The Sky is the Limit

Broadway Tech Centre, Vancouver, B.C. Photo courtesy of Green Roofs for Healthy Cities ( and Sharp & Diamond Landscape Architecture Inc.The green roof and wall industry is growing in North America, and growing along with it are the business possibilities for those in the landscape and irrigation industries. To delve into this expanding market and what it means for landscape and irrigation contractors, Landscape and Irrigation recently spoke with Steven Peck, president of Green Roofs for Healthy Cities.

L&I: Tell us about Green Roofs for Healthy Cities

Peck: We have a mission to develop the green roof and wall industry across North America. We are a multi-disciplinary industry association. That’s one of the things that sets us apart. We have roofing contractors and manufacturers, we have nurseries, we have a whole range of professionals in the building industries from engineers all the way through to architects and landscape architects, horticulturalists. We have researchers that are members, and we have local governments that are members. We’ve always tried to appeal to a wide range of different interests within our industry. One of the ways that we do that is through our conferences. We have a research track and research committees, and we try to network research together, because researchers have an important role to play in terms of future product development, understanding the performance of these products, and even public policy.

On the professional side, our Green Roof Professional (GRP) program is about trying to secure a more positive future for the industry through the development of best practices, and also to push those best practices out into the marketplace. We want to provide an opportunity to those who are prepared to take the time to study and take the exam an edge in the marketplace. At the same time, we try to protect the green roof industry from the inevitable failures that result when people who aren’t fully qualified engage in these activities.

On the manufacturing side, we provide a range of services and work hard to promote them, their products, and their services; and also to develop the market through public policy. We work with a lot of local governments, and we have trade shows and our regular conference.

Jeffrey Bruce coined the phrase that green roofs involve a combination of the black arts — the non-living components of the building — and the green arts — all of the things that support the living portion of the assembly. You need to have both professions working closely together to be able to ensure the success of the project.

L&I: Can you provide a background on the green roof industry as a whole?

Peck: The green roof industry got its start in the late 1970s in Europe and really took off in the ‘80s in Germany when public policy makers recognized that green roofs could be an excellent way of dealing with issues regarding storm water management and air quality. They began to institute either regulatory requirements for green roofs with new construction or, in other cases, provide financial incentives for existing buildings. That was done at the national and local levels. That really helped give rise to the green roof industry. There is now green roof industry in most European countries. We are definitely following on the heels of that effort in Europe. But we’ve had to do a lot of things ourselves <dash> our climate is different, and our laws are different, so there are a lot of new developments in North America that haven’t been developed in Europe.

L&I: What are the key benefits of green roofs?

Peck: The thing about green roofs that differentiates them from other aspects of green building is that there isn’t another technology that can come close to the scale and scope of benefits that green roofs provide — not only in terms of the operation and use of the building, but as it relates to the site and the broader community.

One of the more common benefits from an economic standpoint is extension of the life expectancy of the waterproofing system. In North America you are typically looking at somewhere around a 12 to 15-year life expectancy on waterproofing. Waterproofing on typical buildings is ripped off on a regular basis. But when you put a green roof on a building, you protect the waterproofing from thermal cycles, ultraviolet radiation, and mechanical damage. That has resulted in an extension of the life expectancy. In Europe, the thinking is that if you put a green roof on a building, the waterproofing should last at least 40 years. That will depend on the system, but if you are the building owner there is an economic benefit because you are avoiding replacement costs.

Most green roofs are built over heated and cooled space, so there is an air conditioning benefit. That varies according to a lot of variables. For example, on a 30-story building, where the green roof is a very small part of the entire envelope, it’s going to be a fairly small amount of savings. But on a one-story building, where the roof is a large component of the overall envelope, it’s going to be a much higher benefit. Are we talking about Arizona or are we talking about Alaska? It’s not like a light bulb, where you can say that if you spend a dollar now you will get your money back in six months. You have to take a look at the building and its application to get the best value for your green roof dollar. That’s an important point, because people are always saying, “Tell me how much it will cost, and tell me how much I’m going to save.”


There is also noise reduction, which can be an important, tangible benefit.

So those are the three benefits that are common to all systems. Then you have benefits that are specific to each project and have to be designed in as part of the process. If you have a good design team, you can squeeze more benefits out of your green roofs. For example, human use and enjoyment is a big selling feature on buildings. On a commercial office building it could be creating a usable space for your clients and employees. On a hospital, it could be used for horticultural therapy. There are roofs that are recreational: people are lawn bowling or putting, or there is active park or playground space. Where land is valuable, as it is in many urban centers, using that roof space to create private or public parks adds a lot of value. There was a project recently to build a parking garage, but neighboring condo owners were upset because they didn’t want to look down on parked cars. What we recommended was that they put an extra level on the garage and create a public park. They were also able to charge more for the covered parking, and they were able to cut down on the resistance to the project.

If there is a public relations aspect to your business and you need a marketing angle, and you are creating a green building, what better way to make a statement about “greening” your building than a green roof? People don’t typically get excited about a high-efficiency furnace — not to say that’s not important — but a green roof is a really public way to make a statement about the “greenness” of your building. And a green wall is actually a better way of doing that, because, in almost all cases, a green wall will be visible from the street.

There is a huge host of things you can do with a green roof. You can design it for biodiversity, you can design it for food production, you can integrate the green roof better with the actual mechanical systems of the building, and you can retain storm water and bring it back up for irrigation purposes.

Then there are public benefits, including storm water management. A green roof can retain anywhere from 10 to 90 percent of the storm water that falls on it, depending on the design of the green roof and the climate. Generally speaking, most green roofs are in the range of 40 to 60 percent range. A lot of jurisdictions are beginning to provide incentives because of the storm water management benefits that green roofs bring.

Another public benefit is the urban heat island effect. When you build a city, you pave a lot of the surfaces, you remove vegetation, and you create buildings with rooftops that are black. All of these surfaces absorb heat and then release it back. If you look at thermograph of a city, you will see that parks and areas with vegetation are cooler, and areas with a lot of paved surfaces and rooftops are hotter — anywhere from 8 to 12 degrees Fahrenheit. The problem with that is that when you get to really big cities, it can make a bid difference in livability. Instead of a typical summer day in the city being 86 degrees, it is now 92 or 93. Also, when the temperature of our cities goes up, the residents draw more power. On really hot days, there are blackouts or the cities have to encourage people to limit their air conditioning use. There is also a lot of pollution associated with generating that power — especially when you have coal or any type of fossil fuel being burned. Hotter cities have more air pollution. There is a relationship between smog formation and hotter temperatures. We can cool our cities by installing white roofs and green roofs and reflective pavement and urban forestry. We can save billions of dollars because we don’t have to build extra power plants and we can reduce the pollution associated with energy production. That’s a huge issue that hasn’t really been fully addressed by federal- and state-level public policy makers.

L&I: Is the demand for green roofs being driven by associations such as yours, by industry professionals, the building owners, or by public policy makers?

Peck: It’s kind of a combination. We drive policy by helping policy makers to better understand the performance characteristics of green roofs. We’ve worked in more than 30 cities and had events promoting grassroots efforts to understand how green roofs fit in a particular community. At our conference we engage with policy makers, and the result is usually improved awareness and policy support for roof greening in those jurisdictions. We have published a professional paper on policy making to support green roofs.

The City of Toronto recently took a leadership position, becoming the first major city in North America to require green roofs on new buildings. They went from incentives to saying, “If you build a multi-unit residential building over six stories in Toronto, you will be putting a green roof on it. If you build a hospital, you will be putting a green roof on it. If you build a school, you will be putting a green roof on it. If you build a big box retail store, you will be putting a green roof on it.” The public benefits are so important to the citizens of the City of Toronto. We have been actively involved in that process, because our home base is Toronto. But we are also trying to get some legislation going in Congress with some of our partners in Washington, D.C.

I wouldn’t say that development of the market is contingent on public policy, but if you have a policy that provides an incentive for storm water management for example, like Minneapolis does, then it reduces the upfront capital costs for the building owner — especially if you look at it from a life cycle point of view. So that public benefit — storm water management — now becomes a private benefit as well. It’s good for the building owner and it’s good for the policy maker. New York has an incentive that allows for up to $100,000 per project tax abatement for green roof installation in New York City. Why are they doing that? Because there are urban heat island effect issues in New York and there are storm water runoff issues in New York. They are trying to take a piece of property that is owned by the private sector, not paying for the whole thing, and they are getting a piece of infrastructure that is delivering multiple benefits: air quality, storm water management, urban heat island. So it’s a really good deal for the public policy makers, because they are leveraging space, they are leveraging resources, and they are getting multiple benefits. And they are ultimately taking away a space that is creating problems for the city.

L&I: What opportunities do green roofs present for landscape and irrigation contractors?

Peck: There are really big opportunities. We survey our corporate members, and, based on that, we’re looking at a market that is somewhere in the neighborhood of 7 to 8 million square feet installed throughout North America. A study done by Ryerson University looked at buildings that were over 1,000 square feet of roof space. Their GIS and structural analysis of the City of Toronto, which has a population of approximately 2.5 million, found that in the City of Toronto alone, the total green roofable area is technically 500 million square feet. So you can aggregate that any way you want, but you can see that we are at the tip of the iceberg. In Germany, with more than 20 years of support, the estimate is that somewhere in the range of 15 percent of all slope-to-drain buildings have green roofs on them. In some communities, such as Manheim and Stuttgart, there are green roofs as far as the eye can see.

So there is a big opportunity. The key issue is going to be one of who is going to do the work? The other contracting interest here is the roofing contractor. The National Roofing Contractors Association has begun to step up and take an active interest in green roofing. In some cases there are roofing companies that subcontract out to landscape contractors, and a few cases where landscape contractors will subcontract out to a roofing contractor. It remains to be seen how that will pan out in terms of who is taking a leadership role.

It is very important that landscape contractors and designers get the appropriate training. When you move from the ground around the site onto the building, everything changes — liability changes, your exposure changes, and health and safety changes. It is a different ballgame on the roof or on the wall. When you start dealing directly with the building, you have to have appropriate training and insurance to work in that market. I think our Green Roof Professional training goes a long way toward that, but it is not the “be all, end all” in terms of the things you can learn, especially on the contracting side. Some of our members have their own contractor training, because they have specific technology with specific needs. We don’t get into that with our GRP designation and training. We have four full-day courses that we recommend you take, or you can buy the manuals. That is followed by a two-hour exam that is being offered in multiple cities. We have individual courses, and then we also just started what we call a Boot Camp, which is all four courses available at one location.

L&I: Do you recommend a certain skill set to begin with?

Peck: Not really. The thing with the courses is that they deal with both the green arts and the black arts. So the green arts professionals need to come to term with the black arts, and the black arts professionals need to come to terms with the green arts materials. We have 130 people who have successfully completed the exam, and it is a nice mix of roofing professionals, architects, landscape architects, engineers, manufacturers, and landscape contractors; so I’m not sure anyone has a particular advantage. Our intention is to have our green roof professionals share with us how many projects they have done and what types of projects. We encourage them to keep a record with us. So if we get a call, for example, looking for a green roof professional in St. Paul, Minnesota, the client will be able to look at our Web site for Green Roof Professionals in that area and they will also be able to see the projects they’ve worked on. Our intent is to build a database and allow them to promote themselves that way. It’s all about providing opportunities for professionals to thrive in the marketplace and differentiate themselves; and it’s about protecting the consumer from poor practice.

L&I: For a typical landscape design/build firm, would you recommend that they have one person on their staff become an accredited GRP, or should multiple members achieve certification?

Peck: It’s an emerging market, so it might not make sense for a small firm to invest to have four or five people become GRPs right away, unless they are a green roof company. If they are just emerging in the market, it probably makes sense to have one person invest the time and energy to understand the processes to help ensure a good quality product. That may be against our interests, but I think that’s probably the best way to start.

L&I: Are there any parameters you look for in terms of business size, staff size, expertise, equipment, company location. Or is it wide ranging enough that if someone is not in a major urban area that they can become involved in green roof implementation?

Peck: It depends on what their geographic scope is. If they are in Chicago, which consistently develops more green roof space than anywhere else, it’s obviously more competitive, but there is also more opportunity in that market. So the extent that the work is localized, that probably makes more sense to invest. The market is not evenly developed. So the first thing to do would be to find out how many green roofs are going on in your area, and find out if local government has any policies in place to support this activity. Then make an assessment as to how aggressive you want to be. We don’t want people thinking that green roofs are a get-rich-quick opportunities for landscape designers or contractors. But there are definitely emerging opportunities. Make sure that you have the appropriate insurance in place. Then try to find partners. That’s one thing we help facilitate at our conferences.

L&I: What should they need to be familiar with in terms of the technology to actually build a green roof?

Peck: That’s a big question, because it gets into the nuts and bolts of a green roof. Our second course is about design and installation. So we do talk about design as it relates to the installation, project management and quality assurance. We cover the different technologies used. Just to give you an example, there is a big difference between trees on a five-story roof, which would require cranes to lift them up, and hydroseeding a roof at fifteen stories. There are always different planting techniques, different methods of conveying materials and storing materials, and there best practices associated with that. We cover all of that in our courses.

L&I: Are there opportunities for irrigation professionals in the green roof industry?

Peck: There are really big opportunities. Almost without fail, intensive green roofs — those with more than six inches of growing medium — have irrigation systems built in. That is because the plant material used involves woody plants such as trees and shrubs. In the harsh environment of a rooftop, those plants require irrigation. We have several members in the irrigation industry. We have something called the Integrated Sites and Buildings Water Management (IS&BWM) committee. This is a committee that is trying to identify how to manage water more effectively in order to support vegetation both on the building and around the site using far less potable water. The IS&BWM committee is promoting on-site water harvesting from rainfall, gray water, air conditioning condensate, cooling tower, plus any other available source. These are alternative irrigation sources and that is very important to the irrigation industry and everybody else for genuine water conservation.

We are really looking at how to continue to have “green” — which we all need, and provides so many benefits — while at the same time recognizing that we need to manage water far more wisely.

 Steven Peck is the founder and president of “Green Roofs for Healthy Cities,” established in 1999 after completion of the report “Greenbacks from Green Roofs: Forging a New Industry in Canada.” The association has more than 5,000 members and has completed a number of initiatives designed to generate a market for widespread green roof infrastructure implementation. For more information about Green Roofs for Healthy Cities, including upcoming course and exam schedules, visit

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