ARMA Completes EPDs for Five Types of Asphalt Roofing

The Asphalt Roofing Manufacturers Association (ARMA) has completed a multi-year effort to develop Environmental Product Declarations (EPDs) for asphalt roofing systems. These five new documents provide information that building and construction professionals can use both to support environmental aspects of roof systems as part of sustainable building projects and to better understand their impact over time. EPDs are now available for asphalt shingle roofing systems, SBS and APP modified bitumen systems, and built-up roofing systems. 

When architects and specifiers embark on new green building initiatives, they need to validate the environmental aspects of the building materials they use. EPDs are used to provide this information and to support the credibility of environmental claims.  ARMA worked with thinkstep, a sustainability consulting company, and with UL Environment to validate the EPDs.  These comprehensive documents outline the environmental attributes associated with the manufacturing of various asphalt-related roofing materials. 
ARMA’s development of these five EPDs reflects the continued use and advancement of asphalt roofing materials. In some cases, these documents are needed to fulfill requirements for green building rating systems and initiatives such as Leadership in Energy and Environmental Design (LEED), Green Globes, and the International Green Construction Code (IgCC).

“As the worldwide building and construction community continues to expand the focus on creating environmentally responsible and resource-efficient building projects, asphalt roofing has a critical role to play,” said Reed Hitchcock, ARMA’s executive vice president. “ARMA is committed to supporting sustainable building initiatives, and we are proud to provide the industry with this important environmental information.”

“These EPDs will help architects and engineers make sustainable choices in roof design,” said Amy Ferryman, chair of ARMA’s Sustainability Task Force. “Our work to develop these resources helps ensure that the asphalt roofing industry can fully participate in increasingly important green building practices.”
The five EPDs from ARMA are now publically available and can be accessed on ARMA’s website.

Roofing Torch Program Reduces Fire Hazards During Modified Bitumen Application

CERTA offers a certification program in which authorized trainers deliver behavior-based training to roofing workers who install polymer modified bitumen roof systems.

CERTA offers a certification program in which authorized trainers deliver behavior-based training to roofing workers who install polymer modified bitumen roof systems.

The latest market survey conducted by the National Roofing Contractors Association (NRCA) shows the use of polymer modified bitumen as a percentage of all new roof systems, installed both in new construction and re-roofing projects, comprises about 10 percent of the total low-slope market, according to members responding. The significance of that share of the market for polymer-modified bitumen also highlights the importance of proper training in the use of roofing torches, the most common method for installation of such systems.

Background

In 1986, the Midwest Roofing Contractors Association (MRCA), in conjunction with industry organizations, the Asphalt Roofing Manufacturers Association, and the United Union of Roofers, Waterproofers and Allied Workers, developed a curriculum to train roofing workers in the safe application of torch-applied roof systems. This program was named the Certified Roofing Torch Applicator, or CERTA, program.

In 2003, insurance industry representatives approached NRCA to address concerns about an increase of losses and incidents involving torching activities conducted by roofing workers. One prominent insurer experienced over $7 million in roofing torch-related claims in 2002 spread over more than 30 separate occurrences. The need for enhanced work practices and focused safety training to address torching activities became apparent, and NRCA arranged with MRCA to adopt and revise the nature of and deliverables offered by the CERTA program.

CERTA now offers a unique, comprehensive certification program in which authorized trainers deliver effective behavior-based training to roofing workers who install polymer modified bitumen roof systems. CERTA-authorized trainers undergo a rigorous full-day training session that includes classroom and hands-on instruction in propane safety, hazards related to torch use, proper techniques for safe installation of polymer modified bitumen, and development of training skills. Individuals who successfully complete all aspects of the program then are authorized to deliver training, under the CERTA protocol, to workers who qualify as certified roofing torch applicators.

MRCA continues to work with NRCA to make sure the program is up-to-date and uses the most effective procedures to develop authorized trainers and enhance the curriculum. Since its inception, roofing contractors who have trained their workers under CERTA generally have experienced fewer torch-related fires, injuries and property damage. Insurance industry claims also are a testament to the CERTA program success—the insurer that experienced over 30 torch-related claims in 2002 now can count such average yearly claims on one hand with a significantly reduced average yearly dollar loss.

Safety Specifics

Trainees in a CERTA class spend a great deal of time on some specific aspects of the use of roofing torches to install a polymer modified bitumen roof system. Those specifics have a direct correlation to keeping workers and others safe, and minimizing the likelihood of property damage. First, the CERTA curriculum focuses on the inherent danger of roofing torches and discusses assessing job hazards and establishing controls for torching operations. Details cover the proper personal protective equipment to minimize or eliminate exposure to burns and the critical need to handle propane properly and make sure equipment is in good condition.

Pre-job planning enforces the significance of determining the hazards unique to the particular worksite and developing the necessary controls to address those hazards. In addition to general working conditions and weather issues that may influence job site safety, specific hazards such as the presence of a combustible roof deck, roof penetrations, concealed attic areas and combustible flashing substrates are addressed and suitable controls are suggested and discussed. Also, attendees get comprehensive information on the types and ratings of fire extinguishers and how they are used most effectively along with the minimum CERTA requirements for appropriate fire extinguishers that must be on a roof. In fact, CERTA requires a fire extinguisher capacity far exceeding OSHA’s fire protection requirements during torch operations— two 4A60BC-rated fire extinguishers within 10 feet of torching activity.

Another important fire prevention protocol is the use of a fire watch system. The intent of the fire watch is that a dedicated individual is charged with inspecting the work area after the last torch, or other heat generating tool, is extinguished. Ordinarily, this is accomplished visually, but it can also be done more scientifically with the use of temperature sensing infrared thermometer. These are inexpensive tools that read the temperature of an area that the tool is pointed at and display the reading in degrees on the screen. The fire watch individual would shoot various specific locations where hot work was done—for example, at roof penetrations, flashings or field areas—noting the temperature for each spot. This procedure would be followed for the same spots a short time later, and if the temperature had increased, the possibility that a fire under the roof surface could be a source of the increased heat being generated would require further steps to determine the nature of the heat increase and the proper action to take.

Historically, many industries and building owners have required a 30-minute fire watch be maintained after the last torch or other tool has been extinguished. Under the CERTA protocol, a two-hour fire watch is demanded of a CERTA roofing torch applicator. The fire watch must be maintained not just at the end of the day but at other break times, such as lunch, so that fires do not start when workers may be away from the work area or inattentive during break times.

Another key element of training for the CERTA torch applicator involves installation techniques that are intended to reduce the likelihood of a fire being started. The techniques include specified thermal barriers to protect combustible roof decks and substrate protection for flashing installations, along with an alternative torching technique that minimizes the use of direct torching.

Certa Works

Installation of polymer-modified bitumen roof systems using propane roofing torches requires adherence to a number of safety procedures and an awareness of the hazards that workers may encounter. The CERTA program has a proven track record of enhancing the safe practices of roofing workers who install these systems and the roofing industry, building owners and the general public are all safer because of its development and use.

Photo: NRCA

Prevent Roof Fires During Torch-Down Projects

Torch-Down Safety While driving to work recently, I heard a news story on the radio: An unlicensed roofer was charged with causing a fire at a local apartment complex. When I arrived at the office, I Googled “fires caused by roofers.” The results included stories from across the nation:

  • Roofing crew blamed for a Chicago strip-mall fire.
  • Roofer’s torch likely cause of huge Arizona construction-site blaze.
  • Roofer’s blowtorch sparks a six-alarm fire in Hamilton Township, N.J.
  • Obviously, using an open-flame torch to install torch-down roofing systems can pose a fire risk. Torch-down roofing is a type of roofing that consists of layers of modified bitumen adhered to layers of fiberglass with a flame torch. Torch-down roofing is used only for flat or low-slope roofs. This process is popular with many contractors, mainly because of its ease of installation and its adaptability. With this system, the modified bitumen can bond tightly to metal flashings while the rubbery additives in the asphalt allow the roofing to expand and contract when other roofing systems may crack. In addition, roofers like torch-down roofing because it is easy to apply. Unfortunately, it can also be dangerous!

    It is easy to make a mistake with the torch that could result in disaster. Consider roofers that are torching down a roof and accidentally overheat something in the attic—insulation, for instance. They end their work for the day, not noticing the smoke coming out of soffit vents. Before long, that smoldering material in the attic heats up and starts a fire that quickly spreads throughout the dry, hot attic and, often, to the rest of the structure. 

    Regulations and Best Practices

    OSHA has developed standards that can help prevent these types of fires. Here are some of OSHA’s fire-protection and -prevention rules from the construction and general industry standards:

  • A fire extinguisher must be immediately accessible for all torch-down operations.
  • A fire extinguisher is needed within 50 feet of anywhere where more than 5 gallons of flammable or combustible liquids or 5 pounds of flammable gas are being used on the job site.
  • No one on a job site can be more than 100 feet from a fire extinguisher at all times.
  • There must be at least one fire extinguisher for 3,000 square feet of work area.
  • All flammable or combustible debris must be located well away from flammable liquids or gases.
  • Combustible scrap and debris must be removed regularly during the course of a job.
  • Piles of scrap and debris must be kept at least 10 feet from any building.
  • A fire watch person should be posted to immediately address any possible smolders or flare-ups.
  • The fire watch person should remain on post for 30 minutes after the torch-down job is finished for the day.
  • While the actions spelled out in these construction regulations are mandatory, roofing professionals should be aware that these are minimum requirements. The National Roofing Contractors Association (NRCA) and the Midwest Roofing Contractors Association (MRCA) have developed a roofing torch applicator certification program designed to reduce fire hazards during torch application of modified bitumen products. According to Harry Dietz, Director of Risk Management for NRCA, the Certified Torch Applicator (CERTA) program teaches installers to minimize the exposure of combustible structural materials to the heat and flame of the roofing torch. The program also spells out a number of safe practices that go well beyond OSHA’s regulations in dealing with roofing torch use. Among other program elements, these include:

  • The requirement for two 4A60BC fire extinguishers during torch work (more than 10 times the firefighting capability required under the OSHA rules).
  • A two-hour fire watch performed after the last torch has been extinguished.
  • Following these guidelines for fire prevention can protect roofing professionals and the public. It can also save roofers money and time, as well as protect contractors from lawsuits and other legal charges. 

    “In 2002, a leading insurer of roofing contractors had over $7 million in torch related claims in 33 occurrences prior to requiring CERTA for its insureds,” said Dietz. “In 2015, that same insurance company reported only one torch-related claim with a loss of less than $10,000.”

    Visit this site to learn more about OSHA’s Safety and Health Regulations for Construction, Welding and Cutting, Fire Prevention. To learn more about the Certified Torch Applicator (CERTA) program, click here.

    Two Commercial Installations Are Honored with ARMA’s QARC Awards

    Advanced Roofing Inc. installed two new roofs at a luxury retired-living community in Palm Beach Gardens. These projects were Silver Award winners in ARMA’s 2016 QARC Awards.

    Advanced Roofing Inc. installed two new roofs at a luxury retired-living community in Palm Beach Gardens. These projects were Silver Award winners in ARMA’s 2016 QARC Awards.

    Commercial roofs are the workhorses of a building system. They endure wind, rain, hail and foot traffic while serving as an important line of defense between the outside world and a building’s occupants. If inhabitants never consider the roof over their heads, it means the roof system is doing its job well.

    The Washington, D.C.-based Asphalt Roofing Manufacturers Association (ARMA) showcases these hardworking but rarely celebrated systems in its annual Quality Asphalt Roofing Case- study (QARC) Awards program. Each year, the organization seeks the top asphalt roofing projects in North America that demonstrate durability and high performance, as well as beauty. The QARC awards honor a Gold, Silver and Bronze winning project that illustrates the benefits of asphalt roofing.

    The Silver Winner of ARMA’s 2016 QARC Awards is a prime example of what a commercial roofing system must stand up to while remaining water-resistant and durable. Advanced Roofing Inc. (ARI), which has service areas throughout much of Florida, was hired to install two new roofs at a luxury retired-living community in Palm Beach Gardens. These reroofs were completed in 2015 and were submitted to ARMA’s awards program.

    The two buildings in this community were originally built in the 1990s and were found to have numerous issues that demanded immediate attention when new management reviewed the property. The area’s hot climate requires many air-conditioning units on the roof that frequently have to be serviced. This aspect of a commercial roof can be overlooked by building owners but has a significant impact on its service life and performance. Because HVAC units and related equipment are heavy and may require frequent maintenance that brings extensive foot traffic, they can cause a roof system to deteriorate faster than normal. That was the case with the existing roofs in this living community.

    Toward the end of the roofs’ service lives, temporary fixes, like patching and coatings, were made. These regular repairs only increased the operational budget while the core issues remained unresolved. According to Jessica Kornahrens, project manager at ARI, “The existing roofing system was at risk of a failure that could potentially close the building and leave its elderly residents without a home.”

    ARI was hired by the new building owner and property manager to tear off the existing roofs of these two buildings and install an asphalt roofing system on each. Because of the significant durability required by the new roofs, the roofing contractor chose a high-performance three-ply modified bitumen asphalt roofing system.

    The two buildings in the retirement facility were still occupied during the reroof project, creating an additional challenge during installation, but the work came in on schedule and within budget.

    The two buildings in the retirement facility were still occupied during the reroof project, creating an additional challenge during installation, but the work came in on schedule and within budget.


    “We knew that this type of redundant, multi-layered system would protect these buildings long-term despite the high foot traffic and heavy equipment they have to stand up to while also meeting the project budget,” Kornahrens says. “This particular system also has a Miami-Dade Notice of Acceptance with testing and approvals for Florida’s high-velocity hurricane zone.”

    Between foot traffic and harsh weather, the contractors knew this asphalt roofing system was up to the task.

    Challenging Installation

    Before they could begin the project, ARI had to first stop the existing leaks in the first 45,900-square-foot building and the second 51,000-square-foot building, followed by a tear-off of the roof system down to the light- weight concrete. ARI fastened the modified anchor sheet with twin-lock fasteners directly into the lightweight insulated concrete deck and then torch applied an interply and fire-retardant granulated cap sheet.

    Photos: Smith Aerial Photography

    Pages: 1 2

    Modified Bitumen Membranes Adhere to a Variety of Substrates

    SA-APP KoolCap and SA-APP KoolCap FR modified bitumen roofing membranes adhere to a variety of roofing substrates.

    SA-APP KoolCap and SA-APP KoolCap FR modified bitumen roofing membranes adhere to a variety of roofing substrates.

    Mule-Hide Products Co. has made available SA-APP KoolCap and SA-APP KoolCap FR modified bitumen roofing membranes, which adhere to a variety of roofing substrates. The products deliver the safety and ease of self-adhering application, long-term performance and durability, as well as the benefits of a cool roof. Complementing the membranes is the new SA-APP KoolCap Touch-Up Kit for treating lap areas, details and repairs. The granular-surfaced cap sheets are manufactured using a patented dual-compound technology in which a true APP polymer modified asphalt compound is applied to the top, weathering side and a proprietary adhesive formulation is applied to the bottom surface.

    An Oceanfront Elementary School Poses Tough Problems, but a Coated Aluminum Standing-seam Roof Passes the Test

    Elementary school students sometimes find themselves staring out the window, but few have a view to rival that of the students at Sullivan’s Island Elementary School in Sullivan’s Island, S.C. The school is located on oceanfront property, and when it was time for the original building to be rebuilt, the site posed numerous challenges.

    The standing-seam roof is made up of 0.040-inch coated aluminum panels that are 18-inches wide.

    The standing-seam roof is made up of 0.040-inch coated aluminum panels that are 18-inches wide.

    The original school had been built in the 1950s. It had been designed for 350 students and built on grade. The new school would have to be elevated to conform to modern building codes and service 500 students. The structure would not only have to withstand high winds, severe weather and a salt-air environment, but it also would have to fit into its surroundings. Many residents feared the larger building would look out of place in the cozy beach community. It was architect Jerry English’s job to figure out a way to make it work.

    English is a principal at Cummings & McCrady Architects, Charleston, S.C., the architect of record on the project. He worked with a talented team of construction professionals, including Ricky Simmons, general manager of Keating Roofing & Sheet Metal Co. Inc. in Charleston, to refine his vision and bring it to life. English and Simmons shared their insight on the project, and they both point to the building’s metal roof as a key element in the project’s success.

    CHALLENGING DESIGN

    Cummings & McCrady Architects handles a broad range of commercial, institutional, religious and historic work—new construction and renovation. The firm had done a lot of work with the Charleston County School District over the years, including a small library addition for the original Sullivan’s Island Elementary School after Hurricane Hugo passed through in 1989, and it was awarded the new construction project.

    The building’s foundation system had to meet strict regulations regarding resistance to storm surge. The building is elevated on concrete piers, which were topped with a 6-inch reinforced concrete slab. Metal framing was constructed above the slab. “With our building, we had to raise the underside of the structure almost 7 feet above the grade,” English recalls. “What we did is we built it a little bit higher than that so the underside could be left open and used for playground.”

    For English, coming up with a design that would reflect the character of the local community was the biggest challenge. To achieve that goal, he broke up the building into four sections and spread them across the site with the tallest sections in the center. “We have four linked segments that transition down on each end to the height of the adjacent residences,” he says.

    The roof was also designed to blend in with the neighboring homes, many of which feature metal roofs. “The idea of pitched roofs with overhangs became a strong unifying element,” English explains.

    English checked with several major metal roofing manufacturers to determine which products could withstand the harsh oceanfront environment and wind-uplift requirements. “Virtually every one of them would only warranty aluminum roofing,” he says. “The wind requirement and the resistance to the salt air were what drove us to a coated aluminum roof.”

    The majority of the panels were factory-made, but the manufacturer supplied the rollforming machine and the operator to handle the onsite rollforming of the largest panels.

    The majority of the panels were factory-made, but Petersen Aluminum supplied the rollforming machine and the operator to handle the onsite rollforming of the largest panels.

    The standing-seam roof is made up of 0.040-inch coated aluminum panels that are 18-inches wide. Metal trusses give the roof system its shape. English tapped the resources of roof consultant ADC in Charleston and the metal roofing manufacturer to iron out all the details. English wanted to avoid any cross seams in the metal roofing, so he worked with Dave Landis, the manufacturer’s architectural/technical sales manager, to arrange for the longest panels to be formed onsite.

    The roof also includes two decks that serve as outdoor teaching areas. These sections were covered with a two-ply modified bitumen roof system and protected with a multi-colored elevated concrete paver system.

    Another standout feature is the school’s entry tower, which is topped by a freestanding hip roof featuring curved panels. This roof was constructed with panels that were 12-inches wide. “We found other examples on the island where the base of the roof flares a little bit as a traditional element, and with the closer seamed panels they were able to get those curves,” English says. “It’s a refinement that’s a little different than the rest of the roof, but it’s the proper scale and the fine detailing pulls it together and sets if off from the main roof forms that are behind it.”

    PHOTOS: Petersen Aluminum Corp.

    Pages: 1 2

    The Roof Cover: The Cap on the Roof System

    For nearly two years in this magazine, I have been discussing the various components that make up a roof system: roof deck, substrate boards, vapor/air retarder, insulation and cover boards (see “More from Hutch”, page 3). Although each component delivers its own unique benefit to the system, they are intended to work together. When designing a roofing system, components cannot be evaluated solely on their own and consideration must be taken for a holistic view of the system; all components must work together synergistically for sustainable performance. Unfortunately, I often have seen that when components are not designed to work within the system unintended consequences occur, such as a premature roof system failure. A roof system’s strength is only as good as its weakest link. The roof cover is the last component in the design of a durable, sustainable roof system—defined previously as being of long-term performance, which is the essence of sustainability.

    This ballasted 90-mil EPDM roof was designed for 50 years of service life. All the roof-system components were designed to complement each other. The author has designed numerous ballasted EPDM roofs that are still in place providing service.

    PHOTO 1: This ballasted 90-mil EPDM roof was designed for 50 years of service life. All the roof-system components
    were designed to complement each other. The author has designed numerous ballasted EPDM roofs that are still in place providing service.

    The roof cover for this article is defined as the waterproofing membrane outboard of the roof deck and all other roof-system components. It protects the system components from the effects of climate, rooftop use, foot traffic, bird and insect infestation, and animal husbandry. Without it, there is no roof, no protection and no safety. When mankind moved from cave dwellings to the open, the first thing early humans learned to construct was basic roof-cover protection. Thus, roof covers have been in existence since man’s earliest built environment.

    WHAT CONSTITUTES AN APPROPRIATE ROOF COVER?

    There is no one roof cover that is appropriate for all conditions and climates. It cannot be codified or prescribed, as many are trying to do, and cannot be randomly selected. I, and numerous other consultants, earn a good living investigating roof failures that result from inappropriate roof-cover and system component selection.

    There are several criteria for roof-cover selection, such as:

    • Compatibility with selected adhesives and the substrate below.
    • Climate and geographic factors: seacoast, open plains, hills, mountains, snow, ice, hail, rainfall intensity, as well as micro-climates.
    • Compatibility with the effluent coming out of rooftop exhausts.
    • Local building-code requirements, such as R-value, fire and wind requirements.
    • Local contractors knowledgeable and experienced in its installation.
    • Roof use: Will it be just a roof or have some other use, such as supporting daily foot traffic to examine ammonia lines or have fork lifts driven over it?
    • Building geometry: Can the selected roof cover be installed with success or does the building’s configuration work against you?
    • Building occupancy, relative humidity, interior temperature management, building envelope system, interior building pressure management.
    • Building structural systems that support the enclosure.
    • Interfaces with the adjacent building systems.
    • Environmental, energy conservation and related local code/jurisdictional factors.
    • Delivering on the expectations of the building owner: Is it a LEED building? Does he/she want to go above and beyond roof insulation thermal-value requirements to achieve even better energy savings? Is he/she going to sell the building in the near future?

    ROOF-COVER TYPES

    There are many types of roof-cover options for the designer. Wood, stone, asphalt, tile, metal, reed, thatch, skins, mud and concrete are all roof covers used around the world in steep-slope applications. This article will examine the low-slope materials.

    The dominant roof covers in the low-slope roof market are:

      Thermoset: EPDM

    • Roof sheets joined via tape and adhesive
    • Installed: mechanically fastened, fully adhered or ballasted
    • Thermoplastic: TPO or PVC

    • Roof sheets joined via heat welding
    • Installed: mechanically fastened, fully adhered or plate-bonded (often referred to as the “RhinoBond System”)
    • Asphaltic: modified bitumen

    • Installed in hot asphalt, cold adhesive or torch application
    • EPDM (ETHYLENE PROPYLENE DIENE MONOMER)

      Fully adhered EPDM on this high school in the Chicago suburbs is placed over a cover board, which provides a high degree of protection from hail and foot traffic.

      PHOTO 2: Fully adhered EPDM on this high school in the Chicago suburbs is placed over a cover board, which provides a high degree of protection from hail and foot traffic.


      EPDM is produced in three thicknesses— 45, 60 and 90 mil—with and without reinforcing. It can be procured with a fleece backing in traditional black or with a white laminate on top. The lap seams are typically bonded with seam tape and primer.

      EPDM has a 40-year history of performance; I have 30-year-old EPDM roof systems that I have designed that are still in place and still performing. Available in large sheets—up to 50-feet wide and 200-feet long—with factory-applied seam tape, installation can be very efficient. Fleece-back membrane and 90-mil product have superior hail and puncture resistance. Historical concerns with EPDM lap-seam failure revolved around liquid- applied splice adhesive; with seam tape technology this concern is virtually moot. Non-reinforced ballasted and mechanically fastened EPDM roof membrane can be recycled.

      EPDM can be installed as a ballasted, mechanically fastened or fully adhered system (see photos 1, 2 and 3). In my opinion, ballasted systems offer the greatest sustainability and energy-conservation potential. The majority of systems being installed today are fully adhered. Ballast lost its popularity when wind codes raised the concern of ballast coming off the roof in high-wind events. However, Clinton, Ohio-based RICOWI has observed through inspection that ballasted roofs performed well even in hurricane-prone locations when properly designed (see ANSI-SPRI RP4).

      PHOTOS: HUTCHINSON DESIGN GROUP LTD

      Pages: 1 2 3

    Coating Extends the Life of Aging Roofs

    The new Silicone Roof Coating System from Mule-Hide Products Co. Inc. can be used to restore and repair asphalt, modified bitumen, metal, concrete, TPO, PVC and EPDM roof systems.

    The new Silicone Roof Coating System from Mule-Hide Products Co. Inc. can be used to restore and repair asphalt, modified bitumen, metal, concrete, TPO, PVC and EPDM roof systems.

    The new Silicone Roof Coating System from Mule-Hide Products Co. Inc. can be used to restore and repair asphalt, modified bitumen, metal, concrete, TPO, PVC and EPDM roof systems. It includes a cleaner to prepare the substrate for priming; two primers to improve adhesion of the topcoat; a multipurpose sealant for use with reinforcement roofing fabric to complete repair and maintenance tasks; three topcoats—Silicone Roof Coating (available in white and gray), Silicone Masonry Wall Coating (available in white and gray) and Silicone Skylight Coating; and a cleaner to wash tools and equipment. All products are solvent-free and comply with VOC regulations throughout North America.

    Asphalt-based Low-slope Roof Systems Provide Long-term Service Life

    Asphalt-based roof systems have a long-standing track record of success in the roofing industry. In fact, asphalt-based roof systems have more than a century of use in the U.S. Building owners, roofing specifiers and contractors should not lose sight of this fact. It is important to understand why asphalt roofing has been successful for so long. Asphalt roofs demonstrate characteristics, such as durability and longevity of materials and components, redundancy of waterproofing, ease and understanding of installation, excellent tensile strength and impact resistance. Each of these characteristics helps ensure long-term performance.

    Using a composite built-up/ modified bitumen roof system provides redundancy helping ensure durability and longevity. Surface reflectivity and a multilayer insulation layer provide excellent thermal resistance. Quality details and regular maintenance will provide long-term performance. PHOTO: Advanced Roofing

    Using a composite built-up/
    modified bitumen roof system provides redundancy helping ensure durability and longevity. Surface reflectivity and a multilayer insulation layer provide excellent thermal resistance. Quality details
    and regular maintenance will provide long-term performance. PHOTO: Advanced Roofing

    There are two types of asphalt-based low-slope roof systems: modified bitumen (MB) roof systems and builtup roof (BUR) systems. MB sheets are composed primarily of polymer-modified bitumen reinforced with one or more plies of fabric, such as polyester, glass fiber or a combination of both. Assembled in factories using optimal quality-control standards, modified bitumen sheets are manufactured to have uniform thickness and consistent physical properties throughout the sheet. Modified bitumen roof systems are further divided into atactic polypropylene (APP) and styrene butadiene styrene (SBS) modified systems. APP and SBS modifiers create a uniform matrix that enhances the physical properties of the asphalt. APP is a thermoplastic polymer that forms a uniform matrix within the bitumen. This matrix increases the bitumen’s resistance to ultraviolet light, its flexibility at high and low temperatures, and its ability to resist water penetration. SBS membranes resist water penetration while exhibiting excellent elongation and recovery properties over a wide range of temperature extremes. This high-performance benefit makes SBS membranes durable and particularly appropriate where there may be movement or deflection of the underlying deck.

    BUR systems consist of multiple layers of bitumen alternated with ply sheets (felts) applied over the roof deck, vapor retarder, and most often insulation or coverboard. BUR systems are particularly advantageous for lowslope applications. The strength of the system comes from the membrane, which includes the layers of hot-applied bitumen and the reinforcing plies of roofing felt.

    FACTORS FOR LONG-TERM PERFORMANCE AND SERVICE LIFE

    It is important for building owners and roof system designers to recognize the principles of long-lasting, high-performance roof systems. Roof longevity and performance are determined by factors that include building and roof system design, job specifications, materials quality and suitability, application procedures and maintenance. The level of quality in the workmanship during the application process is critical.

    Longevity and performance start with proper design of the asphalt-based roof system. Proper roof system design includes several components: the roof deck, a base layer supporting a vapor retarder or air barrier when necessary, multi-layer insulation and a coverboard, the asphaltic membrane, appropriate surfacing material or coating, and the attachment methods for all layers. Roof consultants, architects and roof manufacturers understand proper design. Roof design needs to follow applicable code requirements for wind, fire and impact resistance, as well as site-specific issues, such as enhanced wind resistance design, positive drainage and rooftop traffic protection. Roof designers can provide or assist with the development of written specifications and construction details that are specific to a roofing project for new construction or reroofing.

    Low-slope asphalt-based roof systems are redundant; they are multi-layered systems. BUR systems include a base sheet, three or four reinforcing ply sheets and a surfacing, either aggregate (rock) or a cap sheet. MB sheets include one and sometimes two reinforcing layers and are commonly installed over a substantial asphaltic base sheet. Modified bitumen roofs can be granule surfaced, finished with reflective options or coated after installation. Aggregate, granules, films and coatings add UV protection, assist with fire resistance, provide durability to the roof system and can improve roof aesthetics.

    An asphaltic cap sheet with a factory-applied reflective roof coating is installed over three glass-fiber ply sheets and a venting base sheet. The reflective coating reduces heat gain, and insulating concrete provides a stable substrate and high R-value. PHOTO: Aerial Photography Inc.

    An asphaltic cap sheet with a factory-applied reflective roof coating is installed over three glass-fiber ply sheets and a venting base sheet. The reflective coating reduces heat gain, and insulating concrete provides a stable substrate and high R-value. PHOTO: Aerial Photography Inc.

    Coverboards provide a durable layer immediately below the membrane, are resistant to foot traffic and separate the membrane from the thermal insulation layer. Protecting the thermal insulation helps maintain the insulation R-value as specified and installed.

    Asphalt is a durable and long-lasting material for roof membranes and flashings. Asphalt is stable under significant temperature swings and can be highly impact resistant. Various reinforcements can be used to increase an asphaltic membrane’s durability. All asphaltic membranes are reinforced, during installation (BUR) or the manufacturing process (MB membranes). Polyester reinforcement has excellent elongation, tensile strength and recovery. It provides good puncture resistance and stands up well to foot traffic. Glass fiber reinforcement resists flame penetration and provides excellent tensile strength and dimensional stability.

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    SPRI Revises Wind Design Standard Practice for Roofing Assemblies for Inclusion in the International Building Code

    SPRI has revised ANSI/SPRI WD-1, Wind Design Standard Practice for Roofing Assemblies, to prepare the document for submission to and inclusion into the International Building Code (IBC). SPRI represents sheet membrane and component suppliers to the commercial roofing industry.

    This Wind Design Standard Practice provides general building design considerations, as well as a methodology for selecting an appropriate roofing system assembly to meet the rooftop design wind uplift pressures calculated in accordance with ASCE 7, Minimum Design Loads for Buildings and Other Structures.

    “Revisions to ANSI/SPRI WD-1 include additional insulation fastening patterns, along with more detailed practical examples,” says Task Force Chairman Joe Malpezzi. “This Standard Practice is appropriate for non-ballasted Built-Up, Modified Bitumen, and Single-Ply roofing system assemblies installed over any type of roof deck.”

    In addition, SPRI has revised and reaffirmed ANSI/SPRI RD-1, Performance Standard for Retrofit Drains, in compliance with ANSI’s five-year cycle requirements. This standard is a reference for those that design, specify or install retrofit roof drains designed for installation in existing drain plumbing on existing roofs.

    “It is important to note that the RD-1 Standard addresses the design of retrofit primary drains,” says SPRI President Stan Choiniere. “Local codes may also require secondary or overflow drains. SPRI will also be revisiting this standard after upcoming code changes are released.”

    For more information about these standards and to download a copy, visit SPRI’s Web site or contact the association.