GREEN ROOFS IN ORLANDO

Senior Project

Rollins College

Green roof in Chicago, IL,

image from UChicago

ENV 413 SENIOR SEMINAR

Senior Seminar is the capstone experience in the

interdisciplinary Environmental Studies major. The course

emphasizes key ideas from the field of Environmental

Studies and their relationship to contemporary environmental

issues. Senior Seminar is also a Civic Engagement class, and

we will partner with the Orlando Sustainability Office.

The course is designed around a field-based research

project that requires:

1. A booklet (5.5 by 8.5 inches) containing 2,000 words (not

including endnotes) that will:

A. Address a component of sustainability identified in

the Orlando Greenworks Community Action Plan, and

3 UN Sustainability Goals.

B. Apply at least one principle from each of the above

categories to define project.

C. Integrate research that provides 3 precedents, a set of

findings, including costs, benefits and implementation

strategy.

D. Include endnotes

E. The booklet will be highlighted by at least 3 original

charts, drawings, and/or plans that will be the focus

of the presentation

2. A seven-minute presentation limited to 6 slides with up to

4 original charts, drawings, and/or plans that will be the

focus of the presentation.

GREEN ROOFS

Green roofs are a form of green infrastructure that manage

stormwater, expand roof life up to 60 years, reduce air-

conditioning costs, mitigate the “heat island” effect, improve

air quality, and provide wildlife habitat. In addition, they

minimize environmental externalities including sewer

overflow, carbon monoxide impact, and acid rain.1 This

project offers a model green roof design for an Orlando public

school, Jones High School. It meets the Greenworks Plan’s

2040 goals to (1) enhance Orlando’s reputation as “The City

Beautiful” by promoting sustainable landscaping practices, (2)

expand education and outreach efforts to increase

understanding of how to manage water resources and

pollution prevention, (3) ensure Orlando mitigates inland

flooding during future extreme weather events, and (4) reduce

gross potable water consumption per capita by 20%.2

Green roof benefits,

image from the

Centre for

Architectural

Ecology

1

Image from

the ZinCo

U.N. SUSTAINABLE DEVELOPMENT GOALS

“Obtaining a quality education is the

foundation to creating sustainable

development. Inclusive education helps

equip locals with the tools required to

develop innovative solutions to the world’s

greatest problems.”4

“Upgrade infrastructure and retrofit

industries to make them sustainable, with

increased resource-use efficiency and

greater adoption of clean and

environmentally sound technologies and

industrial processes, with all countries

taking action in accordance with their

respective capabilities.”5

This goal aims to “protect and restore water-

related ecosystems, including mountains, forests,

wetlands, rivers, aquifers and lakes” by 2020 and

“by 2030, substantially increase water-use

efficiency across all sectors and ensure

sustainable withdrawals and supply of freshwater

to address water scarcity and substantially reduce

the number of people suffering from water

scarcity.“3

2

PRECEDENTUNIVERSITY OF

CENTRAL FLORIDASTUDENT UNION

In 2005, UCF became the first public school in Florida to install a

green roof through a $340,000 grant from the Department of

Environmental Protection. The green roof overlays an expanded

Student Union and is used as a research project. Half the roof was

left bare and the two sides were compared for temperature, run off,

and roof condition. This extensive green roof has 4 inches of green

materials, 3 inches of growth media (either clay mix or tire crumb

mix, Bold & GoldTM), 2 inches of drainage media and 1 inch of

protection media.6 The expanded clay in Bold & GoldTM provides

outstanding nitrogen and phosphorus extraction, according to Dr.

Wanielista.7 Funds to develop the growing media also came from

the DEP.8 Below the protection media are two layers; insulation

layer and waterproof membrane. A separation fabric between the

drainage media and growing media helps prevent drainage clogs.

Native and non-native plants including Helianthus debilis,

Gaillardia pulchella, Lonicera sempervirens, Myricanthes fragrans,

Clytostoma callistegiodes, Tecomeria capensis, and

Trachelospermum jasminoides sit atop the growing media.9 Using a

cistern places run off reduction at 87%.10 Over the course of a year,

the green roof reduced temperatures by 30% from 130 to 91oF.11

UCF has used the knowledge its gained to build additional green

roofs throughout Orlando in conjunction with Tecta America.12

UCF Student Union green roof,

images from University of Central

Florida

3

PRECEDENTMUSIC CITY CENTER

NASHVILLE, TN

Completed in 2012, Nashville’s Music City Center’s 4-acre green roof

is the largest in the southeast and composed of 3 separate green

spaces on a wavy roof that resembles the rolling hills of Tennessee.

The underlying layer is a waterproof membrane that ties into a system

of ground screens that protects the roof from leaks. Fourteen different

kinds of sedum overlay a growing medium of clay, soil, and

compost.13 A capillary fabric under the growing media stabilizes

plants during wind events and distributes rainwater into a 360,000-

gallon cistern.14 The roof has six structural layers, but only weighs

17.5 pounds per square foot.15 Water from the cistern is used for

flushing toilets and irrigation; accounting for 48% of MCC’s total

water usage.16 This roof also maintains beehives that produced 89

pounds of honey in 2018.17 This project was built by Greenrise

Technologies specifically for MCC with specialized soil, drainage

material, and plants from local sources.18

Nashville City Center green roof,

image from Nashville City Center

4

PRECEDENTREGIS HIGHSCHOOL

MANHATTAN, NY

In 2010, Regis High School installed a 25,000 square foot green roof. It

includes a 20-kW solar panel array, two beehives, a classroom, scientific

monitoring equipment, a weather station, temperature and soil moisture

monitoring stands, a flow rate measurement system, biodiversity

monitoring equipment, and an astronomy observation area.19 The second

largest green roof in Manhattan when it was completed, Regis High School

received the Sustainability Award from the Upper East Side Historic

District. In addition to improving the building envelope, it stabilizes the

interior climate while lowering the cooling costs.20 Designed and

manufactured by Long Island Compost Corporation, the soil is 4 inches in

depth and provides habitat for a variety of sedum plants, native grasses,

native perennials, and wildflowers.21 The system does not require irrigation

and the native plants include: Asclepias tuberosa, Baptisia tinctoria,

Eupatorium, hyssopifolium, Panicum virgatum, Schizachyrium scoparium,

Solidago nemoralis, Sorghastrum nutans, Symphyotrichum laeve,

Danthonia spicata, Deschampsia flexuosa, Dichanthelium clandestinum,

Eupatorium sesslifolium, Lespedeza hirta, Pycnanthemum tenuifolium,

Rudbeckia hirta, and Solidago odora.22 The American Recovery and

Reinvestment Act of 2009 funded the $476,000 project and the ongoing

maintenance.23 The Earth Institute at Columbia University installed

monitoring equipment, which students use to conduct ongoing research and

is streamed online.24 Researchers from Columbia intend on implementing a

experimental meadow featuring native grasses.25

Regis High School green roof,

image from Regis High School

5

IMPLEMENTATION STRATEGIES

The initial costs for installing and maintaining green roofs varies

depending on its size and the vegetation. The initial costs are alleviated

by life cycle benefits that include stormwater mitigation, reducing both

the heat island effect and air conditioning costs, and improving air

quality. According to Dr. Martin Wanielsta, professor of Civil

Engineering and Environmental Sciences at UCF, a green roof at Jones

High School, would provide an invaluable educational tool for

children.26

The City Stormwater Quality Cost Share Policy in Raleigh, NC provides

financial and technical assistance for projects that reduce water quality

impacts.27 Incentives apply to any property owners contributing to the City

of Raleigh Stormwater Utility Fee and providing water quality

improvements in excess of current regulatory requirements. There are two

cost share methods: 1) a 50% City funding if the petitioner maintains the

project to ensure it functions for 5 years and 2) a 75% City funding if the

petitioner ensures the functions properly for 10 years. 28

UCF Student Union

green roof, images

from University of

Central Florida

6

Small Green Roof

Workshop in Raleigh,

images by

greenroofs.com

IMPLEMENTATION STRATEGIES

The city of Portland provided funding for over 130 green roof projects

between 2008 and 2012. “Environmental Services offered property

owners and developers an ‘ecoroof’ construction incentive of $5 per

square foot. Ecoroof costs vary according to project size, design and

complexity. Environmental Services granted almost $2 million in

incentives… that created more than 8 acres of ecoroofs managing an

average of 4.4 million gallons of stormwater annually.” 29

Ecotrust green

roof, images

from Brian

Libby

7

New York City’s 2019 tax abatement program is a two-tiered

system that includes a citywide abatement of $5.23 per square foot.

In addition, it offers a $15.00 per square foot abatement for green

roofs located within specially designated districts. This incentive

only applies to green roof systems with a growing media layer at

least 4″ in depth. 30

New York

City Tax

Abatement

Graphic,

image by

Urbanstrong

MODEL FOR JONES HIGHSCHOOL

The proposed 25,000 square foot green roof for Jones High School

requires materials including soil, geosynthetic wind net, aggregate

drainage, a root barrier, and a waterproof membrane. The estimated

cost of implementation is ~$255,000.31 The vegetation will include

four native Florida perennials that were implemented on the UCF

green roof: Muhlenbergia capillaris, Evolvulus glomeratus, Ipomoea

pes-caprae, and Lotus corniculatus.32 The UCF Green roof program

irrigates them with one-inch of water a week and fertilizes them

twice a year.33 Three varieties of Sedum spurium, and one variety of

Sedum kamtschaticum will be incorporated for their durability to

varying climate consequences such as moisture, drought, shade, and

full sun exposure.34 The orange circle shows where the green roof

will be placed.

8

Jones High School, image from Google Earth

COSTS & BENEFITS

9

10,000 ft2 (all values

from GSA)35

25,000 ft2

(estimates based

on 10k and 50k ft2

roofs)

50,000 ft2 (all

values from

GSA)36

Total cost of

implementation

- $11.40/ ft2 - ~$10.20/ ft2 - $9.70/ ft2

Cost of maintenance - $17.70/ ft2 - ~$17.40/ ft2 - $17.00/ ft2

Net present value

(NPV) stormwater

(fees and related

maintenance)

$13.6/ ft2 ~$13.4/ ft2 $13.20/ ft2

NPV energy (savings

on HVAC)

$6.80/ ft2 ~$7.20/ ft2 $8.20/ ft2

NPV (total;

installation &

maintenance + NPV

stormwater and

energy)

$2.70/ ft2 ~3.50/ ft2 $4.50/ ft2

ROI (Total) 224% ~235% 247%

Payback (in years) 6.2 ~5.9 5.6

Internal rate of return 5.2% ~5.5% 5.9%

Qualitative benefits

Run off • Reduces run off by up to 65%37

Sedum contribute to ~40% of this

reduction38

• Adds 3 hours to the time run off takes to

get to sewer39

• Increases evapotranspiration by 100%

Stormwater Retention • Permanently retains first ½ - ¾ inch of

rainfall40

• Ability to collect water and use for

nonpotable needs (flushing toilets,

irrigation, etc.)

Temperature • Max temp. conventional roof: 150oF

• Green roofs have surface temperatures

30-40oF lower than conventional roofs41

• Decreased Heat Island Effect42

Real estate value • Increases real estate value43

Community benefits • Aesthetics, improved air quality,

decreased Heat Island Effect, increased

productivity44

• Hands-on sustainability education

Jones High School ModelSquare feet: ~25,000

Green roof type: extensive

Materials: Native & non-native

plants, Bold & GoldTM growing

media, aggregate drainage, and

protection membranes

10

Scale: white block, 2’ x 2’ x 10’

Legend

Muhlenbergia capillaris,

Evolvulus glomeratus,

Ipomoea pes-caprae

Lotus corniculatus

Sedum sp.

EXTENSIVE GREEN ROOF LAYERS

11

A layered view of the proposed green roof that includes (top to bottom) 3’’ of

growing media, 1/8’’ filter/separation layer, 2’’ aggregate drainage layer,

1/4’’ moisture retention mat, and a 0.091’’ (2.3mm) waterproof membrane;

adding up to ~6’’ (top left image).45 These layers should have a dry weight of

~19 lb/ ft2 and a saturated weight of ~26lb/ ft2.46

Scale: grey block, 6’’ x 1.36’’ x 1.1’’

CITATIONS

1. “Living Roofs: Modern Green Roof Technology.” Modern Green Roof / Living Roof

Technology. Green Roof Technology. Accessed November 12, 2019.

http://www.greenrooftechnology.com/living-roof.

2. City of Orlando, Community Action Plan (Orlando, 2018), 41.

3. “Water and Sanitation - United Nations Sustainable Development.” United Nations.

United Nations, 2015. https://www.un.org/sustainabledevelopment/water-and-sanitation/.

4. “Education - United Nations Sustainable Development.” United Nations. United

Nations, 2015. https://www.un.org/sustainabledevelopment/education/.

5. “Infrastructure and Industrialization - United Nations Sustainable Development.” United

Nations. United Nations, 2015. https://www.un.org/sustainabledevelopment/infrastructure-

industrialization/.

6.Wanielista, Marty, Melike Minareci, and Necati Catbas. “Green Roofs and Wind

Loading” (Orlando, 2011), 15-22.

7. Ibid.

8. Sonne, Jeff. “Evaluating green roof energy performance.” ASHRAE, Inc. 2006.

9. Wanielista, Marty, Melike Minareci, and Necati Catbas. “Green Roofs and Wind

Loading” (Orlando, 2011), 15-22.

10. Ibid.

11. Sonne, Jeff. “Evaluating green roof energy performance.” ASHRAE, Inc. 2006.

12. “Stormwater Team's Patented Soil Media Deployed in Starbucks' Newly Installed

Green Roof at Downtown Disney.” UCF Stormwater Management Academy. Accessed

February 26, 2020. http://stormwater.ucf.edu/starbucks/.

13. ”Up on the Green Roof.” Music City Center Sustainability. Nashville Music City

Center. Accessed November 12, 2019

https://www.nashvillemusiccitycenter.com/sites/default/files/media/up_on_the_mcc_roof_

2018.pdf

14. Ibid.

15. Ibid.

16. Ibid.

17. Ibid

18. Bertone, Rachel, John McBryde, Jessy Yancey, and Jessica Walker Boehm. “Music

City Center Green Roof Brings Life to Nashville.” Farm Flavor, March 16, 2018.

https://www.farmflavor.com/tennessee/music-city-center-green-roof-brings-life-to-

nashville/.

19. “Regis High School.” Greenroofs.com, 2014.

https://www.greenroofs.com/projects/regis-high-school/.

20. Ibid.

21. Ibid.

22. Ibid.

23. “Rep. Maloney Celebrates a New Green Roof at Regis High School.” Congresswoman

Carolyn Maloney, September 20, 2011. https://maloney.house.gov/media-center/press-

releases/rep-maloney-celebrates-new-green-roof-regis-high-school.

24. “Regis High School: The Centennial Celebration.” Regis High School. Accessed

February 26, 2020. https://www.regis.org/2014/multimedia/roof.cfm.

25. Ibid.

26. “Patented Soil Media on Green Roofs Throughout Florida.” UCF Today. August 19,

2014. https://www.ucf.edu/news/stormwater-teams-patented-soil-media-now-deployed-

50000-square-feet-green-roofs-throughout-florida/.

13

27. Inhabitect, LLC. 2014. Green Roofs for Healthy Cities. Toronto, Canada.

http://www.traversecitymi.gov/downloads/green_roof_policies_incentieves_programs_

case_studies_32014.pdf

28. Ibid.

29. “Ecoroof Incentive.” Ecoroof Incentive RSS. City of Portland, November 5, 2015.

https://www.portlandoregon.gov/bes/article/547491.

30. “NYC's Green Roof Tax Abatement Program Is Back - and Better Than Ever.”

Urbanstrong, January 10, 2020. https://www.urbanstrong.com/nyc-green-roof-tax-

abatement-program/.

31. GSA. “The Benefits and Challenges of Green Roofs on Public and Commercial

Buidlings.” The Benefits and Challenges of Green Roofs on Public and Commercial

Buidlings. GSA, May 2011.

https://www.gsa.gov/cdnstatic/The_Benefits_and_Challenges_of_Green_Roofs_on_Pu

blic_and_Commercial_Buildings.pdf.

32. Wanielista, Marty, Melike Minareci, and Necati Catbas. “Green Roofs and Wind

Loading” (Orlando, 2011), 63.

33. Ibid.

34. Cantor, Steven L. Green Roofs in Sustainable Landscape Design. New York: W.W.

Norton & Co., 2008. ,76

35. GSA. “The Benefits and Challenges of Green Roofs on Public and Commercial

Buidlings.”

36. Ibid.

37. Ibid.

38. Ibid.

39. Ibid.

40. Ibid.

41. Ibid.

42. Ibid.

43. Ibid.

44. Ibid.

45. Beatley, Timothy. Handbook of Biophilic City Planning & Design. Covelo: Island

Press, 2017. 246.

46. Ibid.

47. “319 Grant: Current Guidance.” EPA. Environmental Protection Agency,

December 4, 2019. https://www.epa.gov/nps/319-grant-current-guidance.

48. “Clean Water State Revolving Fund (CWSRF).” EPA. Environmental Protection

Agency, February 6, 2020. https://www.epa.gov/cwsrf.

49. “Nonpoint Source Funds.” Florida Department of Environmental Protection.

Florida Department of Environmental Protection, 2020. https://floridadep.gov/wra/319-

tmdl-fund.

50. “Lovett New Portman Family Middle School.” Lovett New Portman Family Middle

School. Atlanta , GA: The Lovett School, 2019. https://bbk12e1-

cdn.myschoolcdn.com/ftpimages/1059/misc/misc_157635.pdf.

51. Ibid.

52. Ibid.

CITATIONS 14

IMAGE CITATIONS

Front cover:

http://burnhamplan100.lib.uchicago.edu/newberryexhibit/green-

metropolis/index.shtml

Page 1:

https://zinco-usa.com/why-have-green-roof

https://commons.bcit.ca/greenroof/faq/why-green-roofs-benefits/

Page 2:

https://www.un.org/development/desa/disabilities/envision2030-goal6.html

https://www.un.org/development/desa/disabilities/envision2030-goal4.html

https://www.un.org/development/desa/disabilities/envision2030-goal9.html

Page 3:

https://www.greenroofs.com/projects/student-union-expansion-at-the-

university-of-central-florida-ucf/

Page 4:

https://www.nashvillemusiccitycenter.com/about/sustainability/green-roof

Page 5:

https://www.greenroofs.com/projects/regis-high-school/

Page 6:

https://www.ucf.edu/news/stormwater-teams-patented-soil-media-now-

deployed-50000-square-feet-green-roofs-throughout-florida/

https://www.greenroofs.com/projects/raleigh-small-green-roofs-workshop/

Page 7:

https://chatterbox.typepad.com/portlandarchitecture/2010/08/a-new-green-

roof-for-ecotrust.html

https://www.urbanstrong.com/nyc-green-roof-tax-abatement-program/

Page 8:

Google Earth

15

On my honor, I have not given nor received nor witnessed any

unauthorized assistance on this work