Using Engineered Geofoam for Garden Roofs

For most of the past century, the rooftops of commercial and institutional buildings have largely been places to locate unsightly mechanical systems. Architectural treatments, such as parapets and screens, provide visual relief from such equipment. Now, roofing professionals and building owners increasingly look at the roof as “found space”—a place to be planted and used, instead of hidden.

Facebook’s Frank Gehry-designed MPK 20 building sports a 9-acre green roof using EPS geofoam from Insulfoam.

Facebook’s Frank Gehry-designed MPK 20 building sports a 9-acre green roof using EPS geofoam from Insulfoam.

Throughout the U.S., garden roofs (or living roofs) are growing in popularity with more than 5.5 million square feet installed in 2014, according to Green Roofs for Healthy Cities. Most of that total was for private rather than public projects, indicating this is not just a government trend. In addition to providing attractive and usable open space, garden roofs offer environmental benefits, such as helping to slow and filter urban run-off.

Some of America’s largest companies have installed green roofs. Ford’s Dearborn, Mich., truck plant final assembly building sports one of the world’s largest living roofs at 454,000 square feet. In 2015, Facebook opened its MPK 20 office building in Menlo Park, Calif., with a 9-acre living roof featuring a 1/2-mile walking trail and more than 400 trees.

If you haven’t worked on a garden roof yet, it is likely only a matter of time until you do.

Addressing the Challenges of Garden Roofs

Weighing a fraction of soil, EPS geofoam fill creates ultra-lightweight landscaped features on Facebook’s garden roof.

Weighing a fraction of soil, EPS geofoam fill creates ultra-lightweight landscaped features on Facebook’s garden roof.


Adding plants and park-like amenities to a roof increases the complexity of the roofing assembly. Garden roofs present two primary challenges for roofing professionals to solve: minimizing the dead load and preventing moisture intrusion.

The project team for the Facebook MPK 20 building’s green roof met this two-fold need—and more—with expanded polystyrene (EPS) geofoam.

Weighing considerably less than soil, EPS geofoam is an ultra-lightweight engineered fill that can be used to create contoured landscape features, such as hills and valleys. The material weighs from 0.7 to 2.85 pounds per cubic foot, depending on the product type specified, compared to 110 to 120 pounds per cubic foot for soil.

Despite its low weight, EPS geofoam is designed for strength and has better load bearing capacity than most foundation soils. Geofoam’s compressive resistance ranges from approximately 2.2 psi to 18.6 psi (317 to 2,678 pounds per square foot) at a 1 percent deformation, depending on the product.

The garden roof on Facebook’s MPK 20 building provides ample open space and a half-mile walking trail for employees.

The garden roof on Facebook’s MPK 20 building provides ample open space and a 1/2-mile walking trail for employees.

EPS geofoam is also effective at addressing the second challenge of garden roofs: managing moisture absorption. The moisture performance of the various components in a green roof assembly is critical; retained water imposes additional loads on the roof and increases the risk of water damage to the roof assembly. EPS geofoam meeting ASTM D6817 standards works well here as it only absorbs 2 to 4 percent moisture by volume, even over long-term exposure, and it dries quickly. The moisture performance of EPS has been demonstrated in extensive in-situ applications and real-world testing, including research conducted by the U.S. Army Corps of Engineers’ Cold Regions Research and Engineering Laboratory. After burying EPS in wetted soil for nearly three years, the lab found that the material absorbed only 1.7 percent moisture by volume.

In addition to enabling lightweight, durable landscape features and helping to defend against water, EPS geofoam provides thermal insulation in garden roofs. Roofing professionals have used EPS insulation in roof assemblies for decades because it offers the highest R-value per dollar among rigid foam insulations.

Expect More Demand

Although green roofs currently account for a small portion of the billions of square feet of roofs in the U.S., expect to see more demand for them given their aesthetic and environmental benefits. High-performance materials, like EPS geofoam, can help provide a long-lasting, durable green roof assembly.

PHOTOS: Insulfoam

Kill Moss and Algae in an Environmentally Friendly Manner

Moss Melt Concentrate, a moss and algae herbicide from Green Spear Inc., has recently received EPA registration for use on roofs, lawns, turf, and outdoor surfaces and structures.

Moss Melt Concentrate, a moss and algae herbicide from Green Spear Inc., has recently received EPA registration for use on roofs, lawns, turf, and outdoor surfaces and structures.

Moss Melt Concentrate, a moss and algae herbicide from Green Spear Inc., has recently received EPA registration for use on roofs, lawns, turf, and outdoor surfaces and structures. The active ingredient is an emulsified d-Limonene, which acts as a natural degreaser. It strips away the waxy surface of moss and algae without direct sunlight or warm temperatures. The product is rain-fast within one hour. Moss Melt will not stain concrete, brick, pavement, stucco or wood and will not damage gutters, metal flashing or downspouts. One gallon kills up to a 12,500-square-foot area. The product currently is available in the Pacific Northwest.

A Green Roof Provides Residents of a Senior Housing Complex with an Improved View

The Findlay Teller Apartments provides affordable housing for low-income seniors in the Bronx, N.Y. The complex includes 32 one-bedroom and 131 efficiency units. Its 9,925-square-foot green roof is its most prominent green-building element and gives residents a welcomed view of green space.

Built in 1906, the dilapidated building was revitalized by three local Bronx organizations.

Built in 1906, the dilapidated building was revitalized by three local Bronx organizations.

“Many green roofs are on top of buildings where no one can see and enjoy them. The Findlay Teller green roof, particularly the sections installed on the terrace level and second-floor roofs, has many windows that look out on the [green roof sections],” says Antonio Freda, owner of Bronx-based Freda Design Associates Ltd., the architect for the apartment building’s renovation. “In fact, 90 percent of the apartments have a view of the green roof.”

RESTORING A NEIGHBORHOOD LANDMARK

Located at 1201 Findlay Avenue in the Morrisania neighborhood of the Bronx, the community landmark has a long history. The building was constructed in 1906. The Daughters of Jacob, a non-profit service organization, originally used the building as a hospital and nursery facility. It was renovated in 1920. The east and west wings were added in 1952.

Converted to subsidized senior housing under the U.S. Department of Housing and Urban Development (HUD) Section 202 program in 1978, and known as Findlay Plaza, the building deteriorated over the years. By December 2007, the apartments had a lowly score of 34 out of 100 on HUD’s Housing Quality Standards. Buildings must score at least 86 for their conditions to be rated healthy and safe. Eventually, HUD foreclosed on the property.

In 2009, three local organizations, the Citizens Housing and Planning Council, the Local Initiatives Support Corp. and the Belmont-Arthur Avenue Local Development Corp. (BAALDC), worked together to win the support of the building’s tenants and neighborhood leaders to acquire and rehabilitate the property.

Roofing workers spread the growing media on the roof.

Roofing workers spread the growing media on the roof.

BAALDC, which strives to prevent the deterioration, blight and abandonment of at-risk housing in the Bronx, established the Findlay Teller Housing Development Fund Corp. (Findlay Teller HDFC) to take on the challenge of assembling financing and renovating the building.

“The building was in a very sad state of disrepair,” notes Joe Cicciu, executive director of BAALDC and president of Findlay Teller HDFC. “We put together $20 million in funds from many different sources, including a major grant from JPMorgan Chase, to save and rehabilitate the building.”

GREEN BUILDING AND A GREEN ROOF

Notias Construction Inc., Flushing, N.Y., was the general contractor for the project. The firm managed the renovation according to Enterprise Green Communities Criteria, a program of Columbia, Md.-based Enterprise Community Partners, a non-profit dedicated to creating opportunity for low- and moderate-income people through affordable housing in diverse, thriving communities. Required by the New York City Department of Housing Preservation and Development, the criteria define standards for green-building practices applicable to affordable housing. Thus, the renovation included a new structural roof with two layers of insulation, high-efficiency boilers, replacement windows and new energy-efficient lighting. In addition to the green roof, permeable pavement in the parking area reduces stormwater runoff.

PHOTOS: XERO FLOR AMERICA

Pages: 1 2

A Minneapolis Neighborhood Plans to Bring Solar, Vegetation and Bees to its Rooftops

As part of its commitment to maintain and enhance the physical, social and economic environment of its Minneapolis neighborhood, the Southeast Como Improvement Association (SECIA) has begun a program in which it is matching the owners of buildings with low-slope roofs to solar and green roof providers, as well as beekeepers.

The Southeast Como neighborhood is surrounded by industrial buildings and essentially is the last of Minneapolis’ industrial hub. A community resident who considered the industrial buildings’ rooftops wasted but valuable space approached SECIA about partnering with Minnesota Community Solar. The for-profit organization builds large solar arrays in locations ideal for generating solar power—like roofs—and works with utilities so any Minnesota ratepayer can have access to solar energy. While SECIA’s Executive Director Ricardo McCurley was researching that option, he met a green-roof consultant who is part of the Minnesota Green Roofs Council, a nonprofit that supports green roofs in the state. In addition, Minneapolis recently eliminated permit requirements to maintain beehives in the city above 1 story.

“It occurred to me we should just play matchmaker,” McCurley says. “Let’s get a bunch of options on the table and match them to local property owners.”

After receiving a $3,000 grant from Minnesota’s Clean Energy Resource Teams, an organization that connects individuals and their communities to resources that will help them implement community-based clean-energy projects, SECIA began surveying the neighborhood. “We have an intern who currently is looking at aerial images of roofs and doing rough estimates of square footage, as well as collecting contact information for building owners,” McCurley notes. “Then we’ll be contacting all these property owners in person and via telephone and asking them questions about their flat roofs, like ‘Are you planning to reroof any time soon? How is the stormwater management on your property?’”

If the property owners show interest in learning more about sustainable options for their rooftops, SECIA will invite them to a luncheon that McCurley compares to speed dating. “We’ll have different providers of the various technologies at the luncheon, so they can talk about options,” he says. “Then if we make a match, we’re going to help the property owner through the process of finding grants to make it more affordable for them.”

McCurley thinks the program will be a success if just one property owner opts to install solar panels, a green roof or beehives. But he hopes for many installations and to make more connections within the neighborhood to expand how roofs are used. “We’re big into urban agriculture in the neighborhood,” McCurley explains. “Wouldn’t it be cool if one of the green roofs connects with a farmer who would lease the green-roof space?”

Although the program currently is in its infancy, McCurley is certain it will increase Southeast Como residents’ awareness about the benefits of green roofs, solar arrays, bees and even trees. “We’re dealing with the emerald ash borer here in the Twin Cities, particularly in our neighborhood. We’re already losing a lot of our tree canopy,” he says. “If our residents’ buildings were shaded by a beautiful ash tree and now they’re not, they’re going to feel that in HVAC costs. So what are the options to make a building more efficient? This program provides many great options!”

Want to Be Involved?
If you’d like to assist in the Southeast Como Improvement Association’s mission to bring solar, vegetation and bees to its rooftops, email Rooftops@comogreenvillage.info, SEComo@secomo.org or call (612) 676-1731.

Project Profiles: Health Care

MASSACHUSETTS GENERAL HOSPITAL, BOSTON

TEAM

Roofing contractor: Chapman Waterproofing Co., Boston
Architect/engineer: Cambridge Seven Associates Inc., Cambridge, Mass.
Membrane and waterproofing manufacturer: Kemper System America Inc.

Massachusetts General Hospital, Boston, features a Kemperol waterproofing and roofing membrane for its green roof.

Massachusetts General Hospital, Boston, features a Kemperol waterproofing and roofing membrane for its green roof.

ROOF MATERIALS

The Kempertec EP-Primer was used to prepare the substrate surfaces for membrane installation and served as a temporary waterproofing system, allowing the project to be exposed to the harsh New England winter while it was completed in phased stages.

The owners chose the Kemperol waterproofing and roofing membrane, a two-component with catalyst, high-performance, seamless and self-terminating cold-fluid-applied reinforced unsaturated polyester system. The monolithic edge-to-edge rot- and root-resistant Kemper membrane is engineered to resist degradation from UV exposure and heat intensity and is resistant to most common chemicals.

ROOF REPORT

Founded in 1811, Massachusetts General Hospital is the third oldest general hospital in the U.S. and the oldest and largest in New England. The 900-bed medical center offers sophisticated diagnostic and therapeutic care in virtually every specialty and subspecialty of medicine and surgery. When MGH’s owners envisioned constructing a new 9,000-square-foot green roof above the MGH cancer wing, they had two chief concerns: safety and long-term durability.

The landscaped roof design includes four different gardens with extensive shrubbery, trees and grass designed to provide cancer patients with a haven for relaxation and meditation to aid in the healing process.

A key challenge concerning the hospital’s green roof was its hundreds of penetrations, spaced inches apart, for a sprinkler system to irrigate the landscaped roof. A leak-detection system was installed across the entire square footage of the project to detect water before it seeps into the interior of the building. The leak-detection system confirms the project’s seal-tight success. Upon completion, Kemper System provided a 20-year, no-dollar-limit warranty.

PHOTO: KEMPER SYSTEM AMERICA INC.

Pages: 1 2

Nashville, Tenn., Begins Revitalization of Its City Center with a New Convention Space that Features a Truly Unique Roof

It isn’t often that a nightmare becomes a pleasant reality. Andy Baker, vice president of Raleigh, N.C.- based Baker Roofing, recalls the year he spent as project manager for the roofing of the new Music City Center in Nashville, Tenn., as one of his most challenging jobs. “The logistics, a tight spot downtown, the size of the project and everything that goes along with that—thousands of people trying to work and everyone needs their material in that area at the same time. Even the unique shape of the building made it hard,” Baker remembers. “We’re glad it’s done and we can look back on it now and say: ‘Wow! We did that.’”

The Music City Center was built to be the catalyst for more development in the SoBro neighborhood of Nashville, Tenn. It is intended to create a diverse economy that won’t be affected if flooding occurs, like in May 2010.

The Music City Center was built to be the catalyst for more development in the SoBro neighborhood of Nashville, Tenn. It is intended to create a diverse economy that won’t be affected if flooding occurs, like in May 2010.

Baker and his crew of up to 50 roofing workers have much to be proud of. The completed project is the largest capital construction project in Nashville’s history and was designed to bring prosperity to the area known as SoBro, or South of Broadway, which was affected by massive flooding in May 2010. The Music City Center lies outside the flood-prone areas and hopefully will be the catalyst for more development, which will create a diverse economy that won’t be affected if another flood occurs.

In addition to the Music City Center’s imaginative design that resembles various musical instruments, the building boasts a number of features that are ideal for a high-profile project. Many of these features are located in the most opportune of places—the roof. An Energy Star-qualified thermoplastic PVC membrane covers the 643,752-squarefoot roof while a 186,700-square-foot vegetated roof literally mimics the rolling hills of Tennessee’s Highland Rim. The rooftop also hosts a 211-kilowatt solar-power system on the 1-acre area that is over the Grand Ballroom, a rooftop space that resembles an acoustic guitar in shape. Lastly, the roof collects rainwater that is funneled to a 360,000-gallon tank before it is used to irrigate the site and flush hundreds of toilets inside.

Construction Challenges

Baker and his colleagues knew the Music City Center would present many challenges even before work began. “We knew it was going to be a logistical nightmare going in but then you have to live it,” he recalls. “You would think four city blocks would be a large enough area to work from but there were thousands of contractors working and receiving materials at the same time. Trying to keep truck drivers and suppliers happy was difficult. The community was great though; there were a lot of police officers around to direct traffic.”

Baker Roofing's team of up to 50 roofing workers spent one year working on the Music City Center.

Baker Roofing’s team of up to 50 roofing workers spent one year working on the Music City Center.

Installation also proved perplexing because of the roof’s undulating slopes of 1/4:12 to 12:12. Baker likens the rolls to waves and points out in some places they were almost conical in shape. In the areas in which there was no vegetated roof, the crew fastened two layers of 1.7-inch polyisocyanurate insulation followed by 1/4-inch roof board. Then a 60-mil thermoplastic PVC membrane in a light gray color was fully adhered to the assembly. The membrane features a lacquer coating to reduce dirt pickup.

Photos: Keri Baker

Pages: 1 2

Downtown Storm-water Management

Founded in 2002, Xero Flor America (XFA) is the official U.S. distributor of the Xero Flor Green Roof System. XFA has made its home in Durham, N.C., since 2006 when the company relocated its national headquarters from Lansing, Mich. In July 2012, it moved locally into renovated offices in The Republik Building, located at 211 Rigsbee Avenue in downtown Durham’s historic district.

Originally constructed in the 1940s for the Durham Insurance Service Co., The Republik Building is perhaps known to local history buffs as the home of WSSB radio. Robert Shaw West, chairman and CEO of The Republik, a local firm offering brand strategy and communication services, purchased the property from the city of Durham. He renovated the outmoded offices into a more contemporary, open and collaborative work environment in 2006. XFA decided to become more connected to the business community downtown and searched for offices in the historic district—ideally in a building where the company would have the opportunity to showcase its green roof system. West had space available on the second floor for XFA to lease.

Completed in February 2013, the 2,343-square-foot Xero Flor green roof atop The Republik Building is the first green roof installed on a building in Durham’s downtown historic district.

Completed in February 2013, the 2,343-square-foot Xero Flor green roof atop The Republik Building is the first green roof installed on a building in Durham’s downtown historic district.

“It was serendipity,” West says. “Xero Flor was looking for offices downtown, and we had space. Plus, we had to reroof our building last year. Since we needed a new roof, it was an ideal time to also consider adding a green roof, which supports our commitment to sustainability.”

Completed in February 2013, the 2,343-square-foot Xero Flor green roof atop The Republik Building is the first green roof installed on a building in Durham’s downtown historic district.

Going Green on the Roof

In addition to the standard building-permit process, putting a green roof on a historic building required additional review and approval.

According to Anne Kramer, urban designer with the Durham City-County Planning Department, except for certain minor items, such as repainting a previously painted surface, most changes to building exteriors within an official historic district require a Certificate of Appropriateness (COA). The Durham Historic Preservation Commission oversees the process locally.

The commission’s goal is to ensure preservation of the architectural character of the historic district’s buildings and, therefore, had to ensure adding a green roof to the building would not alter or disrupt the appearance of downtown Durham. Demonstrating a green roof would not be visible from the street level was especially important. With the COA from the preservation commission, XFA and The Republik had the green light for the green roof. But first Baker Roofing, Raleigh, N.C., installed the new structural roof.

Pages: 1 2 3 4