Gibraltar Landscape & Construction, LLC of Wauwatosa, Wis., completed the installation of five green roofs on the Silver City Townhomes in Milwaukee.
Each one was 2,315 square feet in area. Pre-vegetated mats with only 1.25 inches of growing medium from Xero Flor Green Roof System were used along with two layers of lightweight, 1/4-inch water retention/filter fleece. Gibraltar Landscape has installed more than a dozen green roofs, and reports that the profit margin on them has been as good as or better than the margins on their other services. Credit: Xero Flor America

At the Keep Indianapolis Beautiful headquarters, Rooftop Green Works, a landscaping company specializing in the installation and maintenance of green roofs and green walls, installed a 3-inch-deep system from Omni Ecosystems that features ultra-lightweight Infinity growing media, which is only 15 pounds per square foot fully saturated but retains as much stormwater as traditional growing media in a 5-inch-deep profile. Its high-efficiency irrigation system uses a Rainbird ESP-me 12-station irrigation controller with a wireless rain sensor, Netafim 17mm techline blank tubing, Hunter triospray microsprayers on ???(R)???AE???(R)?-inch by 12-inch risers from Agrifim. For the last three years, the landscape company has received about 80 percent of their revenue from green roofs. Credit: Omni Ecosystems

In October 2010 when Steve Maria, president, Gibraltar Landscape & Construction, LLC of Wauwatosa, Wis., completed the installation of five green roofs on the Silver City Townhomes in Milwaukee - his first green roof project - he hoped it was the start of adding green roofs as a specialty in his business. Since then, he has installed a dozen green roofs, including a recent project at Sage on Jackson, another sustainable multi-family housing development in Milwaukee. He also has contracts for ongoing maintenance of five green roofs.

The single-family residential green roof she just finished designing for a client's home in Newport Beach, Calif., was also the first for Cherie Ciotti-Roco, president, Terra Prima, Inc., a landscape design and construction company based in Corona Del Mar. Her company will install it once the plants that are presently growing in modular trays are ready. And once installed, Terra Prima is contracted to maintain it. Like Maria, Ciotti-Roco is seeking more green roof work.

Do green roofs present a business opportunity for landscape contractors? The market is growing. Green Roof for Healthy Cities, Toronto, Ont., is the not-for-profit industry association that promotes green roofs and green walls in North America.

According to their annual survey, the North American green roof industry grew by 14 percent in 2013, sustaining the double-digit annual growth the industry has enjoyed over the past decade. The 950 new green roof installations reported in 2013 totaled more than 6.4 million square feet.

How common is it for landscape contractors to be the installers on green roof projects? Angie Durhman, M.S., GRP, says that about half of all projects are awarded to landscapers. Durhman, who owns AD Greenroof, LLC, a green roof consulting firm in Minneapolis, has been involved in more than 300 green roof projects over the past ten years.

Living Roofs, Inc. installed and now maintains this 3,959-square-foot green roof at a vacation home in Lake Toxaway, N.C. The homeowner preferred plants that would complement the autumn colors on the trees around the house so the plant palette includes Sedum spurium and Sedum album. The pre-vegetated, engineered mat system is referred to as "extensive" since it has only two inches of growing medium. "Intensive" installations have more than six inches of growing medium. Credit: Living Roofs, Inc.

"Intensive and semi-intensive installations (with deeper growing media) are less common than extensive," Durhman says. "But almost all those projects go to landscapers. The more landscaping there is to be done, the more roofing contractors entrust the work to landscapers."

"It is common for landscape contractors to install green roofs, but not common enough," says Peter MacDonagh, FASLA, LEED AP, CSLA, owner and director of design and science, Kestrel Design Group, Inc., a sustainable landscape architectural firm in Minneapolis. "Roofing contractors just do not have the plant knowledge of experienced landscape contractors."

MacDonagh encourages landscape contractors to seek opportunities in green roof maintenance. "Building owners and facility managers do not have the necessary expertise to maintain green roofs – reading the rooftop landscape and understanding the micro-climates, identifying and remedying problem areas in the vegetation, preventing costly weed proliferation, monitoring and maintaining green roof irrigation systems, and analyzing and amending the growing medium. Landscape contractors should emphasize their expertise and the benefits of regular maintenance."

"More and more green roof project specifications include two- to five-year maintenance requirements," says Durhman.

"There will be opportunities for smart, hardworking contractors who can offer cost-effective ways to make building owners lives easier and save them money by taking care of their investments in green roofs," says Molly Meyer, M.S., GRP, founder and owner, Rooftop Green Works, LLC, which installs and maintains green roofs in the Midwest. "Some green roofs, especially intensive installations, require more attention than others, but all of them need some basic maintenance. Landscape contractors can be advocates for maintaining green roofs."

On top of the Campus Center building at San Diego County's operations center, ValleyCrest Landscape Companies installed 7,346 square feet of LiveRoof???(R)???AE???? Hybrid Green Roof System, which consists of pre-vegetated modules. The standard depth of the growing medium was 4.25 inches. In the modules, Native Sons Wholesale Nursery Inc. of Arroyo Grande, Calif., planted a blend of two multi-variety Sedum-based plant mixes, accented with a non-invasive, warm-season grass. Credit: LiveRoof, LLC

Rooftop Green Works also installed this 6,000-square-foot green roof, Indianapolis's fourth largest, which sits atop WFYI's television and radio station headquarters. One of the advantages of the roof is sound insulation courtesy of the tall plant canopy provided by the selection of meadow plants; some as tall as four feet high. They include daylilies, echinacea, cosmos, and catmint planted in a 5-inch-deep growing media. Additionally, the green roof has helped reduce the urban heat island effect and mitigate stormwater runoff. Credit: Omni Ecosystems

There is a lot to learn for landscapers interested in getting into the green roof business. Steve Maria recommends checking out green roof conferences and seminars as well as reading relevant publications. Green Roofs for Healthy Cities offers a Green Roof Professional (GRP) accreditation.

As for getting the business? "Find out which systems are getting installed in your area, connect with the designers, and contact the manufacturers. Find out what it takes to become an approved contractor," says Maria. "Network with regional green roof suppliers and plant growers. They know the local market."

MacDonagh has another piece of advice:
"Put a green roof on your own facility. You will learn so much about the installation process and maintenance from even a small green roof. Owning and maintaining your own green roof will also demonstrate your commitment."

David Aquilina, Strategic Storyteller, is a communications consultant and freelance writer in Minneapolis. He can be reached at davida@strategicstoryteller.com.

Green Roof Types
A green roof is a supplemental roofing system that covers a conventional roof with a waterproofing layer, a root barrier, a drainage system, a growing medium for the plants and a layer of vegetation. There are two basic types of green roofs.

• "Intensive" green roofs have six or more inches of growing medium. Because of their weight, about 40 to 300 psf fully saturated, they are only appropriate for structures with high load bearing capacity. Their depth maximizes stormwater retention capacity and allows for a wide range of plants, including turf grasses, flowering ornamentals, shrubs, and even trees. Intensive green roofs have to be maintained like gardens at grade.

• "Extensive" green roofs are typically two to four inches deep, are less expensive to install, require less maintenance and weigh less. With saturated weights of about 10 to 40 psf, they are suited for large-span structures and retrofits on older buildings. They support a more limited range of plants, including succulents such as commonly used Sedum species, and shallow rooted, dry-climate herbs, grasses, and wild flowers.

Green roofs can be "built-in-place," that is, planted up on the roof, or "pre-vegetated;" pre-grown in trays or on mats. Pre-vegetated mats are rolled up, and rolled out, like sod. Xero Flor (www.xeroflora.com) is a pre-vegetated mat system proven in flourishing installations that cover hundreds of millions of square feet around the world. LiveRoof, LLC (www.liveroof.com) manufactures a modular tray system designed with soil-to-soil connection between them to establish an integrated vegetative field, rooted in a continuous layer of soil extending above and across the tops of the trays.