GE Performance Coatings & Sealants Roof Solutions Will Be Displayed at IRE

International Roofing Expo attendees will find roof solutions and product specialists at GE Performance Coatings & Sealants Booth 340. On display during the March 1-3 event in Las Vegas, the 100 percent silicone GE Enduris roof coating is a solution that provides durability.

“GE Enduris is an answer for roofing protection and restoration,” says Peter Friedli, marketing manager. “For over 50 years, contractors and building owners have trusted us to deliver building products. Our team is looking forward to helping attendees leverage our benefits for themselves.”

GE Performance Coatings experts will be on-site to consult about the components of GE Enduris, provide technical insight, and explore application possibilities.

GE Enduris high solids roof coating stops leaks, improves performance, and extends roof life with a single-coat, primerless application. Able to withstand fluctuating conditions and ponding water, GE Enduris can restore most every type of roof substrate.

For more information on GE Enduris, visit GE Performance Coatings & Sealants’ booth at IRE, or click on this link to visit the website.

EcoStar Roof Is Installed on Farmhouse to be Featured on TV Show

An EcoStar roof was installed on This Old House’s 2016 Idea House in Emerson Green, a development in Devens, Mass. The Idea House focused on sustainable design, and EcoStar’s Majestic Slate was chosen for the durability and sustainability.

The Idea House, an updated farmhouse, will use less than a third of the energy of a typical new house of its size. This is done by utilizing efficient systems and sustainable building products. Majestic Slate was used on the home in Black Traditional 12-inch and Smoke Gray Chisel Point tiles. Majestic Slate is manufactured using up to 80 percent post-industrial materials. Millions of pounds of unnecessary waste are diverted annually from landfills or incarnation, and no slates are quarried for the manufacture of EcoStar synthetic slate.

An EcoStar roof offers a solution with little maintenance and can outlast the lifespan of many alternate roofing products. EcoStar products are made in the USA.

The Idea House in Emerson Green is to be featured on the TV show “This Old House” this fall.

Help Homeowners Understand the Quality Proposition of a Tile Roof

Buying a home is the largest purchase most people ever make. Buyers work intensely to identify their needs and wants, assess the individual benefits of various choices and evaluate the long-term financial return to ensure they make a quality decision. Once living in that new home, kitchen remodels and reroofing can be the largest expenses faced by homeowners.

 In addition to increasing curb appeal, modern tile roofing systems and accessories offer an opportunity to improve the energy efficiency of a home.

In addition to increasing curb appeal, modern tile roofing systems and accessories offer an opportunity to improve the energy efficiency of
a home.

We all have firsthand, daily experience with our kitchen. We know what we like and what we don’t. Advertisements showing features and benefits of new appliances, more spacious cabinets and better lighting are appealing. Learning and planning for a new kitchen is fun and exciting. We know we will use it every day and we can show it off to our friends. We choose to do a kitchen remodel.

Reroofing is different. The process usually starts with a surprise—a roof leak a repairman fails to resolve. Then a second attempt, maybe a third, followed by an explanation that the system has reached the end of its useful and serviceable life. Reroofing becomes necessary to preserve the integrity of the home. It’s not fun and it’s not by choice. Compared to new stainless-steel appliances, soft-close drawers and a built-in wine cooler, it’s not exciting.

With little understanding of modern roofing, the first (and often only) question asked is, “How much is it going to cost?” If lowest initial cost was the only criteria for a roof, we would all have blue tarps overhead.

The true cost of roofing is defined by the life-cycle cost, which includes consideration of the initial cost, life expectancy, potential energy savings and potential insurance discounts.

A quality tile roof installation will set a home apart from neighboring homes now and will be a great investment to help the home garner the best sale price later. This is where a knowledgeable contractor can help a homeowner identify his or her needs and wants, assess the benefits of various choices and calculate the value of the given system.

1. IDENTIFY THE HOMEOWNER’S NEEDS AND WANTS

Residential roofing is a functional part of the building envelope. Its primary purpose is to protect the home and its contents from the elements. Residential roofing is also a largely visible part of a home’s curb appeal. A tile roof will increase the curb appeal of a house when compared to similar homes with less substantial roofing materials.

Concrete and clay roof tiles’ resistance to weathering, hail, high winds and UV means that look of quality will be consistent from the day the roof is installed until the day it helps the homeowner get the best return on his/her original investment by enhancing the home’s curb appeal when the house is sold. Without the excitement of center islands and granite counter- tops, the homeowner needs help to be informed about options and benefits a tile roof can provide.

2. ASSESS THE BENEFITS OF VARIOUS CHOICES

In addition to increasing curb appeal, modern tile roofing systems and accessories offer an opportunity to improve the energy efficiency of a home. The inherent insulation properties created by tile’s high thermal mass can be enhanced with above-sheathing ventilation, or ASV. These raised batten systems can “… offer a significant 50 percent reduction in the heat penetrating the conditioned space compared to direct nailed roof systems that are in direct contact with the roof deck,” says Dr. William Miller, Ph.D., P.E., Oak Ridge National Laboratory, Oak Ridge, Tenn.

The energy savings of ASV is recognized by the California Energy Commission, Sacramento, and included in the Title 24 Energy Code revisions for reroofing and alterations. (Learn more about ASV in “Details”, March/April 2015 issue, page 79.)

PHOTOS: Boral Roofing Products

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Metal Roofing and Siding Enhance Waste Collection Building

The Elk Grove Special Waste Collection Center celebrate the industrial chic nature of dealing with hazardous waste products with metal roofing and wall panels.

Metal roofing and siding help the Elk Grove Special Waste Collection Center celebrate the industrial chic nature of dealing with hazardous waste products.

The city of Elk Grove, Calif.’s Special Waste Collection Center opened in April 2014 with a commitment to a cleaner and greener community. The center, which features AEP Span’s architectural metal panels, has earned LEED Gold Certification and, to date, has accepted nearly 300,000 pounds, or 130 tons, of recyclable materials diverted from local landfills.

“With the Elk Grove Special Waste Collection Center project, we wanted to express and celebrate the industrial chic nature of dealing with hazardous waste products at the same time creating a safe, warm and comfortable environment for the center staff,” says Eric Glass, AIA, LEED AP and principal of Santa Rosa, Calif.-based firm Glass Architects. “The project is designed to take a heavily abused, neglected and contaminated site and revitalize it, turning it into a protected habitat.”

“Metal siding and roofing products were a natural choice for this project,” Glass adds. “The inherent durability and recycled content material speaks to the overall mission of this facility. The horizontal and vertical fluted siding creates a strong form and texture, enhancing the building’s character.”

The Elk Grove Special Waste Collection Center project features AEP Span’s 24-gauge Reverse Box Rib in ZACtique II on the lower section of the wall application; 24-gauge HR-36 in Metallic Silver in the upper wall and canopy application; 24-gauge Prestige Series in Metallic Silver in a soffit application; 16-inch, 24-gauge SpanSeam in Hemlock Green in a roof application; and 24-gauge Curved Select Seam in Hemlock Green for the curved canopy application.

The $4.6 million center is the first, and only, facility of its kind in the nation powered by solar energy.

The $4.6 million center is the first, and only, facility of its kind in the nation powered by solar energy.

The $4.6 million center is the first, and only, facility of its kind in the nation powered by solar energy. Since its grand opening in April 2014, the center has been used by more than 8,000 customers to dispose of paint, cleaning supplies, electronics and other household recyclables. The center has also received nearly 1,000 visitors to the reuse room, which offers a wide variety of new or partially used products for free.

Project Details

Project: Elk Grove Special Waste Collection Center, Elk Grove, Calif.
Architect: Glass Architects, Santa Rosa, Calif.
General Contractor: Bobo Construction Inc., Elk Grove
Installer: MCM Roofing, McClellan, Calif., (916) 333-5294
Manufacturer of Architectural Metal Panels: AEP Span

The Qualities of a Top-performing Shingle

Shingle product development has generally been slow compared to technology evolution in other industries. The most important performance requirements of asphalt shingles, like shedding water, fire and wind resistance, durability and code compliance, have been established for decades. Within the past 35 years, though, there has been a push to develop additional performance standards for asphalt shingles.

The current (and long-standing) product standard for fiberglass asphalt shingles is ASTM D3462. This standard focuses on the physical performance measures of shingles at the time of manufacturing. A number of areas tested include the “recipe” of the shingle (glass mat, adhesive, finished weight, etc.) and performance requirements, such as tear strength, behavior on heating, fastener pull-through resistance (the force needed to pull a nail through the shingle at high and low temperatures), and penetration and softening point of the asphalt.

However, some manufacturers have fought to raise the performance requirements that shingles must meet. Rather than focusing on performance at the time of manufacture, these manufacturers want to establish a standard that would reflect how shingles perform over time. In 2011, the ICC Evaluation Service, Brea, Calif., approved a new alternative acceptance criterion for asphalt shingles, AC438. Instead of dictating how to make an asphalt shingle (what raw materials to use), it requires additional physical property and performance testing beyond ASTM D3462.

AC438 contains stringent performance testing requirements, which are meant to evaluate the performance of a shingle over time. “When thinking about shingle performance, it’s imperative we, as an industry, are looking not just at performance at the time of manufacture. AC438 helps test in these extreme environments to give us better insight,” says Emily Videtto, vice president of shingles and new product development at GAF, Parsippany, N.J. The shingles are put through three critical, demanding tests to evaluate durability in a variety of temperatures and weather situations:

  • Temperature cycling. This looks at long-term extreme-temperature resistance—how shingles can withstand winter cold or summer heat. The tests occur in 12- to 24-hour cycles, so it takes 12 days to put the shingle through extreme high and extreme low temperatures. The low temperature is done after soaking in water. Under five times magnification, the shingles are inspected for signs of tearing or cracking that show the glass mat, butt joints in the first course and no separations greater than 1/4 inch, and no evidence of tearing around fasteners or pull through. If any of these conditions exist, the material fails the test.
  • Weather resistance. This test looks at how shingles perform after long-term exposure to the sun. Using ASTM G155, a Xenon Arc weatherometer that tests for accelerated weathering, shingles are subjected to 2,000 hours of light and water in cycles for 83 days. After that’s complete, there is a visual examination for evidence of surfacing loss, erosion or exposed reinforcement. Shingle samples must have a minimum of 80 percent of their original breaking strength to pass this stringent test.
  • Wind-driven rain. This determines how shingles stand up to heavy, driving rain. The shingles are tested under Florida Building Code Test Protocol TAS-100 with the minimum slope specified by the manufacturer. No water should infiltrate through the sheathing and there should be no blow-off, tear-off or release of the shingle (or any portion of it). The test subjects the shingles to 15 minutes of wind and water, then 10 minutes off, then back on again with wind speeds going to 35, 70, 90 and 110 mph. This results in 8 inches per hour of rain to test the shingle’s performance. A camera is mounted on the underside to look for any water intrusion during the test.

AC438 also looks at the weight of the displaced surfacing over the asphalt coating. With ASTM D3462, the requirement is one gram of granule loss. AC438 requires less displaced surfacing, so more granules need to be kept on the surface of the shingle to better protect it.

These additional tests challenge shingle manufacturers to make a better-quality product to meet the requirements found in AC438. GAF was the first shingle manufacturer to provide independent verification to the requirements of AC438 and additional manufacturers have since followed. These tests are a big step forward in evaluating performance and choosing a shingle that has the qualities to stand the test of weather and time. This type of testing ultimately helps roofing contractors because they want to know that the shingles they are installing will pass these stringent tests and provide stronger protection against the elements. For homeowners, they can feel comfortable they are installing a top-performing shingle that will help protect their most valuable asset.

Today, all GAF shingles comply with ASTM D3462 and AC438, as well as pass the industry’s two toughest wind-resistance tests: ASTM D3161, Class F (110 mph), and ASTM D7158, Class H (150 mph). These code advancements and stronger tests have helped to change the manufacturing of roofing shingles from an art to a science. This science comes through years of research, lab testing, and development to find the right mix of materials and production processes to produce a technologically advanced shingle. In fact, GAF created its own shingle science with Advanced Protection Shingle Technology, aimed at pushing the envelope to deliver shingles with the most advanced design, manufacturing, and testing techniques for quality and longevity in an asphalt shingle.

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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An ERA Study Proves EPDM Easily Lasts More than 30 Years

More and more building owners are seeing the light: Roof systems based on historical in situ performance for more than 30 years are the best roof system choice to benefit the environment. EPDM roof membrane has been utilized as a roof cover for more than 40 years, and there are numerous examples of ballasted roofs greater than 30-years old still performing. New seaming technologies, thicker membrane and enhanced design are creating roof systems with projected 50-year service lives. EPDM roof covers’ physical characteristics have changed little in 30 years, and because potential for 50-year-plus service life is possible, they are a solid choice of design professionals, building owners and school district representatives who truly desire a roof system that benefits the environment.

PHOTO 1: This ballasted 45-mil EPDM roof system has been in service for 32 years.

PHOTO 1: This ballasted 45-mil EPDM roof system has been in service for 32
years.

In 2010, the Washington, D.C.-based EPDM Roofing Association (ERA) was determined to answer the question: “How long can an EPDM roof perform?” Consequently, roof membrane samples from five roof systems with a minimum age of 30 years were obtained for testing of their physical properties. The physical and mechanical properties evaluated (using relevant ASTM standards) were overall thickness, tear resistance, tensile set, tensile strength and elongation, and water absorption. The results were positive, showing that even after 30 years of infield exposure nearly all the physical characteristics of EPDM membrane meet or exceed ASTM minimums. But the question of how long EPDM roofs could last remained. Thus, a second phase of testing was undertaken.

These properties were studied for “as received” and “after heat-conditioning” for up to 1,500 hours at 240 F. Results showing how these membranes performed before and after heat-conditioning are presented with the intent of defining characteristics for long-term service life of roof membranes.

TESTING PHASE ONE

Ethylene-propylene-diene terpolymer (EPDM) has been used in waterproofing and roof applications for more than 45 years in North America. Introduced into the roofing market in the 1960s, EPDM grew, especially after the 1970s oil embargo, to be a roofing membrane choice for new construction and roofing replacement projects. EPDM has achieved long-term in situ performance in part because of its chemical structure, mostly carbon black, which resists ozone and material decomposition, as well as degradation caused by UV light, which is the No. 1 degradation element to roofing materials exposed to the sun (see photo 1). The carbon black also provides reinforcement, yielding improved physical and mechanical properties.

Long-term performance of roof-cover material is dependent upon its resistance to the combined effects of ponding water, UV radiation, ozone, heat and thermal cycling. Geographical location can exacerbate or reduce the impact of climatic factors. In ballasted systems, the ballast acts to provide protection from the UV rays and minimizes the effect of climatic influences.

ERA’s study had three specific goals:

    1. Verify the long-term performance characteristics of EPDM membranes over 30 years. (At the time of the study, the only in situ membranes that were around for 30 years were 45-mil EPDM membranes. Currently 60- and 90-mil are the standard choices. It is assumed that results for the 45-mil material can be prorated for the thicker membrane.)

    2. Scientifically validate the empirical sustainability experiences.

    PHOTO 2: This recently installed, ballasted, 90-mil EPDM roof was designed for a 50-year service life.

    PHOTO 2: This recently installed, ballasted, 90-mil EPDM roof was designed for a 50-year service life.

    3. Create a foundation for specifier-to-owner discussions in regard to long-term service life. Five roofs, four ballasted and one fully adhered, with in situ service lives approaching or over 30 years were identified and samples were taken. All roofs were fully performing without moisture intrusion.

The samples were sent for testing per ASTM D4637 for:

  • Elongation
  • Tensile strength
  • Thickness
  • Factory seam strength (psi)

PHOTOS: HUTCHINSON DESIGN GROUP LTD.

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Long-term Performance of Roof Systems

The April e-newsletter distributed by Roofing contained an online exclusive about sustainability. The author, Brooks Gentleman, an owner of window refurbisher Re-View, Kansas City, Mo., questioned whether we’re talking about the right things when referring to a building as sustainable. He says, “During the past 10 years, there has been a great deal of talk about green buildings and sustainability, but how many of these ‘green’ commercial or residential buildings are designed or constructed to last for centuries? When will the life cycle of the structure and the construction materials themselves become factors in the sustainability criteria? It seems to me that more effort is placed on whether a material is recyclable than whether it can perform over the long haul. It is time that the design community, manufacturers and construction processes begin to consider the life of the building if we are truly going to incorporate sustainability in our industry.” (Read the entire article.)

Gentleman’s commentary is the perfect precursor to this issue, which has a focus on the long-term performance of a roof system. Three “Tech Point” articles explain the life spans of metal, EPDM and asphalt, respectively. The authors—Chuck Howard P.E., a Roofing editorial advisor; Thomas W. Hutchinson, AIA, CSI, FRCI, RRC, RRP, a Roofing editorial advisor; and James R. Kirby, AIA—share roof-cover characteristics that achieve and industry studies that prove long-term performance.

Insulation is a component that will help extend the life of a roof system. In “Cool Roofing”, Kyle Menard, president of Bloom Roofing, Brighton, Mich., shares insight about polyisocyanurate, specifically how it contributes to long-term roof performance and why the roofing industry should educate clients about its importance as part of a roof system.

As architects, building owners and occupants increase their expectations for the environmental performance of the buildings they design, operate and dwell in, building component manufacturers have begun rolling out environmental product declarations, or EPDs. EPDs are related to life-cycle assessments and product category rules, all of which are part of an ongoing effort to provide as much transparency as possible about what goes into the products that go in and on a building. In “Environmental Trends”, Allen Barry writes about the significance of EPDs for the roofing industry.

As a longtime proponent of sustainability, it’s wonderful to see the conversation turning toward the critical issue of durability and long-term performance. Yes, specifying materials with recycled content or from sustainably managed forests is a nice consideration, but if those materials will only last a few years and must be replaced, we’re expending more energy—and money—using them. There’s nothing sustainable about that.

Ballasted EPDM Roof Has Been in Service Since 1979

Rob Nelson is a 44-year-old software consultant who owns a multi-tenant, 137,000-square-foot building in Kingston, Pa. Rob’s dad bought the building in 1985, when it was an abandoned cigar factory and Rob took over management of it in 2002. He considers it to have been a good investment for many reasons. It has attracted a variety of tenants and currently houses about 25 businesses, including small, single-office enterprises, an engineering firm and a home-health nursing business. Rob’s family operates a furniture business and an indoor self-storage facility in the building, as well.

Roof Consultant Mark Sobeck inspects a 35-year-old ballasted EPDM roof on a multi-tenant building in Kingston, Pa.

Roof Consultant Mark Sobeck inspects a 35-year-old ballasted EPDM roof on a multi-tenant building in Kingston, Pa.

Besides its track record of attracting tenants, Rob also values his building for another very important reason: its ballasted EPDM roof has been in place since 1979. If you do the math, that’s 35 years. And Rob’s roofing consultant, Mark Sobeck, based in Wilkes-Barre, Pa., says he can realistically expect his building to get another 10 or 15 years of protection from the roof.

Rob and Mark emphasize that maintenance has been important to the roofing system as a whole. One-third of the original roof has been replaced for reasons not related to the membrane performance, and the flashing and expansion joints have been replaced on the original section of the roof. But the membrane itself, according to Sobeck, is still in great shape. “It’s amazing how the EPDM rubber is still lasting. At thirty-five years, it’s still stretchy and pliable and looks good.”

Nelson’s experience with the longevity of his roof is backed up by in-depth testing by the EPDM Roofing Association (ERA). ERA commissioned studies of five EPDM roofs that had been in use for between 28 and 32 years. The roofs, ballasted and fully-adhered, were first inspected in the field, and then small samples of the EPDM membrane were sent to Momentum Technologies, a testing facility for the roofing industry in Uniontown, Ohio. Five key performance characteristics of the samples were tested: elongation, tensile strength, cross-direction thickness, machine-direction thickness and factory-seam strength. The lab results showed that all the samples had physical characteristic properties above or just below the minimum physical characteristics of a newly manufactured 45-mil EPDM membrane. Put another way, after three decades of use, they were performing like new. Roofing experts point out that installation materials and methods have advanced considerably in the last 30 years, giving new roofing systems an expectation of an even longer service life.

A roof that lasts a long time will deliver obvious financial savings to building owners. In an era when environmental benefits must also be considered, experts say that its important to look at sustainability in the broadest possible terms. “If a roof lasts a very long time,” says John Geary, director of Education and Industry Relations for Firestone Building Products and chairman of the board of ERA, “that’s very good news for the environment. Compared to a roof that has to be replaced every 10 years or so, the choice of EPDM means fewer resources are ultimately used in the manufacturing and maintenance of the roofing system. Additionally, EPDM can be recycled, so it also means less materials winds up in a landfill.”

Rob Nelson may not have seen the results of EPDM lab tests, but he sees proof of the durability and longevity of EPDM every time he visits his building. “It’s pretty wild and definitely surprising that we are still kicking along after 35 years,” he says. Given consultant Mark Sobeck’s projections, Nelson can expect another 15 years or so of “wild” service from his EPDM roof.

Substrate Boards

The third installment in my series on the roof system is about the substrate board. (To read my first two articles, “Roofs Are Systems” and “Roof Decks”, see the January/February issue, page 52, and the March/April issue, page 54, respectively.) For the purpose of this article, we will define the substrate board as the material that is placed upon the roof deck prior to the placement of thermal insulation. It often is used in part to support vapor retarders and air barriers (which will be discussed in my next article in the September/October issue).

The type of substrate board should be chosen based on the roof-deck type, interior building use, installation time of year and the cover material to be placed upon it.

The type of substrate board should be chosen based on the roof-deck type, interior building
use, installation time of year and the cover material to be placed upon it.

Substrate boards come in many differing material compositions:
• Gypsum Board
• Modified Fiber Reinforced Gypsum
• Plywood
• High-density Wood Fiber
• Mineral Fiber
• Perlite

Substrate boards come in varying thicknesses, as well: 1/4 inch, 1/2 inch, 5/8 inch and 1 inch. The thickness is often chosen based on the need for the board to provide integrity over the roof deck, such as at flute spans on steel roof decks.

TOUGHNESS

The type of substrate board should be chosen based on the roof-deck type, interior building use, installation time of year and the cover material to be placed upon it. For example, vapor retarder versus thermal insulation and the method of attachment. Vapor retarders can be adhered with asphalt, spray foam, bonding adhesive, etc. The substrate board must be compatible with these. You wouldn’t want to place a self-adhering vapor retarder on perlite or hardboard because the surface particulate is easily parted from the board. Meanwhile, hot asphalt would impregnate the board and tie the vapor-retarder felts in better. The substrate board must have structural integrity over the flutes when installed on steel roof decks. The modified gypsum boards at 1/2 inch can do this; fiberboards cannot. If the insulation is to be mechanically fastened, a substrate board may not be required.

It should be more common to increase the number of fasteners to prevent deformation of the board, which will affect the roof system’s performance.

It should be more common to increase the number of fasteners to prevent deformation of the board, which will affect the roof system’s performance.

The substrate board should be able to withstand construction-generated moisture that may/can be driven into the board. Note: In northern climates, a dew-point analysis is required to determine the correct amount of insulation above the substrate board and vapor retarder, so condensation does not occur below the vapor retarder and in the substrate board.

Substrate boards are often placed on the roof deck and a vapor retarder installed upon them. This condition is often used to temporarily get the building “in the dry”. This temporary roof then is often used as a work platform for other trades, such as masonry, carpentry, glazers and ironworkers, to name a few. The temporary roof also is asked to support material storage. Consequently, the substrate board must be tough enough to resist these activities.

The most common use of a substrate board is on steel and wood decks. On steel roof decks, the substrate board provides a continuous smooth surface to place an air or vapor retarder onto. It also can provide a surface to which the insulation above can be adhered. Substrate boards on wood decks (plywood, OSB, planking) are used to increase fire resistance, prevent adhesive from dripping into the interior, provide a clean and acceptable surface onto which an air or vapor retarder can be adhered, or as a surface onto which the insulation can be adhered.

PHOTOS: HUTCHINSON DESIGN GROUP LTD.

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