California, Davis - Teaching Green

49

This roof garden has been in existence for approximately 25

years now. It was first started through the dedicated work

of YMCA volunteer Peter Hayman (Peck 2002).” Hayman

who put in a lot of initial work to create this rooftop garden,

established most of the larger trees that are still in existance on

the site. Much of the other vegetation on the site has resulted

as a collection of volunteers maintaining the garden.

The roof garden is set up so that most of the vegetation is on

the edge of the roof limit. This vegetation is mainly planted

on containers, and the plant variety varies from pine trees to

the tiniest ground cover hanging aside a pot. Most of the inner

part of the roof is left open for accessibility as a walkway. The

northern part of the roof attracted an informal picnic area,

while the center west part of it resembled an informal stage.

A small area at the southern left corner of the garden was also

dedicated as a storage space for maintenance supplies of the

garden.

Currently, the Central YMCA is looking to relocate a couple of

blocks down from its current location as the result of a need for

an improved facility and general building upgrade. However, as

part of the new facility plan, a green roof is being purposed as

there is talk to “retain sustainability and green roof consultants

including Donald Aiken Associates and Simons and Simon &

Associates (Welcome to YMCA).”

siTe & user anaLysis

Unlike the Yerba Buena Gardens or Union Square Park, the

rooftop garden located at the central YMCA is reserved for a

more serene and private space. The number of individuals at

the time of the site visit was very minimal, never having more

8.2. YMCA. Volunteer assist with upholding the rooftop garden.

Page 61: Green Roof at the University of California, Davis - Teaching Green

50

than three individual up at once. The area was used primarily

as a place to relax, as these individuals just hung out, came to

take a break, and/or mediated yoga. Through speaking with

one of the assistants of the center, it was informed that people

(primarily members) utilize the facility for personal purposes

or group activities. Members who utilize it, also volunteer in

helping maintain the garden and provide its up-keeping. For

the members that tender the garden, they find their time

volunteering on the rooftop as a way to relax, hence making this

garden functional as a healing garden.

generaL FeaTures & Lessons

General elements that can be borrowed from the Central

YMCA rooftop gardens include community planning, active

involvement with maintenance participation, Multi-purpose

open space, access way, and storage facility. Because funding

for the Central YMCA is limited, most of the effort that goes

into the rooftop garden is the result of involved members and

volunteers. The proposal of something similar for a green

roof at UC Davis would help finance maintenance expenses

if students occupying the facility were involved in its upkeep.

Designing areas that are versatile and multifunctional are ideal if

8.3. YMCA. Entry way and storage area of the rooftop garden.

8.3. YMCA. The rooftop garden provides members with a place to relax.

Page 62: Green Roof at the University of California, Davis - Teaching Green

51

considering the green roof design as a learning facility, so long

as it doesn’t take away from the main purpose of the facility. As

access to the rooftop of Hunt Hall would be a primary issue to

address in the considering for such a project, the Central YMCA

serves as an example of a simple, minimal, yet functional access

way. When designating areas for specific purposes, other

possible uses should be considered as well. As the purposed site

at the UC Davis campus would probably restrict access to such a

project, especially during later times of the day, a storage similar

to the one at the Central YMCA rooftop would be functional to

store tools that would be used on a regular basis.

VegeTaTion

Plants at the Central YMCA rooftop varied from trees, to

shrubs, to succulents, and grasses. The following is a list of

plants that were present and thriving on the rooftop:

• Bougainvillea spp. – Bougainvillea

• Iris spp. – Iris

• Pelargonium spp. – Geranium

• Phyllostachys aurea – Golden Bamboo

• Pinus canariensis – Canary Island Pine

PLanT PaLeTTe

8.5. Vegetation at YMCA roof garden.

Page 63: Green Roof at the University of California, Davis - Teaching Green

52

Building/Structure

High Impact Area

Low Impact Area

Open Space/Multi-Purpose

Vegetation/ Planting Area

Seating Area

Storage

Entry Access

Roof Limit

yMca rooFToP garden - siTe anaLysis

No Access

(8.6.)

Page 64: Green Roof at the University of California, Davis - Teaching Green

53

LocaTion

The site for the proposed green roof is located on the rooftop of

the Hunt Hall building located on the north east side of the UC

Davis campus. Hunt Hall is on the corner of Howard Way and

North Quad and is surrounded by the Plant and Environmental

Science Building, Freeborn Hall, Hickey Gym, and the Marya

Welch Tennis Courts.

Hunt Hall Site Analysis

9.1. Hunt Hall vicinity map

Page 65: Green Roof at the University of California, Davis - Teaching Green

54

rooFToP access

Currently, Hunt Hall has access to its rooftop at three different

locations the north wing, the south wing and the center.

However, these access ways are not accessible to students or

faculty and are primarily used for maintenance purposes. Also

at the center part of the building there is an elevator which may

have potential access to the roof. Access on the exterior of the

building through built-in ladders is also present.

sTrucTuraL coMPonenTs

The rooftop of Hunt Hall currently is made-up of a flat roof

with ventilation and heating system structures. The roof

appears to be of a concrete or similar impermeable material,

which is a cause of storm water runoff. The is no barrier at the

edge of the roof, so the roof is flat all around. The fact that

there is no barrier at the edges of the roof-line, should also be

considered as it may lead to a potential safety issue. The roof

does however contain many large structures of various size and

shapes, many of which will be removed after the completion of

Hunt Hall’s renovation.

sunLighT exPosure

Due to the location of the green roof, the site will get full sun

exposure throughout the day. Micro shade areas may exist on

the around of the existing structures. Minimal shade may also

be produced by trees surrounding the building.

9.2. & 9.3. Hunt Hall existing site. North (above) and South(below) sections.

Page 66: Green Roof at the University of California, Davis - Teaching Green

55

Hunt Hall Site Analysis - NORTH SECTION

Page 67: Green Roof at the University of California, Davis - Teaching Green

56

Hunt Hall Site Analysis - CENTER SECTION

Page 68: Green Roof at the University of California, Davis - Teaching Green

57

Hunt Hall Site Analysis - SOUTH SECTION

Page 69: Green Roof at the University of California, Davis - Teaching Green

58

Designing a Green Roof

Through the information attained from the research of this

projects a conceptual design of a green roof for Hunt Hall

was designed. The design is a combination of the information

gathered on the topic of green roofs in general, including the

case studies. By creating a conceptual design for Hunt Hall, I

expected to show the difference that a green roof could make

visually. As Hunt Hall is proposed as the future home for the

Landscape Architecture program, this building seemed ideal as

the students educated in this field will become the leaders in

this technology for years to come. This green roof, however, is

also intended for the use of students within other departments

such as Environmental Horticulture, Hydrology, Soil Science,

Environmental Sciences, among others.

For the purpose of this project, the information found in this

section will not go beyond a conceptual design and suggested

plant listed, and therefore will not specify how each green roof

layer applies to the proposed site. For a general understanding

of each layer including waterproofing, drainage, root barrier,

and soil, please see the Green Roof Layers section. In trying

to provide a green roof design that educates individuals on

Page 70: Green Roof at the University of California, Davis - Teaching Green

59

how each green roof type (i.e. intensive, extensive, and semi-

intensive) differs from each other, a design divided into the

three types was created. The green roof gardens were divided

so that the northern wing would represent an extensive green

roof, the center would represent a semi-intensive green roof,

and the southern wing would represent an intensive green roof.

This section will provide plan view drawings on each of the

green roof types, along with its specific plant list. Each green

roof type will be visually distinct by design and plant selection.

Each section was designated with the green roof type that was

deemed most suitable for that part of the roof on account of

access, existing structures, space and visual interest. Design

components that can not be represented in the concept plan,

but played an important role in design decisions, will also be

discussed in this section

iMPorTanT oVeraLL design coMPonenTs

Potential access Way

Since Hunt Hall already has access ways to its rooftop, the

conceptual design has kept these locations the same. However,

because these access ways are currently used primarily for

maintenance purposes, it is being proposed that these access

ways be expanded and made suitable for access by students and

faculty. The center portion of the building where an elevator

is located is proposed that the elevator access be extended

to the rooftop for purposed of making the green roof ADA

accessible. The elevator would function as the main entry to the

center portions, while the north and south wings of the building

would have a staircase.

9.4. Hunt Hall. Proposed site for a green roof.

Page 71: Green Roof at the University of California, Davis - Teaching Green

60

Dealing With existing conDitions

One of the main issues in designing a green roof for Hunt

Hall was working around the existing ventilation and heating

structures. Because these structures are quite large, coming up

with a design was difficult at first. Eventually the decision was

made to have vegetation growing up to were these structures are

as is often done in many green roof designs. By surrounding

these structures with vegetation and maintaining paths at a

decent distance away from them, potential safety concerns could

be eliminated. Also for the purpose of making these structures

more aesthetically appealing, it is also proposed that they be re-

painted.

aDDressing Potential safety concerns

Currently the proposed rooftop of Hunt Hall has no barrier

on the edge of the roof line, which may be viewed as a safety

issue, especially with large groups of people interacting on the

roof. The conceptual design proposes a three-foot high wall to

address this concern. Another potential safety issue may be the

ventilation and heating structures, which would be separated by

vegetation as stated in the previous subsection.

suitable for Vegetation

Because the proposed site is on a rooftop, all vegetation will have

full sun exposure, except for minimal areas where shade may be

produced by trees surrounding the building. For this reason

all of the suggested plant material is tolerant of full exposure

to the sun and even drought tolerant. Where a concern may

have existed for the intensive green roof, trees were provided

to create partial shade. Due to the fact that the weather in

Davis is extreme, with very dry summers, it is also proposed

that irrigation be installed, with drip irrigation being the main

system used.

The idea behind The concePT

the intensiVe green roof Design

For the design of the Intensive Green Roof, one of the main

ideas was to try and keep it as garden-like as possible. Many

of the plants selected in the suggested list are plants that are

commonly seen throughout landscapes in the city of Davis.

This was the only green roof type with trees in the design, as

it is intensive, and trees are typical. Because intensive green

Page 72: Green Roof at the University of California, Davis - Teaching Green

61

roofs are designed to be accessible, this design has the largest

amount of non-vegetative space in order to provide individuals

with enough room to move around in. Built in seating was also

incorporated in the design to accommodate large groups for

lectures or discussions on the rooftop. The curvy planters were

the result of an effort to separate visitors away from the existing

structure, as well as to break the edges of the roof. The idea

for the ground is for the combination of large tile and ground

cover to collect water that would not be collected otherwise.

Also, having this green roof on the south wing should provide

more of a visual interest for as it is the only side of Hunt Hall

facing campus.

the semi-intensiVe green roof Design

The Semi-Intensive Green Roof was limited to a space, partly

because it joins the other two types together and because this

part of the Hunt Hall is the shortest. The idea behind this

green roof was to incorporate many medium size vegetation, as

semi-intensive green roofs are comprised of just that. In order

to make it more interesting and distinct from the other two

types, a large selection of succulents and grasses were suggested

in the plant list, in an effort to use drought tolerant plants and

to create a desert-like theme green roof. Within this part of the

roof, two storage units were also proposed for the purpose of

easy access of accommodating users.

the extensiVe green roof Design

The Extensive Green Roof was design so that it would have

rolls of different ground covers lined up. All of the plants

suggested in this sections, are ground cover, with the majority

consisting of sedums, as these are the plants most commonly

used in extensive green roofs. In order to maintain minimal

activity on this green roof type, as is commonly typical, only a

small path to allow for occasional access was incorporated.

Page 73: Green Roof at the University of California, Davis - Teaching Green

62

Hunt Hall Conceptual Design - EXTENSIVE GREEN ROOF

ROOF ENTRY ACCESS

UTILITY STRUCTURES (PAINTED)

COREOPSIS GRANDIFLORA - COREOPSIS

STACHYS BYZANTINA - LAMB’S EAR

DELOSPERMA COOPERII - COOPER’S ICE PLANT

SEDUM ACRE - GOLDMOSS SEDUM

SEDUM AIZOON - STONECROP

SEDUM CAUTICOLA - WHITE STONECROP

DENDRANTHEMA PACIFICUM - GOLD CHRYSANTHEMUM

Page 74: Green Roof at the University of California, Davis - Teaching Green

63

Hunt Hall Conceptual Design - SEMI-INSTESIVE GREEN ROOF

ROOF ENTRY ACCESS

UTILITY STRUCTURES (PAINTED)

STORAGE

PENNISETUM ALOPECUROIDES ‘HAMELN’ - DWARF FOUNTAIN GRASS

OPUNTIA VIOLACEA SANTA-RITA - PURPLE PRICKLY PEAR

KNIPHOFIA UVARIA - RED HOT POKER PLANT

CAREX TESTACEA - ORANGE SEDGE

GAZANIA RIGENS - GAZANIA

Page 75: Green Roof at the University of California, Davis - Teaching Green

64

Hunt Hall Conceptual Design - INTENSIVE GREEN ROOF

ROOF ENTRY ACCESS

UTILITY STRUCTURES (PAINTED)

PERSON

LAGERSTROEMIA INDICA - CRAPE MYRTLE

PRUNUS CERASIFERA - PURPLE PLUM TREE

ACER TRUNCATUM - SHANTUNG MAPLE

RHODODENDRON SP. - AZALEA

LAVANDULA ANGUSTIFOLIA - LAVENDER

EUONYMUS FORTUNEI - WINTERCREEPER

PELARGONIUM GRAVEOLENS - GERANIUM

OPHIOPOGON JAPONICUS - MONDO GRASS

ABELIA X GRANDIFLORA - WHITE ABELIA

ROSMARINUS OFFICINALIS - ROSEMARY

Page 76: Green Roof at the University of California, Davis - Teaching Green

Conceptual Design Perspectives

Page 77: Green Roof at the University of California, Davis - Teaching Green

66

Suggested Plant List

exTensiVe PLanT LisT

Achillea spp. - Yarrow

Coreopsis grandiflora - Coreopsis

Delosperma cooperii - Cooper’s Ice Plant

Delosperma nubigena - Hardy Ice Plant

Dendranthema pacificum - Gold Chrysanthemum

Iberis sempervirens - Evergreen Candytuft

Oenothera speciosa - Pink Primrose

Phlox subulata - Moss Pink

Santolina chamaecyparissus - Lavender Cotton

Sedum acre - Goldmoss Sedum

Sedum aizoon - Stonecrop

Sedum cauticola - White Stonecrop

Sedum cauticolum ‘Lidakense’ - Stonecrop

Sedum ochroleucum - European Stonecrop

Sedum sieboldii - October Daphne

Sedum tetractinum - Chinese Sedum

Stachys byzantina - Lamb’s Ear

Page 78: Green Roof at the University of California, Davis - Teaching Green

67

seMi-inTensiVe PLanTing LisT

Agave americana - Century Plant

Agave attenuata - Foxtail Agave

Aloe nobilis - Gold Tooth Aloe

Aptenia cordifolia - Red Apple

Baccharis pilularis - Coyote Brush

Carex testacea - Orange Sedge

Ferocactus sp. - Barrel Cactuses

Festuca brachyphylla - Alpine Fescue

Festuca glauca - Blue Fescue

Gaura lindheimeri - White Gaura

Gazania rigens - Gazania

Kniphofia uvaria - Red Hot Poker Plant

Muhlenbergia rigens - Deer Grass

Opuntia basilaris - Beaver Tail Cactus

Opuntia ficus-indica - Prickly Pear

Opuntia violacea santa-rita - Purple Prickly Pear

Pennisetum alopecuroides ‘Hameln’ - Dwarf Fountain Grass

inTensiVe PLanT LisT

Abelia x grandiflora - White Abelia

Acer palmatum - Japanese Maple

Acer truncatum - Shantung Maple

Caesalpinia gilliesii - Bird-of-Paradise Shrub

Euonymus fortunei - Wintercreeper Euonymus

Lagerstroemia indica - Crape Myrtle

Lavandula angustifolia - Common Lavender

Lavandula stoechas - Spanish Laverder

Leptospermum sp. - New Zealand Tea Plant

Nandina domestica - Heavenly Bamboo

Ophiopogon japonicus - Mondo Grass

Pelargonium graveolens - Geranium

Phormium tenax - New Zealand Flax

Pittosporum tobira ‘Wheeler’s Dwarf ’ - Wheeler’s Dwarf Pitto.

Prunus cerasifera - Purple Plum Tree

Rhododendron sp. - Azalea

Rosmarinus officinalis - Rosemary

Page 79: Green Roof at the University of California, Davis - Teaching Green

68

1. American Psychological Association (APA): Roget’s New Millennium™ Thesaurus, First Edition (v 1.3.1). Retrieved May 2007, from Thesaurus.com website: http://thesaurus.reference.com

2. Beattie, David, and Robert D. Berghage. “Green Roof Research in the USA.” (2004). May 2007 <http://hortweb.cas.psu.edu/research/greenroofcenter/presentations/TextStuttgart1.pdf>.

3. Blyth, Aimee, and Leslie Menagh. “From Rooftop to Restaurant - a University Cafe Fed by a Rooftop Garden.” City Farmer. Nov. 2006. Canada’s Office of Urban Agriculture. May 2007 <http://www.cityfarmer.org/TrentRoof.html>.

4. Braiker, Brian. “Is That a Garden on Your Roof?” Newsweek Enterprise 14 Sept. 2004. Apr. 2007 <http://www.msnbc.msn.com/id/6002705/site/newsweek/>.

5. Chang, Sheng-Chieh, and Brian Pon. Heat Island Group. Aug. 2000. May 2007 <http://eetd.lbl.gov/HeatIsland/>.

6. Chicago Manual Style (CMS): Thesaurus.com. Roget’s New Millennium™ Thesaurus, First Edition (v 1.3.1). Lexico Publishing Group, LLC. http://thesaurus.reference.com (accessed: May 2007).

7. Colwell, Dara. “Green Roofs: Building for the Future.” AlterNet.Org (2007). Apr. 2007 <http://www.alternet.org/environment/48530?page=3>.

8. Dunnett, Nigel, and Noel Kingsbury. Planting Gren Roofs and Living Walls. Portland, Oregon: Timber P, 2004. 1-254.

Bibliography

Page 80: Green Roof at the University of California, Davis - Teaching Green

69

9. Easybib. May 2007 <http://easybib.com>.

10. Francis, Mark. “A Case Study Method for Landscape Architecture.” Landscape Journal 20: 15-29.

11. Grant, Gary, comp. Extensive Green Roofs in London. Vers. Volume 4, Number 1. Urban Habitats. Mar. 2007 <www.urbanhabitats.org>.

12. “Green Roof.” Wikipedia. Apr. 2007. Apr. 2007 <en.wikipedia.org/wiki/Green_roof>.

13. “Green Roof Types.” Green Roof Service, LLC. 2005. May 2007 <http://www.greenroofservice.com/types.html>.

14. “Green Roofs - Cooling Los Angeles.” 2006. City of Los Angeles. Apr. 2007 <http://www.fypower.org/pdf/LA_GreenRoofsResourceGuide.pdf>.

15. Green Roofs for Healthy Cities. Mar. 2007 <www.greenroofs.net>.

16. Hall, Loretta. “Digging for the Green.” SubsurfaceBuildings.Com. 2006. Apr. 2007 <http://www.subsurfacebuildings.com/DiggingfortheGreen.html>.

17. “Hanging Gardens of Babylon.” Wikipedia. Apr. 2007. Apr. 2007. <en.wikipedia.org/wiki/Hanging_Gardens_of_Babylon>.

18. Harris, Brandon. “Green Roof Project Looking Up.” The Traveler 25 Apr. 2007. <http://media.www.thetraveleronline.com/media/storage/paper688/news /2007/04/02/News/Green roof project looking up>.

19. “Heat Island Effect.” U.S. Environmental Protection Agency. Jan. 2007. May 2007 <http://www.epa.gov/hiri/about/index.html>.

20. Holladay, April. “Green Roofs Swing Temperatures in Urban Jungles.” USA Today (2006). Apr. 2007 <http://www.usatoday.com/tech/columnist/aprilholladay/2006-04-24-green-roofs_x.htm>.

21. “Hunt Hall Renovations.” Architects and Engineers, University of California, Davis. Feb. 2007. Apr. 2007 <www.ae.ucdavis.edu/Projweb/ProjectStatus.nsf>.

22. International Green Roof Association. May 2007 <http://www.igra-world.com/home/index.html>.

23. “Living Green Roofs - Ecological Solutions for the Modern City.” The Scandinavian Green Roof Journal. May 2007 <http://greenroof.se>.

24. “Mixed Uses and Incomes Makes San Francisco District Bloom.” Projects for Public Spaces. Apr. 2007 <http://www.pps.org/civic_centers/info/MgmtModels/yerba_gardens>.

25. “Modern History Source Book: Hernan Cortes: From Second Letter to Charles V, 1520.” Internet Modern History Source Book. June 1998. Paul Halsall. Apr. 2007 <http://www.fordham.edu/halsall/mod/1520cortes.html>.

26. Modern Language Association (MLA): Roget’s New Millennium™ Thesaurus, First Edition (v 1.3.1). Lexico Publishing Group, LLC. 12 May. 2007. <Thesaurus.com>.

Page 81: Green Roof at the University of California, Davis - Teaching Green

70

27. Noyes, Katherine. “Plant a Green Roof.” Charity Guide. 2006. Apr. 2007 <http://www.charityguide.org/volunteer/fehours/green-roof.htm>.

28. Osmundson, Theodore. Roof Gardens: History, Design, and Construction. New York, New York: W.W. Norton & Company, 1999. 1-318.

29. Parker, Clifton B. “Building the Future.” CA&ES Outlook (2003).

30. Peck, Donna. “Rooftop Pleasures: Revel in Nature Atop Ten SF Rooftop Gardens.” SFGate. 25 May 2002. Apr. 2007 <http://www.sfgate.com/cgi-bin/article.cgi?file=/gate/2002/05/25/rooftops.DTL>.

31. Penn State Center for Green Roof Research. July 2006. The Pennsylvannia State University, College of Agricultural Sciences. May 2007 <http://hortweb.cas.psu.edu/research/greenroofcenter/presentations/TextStuttgart1.pdf>.

32. “Photo Gallery.” Green Roofs for Healthy Australian Cities. May 2007 <http://greenroofs.wordpress.com>.

33. “Roof Garden.” Wikipedia. Apr. 2007. Apr. 2007 <en.wikipedia.org/wiki/Roof_garden>.

34. Snodgrass, Edmund C., and Lucie L. Snodgrass. Green Roof Plants: a Resource and Planting Guide. Portland, Oregon: Timber P, 2006. 1-189.

35. Stevenson, Violet. Pation, Rooftop and Balcony Gardening. London: W.H. & L. Collingridge Ltd., 1967.

36. “Storm Water Pollution Prevention - Overview.” U.S. Environmental Protection Agency. Apr. 2006. May 2007 <http://www.epa.gov/reg3wapd/stormwater/index.htm>.

37. “Tenderloin Treasures.” Etc. (Spring 2003): 18-21. Apr. 2007 <http://theguardsman.com/etc/spring2003/page18-22.pdf>.

38. “The Green Roof Research Program at Michigan State University.” Green Roof Research Program. Aug. 2006. Michigan State University, Department of Horticulture. May 2007 <http://www.hrt.msu.edu/greenroof/Green%20Roof%20Research%20at%20Michigan%20State%20University>.

39. “The Leaves are Changing, But Students Keep It Green At Virginia Wesleyan.” Virginia Wesleyan College. Mar. 2007. May 2007 <http://www.vwc.edu/news_events/feature/2005/greenroofproject.php>.

40. Thompson, William J., and Kim Sorvig. Sustainalbe Landscape Construction: a Guide to Green Building Outdoos. Covelo, California: Island P, 2000. 112-115.

41. “Union Square.” San Francisco Neighborhood Guide. Apr. 2007 <www.sfgate.com/traveler>.

42. “Union Square, San Francisco.” Wikipedia. Apr. 2007 <http://en.wikipedia.org/wiki/Union_Square_San_Francisco>

43. “Union Square Past & Present.” Apr. 2007 <www.media.wiley.com>.

Page 82: Green Roof at the University of California, Davis - Teaching Green

71

44. “Welcome to the Shih Yu-Lang Central YMCA.” YMCA of San Francisco Central. Apr. 2007 <http://ymcasf.org/Central>.

45. “Why is Storm Water a Problem?” Clean Water Education Partnership. May 2007 <http://www.nccleanwater.org/img/photos/stormwater_problem_large.jpg&imgrefurl>.

46. “Yerba Buena Center.” San Francisco Redevelopment Agency. Apr. 2007 <http://www.sfgov.org/site/sfra_page.asp?id=5610>.

47. “Yerba Buena Gardens.” Wikipedia. Apr. 2007 <http:// en.wikipedia.org/wiki/Yerba_Buena_Gardens>.

48. “Yerba Buena Gardens.” Yerba Buena Gardens. 2004. Apr. 2007 <http://yerbabuenagardens.com>.