Nashville Civic Design Center

Green Roofs Case Study A green roof consists of vegetation, soil or a growing medium, planted over a waterproofing membrane. Root barriers, drain-age and irrigation systems may be included as additional layers. Green roof technology typically utilizes some other forms of green technology, such as rooftop ponds, solar panels or pho-tovoltaic modules. Colored green roofs or green shingles, as well as container gardens, where plants are maintained in pots, are not considered to be green roofs. Green roofs are also sometimes referred to as eco- vegetated or living roofs.

http://www.epa.gov/hiri/strategies/greenroofs.html

Benefits

Green roofs are used to:• “Provide amenity space for building occupants – in effect

replacing a yard or patio.• Grow fruits, vegetables, and flowers.• Reduce heating and cooling loads on a building • Reduce the urban heat island effect.”• Reduce stormwater loads by holding large amounts of rain-

water on site• Absorb air pollution, collect airborne particulates, and store

carbon.

• Protect underlying roof material by eliminating exposure to the sun’s ultraviolet (UV) radiation and extreme daily tem-perature fluctuations.

• Serve as living environments that provide habitats for birds and other small animals.

• Offer an attractive alternative to conventional roofs• Reduce noise transfer from outdoors.• Insulate building from extreme temperatures

Green roofs also reduce storm water run off by absorbing water in a manner, similar to a sponge. “Researches estimate that three to five inches of soil or growing medium absorbs 75% of rain events that are one-half inch or less.”1 The plants retain pollutants in their soil and release the water back into the atmosphere via condensation and transpiration.

Types

Green roofs can be classified into three different types: inten-sive, semi-intensive and extensive. The categorization results from the “depth of planting medium and the amount of main-tenance they need.”2 The intensive type calls for reasonable depth of soil or conventional lawns. It is very labour and time intensive. Irrigation, fertilizing and other maintenance is re-quired. Extensive green roofs are practically self-sustaining. They need minimal annual maintenance (weeding and fertilizer) and can be seeded on a very thin layer of soil. The semi-intensive green roof requires some maintenance between the two other types.

Another differentiation of green roofs is between pitched and flat roofs. Pitched roofs are more traditional and simply de-signed, “because the pitch of the roof reduces the risk of wa-ter penetrating through the roof structure, allowing the use of fewer waterproofing and drainage layers.”3

Disadvantages, Costs and Advantages

Disadvantages of green roofs include added costs. Depending on the roof type, the structure of the building and including

Nashville Civic Design Center • Green Roof Case Study • Nashville area Projects • www.civicdesigncenter.org 1

Sources:

1 http://www.epa.gov/hiri/strategies/greenroofs.html

2 http://en.wikipedia.org/wiki?Green_roof

3 http://en.wikipedia.org/wiki/Green_roof

material and labor, green roofs cost between 5 to 35 dollars per square foot. Sometimes roots penetrate the waterproof membrane and the waterproofing system requires a special structure. Another factor for high costs is the limited number of green roof contractors in a area particular.

But as the popularity of green roofs increases the price will undoubtedly decrease. Vegetation can extend the life of a roof, because less solar energy reaches the roof substrat, limiting the damage from UV radiation. Daily temperature differences are decreased and money is saved by using less energy in heating and cooling the building.

Examples

Green roofs are becoming common in Chicago, as well as At-lanta, Portland and other U.S. cities. Chicago’s City Hall is one of the earliest and most well-known green roof case studies.

Green roof of Chicago City Hall, Illinois.

Different designs of green roofs can also be found all over the country. Following are listed some examples in american cities, San Francisco, New York, Seattle.

Shield Systems Inc. Green Roof,St. Louis, MO, USA

Green roof of the California Academy of Sciences, in San Francisco.

An intensive roof garden in Manhattan

The Ballard Library in Seattle

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Green Roofs in Nashville

In recent years, green roofs have started to become part of Nashville’s cityscape. There are 343,900 sf of completed Green Roofs and 167,000 sf under construction (This does not in-clude the Gulch retail building behind ICON. It does includethe Snodgrass Building). This case-study introduces the latest projects of green roofs in Nashville and Middle Tennessee.

1.) Music Hall of Fame Park

Client:Metro Parks & Recreation

Landscape Architect:Hawkins Partners, Inc.

Completed:2002

Size / Area:3.1 acres

Principal Use:public civic space, underground parking structure

Location / Address:block between 4th and 5th Avenue South and Demonbreun

Green Roof Country Music Hall of Fame Park

Innovative Features:- intensive green roof where pedestrian spaces and landscape sit on top of subterrnean parking garage

Brief Description:- park is a full city block totalling a little over 3 acres- sits atop a 1-story subterranean parking garage- provided a much needed civic green space that had been lack ing in Downtown Nashville

2.) Neuhoff Packing Plant Redevelopment

Owner: Stephen and Louis McRedmond and Anita Sheridan

Architect: Eric Shriner of Pivot Design and Consulting LLC Portland Oregon Landscape Architecture

Roofing Membrane:Famos

Green Roof Systems:Mike Perry of Building Logics

Construction Completed: Fall 2002

Contractor: Houston Herbert of R.D. Herbert & Sons

Size / Area: 2,600 sq. ft. building

Principal Use: mixed-use development

Location / Address: 13131 Adams Street, East Germantown, six blocks from State Capitol, on a rock bluff overlooking the Cumberland River

Neuhoff Green Roof

Innovative Features:- soil mix was organic composted bark mix- all plant material was local cedar glade species- development focused on arts and ecology and employing innovative techniques, and regenerative design

Brief Description:- green roof type: extensive- plants used, grow in full sun, shallow nutrient poor soil with limestone base periodic inundation

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followed by extended drought and TN Cornflower- green roof system: single source provider- roof slope: 0%- abandoned former used meat packing plant in 1977

3.) Public Square Nashville

Client:Metro Parks

Architect: Tuck Hinton Architects

Landscape Architect: Hawkins Partners Inc. and Wallace Roberts Todd

Civil Engineer:Barge Waggoner Sumner Cannon

Structural Engineer:Walker Parking

Construction Completed:Fall 2006

Size / Area:98,010 sq. ft. building, green roof portion is 2.25 acres

Principal Use:public civic space for all to enjoy

Location / Address: Nashville Davidson County Courthouse

Public Square Green Roof

Innovative Features: - 57,000 gallon, below-grade tank for rainwater collection is filtered and used to irrigate the plants in park- several historically significant components from original site including reused granite steps, historical war monuments and commemorative plaques

Brief Description:- green roof type: intensive- green roof system; Single Source Provider- roof slope: 1%- 5 level subterranean parking garage for 1200 cars- rooftop is public plaza- over 43 different species of plants, of which 81 % are native to the Southeast region

4.) Westview Condos

Owner: Ron McClarin was building owner but now is owned by the condominium owners

Landscape Architect: Lose and Associates now with Design Resource

Native Plant Specialist: Mike Berkley of Growild Inc.

Roofing Membrane:Famos

Soil: Mr. Natural

Construction Completed: November 30, 2005

Westview Green Roof

Green Roof Consultant: Ralph P. Velasquez of Integrated Building Technologies LLC

Constructor: Houston Herbert of R.D. Herbert and Sons

Size / Area: 3,000 sq. ft. building

Principal Use: high end and luxury condominiums (7 units from 1,500 - 3,000 sq. ft.)

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Location / Address: 180 9th Avenue North Nashville, TN 3720

Innovative Features: - received grants from TVA- 100% native landscape with wildflowers (including the endangered Echinacea Tennesseensis), grasses, vines,shrubs (including blueberries for eating) and trees- 4 separate sitting areas (including a gazebo) for home owner entertainment, gas grill and wine cooler- all pavers are made of recycled tires- 360 degree vista of State Capital and Downtown- provides a functional and recreational space for residents

Brief Description:- green roof: intensive and extensive all native land scape- green roof system: Single Source Provider- roof slope: 1%- city’s first residential green roof project

5.) Shelby Park Nature Center

Client:Metro Parks & Recreation

Architect: Everton Oglesby Architects

Landscape Architect:Hodgson & Douglas LLC

Construction Completed:Fall 2007

Size / Area: 3,175 square feet building

Shelby Park Nature Center Green Roof

Principal Use:educational center, public meeting space and offices

Location / Address: Shelby Bottoms on the east bank of the Cumberland River, east bank of Shelby Park

Innovative Features: - rain chains for rainfall runoff from different roof top sections- water runoff is collected into rain catch basin- solar shades on river facing windows

Brief description:- 4 inches special soil medium- 7 varieties of drought tolerant sedum plants that will spread to form a solid vegetative covering over the next 2 – 3 years- special briefing by Tremco horticulturalist on main tenance of green roof and structure- roof type: extensive- first roof over occupied public space- all sedums Tremco membrane

6.)Freeman Webb Office Building

Client:Freeman Webb Company

Architect:Hastings Architects

Landscape Architect:Hawkins Partners, Inc.

Construction Completed:2008

Size / Area:10,000 sq. ft.

Principal Use:to provide an amenity for the office users

Location Address:Bedford Avenue, Green HillsInnovative Features:project is currently registered as a LEED Gold Core and Shell

Brief Description:- green roof is an extensive / semi-intensive green roof offering amenity space for the building users- several gathering areas included in the design which will accomodate both small and large groups alike

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7.) Gulch Development

Developer:Amanda and Michael Lindseth of NextGen Properties LLC

Architect: Steve Powell of Powell Design Studio PLLCC

Constructor: The Conseco Group

Construction Start: December 2008

Opening:Summer 2009

Size / Area: 7,000 sq. ft. building

Principal Use: Restaurant

Location / Address: 1000 Division Street, formerly a Citgo gas station

The Gulch Green Roof outline/ draft

Innovative Features: - use of recycled building materials and asphalt from site- water-permeable parking areas- rain gardens- high-efficiency engineering systems

LEED Consultant: Wilmont Inc.

Brief Description: - two story building- built to national environmental standards- native Tennesseean plants and sedums- $ 1.1 million development- less energy while reducing environmental impact- Construction costs will be about 10% more that typical retail projects but finished appraised value will be about 2% more. Savings between 30 – 50% on utilities and longer life for roof

8.) Tennessee Tower

Client: State of Tennessee

Architect:Jack Freeman and Associates

Landscape Architect:Hodgson & Douglas LLC

Engineer:TLC Engineering

Opening:Fall 2009

Size / Area:40,000 sq. ft. (40% hardscape, 60% green roof)

Principal Use:Public and private gathering place, passive use (eating lunch, relaxing, napping)

Location / Address:Block between Union and Charlotte, 7th and 8th Avenue, on axis with both, legislative Plaza and Courthouse Square

Innovative Features: A all native palette was established

Tennessee Tower Green Roof Design

Brief Description:- Tennessee Tower is modern skyscraper designed by SOM Architects in the 1960’s- as part of this building a 40,000 sq. ft. plaza (over the third floor) was constructed of white concrete and travertine paver bands- 4 rectangular raised planters with canopy trees and scrubs were also included in the design- over time, the 4th floor entrance was closed to the public and plaza became an empty, bleak and unused space - 2008 plaza’s waterproof membrane needed to be replaced

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due to leaks: State of Tennessee hired design team to redesign space and include a semi-intensive green roof to be used by general public and state employees- Tennessee Tower is State’s largest office space- new green roof design includes planters of varying depths from 27’’ to 12’’- native canopy trees, flowering trees, shrubs, perennials and areas of lawn to accomodate larger gatherings- seating areas with benches were designed into the space, as well as several contemporary steel trellis shade structures

Tennessee Tower Green Roof Detail

9.) The Pinnacle at Symphony Center

Developer: Barry real Estate

Architects:Everton Oglesby ArchitectsPickard Chilton and Associates of New Haven, Conn.

Opening: January 2010

Size / Area:30,000 sq. ft. green roof

Principal Use: mixed use with office space, restaurant, retail space fitness fa-cility and parking

Location / Address: Between 3rd Avenue and 2nd Avenue along Demonbreun; across from Schermerthorn Symphony Center in SoBro

Innovative Features: - will recycle its own water- catched water used for flushing toilets, urinals and irrigating the building

The Pinnacle Green Roof Plan

Brief Description:- 29 story building- green roof will be above parking area which accounts for about half of the building’s 1,2 million square feet - green roof overlooking Nashville with seating and wireless Internet access- green roof includes two major gather areas: - 1st area is the multi-tenant space designed to allow large tent events - 2nd area is created for a more intimate setting. al lows people to get to the edge and maximize the views- private terrace provided for a single tenant- takes advantage of views to skyline, bridge and river, 48 seats- 25% semi-intensive green roof- 75% extensive green roof- 63% reduction of stormwater run-off

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Other Projects in the Region

1.) Nissan Headquarters Franklin

Client:Nissan North America

Architect: Gresham, Smith and Partners

Constructor: Skanska USA

Completed;July 22, 2008

Size / Area: 7,800 sq. ft. building

Principal Use: Headquarter offices for Nissan North America

Location / Address: 1 Nissan Way, Franklin, TN 37067

Nissan Headquarter Franklin Green Roof

Innovative Features: - sun shades and low E-glass- 6 feet deep Aluminium sunshade outriggers

Brief Description:- 460,000 sq. ft. corporate facility including 1,100 car parking structure and fitness center on a 50 acre site in Franklin, TN for a major automotive maker- 10 story, S-shaped building- 6 varieties of creeping red sedum

2.) City of Franklin Police Headquarters

Client:City of Franklin

Architect:Kennon Architects

Landscape Architect:Hodgson & Douglas LLC

Engineer:EMC Engineers

Opening:Fall 2009

Size / Area:30,000 sq. ft.

Principal Use:Police Headquarters

Location / Address:Intersection of Columbia Avenue and 9th Avenue, Franklin

Franklin Police Headquarters

Innovative Features:- LEED Gold- site design included several other innovative features including collecting all of the storm water from the 40,000 sq. ft. parking garage into a 40,000 gallon cistern used for toilet flushing within the building, and irrigation- all native plant palette- geothermal heating and cooling

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Franklin Police Headquarters

Brief Description:- 30,000 sq. ft. 4’’ deep extensive green roof - green roof planting palette is a sedum / native grass / native perennial mix- roof will not be open for public use- purely functional aspect of building’s design- helping to reduce thermal variation, stormwaterrun-off and root life-cycle- bio-swales and pervious paving were designed to capture and slowdown on-site stormwater, thus reducing offsite erosion and stress on city infrastructure

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