Green roofs and walls provide a wide range of public and private benefits and our industry continues to add new opportunities each year. The nature of the benefits provided through green roofs will vary considerably, depending on factors such as the type of system, the regional climate, what the specific design objectives are for the project, budget, structural loading capacity, building surroundings, and what type of building is used.
Living Architecture for Urban Infrastructure
By Steven W. Peck, GRP, Honorary ALSA
Green roofs and walls provide a wide range of public and private benefits and our industry continues to add new opportunities each year. The nature of the benefits provided through green roofs will vary considerably, depending on factors such as the type of system, the regional climate, what the specific design objectives are for the project, budget, structural loading capacity, building surroundings, and what type of building is used. The diversity of benefits and the associated economic savings that can result from green roofs are quite astounding, and continue to evolve as the industry grows in North America, and as we collectively continue to invest in new product development and research.
Stormwater continues to be a key driver of public policy support for green roofs. Every green roof will provide basic infrastructure services, such as stormwater management — slowing its movement to storm sewers and retaining a percentage of rainfall from ever reaching overburdened storm sewers. Stormwater is a massive, multi-billion dollar infrastructure challenge, with trillions of gallons of untreated stormwater rushing off the roofs, parking lots and streets of our cities each year and contaminating receiving water bodies such as rivers, lakes and estuaries. Cities such as Philadelphia, Milwaukee and New York have begun to look to ‘green infrastructure’ solutions such as urban forests, green roofs and green walls, bioswales and wetlands as new approaches to try to address this and other urban challenges.
The City of Philadelphia’s Green Cities, Clean Waters Plan, recently approved by the Environmental Protection Agency, calls for billions in investment to support the establishment of 9,000 green acres over 25 years to address stormwater challenges.
Another important related infrastructure benefit is the ability to generate more green jobs and lasting green jobs for each public dollar invested than other infrastructure investments. Green roofs and walls are not imported from China, and many of the materials used can often be sourced within 500 miles of the project or less. Green roofs are labor intensive and require ongoing maintenance, which means lasting employment.
One emerging trend, for example, is to use rooftops to grow food in cities, thereby providing additional employment associated with the planting, maintaining, harvesting, processing, sale and distribution of produce. Other green roof projects provide critical amenity space, such as Millennium Park in Chicago. Hospitals are building green roofs to provide opportunities for patients to heal through emerging practices such as horticultural therapy and to help relieve stressed staff. Commercial building owners are building green roofs as amenity spaces with full or partial access to tenants because an increasing body of literature is showing greater productivity and less absenteeism when natural features are incorporated into buildings — as much as 10 percent higher rates of productivity. These types of green roofs produce a multitude of interlocking employment-related benefits, many of which have direct bottom line benefits for both governments and private sector building owners (see “Benefits” sidebar below).
Since 2004, Green Roofs for Healthy Cities (GRHC), the North American green roof and wall industry association, has conducted an independent survey of its Corporate Members, collecting data on the growth and composition of the green roof industry across North America and to track metropolitan regions.
The industry has grown steadily, but this year’s Green Roof Industry Survey found the North American industry grew by 115 percent in 2011 over 2010 when the growth rate was 28.5 percent. One of the reasons for this growth is the recognition of the many public benefits of green roofs, and their ability to help address multiple infrastructure challenges by cities.
Local and regional government support through policies and incentives have undoubtedly aided success in these leading cities. As other governments recognize the environmental, economic, and social values of green roofs through legislation and financial support, we will undoubtedly see other regions joining these leaders. The amazing growth of this new industry is also a function of the dedication of the hundreds of people who work in this field. In 2009, GRHC launched an accreditation program after six years of development involving a multitude of experts. The Green Roof Professional (GRP) accreditation program establishes a benchmark for multi-disciplinary knowledge that is required to successfully design, install and maintain a green roof system. The training focuses on the benefits of green roofs, best practices, and problems that can arise — and how to avoid them or address them. The GRP program is designed to help reduce green roof failure by establishing best practices and promoting education. It also recognizes the more than 500 professionals who have earned the right to call themselves GRPs. Policy makers have even begun to utilize the GRP designation as an approach to help ensure that projects are properly executed and developers have begun to demand that GRPs are part of project teams.
Professional training, for any new industry, is fundamentally important, as is the establishment of standards. GRHC has begun work on an ambitious project to develop a Living Architecture Performance Tool that will define the metrics for green roof and wall performance in a comprehensive manner. This tool will help to inform design practice, focus research, inform how voluntary standards such as the USGBC’s LEED programs and Sustainable Sites relate to green roofs and walls and hopefully address the regional factors that influence performance. At CitiesAlive experts met to deliberate and discuss this important initiative that is designed to strengthen the green roof and wall industry over the long run, and to ensure the maximum benefits for the public and building owners.
Jeffrey L. Bruce delivered the third professional training workshop focused on the emerging field of integrated water management for sites and buildings. Sponsored by Ewing and Jeffrey L. Bruce and Company, these training courses are establishing a new set of principles and practices aimed at moving towards to the difficult goal of “net zero water” set by the Cascadia Green Building Council as part of its leading edge, Living Building Challenge program. This third course focused on the sizing of cisterns and calculating a water-balance for the inputs and outputs for the building and the site. Wise water management is key to the maintenance of any form of living architecture, so we continue to invest in pushing the industry towards a more sustainable, and ultimately profitable platform of practice.
In an era of enormous budget deficits, and bankrupt cities and towns, we need to spend each and every public and private dollar as wisely as possible. Living architecture technologies, such as green roofs and walls hold the promise of being able to contribute significantly to the green building movement, and to the broader infrastructure challenges facing our country. They are able to do this because they reach across traditional divides between professionals and government departments and make use of underutilized spaces — the roofs and walls of our cities. Unlike many forms of infrastructure, they bring a multitude of solutions to the table — the things we need — clean air and water, jobs, efficiency, community health and opportunities to simply relax and enjoy our increasingly urban lives. Diverse applications and diverse benefits are core strengths of this new type of infrastructure which, when combined with public and private investment, will propel the industry forward.
Steven W. Peck, GRP, Honorary ASLA, is the founder and president of Green Roofs for Healthy Cities (GRHC), an industry association whose mission is to develop the industry across North America. For more information, visit www.greenroofs.organdwww.citiesalive.org.
Selected Green Roof Benefits
Employment — direct and indirect
Integration with onsite water management
Extension of membrane durability
Biophilic benefits — reduced absenteeism, faster healing, etc.
Reduce urban heat island effect
Improve membrane durability
Integration with HVAC systems
Integration with rooftop solar panels
Human health, productivity improvements
Property value improvements
Air and water quality improvements
Active and passive recreation
Four season aesthetics
Source: Adapted from “Rise of Living Architecture: Commemorative Edition”, Green Roofs for Healthy Cities, 2012.