Three Polyiso Roof Insulation Options to Simplify Your Next Job

Pre-fabricated roof sumps direct water to a center drain point, helping to ensure proper drainage and minimizing installation time. Photos: Hunter Panels

As a roofing professional, you undoubtedly are familiar with polyiso insulation, as it is used in 70 percent or more of the commercial roofs in North America. Polyiso is popular with roofing professionals because it offers a high R-value per inch, is affordable, readily available, compatible with many roofing systems and meets both FM 4450 and UL 1256.

While you likely have specified or installed flat stock polyiso products, you might be less familiar with specialized product make-ups, which can help you simplify roof insulation jobs. Three options to be aware of are:

  1. Tapered systems
  2. Pre-cut hips and valleys
  3. Pre-fabricated sumps

Tapered Systems

As roofing professionals know, water is the enemy of the roof assembly. To prevent ponding and provide a positive slope to drain, polyiso insulation manufacturers offer sloped panels. Tapered polyiso typically comes in 4-foot-by-4-foot or 4-foot-by- 8-foot panel sizes, and in various compressive strengths. Commonly available slopes (per foot) include 1⁄16 inch, 1⁄8 inch, 3⁄16 inch, 1⁄4 inch, 3⁄8 inch and 1⁄2 inch. Tapered systems range from two-panel to eight-panel repeats, with such systems including varying thicknesses of flat polyiso insulation to complete the taper profile.

Photos: Hunter Panels

Tapered polyiso insulation installs similar to flat stock polyiso insulation, using adhesives or fasteners. As with multi-layer flat stock installations, when installing tapered products, crews should stagger the joints between layers to reduce potential pathways for airflow and condensation within the insulation layers.

Full-service polyiso manufacturers can design a tapered insulation layout based on the roof plan and specified R-value. They then will provide shop drawings showing where to place each tapered and flat stock panel to ensure positive slope and effective drainage across the entire roof.

Pre-Cut Hips and Valleys

In addition to the one-way sloped tapered panels discussed above, roofing professionals have access to pre-cut hips and valleys made of polyiso insulation. The hips and valleys help direct water on more complex roof designs. Well-equipped manufacturers will custom design and fabricate pre-cut, one-piece polyiso hips and valleys to meet your jobsite requirements including slope, and minimum and maximum thicknesses.

While crews can form hips and valleys by field-cutting tapered panels, ordering the pre-cut, one-piece panels reduces labor time and costs, as well as dumpster fees. It also prevents material waste caused by cutting errors.

Pre-Fabricated Sumps

Going a step farther in slope complexity, and further reducing ponding water, some polyiso insulation manufacturers offer pre-fabricated roof sumps. Commonly available as 4-foot-by-4 foot panels that ship flat, pre-fabricated sumps direct water from four directions to a center drain point. Some manufacturers also offer 8-foot-by-8-foot hinged sumps for greater design flexibility. All of these sumps offer a variety of starting thicknesses at the drain from 1/2 inch to 2 inches.

Choosing a Polyiso Supplier

Roofing professionals can obtain polyiso roof insulation from several suppliers. Which one is right for you? Following are a few factors to consider to help simplify your next roofing job.

  • Access to technical support: Some polyiso manufacturers provide customers with a variety of technical services. Having access to designers and estimators who work every day with specialized polyiso products takes the guesswork out of the process for you, saving time and money while helping ensure a high-quality roof.
  • Ready availability: Choosing a supplier with facilities throughout the country helps ensure timely access to specialty polyiso insulations when you need them.
  • Training support: To help your crews get up to speed faster on working with specialized polyiso roof insulation systems, look for a manufacturer that offers training support — whether via online videos, in person or on the jobsite.

Ponding Water Basics: Proper Drainage Design and Low-Slope Roofs

Roofing professionals install a new asphalt roof on the Broward County Stephen Booher Building in Coral Springs, Florida. Photo: Advanced Roofing Inc.

A low-slope asphalt roofing system is cost effective, durable and reliable. Multiple layers of weatherproof membranes protect a building, its residents and the property it houses. There are a few design elements that will help building owners get the most from their roofing system. Managing ponding water is essential to properly maintaining a roof.

Ponding water is defined as the water which remains on a roof 48 hours or longer. Water may accumulate on a low-slope roof due to rain, snow or runoff from rooftop equipment. Ponding water can have major negative consequences, regardless of the type of roofing system. Proper design, installation and maintenance of roofing structures can prevent this condition and its associated problems.

The adverse effects of ponding water on roofs can include:

  • Deformation of the deck structure:Ponding water can substantially increase the load on roof decks. As water accumulates, deck deflections can increase, thereby resulting in additional ponding water, which could compromise the structural integrity of the deck.
  • Damage to the roof surface:Ice formations develop and move constantly with changes in temperature. This movement can “scrub” the roof membrane to such an extent that considerable physical damage to the membrane can occur.
  • Growth of algae and vegetation:When water stands for long periods of time, algae and vegetation growth will likely occur, and may cause damage to the roof membrane. Additionally, vegetation can clog drains and cause additional ponding.
  • Accumulation of dirt and debris in the ponding area:Dirt, debris, and other contaminants can affect and damage the membrane surface. The can also lead to clogged drains.

Proper design and installation are crucial factors in roof system performance. This photo shows an Atactic Polypropylene (APP) modified bitumen membrane being applied by torch to a low-slope roof. Photo: ARMA

Ponding water may lead to accelerated erosion and deterioration of the membrane surface that can result in failure of the roof system. Allowing even relatively small amounts of moisture beneath the roof membrane may reduce the thermal efficiency of the insulation. More importantly, moisture intrusion can cause serious damage to the deck, insulation, and membrane as well as the building’s interior.

The Asphalt Roofing Manufacturers Association (ARMA) recommends that roof designs provide adequate slope (minimum of ¼ inch per foot) to ensure that the roof drains freely throughout the life of the building and to thereby avoid the effects of ponding water. Model building codes also require a minimum ¼ inch per foot slope for new construction projects, and require positive drainage for re-roofing projects. These requirements are intended to prevent water from ponding on roof surfaces.

Managing Ponding Water

Here are a few best practices to manage ponding water:

  • Adequate sloping should be taken into account during the design process. A roof’s structural frame or deck should be sloped, and drainage components like roof drains and scuppers should be included in the design.
  • In addition, secondary (or emergency) drains may be required by local plumbing codes to help reduce the risk of a structural failure due to clogged drainage systems. Talk to your roof membrane manufacturer and/or roof system designer to determine the proper location of these components.
  • If a deck does not provide the necessary slope to drain, a tapered insulation system can be used. A combination of different approaches — single slope, two-way slope, and four-way slope — is often used to achieve the necessary slope and to allow for moisture drainage.
  • Additionally, crickets installed upslope of rooftop equipment and saddles positioned along a low-point between drains, can help prevent localized ponding in conjunction with a tapered insulation system.
  • Building designers and owners should work with contractors and roof manufacturers to determine which methods are best and appropriate for a roof assembly’s long-term performance, whether it’s a new construction or re-roof project.

The NRCA Roofing Manual: Membrane Roof Systems—2015, states the following: “NRCA recommends that designers make provisions in their roof designs for positive slope.”

The manual spells out that slope generally is provided by:

  • Sloping the structural framing or roof deck
  • Designing a tapered insulation system
  • Proper location of roof drains, scuppers and gutters
  • A combination of the above

By following the proper drainage practices detailed above, building owners can positively impact their low-slope roofing system and help to ensure it will remain durable and reliable throughout its service life.

To obtain specific information about ponding water on particular products and systems, contact your roof material manufacturer. For more information about low-slope asphalt roofing systems, visit www.asphaltroofing.org.

Proper Storage and Handling of Polyiso Insulation

Photo: SOPREMA

Punxsutawney Phil certainly got it right this year; we have had six more weeks of winter — and then some — particularly in the Northeast. As winter turns to spring, building and repair projects which frequently involve the roof get underway. As you commence these new and re-roofing initiatives, here are a few key considerations about the storage and handling of polyiso roof insulation on a jobsite.

Storage

Polyiso insulation is typically shipped protected by a plastic wrap, plastic bag or both. This factory packaging is intended for handling the polyiso in the manufacturing plant and during transit; it should not be relied upon as protection at jobsites or other outdoor storage locations unless specified otherwise by the manufacturer.

Material delivery should be carefully coordinated with the roof application schedule to minimize outdoor storage. When short-term outdoor storage is necessary, whether at grade or on the roof deck, the following precautions should be observed:

  • Bundles should be stored flat above the ground utilizing included feet or on raised pallets. If possible, the bundles should be placed on a finished surface such as gravel, pavement, or concrete rather than on dirt or grass.
  • Unless specified otherwise by the manufacturer, cover the package and pallet with a waterproof cover, and secure to prevent wind displacement.

Note: Polyiso insulation is fully cured and fit for installation upon delivery. No additional storage time is required.

Handling

Photo: Johns Manville

Exercise care during handling of polyiso insulation to prevent breaking or crushing of the square edges and surfaces. Remove the polyiso bundles from trucks with proper equipment. Other means of mishandling, such as pushing pallets off the edge of the truck or “rolling” the pallet across the roof deck, must be avoided.

Product Application

Polyiso should always be installed on dry, clean roof decks in dry conditions. Follow the manufacturer’s recommendations regarding product application to ensure performance to the intended design life of the roofing system. Apply only as much polyiso roof insulation as can be covered by completed roofing the same day.

Construction Traffic

Avoid excessive traffic during roof construction of or on a completed roof surface. Although polyiso has been designed to withstand limited foot traffic, protection from damage by construction traffic and/or abuse is extremely important. Roof surface protection such as plywood should be used in areas where storage and staging are planned and heavy or repeated traffic is anticipated during or after installation.

Photo: Johns Manville

Some designers and membrane manufacturers specify the use of cover boards as a means of protecting the insulation. If specified, installers should ensure the cover board used is compatible with all components of the roofing system, is acceptable to the membrane manufacturer, and meets specified fire, wind, and code requirements.

Polyiso roof insulation, like other roofing materials, requires a proper understanding of storage, handling, and application to result in a properly constructed roof system. To find additional information about the proper storage and handling of polyiso insulation and for more technical information on polyiso roof and wall insulation, please visit www.polyiso.org.

Building to Last With Asphalt-Based Roofing

The property owner of this building opted for a BUR/modified-bitumen hybrid system with reflective white coating. Photos: Johns Manville

The advantages of a built-up roofing (BUR), modified bitumen, or hybrid roofing assembly include long life, a variety of maintenance options, and outstanding puncture resistance. This durability means property owners will spend less time worrying about fixing leaking roofs and the associated hassles — lost productivity, disruption in operations, slips and falls, repair bills, and other liabilities.

Recommending clients install a roof system that gives them the best chance of eliminating unproductive distractions is a good business decision for design/construction professionals. A more durable roof will enable property owners to focus on making profits instead of dealing with the aftermath of a roof leak.

“I have no problem endorsing asphalt-based roofing,” says Luther Mock, RRC, FRCI and founder of building envelope consultants Foursquare Solutions Inc. “The redundancy created by multiple plies of roofing is really what sets systems like BUR and modified bitumen apart.”

One can argue BUR’s closest cousin — the modified bitumen (mod bit) assembly — is actually a built-up roof made on a manufacturing line. The reality is the plies of a BUR create a redundancy that can help mitigate any potential oversights in rooftop workmanship.

BUR systems are offered in a variety of attractive and reflective options with a proven track record of performance. Photos: Johns Manville

“I’ve replaced BURs for clients I worked with 30 years ago,” says Mock. “We recently replaced [a BUR] specified in the early 1980s. And the only reason was because some of the tectum deck panels had fallen out of the assembly. Meanwhile, the roof was still performing well after 30 years.”

According to the Quality Commercial Asphalt Roofing Council of the Asphalt Roofing Manufacturers Association (ARMA), one of the main drivers of the demand for BUR systems is the desire of building owners for long life cycles for their roofs.

“A solid core of building owners and roofing professionals in North America continue to advocate asphalt-based roofing systems because of their long lives,” says Reed Hitchcock, ARMA’s executive director.

Benefits of Asphalt-Based Roofing

Over the years, asphalt-based roofing assemblies have earned a reputation for reliability with building owners, roofing consultants, architects, engineers, and commercial roofing contractors. The original price tag tends to be greater than other low-slope roofing options, but these assemblies offer competitive life-cycle costs. BUR enjoys a track record spanning more than 150 years; it provides a thick, durable roof covering and can be used in a broad range of building waterproofing applications.

An aerial view of a reflective roof membrane. Photos: Johns Manville

Available as part of fire-, wind-, and/or hail-rated systems, BUR and modified bitumen assemblies offer proven waterproofing capabilities, high tensile strength, long-term warranties, and a wide choice of top surfacings (including ‘cool’ options). Their components include the deck, vapor retarder, insulation, membrane, flashings, and surfacing material. The roofing membrane can be made up of a variety of components, including up to four high-strength roofing felts, modified bitumen membranes (hybrid systems) and standard or modified asphalt. Hot-applied asphalt typically serves as the waterproofing agent and adhesive for the system.

The roofing membrane is protected from the elements by a surfacing layer — either a cap sheet, gravel embedded in bitumen, or a coating material. Surfacings can also enhance the roofing system’s fire performance and reflectivity ratings.

Another surfacing option is gravel, commonly used in Canadian applications where the existing roof structure can handle the extra weight. There are also several smooth-surface coating options, the most popular of which are aluminum or clay emulsion products offering greater reflectivity than a smooth, black, non-gravel-surfaced roof. These reflective roof coating options are typically used in warmer regions when required by code. Reflective white roof coatings are also becoming more popular.

Cold-Process BUR

Cold application of BUR has provided an alternative to traditional hot-applied systems for more than 48 years. The term ‘cold-applied’ means the BUR roofing system is assembled using multiple plies of reinforcement applied with a liquid adhesive instead of hot asphalt. These cold adhesives are used between reinforced base/ply sheets to provide a weatherproof membrane.

The owner of this shopping mall chose BUR primarily due to its redundancy. Multiple plies of roofing can provide extra insurance against water intrusion. Photos: Johns Manville

In BUR cold-process roof systems, manufacturers typically require that only fully coated, non-porous felts (such as standard base sheets) are used as base and ply sheets. Generally, an aggregate surfacing or a coating is then applied over the completed membrane to provide surface protection and a fire rating for the roof system.

“In the re-roofing market, we’re definitely seeing more cold-applied systems being specified, particularly with modified bitumen,” says Mock. “It’s a natural alternative when a building may be occupied during the reroofing process and hot asphalt is not an option.”

Adhesives can be manually applied with a squeegee, brush, or spray application equipment. When numerous roof penetrations or rooftop access become issues, manual application of adhesives is usually the best option. Proper coverage rates are vital to a successful, long-term, cold-applied roof system. Both spray and manual application methods require the proper amount of adhesive material be installed. If too little adhesive is applied, there is a potential for an improper bond to be formed between the felts. If too much is applied, then the potential for longer setup times and membrane slippage is increased. Additionally, ambient temperatures must be 40 degrees Fahrenheit (5°C) and rising before installation. This limits, but does not preclude, use of cold-process BUR in much of the northern United States and Canada.

“I’m also comfortable specifying BUR, because I’m confident I will have a seasoned contractor on the job,” says Mock. “The commitment in terms of skilled labor and equipment is simply too great for these contractors to be first-timers.”

Flashings are another critical component of every roofing system, particularly in cold-weather applications. Four-ply BURs use modified bitumen flashings almost exclusively. These membranes are predominantly styrene butadiene styrene (SBS)-modified and offer greater elongation in frigid climates where it counts most — at the interface of the roof system with other building components.

Use of a modified-bitumen base ply is one way of handling general flashing requirements, although modified bitumen cap sheets are more common.

BUR Repair and Maintenance

Like all roof systems to some extent, the life expectancy of a BUR system depends on the property owner’s commitment to routine maintenance. All roof systems can benefit from an owner willing to undertake a proactive management plan. BUR installed over an insulation package lends itself well to non-destructive testing in the future (e.g., infrared) as a means to maximize service life.

“Asphalt roofing systems have the potential for a very long life, and preventive maintenance is the key to realizing that potential,” says Hitchcock.

Non-gravel BUR surfacing options include aggregate, a mineral surface cap sheet, or a smooth, surface-coated membrane. Photos: Johns Manville

The goal is for problem areas to be detected and fixed before they develop into leaks. Inspections can reveal potentially troublesome situations, such as a loss of gravel surfacing, which could lead to felt erosion or brittleness. Less commonly, punctures and cuts to the membrane can occur, so it is wise to remove sharp objects and debris from the roof. Clogged drains or poorly sealed flashings also present problems that are repaired easily. The effects of chemical exhausts on roofing materials should also be monitored.

Preventive maintenance actions can help catch problems before they damage larger areas of the roof system. Inspections should be performed not only on aging roofs, but also on newly-installed roofs to guard against errors in installation, design, or specifications.

BUR and modified bitumen also have a long history of proven performance in the northern United States and Canada, where snow and ice buildup are common. Perhaps more than any other roof membrane, the BUR system shrugs off minor abuse.

BUR has proven to be a low-maintenance roofing system, and it can also be effectively repaired when needed. This means property owners can usually get more life out of a BUR. The ability to enhance the performance of existing BUR membranes with coatings, mod bit cap sheets, or flood coats of asphalt explain the long service lives of these systems in demanding applications.

“Property owners rarely have to replace a four-ply BUR until it is absolutely, positively worn out,” says one roofing contractor who asked to remain anonymous. “Based on experience, these asphalt-based systems ‘hang in there’ longer than less-robust roof options.”

When BUR Is Not the Best Option

There is no roofing product solution that will fit every building specification, and that certainly holds true for BUR. Probably more than any other roofing system (except spray polyurethane foam), the built-up roofing application is more of a skill than a science. As alternative systems have been introduced into the market, the job of finding experienced BUR contractors has become more difficult. This is especially true for the hot mopping of multi-ply BUR systems.

BURs are labor intensive and their installed cost will fluctuate with crude oil prices. However, as oil prices have continued to fall, BUR manufacturers have enjoyed the lowest asphalt pricing since the 2008-09 recession. (The price of oil peaked at about $117 a barrel in September 2012 and is $50 a barrel at this writing.) Typically BUR manufacturers will pass on a portion of these savings to their customers.

BUR has always held up well in life-cycle cost analyses. However, if a roof is not expected to last 20 years or more, it usually does not make sense to specify a premium four-ply BUR.

On larger projects, gravel-surfaced BURs are typically not practical from a cost standpoint unless a source of gravel is available locally. Projects where roof access is difficult often present challenges when roofing kettles are used. And despite the preponderance of low-fuming asphalts and kettles, re-roofing occupied buildings is often unacceptable to neighbors and/or the property owner.

Built-up roofing systems have sufficient strength to resist normal expansion and contraction forces that are exerted on a roof; however, they typically have a low ability to accommodate excessive building or substrate movement. Rephrased, if the roof must be used to “hold the walls” together or if the use of “loose-laid insulation” has a benefit, then a traditional three- or four-ply built-up roofing system is not a good choice.

A built-up roof typically provides high tensile strength with low elongation. Guidelines about where expansion joints should be installed in the roofing system should not be ignored by the designer. These guidelines include installing expansion joints where the deck changes direction, approximately every 200 feet (61 meters), although many consider that this dimension can be expanded for single-ply roofing membranes; where there is a change in deck material; and, anywhere there is a structural expansion joint, etc. Based on these requirements, on some projects it simply isn’t practical to use a BUR.

BUR materials must be kept dry before and during installation to prevent blistering in the roof system. Proper storage is the key: Do not overstock the roof; use breathable tarps to cover material on the roof; store material on pallets to minimize the possibility of material sitting in water; and store rolls on-end to prevent crushing. In general, polymeric single-ply membranes like TPO (thermoplastic polyolefin) are less susceptible to storage issues.

Many roof consultants and product manufacturers clearly state that there should be no phased construction of a built-up roof. If phasing is required, then a BUR should not be specified. This is a clean and simple rule to understand; if the roof being constructed is a four-ply BUR, then only as much insulation should be installed as can be covered the same day with all four of the plies in the built-up roofing membrane. Phased construction of a built-up roof greatly increases the potential for blistering of the membrane and does not allow for the total number of plies to be installed in a shingled fashion. Phased application contains other perils, such as roofing over a small amount of overnight precipitation or dew that, even with the best of intentions, can cause harm.

As stated above, costlier modified bitumen materials should be specified for flashings and to strip in metal. Stripping in two plies of felt will most likely result in splitting at the joints in a gravel stop because the two-ply application cannot accommodate the movement in the edge metal. On new or existing buildings where significant expansion/contraction is expected, a TPO, PVC or EPDM roof membrane can save the property owners money and eliminate premature roof failure due to roof splitting.

Conclusion

Manufacturers across North America are making asphalt roofing systems like BUR better and more versatile for architects, builders, contractors, roofing consultants, and building owner/managers. Thanks especially to the addition of polymers that add stretch and strength, architects can now specify a commercial, low-slope roof as part of a multi-ply BUR system any way they want it — hot, cold, torch, or self-adhered (hybrid BUR) — to meet the individual low-slope roofing project’s needs.

Most importantly, asphalt-based roofing products offer exceptional life-cycle cost performance. They have proven to be reliable, easy to maintain, and are trusted to perform exceptionally well in extreme weather conditions.

SPRI Updates and Improves Roof Edge Standards

Low-slope metal perimeter edge details, including fascia, coping and gutters, are critical systems that can strongly impact the long-term performance of single-ply roofs. Photo: Johns Manville

The effect of high winds on roofs is a complex phenomenon, and inadequate wind uplift design is a common factor in roofing failures. Damage from wind events has historically been dramatic, and wind-induced roof failure is one of the major contributors to insurance claims.

Roofing professionals have long recognized the importance of proper low-slope roof edge and gutter designs, particularly in high-wind conditions. For this reason, SPRI, the association representing sheet membrane and component suppliers to the commercial roofing industry, has spent more than a decade enhancing testing and design standards for these roofing details.

SPRI introduced the first version of its landmark standard, ANSI/SPRI/ES-1 “Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems” in 1998. Since then, the association has continually revised, re-designated and re-approved the document as an ANSI (American National Standards Institute) standard.

Testing of edge securement per ANSI/SPRI ES-1 is required per the International Building Code (IBC), which has been adopted by every state in the country.

This standard provides the basic requirements for wind-load resistance design and testing for roof-edge securement, perimeter edge systems, and nailers. It also provides minimum edge system material thicknesses that lead to satisfactory flatness, and designs to minimize corrosion.

Construction professionals have been successfully using the standard, along with the specifications and requirements of roofing membrane and edge system manufacturers to strengthen their wind designs.

Until recently, the biggest news on the wind design front was the approval of ANSI/SPRI/FM 4435/ES-1, “Wind Design Standard for Edge Systems Used with Low-slope Roofing Systems.” Let’s call it “4435/ES-1” for short. SPRI knew recent post-hurricane investigations by the Roofing Industry Committee on Weather Issues (RICOWI) and investigations of losses by FM Global consistently showed that, in many cases, damage to a low-slope roof system during high-wind events begins when the edge of the assembly becomes disengaged from the building. Once this occurs, the components of the roof system (membrane, insulation, etc.) are exposed. Damage then propagates across the entire roof system by peeling of the roof membrane, insulation, or a combination of the two.

Recognizing that edge metal is a leading cause of roof failures, SPRI has redoubled its efforts to create a series of new and revised documents for ANSI approval. As has always been the case, ANSI endorsement is a critical step toward the ultimate goal of getting these design criteria included in the IBC.

A Systems Approach to Enhancing Roof Edge Design

Roofing professionals understand that successful roof design requires the proper integration of a wide variety of roofing materials and components. For years, leading roofing manufacturers have taken a “systems” approach to their product lines. Recently, SPRI has zeroed in on the roof edge. Low-slope, metal perimeter edge details include fascia, coping and gutters, are critical systems that can strongly impact the long-term performance of single-ply roofs.

As part of the ES-1 testing protocol, RE-3 tests upward and outward simultaneous pull of a horizontal and vertical flanges of a parapet coping cap. Photo: OMG Edge Systems

SPRI first addressed roof gutters in 2010 with the development of ANSI/SPRI GD-1. The testing component of this document was recently separated out to create a test standard and a design standard. The test standard, GT-1, “Test Standard for Gutter Systems,” which was approved as an American National Standard on May 25, 2016.

Similarly, SPRI has revised 4435/ES-1 to only be a test standard.

Making both edge standards (4435/ES-1 and GT-1) into standalone testing documents makes it easier for designers, contractors and building code officials to reference the testing requirements needed for metal roof edge systems.

IBC requires that perimeter edge metal fascia and coping (excluding gutters), be tested per the three test methods, referred to as RE-1, RE-2 and RE-3 in the ES-1 standard. The design elements of ES-1 were never referenced in code, which caused some confusion as to how ES-1 was to be applied. The latest version of 4435/ES-1 (2017) only includes the tests referenced in code to eliminate that confusion.

Test methods in 4435/ES-1 2017 have the same names (RE-1, RE-2, and RE-3), and use the same test method as 4435/ES-1 2011. Because there are no changes to the test methods, any edge system tested to the 2011 version would not need to be retested using the 2017 version.

FM Global’s input was instrumental in the changes in 2011 when ANSI/SPRI ES-1 incorporated components of FM 4435 to become 4435/ES-1. However, there are no additional FM related changes in the latest 4435/ES-1 standard.

This gravel stop is being tested according to the ANSI/SPRI ES-1 standard using the RE-2 test for fascia systems. Photo: OMG Edge Systems

Per ANSI requirements, 4435/ES-1 2011 needed to be re-balloted, which is required by ANSI every five years. SPRI took this opportunity to have it approved as a test standard only to eliminate the confusion referenced above. FM Global was consulted and indicated it wanted to keep “FM” in the title. (FM was on the canvas list for the test standard and actually uses it as its own test standard.)

With 4435/ES-1 becoming a test standard for coping and fascia only, and GT-1 being a test standard for gutters, SPRI determined that a separate edge design standard was needed. Meet ED-1, a design standard for metal perimeter edge systems.

The design portions of the ES-1 edge and the GD-1 gutter standards have been combined and are now referenced by SPRI as ED-1. It has been developed and is currently being canvassed as an ANSI standard that will provide guidance for designing all perimeter edge metal including fascia, coping, and gutters.

ED-1 will be canvassed per the ANSI process later this year. However, SPRI is not planning to submit ED-1 for code approval.

SPRI ED-1 will include:

Material Design

  • Nailer attachment
  • Proper coverage
  • Recommended material thicknesses
  • Galvanic compatibility
  • Thermal movement
  • Testing requirements
  • “Appliance” attachment to edge systems

Limited Wind Design

  • Load to be required by the Authorities Having Jurisdiction (AHJ).
  • Tables similar to those included in 4435/ES-1 will be included for reference.

If this sounds a tad complex, imagine the design work required by the dedicated members of SPRI’s various subcommittees.

The Test Methods in Detail

The GT-1 standard is the newest, so let’s tackle this one first. As noted above, the ANSI/SPRI GT-1 test standard was developed by SPRI and received ANSI Approval in May of 2016. Testing of roof gutters is not currently required by IBC; however, field observations of numerous gutter failures in moderate to high winds, along with investigations by RICOWI following hurricanes have shown that improperly designed or installed gutters frequently fail in high wind events. GT-1 provides a test method that can be used by manufacturers of gutters, including contractors that brake or roll-form gutters, to determine if the gutter will resist wind design loads. Installing gutters tested to resist anticipated wind forces can give contractors peace of mind, and may provide a competitive advantage when presented to the building owner.

This gutter is being tested using the test method specified in ANSI/SPRI GD-1, “Design Standard for Gutter Systems Used with Low-Slope Roofs.” Photo: OMG Edge Systems

GT-1 tests full size and length samples (maximum 12 feet 0 inches) of gutter with brackets, straps, and fasteners installed per the gutter design. It is critical that the gutter be installed with the same brackets, straps, and fasteners, at the same spacing and locations as per the tested design to assure the gutter will perform in the field as tested. The fabricator should also label the gutter and/or provide documentation that the gutter system has been tested per GT-1 to resist the design loads required.

GT-1 consists primarily of three test methods (G-1, G-2, and G-3). Test method G-1 tests the resistance to wind loads acting outwardly on the face of the gutter, and G-2 tests the resistance to wind loads acting upwardly on the bottom of the gutter. G-3 tests resistance to the loads of ice and water acting downwardly on the bottom of the gutter.

Tests G-1 and G-2 are cycled (load, relax, increase load) tests to failure in both the original GD-1 standard and the new GT-1. The only change being that in GD-1 the loads are increased in increments of 10 lbf/ft2 (pound force per square foot) from 0 to failure, and in GT-1 they are increased in increments of 15 lbs/lf (pounds per linear foot) from 0 to 60 lbs/lf, then in 5 lbs/lf increments from above 60 lbs/lf to failure.

Note also that the units changed from lbf/ft2 (pound force per square foot) to lbs/lf (pounds per linear foot), which was done so that the tests could be run using the test apparatus loads without having to convert to pressures.

The GT-1 standard specifies a laboratory method for static testing external gutters. However, testing of gutters with a circular cross-section is not addressed in the standard, nor does the standard address water removal or the water-carrying capability of the gutter. In addition, downspouts and leaders are not included in the scope of the standard.

SPRI intends to submit ANSI/SPRI GT-1 for adoption in the next IBC code cycle.

As referenced above, IBC requires that perimeter edge metal (fascia and coping), excluding gutters, be tested per three test methods, referred to as RE-1, RE-2 and RE-3 in the ES-1 standard.

RE-1 tests the ability of the edge to secure a billowing membrane, and is only required for mechanically attached or ballasted membrane roof systems when there is no peel stop (seam plate or fasteners within 12 inches of the roof edge). RE-2 tests the outward pull for the horizontal face of an edge device. RE-3 tests upward and outward simultaneous pull on the horizontal and vertical sides of a parapet coping cap.

Calculating Roof Edge Design Pressures

All versions of ANSI/SPRI ES-1 and ANSI/SPRI GD-1, the 2011 version of ANSI/SPRI 4435/ES-1, and the new ED-1 standard all provide design information for calculating roof edge design pressures. These design calculations are based on ASCE7 (2005 and earlier), and consider the wind speed, building height, building exposure (terrain), and building use.

A gravel stop failure observed during roof inspections after Hurricane Ike in Sept. 2008. Photo: OMG Edge Systems

However, as stated above, IBC requires that the load calculation be per Chapter 16 of code, so the SPRI design standards are intended only as a reference for designers, fabricators, and installers of metal roof edge systems.

ES-1-tested edge metal is currently available from pre-manufactured suppliers, membrane manufacturers and metal fabricators that have tested their products at an approved laboratory.

The roofing contractor can also shop-fabricate edge metal, as long as the final product is tested by an approved testing service. The National Roofing Contractors Association (NRCA) has performed lab testing and maintains a certification listing for specific edge metal flashings using Intertek Testing Services, N.A. Visit www. nrca.net/rp/technical/details/files/its details.pdf for further details.

A list of shop fabricators that have obtained a sub-listing from NRCA to fabricate the tested edge metal products are also available at www. nrca.net/rp/technical/details/files/its details/authfab.aspx.

SPRI Continues to Take Lead Role in Wind Testing

As far back as 1998, SPRI broke ground with its ANSI/SPRI/ES-1 document addressing design and testing of low-slope perimeter edge metal. Today, the trade association has a variety of design documents at the roofing professional’s disposal, and is working to get ED-1 approved as an Edge Design Standard to be used for low-slope metal perimeter edge components that include fascia, coping and gutters.

All current and previously approved ANSI/SPRI standards can be accessed directly by visiting https://www.spri.org/publications/policy.htm.

For more information about SPRI and its activities, visit www.spri.org or contact the association at info@spri.org.

Steep-Slope Projects: Risks, Considerations and Best Practices for Contractors

Photos: Atlas Roofing

Photos: Atlas Roofing

Many contractors treat residential roofing as routine. However, whether a re-roof or new construction, each project can be infinitely complex and should be addressed as such by always accounting for weather and safety issues, as well as proper installation and customer service.

One of the most prominent and popular elements of residential architecture is a steep-slope roof. According to the Occupational Safety and Health Administration (OSHA), steep-slope roofs have slopes greater than 4:12 and range from 18.5 degrees to 45 degrees or more. While the process of installing a roof with these angles isn’t necessarily much different from a low-slope roof, it can pose more risks and considerations for workers.

Weather Woes

Weather plays an important role in every roofing project, but staying on top of potential issues from Mother Nature is especially crucial during steep-slope jobs.

Photos: Atlas Roofing

Photos: Atlas Roofing

In high temperatures, workers may fall victim to heat cramps, heat exhaustion, heatstroke or worse. The best way to beat the heat is to start early and get as much done as possible before the temperature peaks. Starting early in the summer—specifically in the South—can allow work to be completed before daily rain showers roll in. Proper hydration and attire are also important.

Cold temperatures can create even more complications because some manufacturers advise against installing their products in weather below 45 degrees Fahrenheit and certain equipment is susceptible to freezing. Furthermore, workers have to pay extra attention to the grip of their shoes to avoid slipping and falling. Not to mention, freezing-cold hands and feet may cause an otherwise adept worker to become clumsy. Wearing the proper clothing is key during cold-weather jobs, and workers should be advised to keep an eye out for the first signs of frostbite, including cold skin, redness, tingling and numbness.

Safety Considerations

In 2015, falls were the leading cause of private-sector work deaths in the construction industry, accounting for nearly 40 percent of worker fatalities, according to OSHA. In addition, OSHA reports nearly 90 percent of fatal falls happen due to the lack of a fall-protection system.

Photos: Atlas Roofing

Photos: Atlas Roofing

When working on a roof slope greater than 4/12, OSHA requires additional safety measures, which include either a guardrail system with toeboards, safety net systems or personal fall arrest systems. Yet, many contractors—especially residential roofers—choose to forgo protective devices because they feel they are not feasible or create a greater hazard. In such cases, OSHA does allow the use of alternative fall-protection methods in residential construction, as long as contractors develop a written, job-specific fall-protection plan that complies with OSHA regulations.

Proper Installation

During the installation process, roofers should keep a few things in mind whether they’re applying shingles to a steep-slope or low-slope structure.

  • Valleys
Photos: Atlas Roofing

Photos: Atlas Roofing

Valleys are a critical part of proper roof installation because they experience the most water flow during rainstorms and can be potential leak points.

In an open valley, a piece of aluminum, copper or other type of metal is used to help keep rainwater flowing off the roof. Open valleys are often used when a homeowner wants a showier look, such as on a Colonial-style home.

Closed valleys—the most common valley installation method—use asphalt shingles and offer a more traditional look. When properly installed, they keep water from getting trapped in the valley and allow for proper drainage.

In addition to open and closed valleys, contractors also have the option to create a weave valley, which alternates shingles through the valley from both sides, creating a braid-like effect.

Laminate/architectural shingles should not be used for weave valleys. Because laminate shingles aren’t one-dimensional, they do not create the flat surface needed for a weave valley, which should only be used with three-tab shingles.

When using laminate shingles, be sure to follow instructions on the wrapper for either an open or closed application.

Contractors also need to be extremely careful around obstacles such as chimneys and skylights, which require their own flashing and water divergence methods. For instance, more flashing may be needed in these areas to divert water and prevent leaks.

  • Starter Shingles

Starter shingles allow the first course of shingles to properly seal down, protecting the edge of the roof and providing anchoring power for high-wind resistance at the critical eave and rake areas. They further protect the roof by filling in spaces under the cutouts and edges for the first course of exposed shingles, preventing wind uplift.

Photos: Atlas Roofing

Photos: Atlas Roofing

The most common mistake when installing starter shingles or modifying traditional three-tab shingles is putting them on backward or upside-down.

Additionally, the overhang should be no more than three-quarters of an inch to prevent wind from penetrating beneath shingles, as well as to keep shingles from curling or cracking.

In addition, many manufacturers caution against double-stacking pallets of starter shingles, which can cause the bottom shingles to warp. Be sure to read all storage and handling instructions prior to installation.

  • Underlayment

Underlayment is an important part of the roofing process and is required by code for residential properties to meet Class A fire requirements. Serving as a secondary barrier, underlayment protects rakes, eaves and critical flashings from water infiltration. Most warranties also require underlayment for the roof to be ASTM compliant. However, some contractors still opt not to use it because they want to save time on a project or their customer balks at the cost.

Photos: Atlas Roofing

Photos: Atlas Roofing

Another frequent error during underlayment installation is incorrect overlaps. On low-slope roofs (slopes between 2:12 and 4:12), underlayment should have double coverage. And while traditional installation is fine on steep-slope roofs, always follow manufacturer instructions for overlaps from course to course.

Last but not least, be sure to keep underlayment from wrinkling, which can cause ripples in the shingles. While trying to keep underlayment as flat as possible, avoid pulling it too tight because it has a natural expansion and contraction. If underlayment gets wet, be sure it adequately dries out before continuing the installation process.

  • Shingles and Nails

Shingles should be installed with the manufacturer’s recommended offset, which will help prevent leak points and also properly align the shingles across the roof. Once all of the shingles are aligned, only the shingles themselves should be exposed—not the nails.

Because the common bond area is the strongest part of a shingle, manufacturers require nails be placed there to achieve the advertised wind performance. Nails should not be too high or too low, or unevenly spaced. If nails aren’t positioned correctly, the manufacturer’s wind warranty may not be valid.

Customer Service Follow-Up

Providing excellent customer service is key to every roofing job. Homeowners who have a good experience are more likely to share positive reviews and opinions.

Photos: Atlas Roofing

Photos: Atlas Roofing

Before starting a steep-slope project, be sure to discuss the entire process with homeowners to ensure that they know what to expect, as well as the types of warranties they will receive with their new roof. In addition, prepare the surrounding property, such as windows and landscaping, to prevent damage during the installation process.

During the job, be sure workers are vigilant about not dropping nails anywhere on the jobsite. After the job, walk the property with the homeowners to ensure all debris and materials were cleaned up; magnets can be used to double-check for stray nails. If the homeowners are happy with the finished product and their experience, don’t be afraid to ask them to write a nice review on the company website, Angie’s List, Yelp or other customer referral app.

Most of the best practices for steep-slope roofing can be applied to any type of roofing project. However, steep-slope work can pose additional challenges that other projects may not. Always follow manufacturer’s instructions and OSHA guidelines on all roofing jobs, but especially on steep-slope projects, when one minor slip could turn into major consequences for all involved.

About the Author: Paul Casseri is the product manager of the Roofing Shingles and Underlayment Division for Atlas Roofing Corp., www.atlasroofing.com. He is responsible for all areas of product management, including product initiation, feasibility, design, development and testing. He is a graduate of Penn State University with more than 20 years of experience in the building products industry.

 

Feeling Comfortable With Metal Roofing

Metal Roof Consultants Inc

Photo: Metal Roof Consultants Inc.

Theodore Roosevelt once said, “The best thing you can do is the right thing; the next best thing you can do is the wrong thing; the worst thing you can do is nothing.” 

Throughout our lives, we must decide what to do and how to deal with the inevitable fear that surrounds doing anything for the first time. Remember that bicycle in the garage that looked so inviting—until you thought of how it would be impossible for you to balance yourself on those two tiny wheels and pedal it forward without falling and hurting yourself. Your mind focused on falling and not the excitement of being able to conquer riding that bicycle. Yet, as Theodore Roosevelt said many years ago, “the worst thing you can do is nothing.” 

We are faced with new things throughout our lives, and when we do we usually must weigh the possibilities of doing the right thing, the wrong thing, or nothing. However, if we expect to have a productive and peaceful life, we must force ourselves to always do “something.”  

Finally, we must also ask ourselves why we even consider new things we contemplate doing. When we take on a new task and we know why we are doing it, we are comfortable with taking whatever risk is anticipated. When we know that the only wrong thing to do is nothing, we have the possibility to achieve even greater things. Even if it turns out to be the wrong thing, we will learn valuable lessons about ourselves and the task we were trying to accomplish.  

Now, let’s look at the metal roofing industry and ask ourselves whether we are “doing nothing” either because we are afraid of “falling off the bicycle” or because we haven’t determined why we want to enter this market. Both reasons limit your personal and business potential to what you are doing now. Now, let’s explore some of the reasons you might not be comfortable entering the metal roof market, thereby limiting your growth potential. 

The Metal Market

Metal roofing has been around since 1932, when the first standing seam roof panel was introduced by Armco steel at the World’s Fair in Chicago. However, it is still a rather small percentage of the total roofing market. Why? In part, it’s because some contractors fear entering this market. Let’s look at some of the reasons that the unknown aspects of metal roofing, or the incorrect perception of a metal roofing system, can cause contractors to avoid this market: 

Metal Roof Consultants Inc.

Photo: Metal Roof Consultants Inc.

Specialized workforce. There is the perception that this market requires a field force that is very difficult to gather. The reality is that the metal roofing systems in today’s market include parts and components that are easily put together. Manufacturers provide training in how to install their specific pre-manufactured components that make up a metal roof system. In general, there are panels, clips, and termination components (ridge, rake, gutter/eave, curbs, etc.). These components have been developed over decades of trial and error and, when installed correctly, will create a leak-proof roof system which will last as long as any of the other building components. In addition to the metal roof manufacturers, the Metal Buildings and Erectors Association (MBCEA) is a group that provides independent training on the proper erection of metal buildings, including all components of a metal roof system. 

Engineering. The engineering associated with a metal roof system is the responsibility of the manufacturer per the International Building Code (IBC). Local engineering for a particular metal roof can be provided by a professional engineer licensed in the locale of the particular job site. Both sources are readily available to the contractor that wishes to enter the metal roof contracting business. The contractor should not have any concerns about this aspect of a metal roof if he does his due diligence and partners with a manufacturer that will provide the tested engineering characteristics of a particular roofing system and a local engineer who can take that information and perform a code-required analysis. 

Details. As opposed to sheet membrane or shingled roof systems, the metal roof system has its own details. These details require a different understanding of water protection. Metal components, including the actual roof sheet, will not allow water to penetrate and, if protected with a galvalume coating, will last well over 60 years (refer to Metalconstruction.org, Technical Resources, “Service Life Assessment of Low-Slope Unpainted 55% Al-Zn Alloy Coated Steel Standing Seam Metal Roof Systems”).  

These metal components, however, need to be joined and terminated with sealants and fasteners to create a total water-resisting barrier. Again, the panel manufacturers have time-tested details to assist contractors. A word of caution, however: Make sure that you properly select the panel type (standing seam, corrugated panel, snap seam panel, etc.) that best suits the project, and match those selections with a manufacturer and the detail that will perform best. Finally, the local engineer must be used to ensure the detailing will resist the local design loads. The contractor is only responsible to select that qualified manufacturer and engineer—not become one. 

Cost. “Since metal roofs cost a lot more than conventional roofs, they must be hard to sell.” While this statement is prevalent in the metal roofing market, it is blatantly untrue. While the initial cost may be higher than a conventional roof, a metal roof offers an exceptional value over its lifetime. In fewer than 20 years, the cost of a metal roof system can be as much as 50 percent less than that of many conventional roofs, and conservatively one-third the cost of these roofs over a 60-year time frame. End of argument!  

The Retrofit Segment

What about metal retrofit roofing? While that question might scare you more than merely considering entering the overall metal roofing market, it can definitely expand your horizon and offers more potential than just riding a bicycle. If you’ve ever ridden in a car, you know that the experience, comfort and potential for getting places is greatly enhanced. The same concept applies when expanding your metal roof market possibilities to include the lucrative metal retrofit roofing market. This market, with its extremely limited contractor participation and increasing customer demand, makes it very interesting to consider.  

Metal Roof Consultants Inc.

Photo: Metal Roof Consultants Inc.

A recent metal retrofit roofing package of six roofs totaling more than $20 million bid in North Carolina, and only three companies submitted bids. Each contractor ended up with two projects each, totaling between $6 and $9 million per contractor. During this same time, single-ply and shingle projects in the same geographical area attracted many more contractors. Again, you may feel that all-too-familiar twinge in your stomach caused by only looking at the negative consequences you might encounter. However, doing nothing is the worst thing you can do. It is true that finding manufacturers and engineers to assist you when entering the retrofit market can be difficult, as the pool is much more limited than that of the metal roofing industry in general, but these resources are available to you. Just be diligent and look harder!  

Finally, consider what a very wise man said many years ago to a young man just out of college. He said, “Can’t never did anything.” That wise man was my father, and he spoke those words on my college graduation day. My experience has seen the metal roof market develop with many new innovations. The metal retrofit roofing market was not even in existence in the 1970s, but it has since become a market that grows year after year. I have been lucky enough to see, and be part of, a revolution in the roofing industry with respect to metal roofing’s place. All the tools you need to enter the market are out there, but, like that bicycle many years ago, you must first determine why you want to ride it and be willing to risk falling off a few times. The rewards are worth it, even if you get your knees scraped a few times. 

Hot-Air Welding Under Changing Environmental Conditions

The robotic welder’s speed, heat output and pressure should be properly programmed before the welding process begins. Photo: Leister.

The robotic welder’s speed, heat output and pressure should be properly programmed before the welding process begins. Photo: Leister.

Today’s most powerful hot-air welders for overlap welding of thermoplastic membranes are advertised to achieve speeds of up to 18 meters (59 feet) per minute. That’s fast enough to quickly ruin a roofing contractor’s day.

These robotic welders are digitally monitored to achieve consistent overlap welding performance, but they cannot adapt to changing environmental conditions automatically. It’s the contractor’s job to monitor and assess seam quality before the base seam is welded and when ambient temperatures or other factors potentially influence welding performance.

Successful hot-air welding requires the use of specialized, properly maintained and adjusted equipment operated by experienced personnel familiar with hot-air welding techniques. Achieving consistent welds is a function of ensuring that the roofing membrane surface is clean and prepared for heat welding, conducting test welds to determine proper equipment settings, and evaluating weld quality after welding has been completed.

Setting up hot-air robotic welders properly is the key to having a properly installed thermoplastic roof, and performing test welds is one of the most important steps. Making appropriate adjustments before the welding process begins ensures that the correct combination of welder speed, heat output and pressure is programmed into the robotic welder.

For most roofing professionals, these procedures have been firmly established in the minds of their crews and equipment operators through education and field training. But let’s not forget that Murphy’s Law often rules on both large and small low-slope roofing projects.

The frightening reality about using robotic welders is if they are set-up incorrectly or environmental conditions change, the applicator may weld thousands of feet of non-spec seam before anyone even bothers to check. If you probe for voids at the end of the day, it is probably too late.

If serious problems are discovered, the applicator must strip in a new weld via adhesive, cover tape, or heat welding, depending on what the membrane manufacturer will allow. If seams must be re-welded, the operator has to create not one, but two robotic welds on each side of the cover strip. The sheet will also need to be cleaned and re-conditioned no matter what method is used.

Can these errors be corrected? Absolutely. Except now the crew is in a real hurry because the roofer is working on his own time, and application errors tend to snowball under these conditions.

Reality Check

What goes on in the field is sometimes quite different than what one sees when hot-air welding thermoplastics under an expert’s supervision.To support this view, we asked four field service reps, each with a minimum of 35 years of roofing experience, to comment. The most senior “tech” has worked for six different thermoplastic membrane manufacturers in his career. Their names shall remain anonymous, but this writer will be happy to put readers in touch with them upon request.

Successful hand welding is a skill that is developed and refined over time. The correct selection of welder temperature and nozzle width can have a significant effect on the quality of the hand weld. Photo: GAF.

Successful hand welding is a skill that is developed and refined over time. The correct selection of welder temperature and nozzle width can have a significant effect on the quality of the hand weld. Photo: GAF.

So, let’s welcome Christian, Dave, Mark and Walter, and get straight to the point: Is the average roofing crew diligent enough when it comes to properly testing welds using industry best practices?

“I would say ‘probably not,” exclaims Walter. Dave just shakes his head as his colleague Mark adds, “I would have to say no.”

Considering the generally laudable performance of thermoplastic membranes over the last decade or so, we must interpret our experts’ opinions as suggesting the need for further improvement in hot-air welding techniques. Hence, the purpose of this article.

“There are a few outstanding issues causing bad welds,” says Walter. “These include welding over dirty or contaminated membranes; improper equipment setup; using crews with inadequate training; and knowing the difference between the weldability of various manufacturers’ membranes.”

Welding equipment consists of three main components: the power supply, the hot air welder (either automatic or hand-held), and the extension cord. A stable power supply of adequate wattage and consistent voltage is critical to obtaining consistent hot air welds and to prevent damage to the welder.

The use of a contractor-supplied portable generator is recommended, although house-supplied power may be acceptable. Relying on power sources that are used for other equipment that cycle on and off is not recommended. Power surges and/or disruptions and insufficient power may also impact welding quality. Proper maintenance of welding equipment is also of obvious importance.

“Contractors seem to never have enough power on the roof,” observes Mark. “The more consistent your power is, the more consistent your welds will be. Too many times, I’ve seen too many tools (hand guns, auto welder, screw guns and a RhinoBond machine) plugged into one generator.”

Generator-induced challenges on the jobsite are going to arise, agrees Christian. “But at least today there is more experience in understanding, dealing with, and ultimately preventing these issues,” he says.

Most TPO and PVC membrane suppliers also recommend using the latest automatic welding equipment, which provides improved control of speed, temperature and pressure. Our four experts generally agree that field welding performance has improved over the years and programmable robotic welders have helped. They also point to proper training and experience as crucial factors.

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Tips for Reducing Insulation Labor Time and Costs on Commercial Jobs

Composite products can help simplify insulation installation on high-traffic roofs.

Composite products can help simplify insulation installation on high-traffic roofs.

It’s no secret that the roofing industry continues to suffer a severe shortage of skilled labor, resulting in lost business and profits. Former National Roofing Contractors Association (NRCA) chairman of the board Nelson Braddy Jr. was quoted in the Wall Street Journal last fall saying his Texas roofing company had to decline $20 million in projects over the past two years due to worker shortages. “It’s the worst I’ve seen in my career,” he said.

While there is no silver bullet to fix this problem, using materials and methods that simplify installation can help you maximize the people you do have, and potentially even reduce material costs. It’s a win-win for improving profitability.

This article highlights some simple-to-use options for streamlining insulation work on re-roofing jobs and new construction.

Measuring What Matters

When it comes to insulation, roofers can choose from several commonly used rigid foam insulations: polyisocyanurate (polyiso), extruded polystyrene (XPS), and expanded polystyrene (EPS).

The first step in reducing insulation costs is to consider which metric matters most to your bottom line. As the job of insulation is to reduce heat loss through the roof assembly, many manufacturers promote their products’ R-value per inch of thickness. Although this can be helpful if the goal is to build the thinnest roof assembly possible, it says nothing about the material’s benefit vs. cost. To figure out which insulation products will give you the biggest bang for your buck, it is important to evaluate the R-value per dollar.

Figure 1

Figure 1. R-Value per dollar for common types of insulation, including materials and labor.

The table in Figure 1 compares how rigid foam insulations stack-up for R-value per dollar. While specific R-value per dollar figures change frequently, EPS consistently rates highest when compared to other rigid foam insulations.

Easy, Economical Insulation Solutions

For roofing pros who select EPS insulations for their benefit/cost advantages, along with outstanding moisture performance and stable long-term R-values, following are five practical ways to help save tens of thousands of dollars, or more, depending on your job’s size.

1. Build-up of low-sloped roofs. Converting a flat or low-sloped roof to a greater slope for better drainage typically requires roof crews to stack multiple layers of insulation. This can be a labor-intensive process with XPS and polyiso, as crews must haul and place numerous rigid foam sheets of only a few inches of thickness. By comparison, EPS insulation is available in blocks up to 40 inches thick. As some manufacturers will cut those blocks to virtually any slope and any shape to fit roof crickets, saddles, valleys and ridges, tapered EPS speeds insulation installation, and can reduce roof insulation costs up to 30 percent compared to other tapered insulations. The saved man-hours can be deployed to other jobs to help you build your business. Additional cost savings result from reduced dumpster fees to dispose of insulation cut-offs.

2. Roof re-covers. An easy-to-use option for roof re-covers is EPS panels pre-folded into bundles, and with polymeric facers on both sides. Such products are available in standard sizes up to 200 square feet, comprised of 25 panels that are 2 feet by 4 feet each. A typical two-square bundle weighs less than 11 pounds, so is easy for one person to carry.

Fan-folded bundles of EPS require fewer fasteners per square foot than most roofing insulations, and are less expensive than virtually every re-cover board. The man-hours needed to install fan-fold bundles are about 60 percent less than individual sheets. Material costs are also lower than wood fiber, perlite, or gypsum board. On large projects, the total savings can add up to tens of thousands of dollars.

Flute fill insulation helps reduce labor costs on re-covers of standing seam metal roofs.

Flute fill insulation helps reduce labor costs on re-covers of standing seam metal roofs.

3. Metal roof re-covers. Up to 70 percent of metal roofing jobs involve standing seams. Both architectural and structural standing seams make it challenging to create a flat, stable surface during roof re-covers. A simple way to insulate the roof and provide an even surface for other parts of the roof assembly is to install “flute fill” insulation. Such products fit between the spaces of the metal roof’s flanges and are designed to fit into place easily.

An advantage of EPS flute fill over other insulations is that it can be custom-cut to fit any metal roof flange profile. It also comes in a range of compressive strengths suitable for nearly any roofing application. EPS flute fill can save up to 25 percent in costs compared to similar polyiso products.

4. High-traffic roofs. For roofs that need additional strength to withstand foot traffic and severe weather, an ideal option is composite insulation. One product incorporates EPS as a lightweight, insulating and resilient insulation, while a polyiso layer serves as a durable, insulating cover board. Some composite products of this type carry a UL Class A fire rating for both combustible and non-combustible decks, and are compatible with a range of roofing membranes, including EPDM, TPO, PVC, CSPE, as well as low-sloped, built-up and modified bitumen membrane systems.

The Facebook headquarters garden roof uses EPS geofoam as a lightweight fill material to form landscape contours.

The Facebook headquarters garden roof uses EPS geofoam as a lightweight fill material to form landscape contours.

5. Planted roofs. For planted roofs that include landscape contours for hills and valleys, roofers face the challenge of not adding excess weight while defending against moisture intrusion. An effective solution is provided by EPS geofoam. Successfully used in civil engineering and building projects for decades, the material is an ultra-lightweight engineered fill that can be used to create contoured landscape features such as hills and valleys. EPS geofoam weighs from 1 to 3 pounds per cubic foot, depending on the product type specified, compared to 110 to 120 pounds per cubic foot for soil.

And, as EPS geofoam dries quickly and has minimal long-term moisture retention, it helps defend planted roofs from moisture intrusion.

The project team for Facebook’s MPK 20 building in Menlo Park, California, used EPS geofoam in the building’s 9-acre landscaped roof. Landscape contours, more than 400 trees and a half-mile walking trail create a relaxing, park-like setting.

Selecting an Insulation Supplier

Many domestic and foreign companies manufacture EPS insulation, but quality and capabilities can vary widely. To help streamline your insulation material and labor costs further, while ensuring a quality roofing job, it is important to evaluate manufacturers for the following:

  • Technical support: What support services does the manufacturer offer that can reduce roofing contractor costs? Examples include design expertise, material take-offs, consultation on product substitutions, and in-field support.
  • Customized products: Can the manufacturer supply custom-cut insulation components to help reduce field labor?
  • Code compliance: Does the manufacturer have code acceptance reports for its products, including testing to industry standards?
  • Photos courtesy of Insulfoam.

    The Benefits of Above-sheathing Ventilation

    We know proper ventilation of the attic space is an important part of construction. But what is “above-sheathing ventilation”?

    Most roofing materials lay directly on the sheathing. Heat from solar radiation and interior heat loss from the conditioned space are easily transferred through the deck and roof system. This can increase energy costs and cause ice damming. The build-up of heat and extreme temperatures wings can also reduce the life of underlayment and other system components.

    Tile roofs have an air space between installed roof tiles and the roof sheathing. This space reduces heat transfer and allows heat buildup to dissipate from the sheathing and roofing materials. This above-sheathing ventilation, or ASV, inherent to tile roof installations can be enhanced using counter battens, shims or manufactured systems to raise the horizontal battens above the roof deck. The system design will vary with the environmental challenge and goals. Specific examples are described below.

    The Elevated Batten System by Boral Roofing uses treated 1 by 2s with high-grade plastic pads, a vented eave riser flashing and vented weather blocking at the ridge. With these components in place, heat transfer is minimized and heat buildup is dissipated, which reduces energy costs.

    The Elevated Batten System by Boral Roofing uses treated 1 by 2s with high-grade plastic pads, a vented eave riser flashing and vented weather blocking at the ridge. With these components in place, heat transfer is minimized and heat buildup is dissipated, which reduces energy costs.

    Energy Conservation in Hot Climates

    In hot and dry climates, the natural ASV and thermal mass of the tile provide a layer of insulation when exterior daytime temperatures are greater than the conditioned space in the home. Vertical counter battens or shims that raise the horizontal battens increase this space and the corresponding benefit. The addition of vented eave riser flashing and ridge ventilation completes an energy-saving ASV system. The system shown below is the Elevated Batten System made by Boral Roofing, which uses treated 1 by 2s with high-grade plastic pads, a vented eave riser flashing and vented weather blocking at the ridge. With these components in place, heat transfer is minimized and heat buildup is dissipated, which reduces energy costs. The upgraded ASV reduces temperature extremes that shorten the life of the underlayment and other roofing components. These benefits are achieved with no mechanical or moving parts.

    Cool and Humid Climates

    The same installation can provide a different benefit in cool and humid regions. The Tile Roofing Institute and Western States Roofing Contractors Association’s Concrete and Clay Tile Installation Manual for Moderate Climate Regions says that in areas designated “Cool/Humid” zones, “Batten systems that provide drainage/air-flow (shims, counter battens or other approved systems) are required.” The area designated “Cool/Humid” in the current manual runs from approximately Eureka, Calif., to the Pacific Northwest, west of the Cascade Mountains. In this climate, moisture-laden air can migrate under the tile and condense in the space between the tile and roof deck. The underlayment is there to protect the sheathing but if the battens are raised above the deck, condensation will be reduced. Raised battens also allow moisture under the tile to escape to the eave. When roof tiles are fastened to a raised batten, underlayment penetrations are minimized.

    Cold and Snowy Regions

    Ice dams are one of the most damaging phenomena roofing contractors face. Snow movement on roof surfaces can cause damage to people and property. The goal in cold and snowy environments is to prevent ice dams by enhancing the ASV under the tile roof. Typically, a more substantial air space is created using larger vertical battens. A well-designed “cold roof” system that includes proper snow retention is the solution.

    The TRI/WSRCA Concrete and Clay Tile Installation Manual for Moderate Climate Regions refers installers to the TRI/WSRCA Concrete and Clay Roof Tile Design Criteria Installation Manual for Cold and Snow. Regions “in locations where the January mean temperature is 25 deg. F or less or where ice damming often occurs”.

    For more information and to download the Tile Roofing Institute’s installation manuals, visit the Tile Roofing Institute at TileRoofing.org.

    ILLUSTRATION: Boral Roofing