Virginia Tech Study Measures the Impact of Membranes on the Surrounding Environment

Equipment tripods are set up to hold air temperature and EMT temperature sensors.

Equipment tripods are set up to hold air temperature and EMT temperature sensors.

For much of the past decade, the debate over when and where to install reflective roofing has been guided by two basic assumptions: first, since white roofs reflect heat and reduce air conditioning costs, they should be used in hot climates. Second, since black membranes absorb heat, they should be used in cool-to-colder climates to reduce heating costs. This reasoning has been broadly accepted and even adopted in one of the most influential industry standards, ASHRAE 90.1, which requires reflective roofing on commercial projects in the warm-weather portions of the United States, Climate Zones 1–3.

But as reflective membranes have become more widely used, there has been a growing awareness that the choice of roof color is not simply a matter of black or white. Questions continue to be debated not only about the performance and durability of the different types of membranes, but on the impact of other key components of the roof system, including insulation and proper ventilation. The issue of possible condensation in cooler or even cold climates is garnering more attention. Given these emerging concerns, the roofing community is beginning to ask for more detailed, science-based information about the impact of reflective roofing.

One recent area of inquiry is centering on the impact of “the thermal effects of roof color on the neighboring built environment.” In other words, when heat is reflected off of a roofing surface, how does it affect the equipment and any other structures on that roof, and how might the reflected heat be impacting the walls and windows of neighboring buildings? Put another way, where does the reflected heat go?

THE STUDY

To help answer those questions, the Center for High Performance Environments at Virginia Tech, supported by the RCI Foundation and with building materials donated by Carlisle Construction Materials, designed and implemented a study to compare temperatures on the surface and in the air above black EPDM and white TPO membranes. In addition, the study compared temperatures on opaque and glazed wall surfaces adjacent to the black EPDM and white TPO, and at electrical metallic tubing (EMT) above them.

Specifically, the Virginia Tech study was designed to answer the following questions:

  • What is the effect of roof membrane reflectivity on air temperatures at various heights above the roof surface?
  • What is the effect of roof membrane reflectivity on temperatures of EMT at various heights above the roof surface?
  • What is the effect of roof membrane reflectivity on temperatures of opaque wall surfaces adjacent and perpendicular to them?
  • What is the effect of roof membrane reflectivity on temperatures of glazed wall surfaces adjacent and perpendicular to the roof surface?

To initiate the study, the Virginia Tech team needed to find an existing roof structure with the appropriate neighboring surfaces. They found a perfect location for the research right in their own backyard. The roof of the Virginia-Maryland College of Veterinary Medicine at Virginia Tech was selected as the site of the experiment because it had both opaque and glazed wall areas adjacent to a low-slope roof. In addition, it featured safe roof access.

In order to carry out the study, 1.5 mm of reinforced white TPO and 1.5 mm of non-reinforced black EPDM from the same manufacturer were positioned on the roof site. A 12-by-6-meter overlay of each membrane was installed adjacent to the opaque wall and a 6-by-6-meter overlay of each was installed next to the glazed wall. At each “location of interest”—on the EPDM, on the TPO, and next to the opaque and glazed walls—the researchers installed temperature sensors. These sensors were placed at four heights (8, 14, 23, and 86 centimeters), and additional sensors were embedded on the roof surface itself in the TPO and EPDM. Using these sensors, temperatures were recorded on bright, sunny days with little or no wind. The researchers controlled for as many variables as possible, taking temperature readings from the sensors on and above the EPDM and TPO on the same days, at the same time, and under the same atmospheric conditions.

The roof of the Virginia-Maryland College of Veterinary Medicine at Virginia Tech is the site of the experiment because it has opaque and glazed wall areas adjacent to a low-slope roof.

The roof of the Virginia-Maryland College of Veterinary Medicine at Virginia Tech is the site of the experiment because it has opaque and glazed wall areas adjacent to a low-slope roof.

THE RESULTS

The output from the sensors showed that at the surface of the roof, the black membrane was significantly hotter than the white membrane, and remained hotter at the measuring points of 8 cm and 14 cm (just over 3 inches and 5.5 inches, respectively). However, the air temperature differences at the sensors 23 centimeters (about 9 inches) and 86 centimeters (just under three feet) above the surface of the roof were not statistically significant. In other words, at the site the air temperature just above the white roof was cooler, but beginning at about 9 inches above the roof surface, there was no difference in the temperature above the white and black membranes.

On the precast concrete panel adjacent to the TPO and EPDM, temperatures were warmer next to the TPO than adjacent to the EPDM, leading the study authors to hypothesize that the TPO reflected more heat energy onto the wall than did the EPDM. Exterior glazing surface temperatures were found to be approximately 2 degrees Celsius hotter adjacent to the TPO overlay as compared to the EPDM overlay.

Elizabeth Grant led the team that designed and implemented the study. She says her findings show that you need to take the entire environment into account when designing a roof system. “You need to think about what’s happening on top of the roof,” she says. “Is it adjacent to a wall? Is it adjacent to windows? Is it going to reflect heat into those spaces?”

Samir Ibrahim, director of design services at Carlisle SynTec, believes the study results will help frame additional research. “These findings are an important reminder that the full impact of reflective roofing on a building and on surrounding buildings is not fully understood,” he says. “Additional research and joint studies, covering different climatic conditions, are certainly warranted to broaden the knowledge and understanding of the true impact on the built-environment.”

Ensure Blister-free Installation of EPDM Bonding Adhesive

EPDM x-23 Low-VOC Bonding Adhesive boosts roofing crew productivity while helping ensure blister-free installations of EPDM roofing systems.

EPDM x-23 Low-VOC Bonding Adhesive boosts roofing crew productivity while helping ensure blister-free installations of EPDM roofing systems.

With its fast flash-off, easy application and extended open time, EPDM x-23 Low-VOC Bonding Adhesive from Mule-Hide Products Co. boosts roofing crew productivity while helping ensure blister-free installations of EPDM roofing systems. The adhesive quickly creates a strong bond between EPDM membranes and a variety of porous and non-porous substrates. It is easily applied using a 9-inch medium nap roller. An extended open time—the period after flash-off during which the adhesive film remains tacky—makes EPDM x-23 Low-VOC Bonding Adhesive a good choice when working with larger EPDM sheets. It also allows sheets to be left open longer, enabling more solvent to escape and further reducing the potential for blistering.

OMG Roofing Products Demonstrates Induction Welding System

OMG Roofing Products demonstrated its new RhinoBond Foil Tool, an induction welding system for securing single-ply commercial roofing membranes, at the BAU show in Munich.

OMG’s RhinoBond Foil Tool is specifically designed for use over foil face PIR insulation. The welding tool includes plate sensor technology to help users locate RhinoBond Plates installed under the roofing membrane, and assists with tool alignment for optimum bonding. A tone and a visual indicator light lets operators know when the weld cycle is complete.

The RhinoBond System is induction based technology used for installing commercial roofing systems. To date, more than 170 million m2 of commercial roofing membranes have been installed around the globe with RhinoBond, including more than 125 projects in Europe accounting for more than 3,200,000 m2.

The company was also looking for new distribution partners in targeted geographies throughout Europe during the show.

“As more roofing contractors have seen the labor savings and roof performance benefits that the RhinoBond System can offer, we have had tremendous growth,” says Lennard Spirig, Europe market manager. ”With updated technology and expanded distribution, we expect acceptance of the RhinoBond System across the region.”

RhinoBond is a method for installing thermoplastic and soon will be available for certain clean EPDM membrane. The system consists of a stand-up induction welding tool and magnetic cooling clamps. Contractors install roofing insulation using fasteners and specially coated plates designed specifically for the type of membrane being installed – PVC, TPO or Clean EPDM. Each plate is then bonded to the roof membrane installed over the top with the RhinoBond plate welding tool. The result is a roofing system that can provide enhanced wind performance with fewer fasteners, fewer membrane seams and zero penetrations of the new membrane.

Currently the RhinoBond System conforms with CE requirements and is approved for use in Europe by many roof system providers, including Bauder, Carlisle/Hertalan, Danosa, Fatra, FDT, Firestone, GAF, IcoPal, IKO, Renolit, Sika, Siplast, and Soprema/Flag.

Headquartered in Agawam, Mass., OMG Roofing Products is a supplier of commercial roofing products including specialty fasteners, insulation adhesives, roof drains, pipe supports, roof repair tape as well as productivity tools such as RhinoBond. The company’s focus is delivering products and services that improve contractor productivity and enhance roof system performance. For additional information, please contact OMG Roofing Products at (413)789-0252 or visit the website.

OMG RhinoBond Projects Are Being Completed Across Europe

OMG Roofing’s RhinoBond System has left marks across Europe with more than 125 completed projects and more in the pipeline. Collectively, these projects represent more than 300,000 square meters (3.2 million square feet) of single-ply roofing.

“In last two years, the RhinoBond System has started to take off across Europe, as more roofing contractors have seen the roof performance benefits that the system can offer,” states Web Shaffer, vice president of marketing for OMG Roofing Products. “We have completed projects across Europe and we are expanding to new countries in the region, most recently, into South East Europe.”

RhinoBond is a method for installing thermoplastic and now also clean EPDM membrane. The system consists of a stand-up induction welding tool and magnetic cooling clamps. Contractors install roofing insulation using fasteners and specially coated plates designed specifically for the type of membrane being installed – PVC, TPO or Clean EPDM. Each plate is then bonded to the roof membrane installed over the top with the RhinoBond plate welding tool. The result is a roofing system that can provide wind performance with fewer fasteners, fewer membrane seams and zero penetrations of the new membrane.

The RhinoBond System is approved for use in Europe by many roof system providers, including Bauder, Carlisle/Hertalan, Danosa, Fatra, FDT, Firestone, GAF, IcoPal, IKO, Renolit, Sika, Siplast, and Soprema/Flag.

Headquartered in Agawam, Mass., OMG Roofing Products is a supplier of commercial roofing products including specialty fasteners, insulation adhesives, roof drains, pipe supports, emergency roof repair tape as well as productivity tools such as RhinoBond. The company’s focus is delivering products and services that improve contractor productivity and enhance roof system performance. For additional information, please contact OMG Roofing Products at (413)789-0252 or visit the OMG Roofing website.

A Michigan Contractor Is Challenged to Recreate a Roof’s 40-year-old Mural

Kevin Clausen has faced a lot of challenges during his 30 years at Great Lakes Systems, a Jenison, Mich.-based construction company specializing in single-ply commercial roofs. But when he received a call several years ago from a Kent County official about an unusual upcoming project, Clausen knew he might be taking on a challenge unlike any other.

Artist Alexander Calder created the 127-square-foot red, black and white mural painted on the roof of the Kent County Administration building.

Artist Alexander Calder created the 127-square-foot red, black and white mural painted on the roof of the Kent County Administration building.

Kent County is home to Grand Rapids, Mich. To understand the challenge that Clausen was about to face, it’s important to understand a little Grand Rapids history. In the late 1960s, swept along by the tide of enthusiasm for urban renewal, the city demolished 120 buildings in its aging downtown core and built a new City Hall and County Administration building, surrounded by a concrete plaza. The new government buildings were designed by architects who were shaped by mid-century ideas of good urban design: sleek, boxy single-use structures, easily accessed by automobile and, therefore, providing ample parking. Pedestrians were something of an afterthought.

At about the same time, the National Endowment for the Arts initiated its Art in Public Places Program. There was general agreement in Grand Rapids that the broad plaza in front of the new buildings seemed empty and generally lacked visual interest. The city applied for a grant to support the funding of a monumental sculpture to serve as a focal point for its new plaza and selected renowned sculptor Alexander Calder for the commission. Two years later, Calder’s sculpture—bright red, 43- feet tall, 54-feet long, 30-feet wide, weighing 42 tons—took its place on the central plaza. It was named “La Grande Vitesse”, which roughly translates into “Grand Rapids”. For obvious reasons, the broad plaza has been called Calder Plaza—and has been the focus of controversy ever since.

The Calder sculpture at ground level on the plaza inspired another important work of art in the area. The flat, unadorned roof of the administration building adjacent to the plaza was drawing attention for the wrong reasons. It was easily viewed from the nearby taller buildings, including the new City Hall, and several city administrators thought some sort of added visual element was necessary for the space. Calder again was pressed into service and designed a large mural for the roof of the administration building. When it was completed in 1974, the 127-square-foot red, black and white mural painted on the roof of the Kent County Administration building was the largest Calder painting in the world.

A DURABLE ROOF

Fast-forward three decades and the aging modified bitumen roofing membrane, which supported the Calder mural, had weathered badly and was in need of repair or replacement. The challenge? How to repair the roof and still preserve the Calder mural. Given the deteriorated condition of the roofing membrane, a complete tear-off was required. Basically, the task at hand was to replace the canvas of a painting and recreate the painting, maintaining its original appearance.

Great Lakes Systems, Jenison, Mich., was challenged to recreate the Calder mural on a new EPDM roof after tearing off the modified bitumen roof on which the mural was originally painted.

Great Lakes Systems, Jenison, Mich., was challenged to recreate the Calder mural on a new EPDM roof after tearing off the modified bitumen roof on which the mural was originally painted.

The team at Great Lakes Systems has a long track record of doing work for Kent County, including the jail, juvenile facility and several libraries. Therefore, county leaders turned to Great Lakes Systems when they realized they need- ed a creative solution to repair their unique roof. Clausen says the county wanted to preserve the mural, but a long-lasting, durable roof was a top priority. “They definitely wanted a high-quality roof,” he says.

The project faced other constraints, in addition to the painted surface. The administration building is located in a prominent spot in the middle of downtown Grand Rapids, near the museum dedicated to former President Gerald Ford and adjacent to two major expressways. No interruption of normal activities could be allowed—either on the plaza or in the building supporting the Calder mural. And—perhaps most challenging—Great Lakes Systems was given three weeks to complete the project before the inaugural ArtPrize competition would take over much of downtown Grand Rapids. That meant the team would have two weeks for the roof installation, leaving one week to repaint the mural. This was less than half the time usually required for a comparable project.

For Clausen, one part of the project was easy. He had used EPDM membrane on a variety of prior projects for county buildings, and county officials had been pleased with the results, especially the balance of cost-effective installation and long service life. “We looked at other membranes, given the nature of the project, but we always came back to EPDM, given its 30-year plus lifespan,” Clausen notes. “If we have to paint again, that’s OK, but we don’t want to reroof.”

For this project, fully adhered EPDM, as well as insulation ad- hered to the concrete deck, offered two important benefits: a painting surface that would be appropriate for the repainted mural and minimal noise (compared to a mechanically attached system) so that work in the building below could continue as normal.

Great Lakes Systems used 60-mil EPDM to replace the aging modified bitumen system. The 18,500-square-foot roof was backed by two layers of 2-inch polyiso insulation, and the EPDM membrane was covered with an acrylic top coat to provide a smooth surface for the new painting. The top coat matched the three colors of the mural—red, black and white. The red was a custom tinted acrylic paint deemed to be compatible with the EPDM membrane and the black and white acrylic top coat provided by the EPDM manufacturer.

Great Lakes Systems took aerial photos of the existing roof, created a grid of the roof and—scaling the design from the photos—recreated the mural exactly, a sort of large-scale paint- by-number approach.

Great Lakes Systems took aerial photos of the existing roof, created a grid of the roof and—scaling the design from the photos—recreated the mural exactly, a sort of large-scale paint- by-number approach.

A BEAUTIFUL ROOF

The Great Lakes Systems’ team applied a creative approach to recreate the mural, adhering carefully to the original design. Because the county used the same colors on its street signs as in the original mural, color codes were available to allow the team to access colors that were identical to those specified by Calder.

Great Lakes Systems took aerial photos of the existing roof, created a grid of the roof and—scaling the design from the photos—recreated the mural exactly, a sort of large-scale paint-by-number approach. The most intricate part of the painting was the layout. Although some free-hand painting had to be done along several jagged edges, the team painstakingly followed the scaled grid and applied chalk lines to outline the original design on the repaired roof. Roller applications were used at the border of the chalk lines to define individual spaces and mark the stopping and starting points for the different colors. Following this “outlining” work, the large areas were sprayed to complete the painting process. The three-man painting crew finished the job with several days to spare, helped along with very good weather.

The roofing project was an informal jump-start toward reimagining uses for Calder Plaza. This past summer, Grand Rapids residents were given the opportunity to voice their preferences for new landscaping for the plaza, provide input for activities that would attract more families and children, and generally make the space more pedestrian friendly. The new proposals are generating excitement and enthusiasm in Grand Rapids. As the new plans become reality, the citizens of Grand Rapids can be assured the Calder mural and the roof supporting it will be doing their part to add beauty and shelter to Calder Plaza and its buildings for decades to come.

Roof Materials

60-mil EPDM: Firestone Building Products Co.
2-inch Polyiso Insulation: Firestone Building Products
Black and White Acrylic Top Coat: Firestone Building Products

PHOTOS: Great Lakes Systems

Project Profiles: Retail

Sierra Nevada Brewery, Mills River, N.C.

About 58,000 pounds of copper were installed on the brewery.

About 58,000 pounds of copper were installed on the brewery.

TEAM

Roofing Contractor: The Century Slate Roofing Co., Durham, N.C.
Architect: Matthew Galloway of Russell Gallaway Associates Inc., Chico, Calif.

ROOF MATERIALS

Approximately 423 squares of 1/2-inch-thick, 18-inch-tall by random width Unfading Green Slates were installed by hand on the project. This was close to 750,000 pounds of slate, or 375 tons.

About 3,000 feet of custom copper gutters and downspouts, conductor heads and 100 squares of painted standing-seam panels were fabricated, and pre-built copper clad dormers and decorative copper cornices were installed.

The project also included 35 squares of copper standing-seam roofing, 25 squares of soldered copper flat-seam roofing and 115 squares of copper wall cladding. About 58,000 pounds of copper were installed on the brewery.

Everything on the building is oversized and that meant everything had to be built to support the heavy structural loads and live loads from wind and mountain snow. The large roof faces called for 10-inch custom copper gutters. When you have gutters that large in the mountains of North Carolina you have to consider the extraordinary weight of the annual snow.

In addition to snow guards being installed on the slate roof, custom 1/4-inch-thick copper gutter brackets fastened the gutter to the fascia. It is typical on steel-framed construction, particularly on this scale, that the framing is out of square and there is widely varying fascia and rake dimensions.

Approximately 423 squares of 1/2-inch-thick, 18-inch-tall by random width Unfading Green Slates were installed by hand on the project.

Approximately 423 squares of 1/2-inch-thick, 18-inch-tall by random width Unfading Green Slates were installed by hand on the project.

However, these items should not appear out of square or have varying dimensions. Great care had to be taken to measure and custom bend onsite all the detail flashings so everything appeared perfect. This took many skilled craftsmen, a great deal of time and the absolute drive to provide the highest quality work.

Slate Manufacturer: Evergreen Slate Co. Inc.
Copper Fabricator: K&M Sheet Metal LLC
Supplier of Underlayment, Copper Sheets and Coil, Insulation and Nailbase Sheathing: ABC Supply Co. Inc.

ROOF REPORT

The new-construction project began in November 2013 and was completed in September 2015.
The team completed the slate installation so well that The Century Slate Co. was awarded the 2015 Excellence in Craftsmanship Award by Evergreen Slate for the project.

PHOTOS: The Century Slate Roofing Co.

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Denver International Airport Is Reroofed with EPDM after a Hailstorm

The millions of passengers who pass through Denver International Airport each year no doubt have the usual list of things to review as they prepare for a flight: Checked baggage or carry-on? Buy some extra reading material or hope that the Wi-Fi on the plane is working? Grab
a quick bite before takeoff or take your chances with airline snacks?

The storm created concentric cracks at the point of hail impacts and, in most cases, the cracks ran completely through the original membrane.

The storm created concentric cracks at the point of hail impacts and, in most cases, the cracks ran completely through the original membrane.

Nick Lovato, a Denver-based roofing consultant, most likely runs through a similar checklist before each flight. But there’s one other important thing he does every time he walks through DIA. As he crosses the passenger bridge that connects the Jeppeson Terminal to Gate A, he always looks out at the terminal’s roof and notices with some pride that it is holding up well. Fifteen years ago, after a hailstorm shredded the original roof on Denver’s terminal building, his firm, CyberCon, Centennial, Colo., was brought in as part of the design team to assess the damage, assist in developing the specifications and oversee the installation of a new roof that would stand up to Denver’s sometimes unforgiving climate.

HAIL ALLEY

DIA, which opened in 1995, is located 23 miles northeast of the metropolitan Denver area, on the high mountain desert prairie of Colorado. Its location showcases its spectacular design incorporating peaked tent-like elements on its roof, meant to evoke the nearby Rocky Mountains or Native American dwellings or both. Unfortunately, this location also places the airport smack in the middle of what is known as “Hail Alley”, the area east of the Rockies centered in Colorado, Nebraska and Wyoming. According to the Silver Spring, Md.- based National Weather Service, this area experiences an average of nine “hail days” a year. The reason this area gets so much hail is that the freezing point—the area of the atmosphere at 32 F or less—in the high plains is much closer to the ground. In other words, the hail doesn’t have time to thaw and melt before it hits the ground.

Not only are hail storms in this area relatively frequent, they also produce the largest hail in North America. The Rocky Mountain Insurance Information Association, Greenwood Village, Colo., says the area experiences three to four hailstorms a year categorized as “catastrophic”, causing at least $25 million in damage. Crops, commercial buildings, housing, automobiles and even livestock are at risk.

Statistically, more hail falls in June in Colorado than during any other month, and the storm that damaged DIA’s roof followed this pattern. In June 2001, the hailstorm swept over the airport. The storm was classified as “moderate” but still caused extensive damage to the flat roofs over Jeppesen Terminal and the passenger bridge. (It’s important to note that the storm did not damage the renowned tent roofs.) The airport’s original roof, non-reinforced PVC single-ply membrane, was “shredded” by the storm and needed extensive repair. Lovato and his team at CyberCon assessed the damage and recommended changes in the roofing materials that would stand up to Colorado’s climate. Lovato also oversaw the short-term emergency re- pairs to the roof and the installation of the new roof.

The initial examination of the roof also revealed that the existing polystyrene rigid insulation, ranging in thickness from 4 to 14 inches, was salvageable, representing significant savings.

The initial examination of the roof also revealed that the existing polystyrene rigid insulation, ranging in thickness from 4 to 14 inches, was salvageable, representing significant savings.

Under any circumstances, this would have been a challenging task. The fact that the work was being done at one of the busiest airports in the world made the challenge even more complex. The airport was the site of round-the-clock operations with ongoing public activity, meaning that noise and odor issues needed to be addressed. Hundreds of airplanes would be landing and taking off while the work was ongoing. And three months after the storm damaged the roof in Denver, terrorists attacked the World Trade Center, making security concerns paramount.

INSPECTION AND REROOFING

Lovato’s inspection of the hail damage revealed the extent of the problems with the airport roof. The original PVC membrane, installed in 1991, was showing signs of degradation and premature plasticizer loss prior to being pummeled by the June 2001 storm. The storm itself created concentric cracks at the point of hail impacts and, in most cases, the cracks ran completely through the membrane. In some instances, new cracks developed in the membranes that were not initially visible following the storm. The visible cracks were repaired immediately with EPDM primer and EPDM flashing tape until more extensive repairs could begin. Lovato notes that while nature caused the damage to DIA, nature was on the roofing team’s side when the repairs were being made: The reroofing project was performed during a drought, the driest in 50 years, minimizing worries about leaks into the terminal below and giving the construction teams almost endless sunny days to finish their job.

The initial examination of the roof also revealed that the existing polystyrene rigid insulation, ranging in thickness from 4 to 14 inches, was salvageable, representing significant savings. Although a single-ply, ballasted roof was considered and would have been an excellent choice in other locations, it was ruled out at the airport given that the original structure was not designed for the additional weight and substantial remediation at the roof edge perimeter possibly would have been required.

Lovato chose 90-mil black EPDM membrane for the new roof. “It’s the perfect roof for that facility. We wanted a roof that’s going to perform. EPDM survives the best out here, given our hailstorms,” he says. A single layer of 5/8-inch glass-faced gypsum board with a primed surface was installed over the existing polystyrene rigid insulation (secured with mechanical fasteners and metal plates) to provide a dense, hail-resistant substrate for the new membrane.

In some areas adjacent to the airport’s clerestory windows, the membrane received much more solar radiation than other areas of the roof.

In some areas adjacent to the airport’s clerestory windows, the membrane received much more solar radiation than other areas of the roof.

In some areas adjacent to the airport’s clerestory windows, the membrane received much more solar radiation than other areas of the roof. When ambient temperatures exceeded 100 F, some melting of the polystyrene rigid insulation occurred. “That section of the roof was getting double reflection,” Lovato points out. To reduce the impact of this reflection, the roof was covered with a high-albedo white coating, which prevented any further damage to the top layer of the polystyrene rigid insulation board and also met the aesthetic requirements of the building.

LONG-TERM SOLUTION

Lovato’s observations about the durability of EPDM are backed up by field experience and controlled scientific testing. In 2005, the EPDM Roofing Association, Washington, D.C., commissioned a study of the impact of hail on various roofing membranes. The study, conducted by Jim D. Koontz & Associates Inc., Hobbs, N.M., showed EPDM outperforms all other available membranes in terms of hail resistance. As would be expected, 90-mil membrane offers the highest resistance against punctures. But even thinner 45-mil membranes were affected only when impacted by a 3-inch diameter ice ball at 133.2 feet per second, more than 90 mph—extreme conditions that would rarely be experienced even in the harshest climates.

Lovato travels frequently, meaning he can informally inspect the DIA roof at regular intervals as he walks through the airport. He’s confident the EPDM roof is holding up well against the Denver weather extremes, and he’s optimistic about the future. With justified pride, Lovato says, “I would expect that roof to last 30-plus years.”

PHOTOS: CyberCon

Roof Materials

90-mil Non-reinforced EPDM: Firestone Building Products
Gypsum Board: 5/8-inch DensDeck Prime from Georgia-Pacific
Plates and Concrete Fasteners: Firestone Building Products
White Elastomeric Coating: AcryliTop from Firestone Building Products
Existing Polystyrene: Dow

Choose Sustainable, Durable and Geographically Appropriate Roofs

Carlisle SynTec Systems has made available its RoofEd eBook for download through iTunes and Google Play.

Carlisle SynTec Systems has made available its RoofEd eBook for download through iTunes and Google Play.

Carlisle SynTec Systems has made available its RoofEd eBook for download through iTunes and Google Play. The first chapter of RoofEd focuses on EPDM roofing systems and their attributes. RoofEd contains videos, articles, case studies and photos, all of which are designed to give readers a deeper understanding of their commercial roofing system options. RoofEd can also be used as an on-the-road sales tool to help building owners choose the most sustainable, durable and geographically appropriate roof for their buildings.

After Years of Roof Leaks, a Laboratory That Produces Theatrical Equipment and Software Undergoes a Complex Reroofing

Founded in 1910, Rosco Laboratories is a multi-national producer of equipment, software and products for the theatrical, film, and television industries and architectural environment. As with every aging flat roofing system, water leakage was becoming a recurring problem at Rosco’s Stamford, Conn., facility. The severity of the leakage was further exacerbated by the lack of roof drainage (only two roof drains serviced the entire building) and poor deck slope conditions (less than 1/16 inch per foot).

The gypsum decking was cut out within the limits of the entire framing “bay” and infilled with galvanized metal decking. The longitudinal deck panel edge was seated atop the horizontal leg of the bulb-tee section (visible in the center of the photograph) and mechanically fastened using self-tapping screws. The ends were supported by the steel purlins. The underside of the decking was prepainted to match the ceiling finish. Supplemental structural support consisting of strips of 14-gauge galvanized sheet metal were attached to the bottom of each bulb-tee section contiguous to the repair to provide additional support for the adjacent gypsum roof decking segment.

The gypsum decking was cut out within the limits of the entire framing “bay” and infilled with galvanized metal decking. The longitudinal deck panel edge was seated atop the horizontal leg of the bulb-tee section (visible in the center of the photograph) and mechanically fastened using self-tapping screws. The ends were supported by the steel purlins. The underside of the decking was prepainted to match the ceiling finish. Supplemental structural support consisting of strips of 14-gauge galvanized sheet metal were attached to the bottom of each bulb-tee section contiguous to the repair to provide additional support for the adjacent gypsum roof decking segment.


Rosco representatives employed traditional methods to control and/or collect the moisture within the building by use of several water diverters. This technique was effective but Rosco representatives soon recognized this was not a viable long term solution as the physical integrity of the roof structure (deck) became a principal concern to the safety of the building occupants.

The Fisher Group LLC, an Oxford, Conn.-based building envelope consulting firm was retained by Rosco in March 2009 to survey the existing site conditions and determine the need for roofing replacement. The existing roofing construction, which consisted of a conventional two-ply, smooth-surfaced BUR with aluminized coating, exhibited numerous deficiencies (most notably severe alligatoring) and was deemed unserviceable. Construction documents, including drawings and specifications and a project phasing plan were developed by Fisher Group to address the planned roof replacement.

Bid proposals were solicited from prequalified contractors in June 2010, and F.J. Dahill Co. Inc., New Haven, Conn., was awarded the contract on the basis of lowest bid.

Existing Conditions

The building basically consists of a 1-story steel-framed structure constructed in the 1970s. It is a simple “box”-style configuration, which is conducive to manufacturing.

In conjunction with design services, destructive test cuts were made by Fisher Group in several roof sections as necessary to verify the existing roofing composition, insulation substrate, moisture entrapment, and substrate/deck construction. A total of four distinct “layers” of roofing were encountered at each test cut. The existing roofing construction consisted of alternating layers of smooth- and gravel-surfaced, multi-ply felt and bitumen built-up roofing. The bitumen contained throughout the construction was fortunately asphalt-based. Succeeding layers of roofing were spot mopped or fully mopped to the preceding layer (system). The combined weight of the roofing construction was estimated to be upwards of 20 to 22 pounds per square foot when considering the moisture content. This is excessive weight.

The roof insulation panels were set into ribbons of low-rise polyurethane foam insulation adhesive. The adhesive was applied in a continuous serpentine bead, spaced 6 inches on-center throughout the field of the roof.

The roof insulation panels were set into ribbons of low-rise polyurethane foam insulation adhesive. The adhesive was applied in a continuous serpentine bead, spaced 6 inches on-center throughout the field of the roof.


It is interesting to note that a minimal amount of roof insulation was present in the existing construction. Insulation was limited to a single layer of 1/2-inch-thick fiberboard. Additional insulation would need to be provided as part of the replacement roofing construction to increase the roof’s thermal performance and comply with the prescriptive requirements of the Connecticut State Energy Conservation Construction Code.

The structural substrate, or decking, is conventional in nature, comprised of poured gypsum roof decking. The roof decking incorporates 1/2-inch gypsum formboard loose laid between steel bulb-tee supports spaced about 32 inches on-center. The poured gypsum roof decking in this instance was utilized as the structural substrate and for insulating purposes. Poured gypsum roof decking has a minimal insulating value of perhaps R-2 to R-3, which is obviously considered to be minimal by present standards.

A representative number of bulk material samples were obtained by Fisher Group from the existing roofing construction as necessary to determine the material composition. The sampling included field membrane roofing plies, coatings and cements, and associated roof penetration and perimeter flashings. Laboratory analysis revealed that the second, third and, in some instances, fourth roofing “layers” (field membrane plies) contained varying amounts—5 to 10 percent—of asbestos (chrysotile) which would necessitate full abatement of the roofing construction.

PHOTOS: The Fisher Group LLC

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You Can Influence Codes and Standards

As associate executive director of the Washington, D.C.-based EPDM Roofing Association (ERA), I focus a great deal of my time and energy on the codes and standards that regulate or guide the roofing business. In the current environment, driven by constant upgrades in technology, as well as the need to save energy, these codes—and the standards that often inform them—seem to be undergoing steady revision. Believe it or not—and the word “geek” does come to mind—I find participating in this process extremely interesting. In fact, following and sometimes influencing emerging codes and standards is among the most important responsibilities of my job.

I’ll be the first to admit that a detailed review of a standards manual is probably not anyone’s idea of exciting reading. But given the importance of codes and standards to the construction industry, we ignore them at our own risk.

For a start, what’s the difference between a code and a standard? Ask enough people in the roofing industry and you will get a variety of answers. But generally, codes are the “top-tier” documents, providing a set of rules that specify the minimum acceptable level of safety for manufactured, fabricated or constructed objects. They frequently have been enacted into local laws or ordinances and noncompliance can result in legal action. Standards, on the other hand, establish engineering or technical requirements for products, practices, methods or operations. They literally provide the nuts and bolts of meeting code requirements. If codes tell you what you have to do, standards tell you how to do it. Frequently, standards—especially “voluntary consensus standards”—are the precursors for what becomes law years down the road.

ERA has represented the manufacturers of EPDM roofing for more than a decade. Through the years, we have learned the importance of interfacing with standard-setting and regulatory bodies. One of our first, and most important, learning experiences was working with the Northeast and mid-Atlantic states when they issued regulations designed to achieve federally mandated air-quality standards. (See the article in Roofing’s September/October 2014 issue, page 58.) The initial regulations, which lowered the amount of VOCs in many roofing products, were based on those used in southern California and incorporated provisions that were effective in the climactic and market conditions of that state. But states in the affected areas, from Virginia to Maine, confronted a situation where the new regulations threatened to bring the roofing industry to a sudden halt. In some instances, no adhesives and sealants were available to meet the new standards. And the new products, when they became available, would need to be effective in very cold climates totally unlike those on the West Coast.

ERA worked with officials throughout the impacted areas, helping to create “phase-in” schedules that would give industry enough time to develop products to meet the new standards. In state after state, the local regulators welcomed our input. Our point-of-view was based on a deep understanding of the business needs of our industry. Just as important, we understood the science behind the proposed regulations and could work with the regulatory bodies to ensure the air-quality needs and the needs of the roofing industry were met.

This experience has informed our ongoing approach to code-setting and regulatory bodies. Since our work with the states setting VOC standards, we have invested staff time and resources to stay current with and even ahead of proposals that would impact our members and their customers. We have testified before the South Coast Air Quality Management District in California on its proposal to limit VOCs. ERA has organized an ad-hoc coalition to successfully oppose an unnecessarily stringent proposal to require reflective roofs in the Denver area. And our organization is currently providing input to Atlanta-based ASHRAE’s efforts to clarify its regulation regarding air leakage. This issue—of great importance to the roofing industry—relates to other work being done in ASHRAE working groups and subcommittees on thermal bridging, as well as the definition of walls and wall assemblies. ASHRAE has convened an “Air Leakage Work Group” whose charge is to review the pertinent sections of Standard 90.1 and make recommendations for revising it. ERA staff will be present at this group’s meetings and will once again provide input based on the expertise of our members.

When I work with code-setting and regulatory groups, I am reminded of that very familiar saying, “It’s not whether you win or lose, it’s how you play the game.” Based on our work at ERA, I’d like to revise that. Your skill at “playing the game” will definitely influence whether you win or lose. Our experience tells us that staying involved with regulatory groups and providing them with input based on firm science and field experience leads to a winning outcome for the roofing business.