Green Roofing
Alec LeSher (author), Jonathan Rosenbloom & Christopher Duerksen (editors)INTRODUCTION
Several municipalities have found it beneficial to offer incentives for or to make it mandatory to construct and maintain “Green Roofs.”[1] Developers that are required or choose to participate in such programs may be rewarded with benefits for constructing and maintaining green roofs on a variety of buildings. The incentives can provide a developer with a variety of benefits, such as expedited permitting, increased floor area ratio (FAR) or density bonuses, or tax credits to offset the costs of green roofing. Alternatively, at least one city has required green roofs as part of development and imposed penalties for developers that do not incorporate a green roof into their building.[2]
A “Green Roof” is a roof that is used to grow plant life.[3] The vegetation can be anything including grasses, wildflowers, or agricultural products. In some situations a low maintenance collection of grasses may be most appropriate,[4] while in other instances a vegetable/fruit garden can be grown to make agriculturally productive use of the area.[5] To decrease energy and stormwater management demands (discussed below), plant life should typically cover the majority of the surface area of the roof.[6] Restrictions in size and type of vegetation are often dictated by climate and building load capacities.[7] Due to the soil used in the construction of green roofs and soil water retention, green roofs are typically heavier than traditional roofs.[8] As a result, they may require additional support to ensure their proper safety and functioning.[9] They also require a membrane lining around the soil to prevent water from damaging the structure underneath.[10]
Green roof implementation can be encouraged through municipalities initiating pilot programs, providing direct or indirect financial incentives, or passing regulation.[11] Pilot programs can be accomplished through construction of green roofs on municipal buildings to market the positive benefits of green roofs.[12] Another tool municipalities may use to encourage green roofing is through the issuance of grants, tax credits or fee waivers for the construction of green roofs.[13] Alternatively, granting developers variances or additional floor area ratio or expedited permits subject to their structure having green roofs encourages green roof construction among developers.[14] Ordinances requiring green roofs for new structures in certain districts (downtown, high-traffic area) is also an effective method municipalities may utilize to promote green roofing.[15]
EFFECTS
Green roofs help turn otherwise unproductive spaces, and often costly spaces, into environmentally beneficial spaces. The majority of rooftops in a jurisdiction are often unused spaces that serve only to direct water towards gutters and absorb heat.[16] Green roofs transform these unused spaces into productive and efficient areas that mitigate stormwater run-off from impervious roof cover, improve the energy efficiency of the building, reduce heat island effect, provide open space for use by building residents and potentially the public for educational economic and aesthetic benefits.[17]
The addition of soil and vegetation to exposed surfaces, such as roofs, can significantly reduce stormwater runoff.[18] The soil and plants turn impervious surfaces into permeable surfaces, diverting water from entering the public stormwater system.[19] This is important as it saves the local jurisdiction costs in stormwater management, and also reduces greenhouse gas (GHG) emissions involved with water treatment.[20] In addition to helping with stormwater management, green roofs can help insulate the building reducing both heating and cooling costs and lowering GHG emissions.[21] Green roofs may also provide a source for numerous plant based and agricultural products that may otherwise be unavailable due to a lack of open spaces.[22]
EXAMPLES
Chicago, IL
Chicago’s city ordinance 17-4-1015,[23] incentivizes the construction of green roofs on buildings in the Chicago downtown mixed used district to reduce the stress rainwater runoff places on storm water management systems. The ordinance provides that developers building in the downtown mixed-used districts may receive a Floor Area Ration (FAR) bonus when green roof is applied into the developers building. This additional footage allows developers to maximize profit by constructing more units on the same lot. The ordinance has several requirements developers must satisfy to receive the bonus. Requirements include: a green roof must cover fifty percent of the net roof area or 2,000 square feet of contagious roof area, and the roof must be structurally fit to withstand the weight of the green roof. This ordinance is notable because the city saves on stormwater management systems in the long-term and reduces the urban heat island effect plaguing Chicago’s downtown in the summer months.
To view the provision, see Chicago, IL, Municipal Code of Chicago § 17-4-1015 (2017).
In addition, Chicago requires that most dwelling units within the downtown area maintain a minimum amount of open space on-site.[24] The “open space must be outdoors and designed for outdoor living, recreation, or landscaping.”[25] Each development is required to supply at least 36 square feet of open space for each dwelling unit.[26] This space can be supplied on the ground, as decks or patios, or on roofs.[27] The calculation to determine the amount of space necessary is to multiply the number of units for the planned development by 36 square feet.[28] So a 100 unit development would need to supply 3,600 square feet of open space in total. One option to fulfill this requirement is by using some combination patios and ground level open space. However, in areas where ground space is in high demand, it may be more efficient to locate the required open space on roofs.
To view the provision see Chicago, IL, Municipal Code of Chicago § 17-4-0410 (2017).
Denver, CO
Denver’s Denver Green Roof ordinances requires the construction of green roofs for new buildings over 25,000 square feet, and for existing buildings at least 25,000 square feet when the building requires a roof replacement. The code defines a green roof as an extension above the roof, which allows vegetation to grow. The portion of the roof required to be dedicated to green roofing increases along with the gross square footage of the building. For example, a 25,000 square foot building must be covered by 20% green roof, whereas a building with 200,000 square foot or more must be covered by 60% green roof. Owners may combine solar paneling and green roofing to meet the requirements. The ordinance further creates a green roof technical advisory board, which is composed of experts in green roofing and advises the city planning board on green roof issues. The planning board and technical advisory board also promulgate guidelines for the construction of green roofs, to assist developers in complying with the ordinance.
The ordinance imposes penalties for property owners that forego construction of green roofs for buildings that received a permit to build after January 1, 2018.[29] If a property does not comply with the requirements, the owners or occupiers thereof are subject to a fine of no more than $999 per violation, or imprisonment for a maximum of one year per violation. A violation occurs every 24 hours that the property is out of compliance with green roof requirements. Voters approved these measures by referendum, hoping to reduce urban heat island effects, provide habitat for bees and other wildlife, and reduce GHG emissions. Notably, the requirements are not imposed on residential buildings less than 4 stories or 50 feet in height, or greenhouses and their related structures.
To view the provision see Denver, CO, Code of Ordinances §§ 10-300 to 10-308 (2017).
New York City, NY
New York City’s Green Roof Property Tax Abatement Program[30] is a direct incentive tool utilized by New York City to encourage retrofitting of green roofs or construction of green roofs on new structures. The program offers building owners or developers $4.50 per square feet of green roof or a maximum abatement of $100,000 or the building tax liability (whichever is lesser) subject to several building and compliance conditions. Some of these conditions include: (1) construction of a green roof must have commenced after August 5, 2008; (2) at least fifty percent of eligible roof space must be covered by the green roof: (3) guidelines on structural compliance of the green roof; and (4) post construction maintenance. Due to the congestion in New York City and lack of green space, this program hopes to encourage construction of green roofs, that will help reduce the urban heat island effect. This program does not place a significant burden on the city’s budget, because the resources used to monitor this program currently exists—architects and engineers employed by the Department of Building. Additionally, this program has significant economical benefits to developers and property owners, and provides for a healthier and cleaner environment.
To review the provision see New York City, NY, Zoning Code 1 RCNY §105-01 (2008).
ADDITIONAL EXAMPLES
Philadelphia, PA, Philadelphia Code § 19- 2604 (8) (2017) (provides for tax credits available for qualifying green roofs).
Austin, TX, Land Development Code § 25-2-586 (E) (11) (2014) (creates a bonus floor area incentive program).
Minneapolis, MN, Zoning Code § 527.120 (2009) (adds green roofs to a program of alternatives to zoning standards, if a developer desires to adjust some zoning regulations they may do so by adding amenities one of which is a green roof).
San Francisco, CA, Planning Code § 149 (2016) (allows “living roofs” to meet the requirements of a state law that mandates a portion of roofs be “solar ready”).
Portland, OR, City Code § 33.510.210 (C) (5) (2018) (grants an extra square foot of floor area ratio for every square foot of green roof incorporated onto the building).
Nashville, TN, Code of Ordinances § 15.44.050 (E) (b) (2012) (grants a $10 rebate on a private property owner’s sewer bill for each square foot of qualifying green roof installed).
Sustainable Land Use Code Project § 1.2.2 (Capital Region Council of Gov’ts 2013) (model green roof ordinances that provides floor area bonuses, open space credit, and stormwater management credit).
CITATIONS
[1] Chicago, IL, Municipal Code of Chicago § 17-4-1015 (2017); Portland, OR, City Code § 33.510.210 (C) (5) (2018); Minneapolis, MN, Zoning Code § 527.120 (2018); Denver, CO, Code of Ordinances § 10-301 (2018).
[2] Denver, CO, Code of Ordinances § 308(b)(2) (2018).
[3] Emily W, O’Keefe et al., Raise the Roof: Green roofing options offer lower energy costs and better aesthetics, 2008 J Prop. Mgmt. 64, 64; David Johnston & Kim Master, Green Remodeling: Changing the World One Room at a Time, 212-213 (2004); US Environmental Protection Agency, Soak Up the Rain: Green Roofs https://perma.cc/VFS6-4AZP (last visited May 14, 2018).
[4] Dyanna Innes Smith, Green Technology: An A-to-Z Guide, Green Roofing, 230, 231-32 (Dustin Mulvaney ed., 2011); Johnston & Master, supra note 2, at 213.
[5] Dyanna Innes Smith, supra note 3, at 231-32; Johnston & Master, supra note 2, at 213.
[6] O’keefe, supra note 2, at 64
[7] O’keefe, supra note 2, at 64
[8] Johnston & Master, supra note 3, at 213.
[9] Id.
[10]Johnston & Master, supra note 3, at 212-213; Dyanna Innes Smith, supra note 3, at 231.
[11] See Malina, Supra note 1.
[12] CITY OF CHI. DEP'T OF ENV'T, GREEN ROOF TEST PLOT 2003 END-OF-YEAR PROJECT SUMMARY REPORT (2004), http://egov.cityofchicago.org/webportal/COCWebPortal/COC_ATTACH/2003GreenRoof-Report.pdf.
[13] New York City, NY, Zoning Code 1 RCNY §105-01 (2018).
[14]Chicago, IL, Municipal Code of Chicago § 17-4-1015 (2017).
[15] Denver, CO, Code of Ordinances § 10-301 (2018) (Newly enacted legislation in Denver, Colorado providing for buildings constructed after January 1, 2018 with 25,000 square feet to have a certain percentage of roof space covered by green roof or solar panel.); Jackie Snow, Green Roofs Take Root Around the World (October 27, 2016), https://perma.cc/3YVA-C8KD.
[16] Richard K Sutton, Introduction to Green Roof Ecosystems, 223 Ecological Studies 1, 3-5 (2015).
[17] See Catherine Malina, Up on the Roof: Implementing Local Government Policies to Promote and Achieve the Environmental, Social, and Economic Benefits of Green Roof Technology, 23 Geo. Int’l Envtl. L. Rev. 437 (2011); Environmental Protection Agency, Using Green Roofs to Reduce Heat Islands, https://perma.cc/6SDL-W8M5.
[18] O’keefe, supra note 2, at 66; Johnston & Master, supra note 2, at 212-213.
[19] Johnston & Master, supra note 2, at 212-213; Sutton, supra note 10, at 3-5.
[20] Sutton, supra note 10 at 5.
[21] Dyanna Innes Smith, supra note 3, at 233; O’keefe, supra note 2, at 66; Johnston & Master, supra note 2, at 212-213.
[22] O’keefe, supra note 2, at 66.
[23] Chicago, IL, Municipal Code of Chicago § 17-4-1015 (2017).
[24] Chicago, IL, Municipal Code of Chicago § 17-4-0410-A (2017).
[25] Chicago, IL, Municipal Code of Chicago § 17-4-0410-B (2) (2017).
[26] Chicago, IL, Municipal Code of Chicago § 17-4-0410-A (2017).
[27] Chicago, IL, Municipal Code of Chicago § 17-4-0410-B (2) (2017).
[28] Chicago, IL, Municipal Code of Chicago § 17-4-0410-A (2017).
[29] Denver CO, Code of Ordinances § 308(b)(2) (2018).
[30] New York City, NY, Zoning Code 1 RCNY §105-01 (2018).