Search Results for: commercial roof damage

The Federal Government Is Making Energy-Efficient Roofing Attractive

Small businesses are now able to deduct the full cost of replacing a roof on an existing non-residential building in the year the project was completed instead of depreciating that cost over a 39-year period, as was previously required. Photo: SOPREMA

It is fair to say that Washington, D.C., is far from dull. From the recent Tax Cut and Jobs Act to rolling debates on passing a federal budget, there is a great deal going on at the federal level that impacts the building and roofing industries. In particular, new reforms allow qualifying building owners to expense, or deduct, up to $1 million for the cost of certain building improvements in the year the work is performed, including adding insulation during roof replacement projects to meet or go beyond modern building energy code requirements. The impact can be significant for capital improvement projects. For example, a building owner that expenses the cost of a full roof replacement can reduce the net cost of the entire project by 25 percent to 30 percent.

Commercial Building Roof Replacements

The Tax Cut and Jobs Act, signed into law by President Trump on December 22, 2017, includes a provision that reduces the overall cost associated with re-roofing and significantly improves the cost-effectiveness of commercial roof replacements that comply with building energy codes. The vast majority of state and local governments require minimum insulation levels for both new roofs and roof replacements (but not for roof repairs or recovers). These requirements apply to existing buildings because the most economical time to improve a roof’s thermal performance is when the roof membrane is pulled off and replaced. Also, roof replacements are one of the best opportunities for improving energy efficiency in existing buildings, which account for 40 percent of U.S. energy use.

Starting in 2018, the new federal tax law expands the definition of “qualified real property” under the small business expensing provisions of Internal Revenue Code section 179 to include improvements to existing nonresidential roofs. Section 179 allows businesses to fully expense (deduct) up to $1 million (indexed for inflation after 2018) in one year for qualified business expenses, such as equipment purchases and specific building improvements. With this change, small businesses are now able to deduct — in the year completed — the full cost of replacing a roof on an existing non-residential building instead of depreciating that cost over a 39-year period, as was required under prior law. As a mechanism intended to limit the deduction to small businesses, the benefit is phased out for businesses that spend more than $2.5 million (also indexed for inflation) on qualified equipment and real property. This change takes effect in 2018 and, unlike some provisions of the new law, is permanent.

A typical scenario under which a commercial building roof replacement is required to comply with a building energy code is one where an older building with a low-slope roof has R-11 or R-12 insulation in the roof prior to the roof replacement. The R-12 assumption is based on a U.S. Department of Energy (DOE) study that evaluated the level of existing insulation in commercial building roofs. For most of the country, current building energy codes require roof replacements to have a minimum level of R-25 or R-30, depending on the climate zone.

The average simple payback period for meeting the energy code is 11.6 years, according to a comprehensive energy modeling study completed in 2009 (“Energy and Environmental Impact Reduction Opportunities for Existing Buildings with Low-Slope Roofs,” produced by Covestro).

The payback period is the amount of time it takes for the energy savings to equal the cost of installing the additional insulation. By allowing a building owner to deduct the full cost of the roof replacement, including the cost for installing additional insulation, the net cost of the entire project is reduced by 25 percent to 30 percent, depending on a tax payer’s tax rate. (The Tax Cuts & Jobs Act reduced the corporate tax rate to 21 percent, but the pass-through rates, which are more relevant to small businesses, are closer to 30 percent, which increases the impact of this new deduction.) More importantly, the deduction shortens the average payback period on the cost of installing additional insulation to 8.1 years, making the investment in energy efficiency even more cost effective for the building owner.

Disaster Relief Reforms and Resilient Buildings

Recent maneuvers by Congressional budget writers provided several positive reforms that will impact the resiliency of buildings in some of the most vulnerable parts of the country.

First, Congress passed improvements to the Federal Cost Share Reform Incentive that increases post-disaster federal cost-share with states from 75 percent to as high as 85 percent on a sliding scale based on whether a state has taken proactive steps to improve disaster preparedness. These steps can include the adoption and enforcement of the most recent building codes. This further incentivizes states to maintain robust and current building codes, including the energy code.

Second, under reforms to the Stafford Act, federal disaster relief funds administered by the Federal Emergency Management Agency may be used to replace or restore the function of a facility to industry standards without regard to pre-disaster condition and replace or restore components of the facility not damaged by the disaster where replacement or restoration is required to fully restore the function of a facility. This allows post-disaster funds to be more effectively used to improve the resiliency of damaged buildings and should create opportunities for higher performing roof systems to replace those damaged in disasters.

While the built environment is likely to benefit under recent Congressional action, other policy priorities for the construction and energy efficient industries have been left unresolved. For example, Congress “extended” several clean energy and energy-efficiency related tax provisions, including the Section 179D deduction for commercial building energy efficiency. However, in head-scratching fashion, this and other tax provisions were only extended through December 31, 2017. This means more work is ahead to preserve the policies for the long term and add much needed certainty to the marketplace.

Unpredictable is a polite (and likely understated) description of the policy environment in our nation’s capital. You need not look beyond the recent FY2018 budget deal for an example. Building energy efficiency advocates spent countless hours educating lawmakers on the importance of funding federal research led by the Department of Energy (DOE). Fearing a federal budget that would cripple these vital programs by slashing budgets, advocates saw an 11 percent increase to the DOE’s Office Energy Efficiency and Renewable Energy budget, which leads research on building energy performance. And while history is a poor predictor of future success, recent action impacting buildings demonstrates that policymakers understand the need for strong policies that encourage and lead to more efficient and resilient construction.

Green and Sustainable Roof Systems Highlight Durham Custom Home

The custom home in Durham, North Carolina features a standing seam metal roof, a balcony, a roof deck and a garden roof. The carport roof is made from solar panels. Photo: David Solow.

When Alison Trott purchased a vacant corner lot in the historic Cleveland-Holloway neighborhood in Durham, North Carolina, she wanted to use the space to construct her dream home. She wasn’t sure exactly what she wanted, but she had several priorities in mind. “When I built the house, I wanted to try and focus on sustainability as much as possible,” says Trott. “I wanted to try to focus on green building, and I wanted to try to utilize local resources as much as possible — local materials, local builders, local companies, and local craftsmen.”

She worked with a talented team of design and construction professionals to bring her vision to life, and the sustainable roof systems on the home became a crowning focus of the project.

At some point in the design process, the architect mentioned the possibility of incorporating a garden roof, and Trott jumped at the idea. “I said, ‘I want that!’” Trott recalls. “I was very excited about the idea, but I’d only seen green roofs on large commercial projects.”

The Lead Architect

Tina Govan, now principal of Somos Design, located in Raleigh, North Carolina, hit it off with Alison Trott right away. The two worked together on the design for several years, inviting CUBE design + research, an architecture firm in nearby Chapel Hill, to collaborate on the project.

The goals included constructing a modern home that would blend in with the historic neighborhood. The house was also designed to be part of the natural landscape. A key priority was saving two large oak trees on the property. “We wrapped the house around the trees,” notes Govan. “That way the house bends to nature.”

The key themes of the overall design are exemplified by the roof systems. The house features a metal gable roof with a balcony at one end, echoing historic homes in the area. The 950-square-foot garden roof was installed over the master wing of the house, and the roof of the carport was constructed from solar panels.

“It’s a very green house,” Govan notes. “Solar panels over the carport take care of most of the energy needs of the home. The green roof replaces what was disturbed — the ground below — and brings it up. The green roof blends well with the landscape, and with it the house doesn’t seem as big.”

The green roof is visible from many parts of the house, including the roof deck, which is separated from it by a glass railing. “I love green roofs,” says Govan. “They replace habitat and make building softer. It’s alive. It’s so much more dynamic and rich than any other type of hardscape.”

The Builder

Bob Wuopio is the owner of Form Design/Build LLC, headquartered in Raleigh, North Carolina. The company specializes in one-of-a-kind, complex projects, so this custom house was right up its alley. “We love unique projects,” Wuopio says. “Our preference is to make everything — the doorknobs, the pulls, the lights, the cabinets. We try to fabricate everything. That’s our niche.”

Located on a corner lot in the historic Cleveland-Holloway neighborhood, the modern home was designed to preserve two large trees and wrap around a courtyard to provide privacy. Photo: David Solow.

Numerous custom details throughout the house put the company to the test. For its relatively small footprint — 3,400 square feet — the house has its fair share of different roofing systems. “We have almost every type of roof system on that project,” says Wuopio. “We have a standing seam metal roof on the high gable. We have standing seam metal roof that becomes a metal wall. We have a built-up roof with a floating deck and a glass railing system. There is a green roof over a whole wing of the house.”

Getting the deck and green roof areas sloped perfectly was essential, and that begins with the substructure. “Getting a roof with a slope of 1/8 inch per foot right requires a pretty good framer,” Wuopio notes.

Form Design/Build served as the general contractor on the project, and Wuopio was responsible for scheduling multiple trades at the site. One key concern was making sure that the low-slope roof system wouldn’t be damaged after it was installed. “You don’t want anyone poking holes in it,” says Wuopio. “We spray foamed underneath the deck, so if you did have a small leak, you might not notice it for years, potentially.”

Wuopio knew the roof under the garden roof assembly was crucial. “I knew we needed a bulletproof roof, so I called Jim Pickard. He knew exactly what we needed.”

The Roofing Contractor

James Pickard III is the owner and president of Pickard Roofing Company Inc. in Durham, North Carolina. He represents the third generation of his family to run the business, which is more than 90 years old.

Pickard Roofing handles all types of commercial and residential projects, including historical restoration work. Most of the company’s projects are within 25 miles of the office, including this one, which was just two miles down the road.

The red metal roof is complemented with matching half-round gutters, which incorporate “rain chains” as downspouts. Photo: David Solow.

Crews at the company don’t do as much hot-mop BUR work as they used to, but they still have that club in their bag for below-grade waterproofing projects and garden roof assemblies. For this green roof project, Pickard recommended a coal tar pitch roof system. “We use hot-mopped coal tar pitch in situations where the material is in constant contact with water because the pitch doesn’t degrade,” Pickard notes. “You don’t want to have to take the dirt off of a garden roof and start looking for leaks. You have to do everything you can to make sure nothing can cause problems.”

That includes making sure the deck is secured with screws and not nails, which can back out and damage the roof assembly. Gravel stops should either be copper or stainless steel so they won’t corrode. “The whole idea is permanence,” Pickard says.

The hot-mopped system manufactured by Durapax consists of four plies of tar-coated fiberglass felt, which were set in four layers of coal tar pitch. A fifth layer of pitch was added as a top coat.

Pickard Roofing also installed the metal roof system. Snap Lock panels were custom fabricated in the company’s metal shop from 24-gauge Kynar-coated steel from Firestone Building Products in a wine-red color chosen by the homeowner. A synthetic underlayment, Titanium PSU 30 from InterWrap, was applied to the wooden deck before the panels were secured in place.

“The great thing about the Snap Lock system is there is virtually no fastening through the face of the metal,” Pickard says.

The 950-square-foot green roof covers one wing of the house. Pre-vegetated sedum mats were installed in most of the green roof area, and native plants are also featured in areas with more growing media. Photo: Living Roofs Inc.

“The panels are secured with cleats and clips in the seams.”

Snow guards from Berger Brothers were attached to the seams using non-penetrating screws. Half-round gutters were fabricated from the same metal as the roof and complemented with “rain chains” that serve as downspouts.

Many of the copper details and flashings were custom fabricated on site. “One of our strengths is in our flashing design,” notes Pickard. “The company has a lot of soldering irons. We still use a lot of the old techniques.”

The roofing installations went smoothly. As Pickard Roofing completed the roofs on the home, crews from Southern Energy Management, headquartered in Morrisville, North Carolina, constructed the carport roof from partially transparent solar panels.

“Everyone’s priority was on doing the job right,” Pickard says. “In this case, the emphasis was on the quality, not just the cost. The cost is important, don’t get me wrong, but in this case the budget was increased if there was a product that could do the job better. Ultimately, you have to put the quality where it counts, and that’s why this project worked out so well.”

The Green Roof Installers

Landscape architect Kathryn Blatt Ancaya co-founded Living Roofs Inc. in Asheville, North Carolina, along with her husband, Emilio Ancaya. The company handles all aspects of green roof and living wall projects, including design, installation and long-term maintenance. “Our work ranges from small residential projects to large complex commercial and institutional projects — and of course, everything in between,” she says.

These photos show the roof right after it was installed (left) and after three months of growth. Photos: Living Roofs Inc.

Living Roofs is a certified installer with garden roof system manufacturer Xero Flor America LLC, which is headquartered in Durham. Clayton Rugh, the director of Xero Flor, contacted the Ancayas after Trott and Govan toured the company’s own garden roof. They asked for help designing a version of the company’s lightweight extensive roof system for the project. As Rugh notes, “One of the benefits of the Xero Flor green roof system is its adaptability to nearly any roof situation — load limits down to 10 pounds per square foot, dynamic slope changes between zero and 45 degrees, and compatibility with most commercial waterproofing, including TPO, PVC, modified bitumen and asphaltic BUR assemblies.”

“We collaborated with the architect, Tina Govan, and Xero Flor to design an extensive pre-vegetated green roof with areas of deeper soil to support native grasses and perennials,” Ancaya explains.

The Living Roofs crew installed the Xero Flor XF300 green roof system with growing media depths ranging from 2.5 to 5 inches. After the root barrier was installed over the coal tar pitch roof, it was covered with a drain mat and filter fleece. The growing medium was then lifted into place using a telehandler.

Most of the garden roof area was overlaid with pre-vegetated Xero Flor sedum mats. Plugs of herbaceous plants were inserted in the deeper areas. “The grasses we used were grown by Hoffman Nursery, a local grower, and we used perennials by North Creek Nursery,” Ancaya notes.

The sedum mats are an attractive option because they are fully covered when they are installed, notes Ancaya. “Incorporating the areas of deeper soil also allowed us to create a more dramatic visual effect by contrasting the low-growing Xero Flor mats with taller and more textured plants,” she says.

The green roof installation took less than eight hours over the course of two days. “Kate is the design arm of Living Roofs, and Emilio is the installation arm, and the two of them teamed up on this project to knock it out of the park,” Rugh says.

A Happy Home

Trott enjoyed watching the building process. “I learned a ton,” she says. “I just love watching craftsmen who are passionate about what they do. I had fun out there!”

The home was completed in the spring of 2017, and Trott is thrilled with the result. “It’s better than I even imagined it would be,” she says. “I love it, and my cats love it. In fact, I think they are pretty sure that I did all of this just to entertain them.”

The growth and changing color palette of the rooftop garden has been interesting to watch. “The green roof has been amazing,” she says. “It’s just been one year, but the green roof keeps getting lusher and lusher. Every feature is my favorite feature in the house, but the green roof — I love it. I really do.”

In fact, Trott has become something of a residential green roof ambassador. “I’ve been spreading the word,” she says.

TEAM

Architects: Tina Govan, Architect, Raleigh, North Carolina, www.somosdesign.us, in collaboration with CUBE design + research, Chapel Hill, North Carolina, www.cubedesignresearch.com
General Contractor: Form Design/Build LLC, Raleigh, North Carolina, www.formdesignbuild.org
Roofing Contractor: Pickard Roofing Company Inc., Durham, North Carolina, www.PickardRoofing.com
Green Roof Installer: Living Roofs Inc., Asheville, North Carolina, www.livingroofsinc.com
Solar Installer: Southern Energy Management, Morrisville, North Carolina, www.southern-energy.com

MATERIALS

Low-Slope System
Coal Tar Pitch: Coal Tar Roofing and Waterproofing Pitch, Durapax, www.Durapax.com
Fiberglass Felt: Tar Coated Fiber Felt, Durapax

Steep-Slope System
Synthetic Underlayment: Titanium PSU 30, InterWrap, www.InterWrap.com
Metal Panels: 24-gauge Kynar-coated steel, Firestone Building Products, www.FirestoneBPCO.com

Green Roof System
Extensive and Semi-Intensive Garden Roof: Xero Flor XF300, Xero Flor America LLC, Durham, North Carolina, www.xeroflornorthamerica.com

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.

Why Planning Ahead for Post-Roofing Fall Protection Matters

Incorporating permanent fall protection systems into the overall construction plan benefits workers during the initial construction phase and while conducting building maintenance. Photos: MSA, The Safety Company

The majority of new and existing buildings require safe access to the roof area for ongoing building maintenance, as well as to service equipment such as telecommunications masts, skylights, air conditioning units, elevator machinery, and PV panels.

As such, failing to plan is planning to fail—especially when it comes to incorporating fall protection systems into the design, construction, and maintenance of a facility.

Without question, construction is a high-hazard industry and worker safety is, of course, paramount. The U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) helps ensure workplace safety standards by requiring fall protection equipment, fall arrest systems, and fall protection training for workers at height in the construction industry.

And yet there are pervasive numbers of architects, builders, general contractors, and building owners who are simply unaware that incorporating fall protection systems into their overall construction plan is not only possible, but highly desirable—not just to the benefit of the construction worker or roofer, but also to the overall building aesthetics, as well as ease and safety of ongoing building maintenance.

When it comes to commercial and infrastructure construction, the most important safety concerns are prevention of fall- and falling object-related accidents. In fact, 100 percent of fall-related accidents are preventable; yet, statistics show that falls are the leading cause of construction-related deaths.

That’s why OSHA holds fall-prevention planning in such high regard, as evidenced by its Fall Prevention Campaign, which urges construction employers to “plan projects to ensure that the job is done safely,” including “how the job will be done, what tasks will be involved, and what safety equipment may be needed to complete each task.”

Planning for, and incorporating, fall protection systems into the building design before construction offers these four key benefits:

  1. It allows for appropriate and proper safety equipment outfitting and training of the worker at height at all phases of construction and maintenance, giving building owners and facility managers peace of mind that maintenance staff have the safety systems they need to carry out their duties.
  2. It maintains the integrity of the original building design, giving architects more aesthetic control over the building.
  3. It saves the cost, confusion, and chaos of retrofitting buildings with OSHA-required at-height fall protection systems, allowing for the planning and implementation of high-quality, versatile systems.
  4. It protects roof structures from potential damage caused by post-construction add-on systems.

Mitigating Risk

From trips to slips, and from falls to fatalities, the most often cited OSHA fall-related violations involve skylights, steep-slope roofs, and unprotected edges.

To reduce risk, it is imperative to plan and implement a comprehensive, engineered fall protection system specific to the building design. Components may include such fall-protection products as:

  • Designated walkway systems
  • Energy-absorbing force posts
  • Engineered horizontal lifelines
  • Fall arrest systems and fall limiters
  • Fixed ladder fall protection
  • Guardrail systems
  • Hands-free anchors
  • Overhead protection systems
  • Safety net systems
  • Self-retracting lifelines
  • Vertical lifeline systems

Training everyone on the proper use of safety systems is a crucial part of the process. Remember, workers at height are always at risk of falling, and it’s your job to protect them. Early-stage planning helps make sure that the systems used are perfectly integrated into the building to not only protect the worker but also to seamlessly fit with the building design.

Best Practices

Here are some best practice recommendations when planning an engineered fall protection system:

  • Start early. Your in-house specification team should work with your solutions provider to assess your building’s unique installation requirements.
  • Design to requirements. Ask your solutions provider to design a system that meets both pre- and post-construction requirements. Stipulate that your provider help with CAD concepts, working drawings, and plans, as necessary.
  • Confirm the approach. Request a “checking service” to make sure that the recommended approach is the absolute best available for your particular application.
  • Ensure versatility. Since access requirements vary by build or retrofit, make sure your solutions provider has the ability to adapt to a wide range of roofing shapes, materials, and contours.
  • Confirm safe access post-construction. While construction-related safety is important, it’s also critical to ensure total safety for workers with a system that allows safe access to the finished roof.
  • Consider building aesthetics. Ask your safety solutions provider to consider form as well as function; namely the appearance of the building and surrounding areas. For example, components of safety systems, such as bodies and base plates of our posts, can be powder-coated to soften their appearance against the roofing material.

When specifying fall protection systems, make sure you consider all aspects of a well-engineered system, from quality, versatility and lifespan, to aesthetic appeal, teamwork, and innovation.

About the Author: Anne Osbourn is an Industrial Marketing Manager at MSA, The Safety Company, http://us.msasafety.com.

New NHL Practice Facility and Community Center Sports Vegetative Roof

The American Hydrotech Extensive Garden Roof Assembly was installed on two sections of the roof. The system was topped with pre-grown mats featuring mature sedum plants. Photo: American Hydrotech Inc.

The Chicago Blackhawks have captured the hearts of the city of Chicago along with three Stanley Cups in the last decade. The Blackhawks routinely lead the league in attendance at the United Center, and fans were excited when the team announced it would build a new 125,000-square-foot training facility and community center in downtown Chicago.

Completed earlier this year, the MB Arena features two NHL-sized ice rinks and other amenities including a fitness center, dining options, and spaces that can be rented for outings and events. The facility is the practice site for the Blackhawks and also hosts youth hockey, adult hockey leagues and public skating.

When plans for the project were unveiled, architects and planners mandated the facility meet or exceed all green and sustainable standards for the city. Chicago has been a leader in promoting vegetative roofs to help control storm water runoff, and this new construction project was no exception. The arena includes the construction of 24,000 square feet of green roof systems to complement the structure’s 68,000-square-foot main roof. A 60-mil TPO system manufactured by Carlilse SynTec was specified for the upper roof assembly, and plans called for an American Hydrotech Extensive Garden Roof Assembly to be placed on two lower sections of the roof.

The Garden Roof Assembly

Architect HOK worked with American Hydrotech during the design stage to select roofing components and plants that were optimized for the climate conditions and the building’s structural limitations.

According to Dennis Yanez, national marketing manager, American Hydrotech, and Kevin Serena, garden roofing technical sales coordinator for the central region, the structure’s metal deck necessitated a lightweight system.

The 125,000-square-foot facility 24,000 square feet of green roof systems that complement the structure’s 68,000-square-foot main roof. Photo: Chicago Blackhawks.

“Our 4-inch extensive garden roof system was ideal for this project,” says Yanez. “Since part of this project had a metal deck, there are more structural capacity concerns than with a concrete deck, so we were able to put together a lightweight, built-in-place system.”

The assembly consists of a hot-applied rubberized asphalt membrane, MM6125, which is applied to the roofing substrate to form a monolithic coating. It is topped with a root barrier and Dow Styrofoam insulation. The system also incorporates Hydrotech’s Gardendrain GR15, a molded polyethylene panel designed to retain water, filter fabric, lightweight growing media, and mature plants.

The plants are installed in the form of the InstaGreen Sedum Carpet, a pre-grown mat that comes in 25-square-foot rolls. It contains between nine and 15 different types of sedum and provides instant coverage when it is installed.

Key benefits of the system include reducing the urban heat island effect, purifying the air, and limiting storm water runoff, notes Yanez. “The Extensive Garden Roof Assembly is able to capture more than 1.5 inches of water on the roof, which plays a major role in storm water management,” he says.

The system also protects the membrane from ultraviolet (UV) degradation and damage from wind-blown debris. “Most importantly, for us, a garden roof is just another version of a PMR, or protected membrane roofing,” says Yanez. “Because the membrane is always in a PMR application, with Dow insulation over it, whatever ballast — whether it’s gravel ballast, or architectural pavers, or the garden roof assembly — is in place makes it literally impossible for the membrane to get damaged. It also mitigates the climate swings, keeping the membrane at a more constant temperature year-round.”

This system has a proven track record, according to Yanez. “We’ve been doing this going back 50 years on parking decks under regular topsoil, where weight wasn’t a concern,” he points out. “This is just a more modern version of that, but we’re putting it on the 4th, or the 14th, or the 99th floor.”

The Roofing Installation

All American Exterior Solutions, Lake Zurich, Illinois, is an approved applicator for both key manufacturers. The union contractor installed the Carlisle TPO system on the building’s main roof and the Hydrotech green roofs on the two lower roof levels.

Willie Hedrick, division manager at All American Exterior Solutions, notes that the TPO roof was installed first. “The deck was acoustic, so first we had to lay strips insulation in the flutes over the entire main roof,” he says.

The lightweight growth media was lifted to the roof in 2-yard totes. Photo: Christy Webber Landscapes.

Areas that housed mechanical equipment were reinforced with two layers of 5/8-inch DensDeck from Georgia-Pacific. Two layers of 2.6-inch insulation were then installed, followed by the 60-mil TPO, which was mechanically attached using the RhinoBond system from OMG Roofing Products. The attachment system uses induction welding technology to attach the membrane to the fasteners and plates that secure the insulation — without penetrating the membrane.

The main roof was originally designed as fully adhered system, but work began in January, and the temperature constraints ruled out some adhesives. “Once we made the switch to RhinoBond, we were able to install the membrane even though we did it during the winter,” Hedrick says.

Most of the TPO roof was surrounded by high parapet walls, and in other areas the safety perimeters were marked with flags. “At a few points at the highest points of the main roof we had to put up some the flags, and if you were outside of the flags you had to be tied off,” notes Hedrick. “The mid-roofs had short parapet walls, and on those roofs, we set up flags and had 100 percent fall protection outside the safety perimeter. For the lower green roof, we put guardrails up on the parapet to eliminate the fall hazard.”

The Garden Roofs

After the TPO sections were installed, work began on the extensive garden roof assemblies. The mid-roof had a metal deck, so the first step was to screw down 5/8-inch USG Securock cover board and strip in the seams. “At that point, we installed the liquid-applied membrane and the protection board,” Hedrick says.

The second green roof was installed over a concrete deck, so the application was a bit different. The membrane was applied directly to the concrete. A late change was made in the configuration of the lower green roof to take advantage of the space. “The owner decided to add a terrace to the lower green roof so people could walk out and see the roof and views of the city,” Hedrick recalls.

Before the growing media and plants were added, electronic field vector mapping (EFVM) was conducted by International Leak Detection to determine if there were any voids in the membrane. “You’ve got to confirm everything is 100 percent watertight before we start setting the components down,” Hedrick says. “We usually do the test and start putting the components down the next day to minimize exposure. The subcontractor we worked with to do the landscaping, Christy Webber, performed well. Since some of the components are loose laid, we worked with them to put down enough soil to hold everything in place. We worked hand-in-hand getting the all of the components and soil in.”

The Landscape Work

Jim Waldschmidt, project manager for Christy Webber Landscapes, Chicago, oversaw the installation of the lightweight growing media and sedum mats on the roof. Christy Webber is a full-service union landscaping company, and Waldschmidt notes that roofing work is a small but growing share of the company’s business. “We work with a few different commercial roofers,” he says. “This year we’ve done maybe 10 commercial projects.”

After the growing media was evenly spread out, the sedum mats were laid into place by crews from Christy Webber Landscapes. Photo: Christy Webber Landscapes.

Logistics at the site made for an easy delivery and setup — an unusual situation in downtown Chicago. “We were able to deliver the soil almost a week before we were scheduled to go out there, so we had everything on site and knew we wouldn’t have to worry about waiting,” Waldschmidt notes. “We just had to bring in a crane and lift up the soil bags. We had a pretty easy installation compared to other green roofs we’ve done.”

Growing media was lifted to the roof in 2-yard tote bags, which were cut open to disperse the contents. Three days after the growing media was in place, Christy Webber crews returned to install the sedum mats. “The sedum mats are delivered on pallets almost like the way a roll of sod would be delivered,” says Waldschmidt. “We just had to set the pallets on the roof, pull off the sedum mats and unroll them.”

A temporary irrigation system was set up to help the plants get established in the hot July temperatures. “Everything looks great now,” Waldschmidt says. “All of the sedum up there is thriving.”

Growth Sector

In this high-profile project, with a high-profile owner, making sure the system was error-free was critical, notes Serena. “Chicago is definitely the leader in vegetative roofs, and has been for more than 10 years,” he says. “This is another prime example. There was never a question whether this building would have a green roof on it. It’s a credit to Chicago, and it is a credit to the Chicago Blackhawks.”

Hedrick is proud to be part of the green roof movement. “I like the challenge, and I like the diversity,” he says. “When the Blackhawks went to the Stanley Cup championship and the blimp was hovering over the arena, I could see a couple of my projects on TV. It reminded me of all the time, effort, attention to detail, and collaborative hard work that it took to produce the final product. We’re turning typically unusable roof areas into useful space for amenities.”

The key driver of green roofs is storm water management, notes Yanez, but turning rooftops into useful space is another key benefit. “We’re seeing more and more city incentives for storm water management,” he says. “In urban areas, people are also taking advantage of existing space with green roofs. It’s a growing industry — pun intended.”

TEAM

Architect: HOK, Chicago, www.HOK.com
General Contractor: James McHugh Construction, Chicago, www.McHughConstruction.com
Roofing Contractor: All American Exterior Solutions, Lake Zurich, Illinois, www.AAEXS.com
Landscape Contractor: Christy Webber Landscapes, Chicago, www.ChristyWebber.com

MATERIALS

Garden Roof System:
Cover Board: Securock Gypsum-Fiber Roof Board, USG, www.USG.com
Membrane: MM6125 hot rubberized asphalt membrane, American Hydrotech Inc., www.HydrotechUSA.com
Protection Sheet: Hydroflex 30, American Hydrotech Inc.
Root Barrier: Root Stop, American Hydrotech Inc.
Insulation: DOW Styrofoam, DOW Chemical, www.Dow.com
Drain Board: Gardendrain GR15, American Hydrotech Inc.
Filter Fabric: System Filter fabric, American Hydrotech Inc.
Growing Media: LiteTop Engineered Growing Media, American Hydrotech Inc.
Plants: InstaGreen Sedum Carpet, American Hydrotech Inc.

TPO Roof System:
Membrane: 60-mil TPO, Carlisle SynTec, www.CarlisleSyntec.com
Cover Board: DenDeck, Georgia-Pacific, www.BuildGP.com
Attachment System: RhinoBond, OMG Roofing Products, www.OMGroofing.com

Single-Ply Roofing Best Practices: Doing Everything Right the First Time.

Figure 1: Designing resilient roof systems is the best of practices. When developing details, we find it very helpful to draft out the roof system (for each different system), noting materials and installation methods. Photos: Hutchinson Design Group

Single-ply membranes have risen from being the “new guy” in the market in the early ’80s to become the roof cover of choice for most architects, consultants and contractors. Material issues have for the most part been resolved, and like no other time in recent history, the industry is realizing a period of relative calm in that regard. Whether EPDM, TPO or PVC, the ease of installation, the cleanliness of the installation (versus the use of hot or cold bitumen), the speed at which they can be installed, and the material costs all blend to make these materials a viable option for watertight roofing covers. But with this market share comes issues and concerns, some of which are hurting owners, giving forensic consultants such as myself too much business, enriching attorneys, and costing contractors and, at times, designers dearly.

Following are some of my thoughts on various issues that, in my opinion, are adversely affecting single-ply membrane roof systems. Paying attention to these issues will bring about best practices in single-ply applications.

Specifying the Roof by Warranty

OMG, can architects do any less? Don’t get me started. The proliferation of “canned” Master Specs which call for a generic 10-year or 20-year warranty and then state to install the product per manufacturer’s guidelines is disheartening. Do

Figure 2: Coordinating with the mechanical engineer in the detailing of the pipe penetrations is critical. Here you can see all the components of the curb, penetrations, roofing and waterproofing are noted. We recommend that the same detail be on the mechanical sheets so that at least an 18-inch curb is known to all. Photos: Hutchinson Design Group

designers realize that manufacturers’ specifications are a market-driven minimum? When architects leave out key details, they are simply relying on the roofing contractor to do what is right. This deserves another OMG. The minimum requirements for a warranty can be very low, and the exclusions on a warranty quite extensive. Additionally, a design that calls for products to be installed based on achieving a warranty may result in a roof system that does not meet the code. Owners are often oblivious to the warranty requirements, and all too often fail to ensure the standard of care until the service life is shortened or there is storm damage — sometimes damage the roof should have withstood if it were properly designed and detailed.

If one is not knowledgeable about roof system design, detailing and specification, then a qualified roof consultant with proven experience in single-ply membranes should be retained. Roof systems and their integration into the impinging building elements need to be designed, detailed and specified appropriately for the building’s intended use and roof function. By way of example, we at Hutchinson Design Group typically design roof systems for a 40- to 50-year service life (see Figure 1); the warranty at that point is nice, but almost immaterial. Typical specifications, which are project specific, cover all the system components and their installation. They are typically 30 pages long and call out robust and enhanced material installations.

More Than the Code

I recently had a conversation with a senior member of a very large and prominent architectural firm in the Chicago area and inquired about how they go about designing the roof systems. The first thing he said was, “We do what is required by code.”

Photo 1: The roof drain sump pans shown here were provided and installed by the plumbing contractor, not the steel deck installer. Having the roof drain level with the top of the roof deck allows for a proper integration of the roof drain and roof system.

What I heard was, “We give our clients the absolute poorest roof the code allows.” An OMG is allowed here again. Does it really need to be said again that the code is a minimum standard — as some would say, the worst you are allowed to design a building by law? Maybe you didn’t realize it, but you are allowed to design above the code. I know this will shock a few of you, but yes, it’s true. Add that extra anchor to prevent wood blocking from cupping. Add extra insulation screw fasteners to improve wind uplift resistance; if too few are used, you may meet the code, but your insulation will be susceptible to cupping. Add that extra bead of polyurethane adhesive. (If I specify 4 inches on center, then perhaps by mid-day, on a hot and humid day, I might get 6 inches on center — as opposed to specifying 6 inches or 8 inches on center, and getting 12 inches on center in spots.) Plan for construction tolerances such as an uneven decks and poorly constructed walls. Allow for foot traffic by other trades. These types of enhancements come from empirical experiences — otherwise known as getting your butt in the ringer. Architects need more time on the roof to observe what goes on.

It’s About Doing What is Right

Doing it right the first time isn’t all that difficult, and it’s certainly less stressful than dealing with the aftermath of doing so little. The cost of replacing the roof in the future could easily be more than double the original cost. Twenty years ago, I

Figure 3: Coordinating with the plumbing engineer, like coordinating with the mechanical engineer, is a requirement of best practices. In this drain detail, we can see the sump pan is called out correctly, and the roof drain, integration of the vapor barrier, extension ring, etc., are clearly defined. Photos: Hutchinson Design Group

chaired an international committee on sustainable low-slope roofing. At that time, the understanding of sustainability was nil, and I believe the committee’s Tenets of Sustainability, translated into 12 languages, helped set the stage for getting designers to understand that the essence of sustainability is long-term service life. That mantra seems to have been lost as a new generation of architects is at the helm. This is unfortunate, as it comes at a time when clients no longer ask for sustainable buildings. Why? Because they are now expected. The recent rash of violent and destructive storms — hurricanes, hail, intense rain, high winds and even wildfires — have resulted in calls for improvement. That improvement is called resiliency. If you have not heard of it, you are already behind. Where sustainability calls for a building to minimize the impact of the building (roof) on the environment, resiliency requires a building (roof) to minimize the impact of the environment on the building. This concept of resiliency requires designing a roof system to weather intense storms and to be easily repaired when damaged. (Think of Puerto Rico and consider how you would repair a roof with no power, limited access to materials, and manpower that might not be able to get to your site.)

Achieving resiliency requires the roof system designer to:

  1. Actually understand that roofs are systems and only as good as their weakest link. Think metal stud parapet and horizontal base anchor attachment; only forensic consultants and attorneys like to see screws into modified gypsum boards.
  2. Eliminate your old, out-of-date, incorrect details. Lead vent flashing and roof cement cannot be used with single-ply membrane.
  3. Design the roof system integration into associated barrier systems, such as where the roofing membrane (air/vapor retarder) meets the wall air barrier. You should be able to take a pencil and draw a line over the wall air barrier, up the wall and onto the roof without lifting it off the sheet. If you cannot, you need to redesign. Once you can, you need to consider constructability and who may get there first — the roofer or air barrier contractor. Then think material compatibility. Water-based air barrier systems don’t react well when hit with a solvent-based primer or adhesive.

    Photo 2: This roof drain is properly installed along with 6 inches of insulation and a cover board. The drain extension ring is 1/2 inch below the top of the cover board so that the water falls into the drain and is not held back by the clamping ring, resulting in ponding around the roof drain.

    Perhaps the roofing needs to be in place first, and then the air barrier brought over the top of the roofing material. This might require a stainless-steel transition piece for incompatible materials. Maybe this requires a self-adhering membrane over the top of the roof edge prior to the roofing work, as some membranes are rather rigid and do not bend well over 90-degree angles. You as the designer need to design this connectivity and detail it large and bold for all to see.

  4. Design the roof system’s integration into the impinging building elements, including:
  • Roof curbs for exhaust fans: Make sure they are insulated, of great enough height, and are not installed on wood blocking.
  • Rooftop unit (RTU) curbs: The height must allow for future re-roofing. Coordinate with the mechanical engineer regarding constructability – determine when the curb should be set and when the HVAC unit will be installed. Roof details should be on both the architectural and mechanical drawings and show the same curb, drawn to scale. Be sure the curb is insulated to the roof’s required R-value. Avoid using curb rails to support mechanical equipment. The flashing on the interior side of the rails may be inaccessible once the equipment is placed. Use a large curb where all four sides will remain accessible.
  • Piping penetrations: Detail mechanical piping penetrations through the roof and support of same, where insulation and waterproofed pipe curbs are needed (see Figure 2). If you are thinking pourable sealer pocket, stop reading and go sign up for RCI’s Basics of Roof Consulting course.
  • Roof curbs, RTU, pipe curbs and rails: Coordinate their location and show them on the roof plan to be assured that they are not inhibiting drainage.
  • Roof drains: Coordination with the plumbing engineer is essential. Sump pans should be installed by the plumbing contractor, not the steel deck installer (see Photo 1), and the location should be confirmed with the structural engineer. Be sure drains are located in the low point if the roof deck is structurally sloped — and if not, know how to design tapered insulation systems to move water up that slope. Do not hold drains off the deck to meet insulation thickness; use threaded extensions. Be sure any air/vapor barrier is integrated into the curb and that the insulation is sealed to the curb. I like to hold the drain flange a half-inch down below the insulation surface so that the clamping ring does not restrain water on the surface. Owners do not like to see a 3-foot black ring at the drain, where ponding water accumulates debris (see Figure 3 and Photo 2).
  1. Understand the roof’s intended use once the building is completed. Will the roof’s surface be used for anything besides weather protection? What about snow removal? Will there be excessive foot traffic? What about mechanical

    Photo 3: Gaps between the roof insulation and roof edges, curbs and penetrations are prevalent on most roofing projects and should be sealed with spray foam insulation as seen here. It will be trimmed flush once cured.

    equipment? Photovoltaic panels? Yes, we have designed roofs in which a forklift had to go between penthouses across the roof. Understanding how the roof will be used will help you immensely.

  2. Understand the construction process and how the roof might be used during construction. It is amazing how few architects know how a building is built and understand construction sequencing and the impact it can have on a roof. I firmly believe that architects think that after a lower roof is completed, that the masons, carpenters, glazers, sheet metal workers, welders, pipe fitters, and mechanical crews take time to fully protect the newly installed systems (often of minimal thickness and, here we go again, without a cover board — OMG) before working on them. I think not. Had the architect realized that temporary/vapor retarders could be installed as work surfaces, getting the building into the dry and allowing other trades to trash that rather than the finished roof, the roof system could be installed after those trades are off the roof.
  3. Coordinate with other disciplines. Roof systems cannot be designed in a vacuum. The architect needs to talk to and involve the structural, mechanical and plumbing engineers to ensure they realize the importance of essential details. For example, we cannot have steel angle around the drain whose flange rests on the bar joist, thus raising the roof deck surface at the roof drain. Ever wonder why you had ponding at the drain? Now you know. I attempt to always have a comprehensive, specific roofing detail on the structural, mechanical and plumbing sheets. I give the other disciplines my details and ask that they include them on their drawings, changing notes as required. That way, my 20-inch roof curb on the roof detail is a 20-inch curb on the mechanical sheets — not a standard 12-inch curb, which would more often than not be buried in insulation.
  4. Detail, detail, detail, and in case you glossed over this section, detail again. Make sure to include job-specific, clearly drawn details. Every condition of the roof should be detailed by the architect. Isn’t that what the client is paying for? Do not, as I once saw, indicate “RFO” on the drawings. Yes, that acronym stands for “Roofer Figure Out.” Apparently, the roofer did not figure it out. I enjoyed a nice Hawaiian vacation as a result of my work on that project, courtesy of the architect’s insurance company. How do you know that a condition works unless you design it and then draw it to scale?

    Figure 4: Insulation to curbs, roof edge and penetrations will not be tight, and to prevent a thermal short, the gaps created in construction need to filled with spray foam, as noted and shown here in this vent detail. Photos: Hutchinson Design Group

    I’ve seen roof insulation several inches above the roof edge because, OMG, the architect wanted gravel stop and forgot about camber. Not too big a deal (unless of course it’s a large building) to add several more layers of wood blocking and tapered edge strips at the now high wood blocking in the areas that were flush, but now the face of the roof edge sheet metal needs to increase. But what if the increase is above the allowable ANSI-SPRI ES1 standard and now a fascia and clip are required? You can see how the cost spirals, and the discussion ensues about who pays for what when there is a design error.

  5. Develop comprehensive specifications that indicate how the roof system components are to be installed. This requires empirical knowledge, the result of time on the roof observing construction. It is a very important educational tool that can prevent you, the designer, from looking like a fool.

Components

Best practices for single-ply membranes, in addition to the design elements above, also involve the system components. Below is a listing of items I feel embodies best practices for single-ply roof system components:

  1. Thicker membranes: The 45-mil membrane is insufficient for best practices, especially when one considers the thickness of the waterproofing over scrim on reinforced sheets. A 60-mil membrane is in my opinion the best practices minimum. Hear that? It’s the minimum. You are allowed to go to 75, 80 or 90 mils.
  2. Cover boards: A cover board should be specified in fully adhered and mechanically attached systems. (Ballasted systems should not incorporate a cover board.) Cover boards have enhanced adhesion of the membrane to the substrate over insulation facers and hold up better under wind load and hail. Cover boards also protect the insulation

    Photo 4: The greatest concern with the use of polyurethane adhesives is that the insulation board might not be not fully embedded into the adhesive. Weighting the boards at the corners and center with a minimum of 35 pounds for 10 minutes has proven to work well in achieving a solid bond.

    from physical damage and remain robust under foot traffic, while insulation tends to become crushed. Cover boards are dominated by the use of mat-faced modified gypsum products. Hydroscopic cover boards such as fiberboards are not recommended.

  3. Insulation: Now here is a product that designers seldom realize has many parts to be considered. First, let’s look at compression strength. If you are looking to best practices, 25 psi minimum is the way to go. The 18-psi insulation products with a fiber reinforced paper facer can be ruled out entirely, while 20 psi products are OK for ballasted systems. Now let’s look at facers. If you think about it for a second, when I say “paper-faced insulation,” you should first think “moisture absorbing” and secondly “mold growth.” Thus paper-faced products are not recommended to be incorporated if you are using best practices. You should be specifying the coated glass-faced products, which are resistant to moisture and mold resistant. A note to the manufacturers: get your acts together and be able to provide this product in a timely manner.

Additional considerations regarding insulation:

  • Insulation joints and gaps: You just can’t leave joints and gaps open. Show filling the open joints at the perimeter and curbs and around penetrations with spray foam in your details and specify this as well (see Photo 3 and Figure 4).
  • Mechanical attachment: Define the method of attachment and keep it simple. On typical projects, I commonly specify one mechanical fastener every 2 square feet over the entire roof (unless more fasteners are needed in the corners). Reducing the number of fasteners in the field compared to the perimeter can be confusing for contractors and the quality assurance observer, especially when the architect doesn’t define where that line is. The cost of the additional screws is nominal compared with the overall cost of the roof.
  • Polyurethane foam adhesive: Full cover spray foam or bead foam adhesive is taking over for asphalt, at least here in the Midwest, and I suspect in other local markets as well. The foam adhesive is great. It sticks to everything: cars, skylights, clerestories, your sunglasses. So, it is amazing how many insulation boards go down and don’t touch the foam. You must specify that the boards need to be set into place, walked on and then weighted in place until set. We specify five 35-pound weights (a 5-gallon pail filled with water works nicely), one at each corner and one in the middle for 10 minutes (see Photo 4). Yes, you need to be that specific.
  1. Photo 5: The design of exterior walls with metal studs that project above the roof deck is a multi-faceted, high-risk detail that is often poorly executed. Here you can see a gap between the deck and wall through which warm moist air will move and result in the premature failure of this roof. The sheathing on the wall cannot hold the horizontal base anchor screw, and the joints in the board allow air to pass to the base flashing, where is will condense. This is the type of architectural design that keeps on giving — giving me future work.

    Vapor/air barrier: A vapor air barrier can certainly serve more than a function as required for, say, over wet room conditions: pools, locker rooms, kitchens, gymnasiums. We incorporate them in both new construction and re-roofing as a means of addressing construction trade phasing and, for re-roofing, allowing time for the proper modification of existing elements such as roof edges, curbs, vents, drains, skylights and pipe curbs. Be sure to detail the penetrations and tie-ins with wall components.

  2. Deck type: Robust roof decks are best. Specify 80 ksi steel roof decks. Try staying away from joint spacing over 5 feet. Decks should be fully supported and extend completely to roof edges and curbs.
  3. Roof edge design: A key aesthetic concern, the termination point for the roof system, the first line of defense in regard to wind safety — the roof edge is all of these. The construction of the roof edge on typical commercial construction has changed drastically in the last 20 years, from brick and block to metal stud. Poorly designed metal stud parapets will be funding my grandkids’ college education. The challenge for the metal stud design is multifaceted: It must close off the chimney effect, prevent warm moist air from rising and condensing on the steel and wall substrate, create an acceptable substrate on the stud face in which to accept base anchor attachment, and — oh, yes — let’s not forget fire issues. Tread lightly here and create a “big stick” design (see Photo 5).
  4. Roof drains and curbs: As discussed above, there is a great need for coordination and specific detailing here. The rewards will be substantial in regard to quality and efficiency, minimizing time spent dealing with “what do we do now” scenarios.
  5. Slope: Design new structures with structural roof deck slope, then fine tune with tapered insulation.

Final Thoughts

Best practices will always be a balancing act between cost and quality. I believe in the mantra of “doing it right the first time.”

The industry has the material and contractors possess the skill. It’s the design and graphic communication arm that needs to improve to keep everyone working at the top of their game.

Designers, get out in the field and see the results of your details. See firsthand how a gypsum-based substrate board on a stud wall does not hold screws well; how a lap joint may not seal over the leading edge of tapered insulation; how the roof either ponds water at the roof drain or doesn’t meet code by drastically sumping; or how the hole cut in the roof membrane for the drain might be smaller than the drain bowl flange, thus restricting drainage. Seeing issues that the contractors deal with will help you as the designer in developing better details.

Contractors, when you see a detail that doesn’t work during the bidding, send in an RFI and not only ask a question, but take the time to inform the architect why you don’t think it will work. On a recent project here in Chicago, the architect omitted the vapor retarder over a pool. The contractor wrote an explicit explanation letter and RFI to the architect during bidding, and the architect replied, “install as designed.” In these situations, just walk away. For me, this is future work. A local contractor once told me, “I don’t get paid to RFI, I get paid to change order.” He also said, “If I ever received a response to an RFI, I would frame it!”

Manufacturers, too, can raise the bar. How about prohibiting loose base flashings at all times, and not allowing it when the salesman says the competition is allowing it. Have contractors on the cusp of quality? Decertify them. You don’t need the hassles. Owners don’t need the risk.

Seek out and welcome collaboration among contractors, roof systems designers, knowledgeable roof consultants, and engineers. Learning is a lifelong process, and the bar is changing every year. Too often we can be closed off and choose not to listen. At HDG, I am proud to say we have the building owners’ best interests at heart.

By all working together, the future of single-ply membranes can be enhanced and the systems will be retained when the next generation of roof cover arrives — and you know it will.

Roof Restoration Project Brings Back Luster to Quicken Loans Arena

The 170,000-square-foot roof of Quicken Loans Arena was completely restored using a liquid-applied system from Tremco Roofing. Photos: Tremco Roofing and Building Maintenance

Re-roofing sports and entertainment venues presents its own set of challenges. Sports arenas usually host concerts and other events, so scheduling and logistics can be difficult. Quicken Loans Arena in Cleveland — also known as “The Q” — is home to the Cleveland Cavaliers of the NBA, and it hosts some 200 other diverse events every year, including concerts and conventions. In 2015, realizing the roof was reaching the end of its useful life, the owners looked for advice on their next move. A team of roofing professionals recommended a roof restoration system that would provide the protection and recreate the aesthetics of the original roof — and keep disruption to the facility at a minimum.

Ohio companies stepping up to help the home team included architect Osborn Engineering, headquartered in Cleveland; roof consultant Adam Bradley Enterprises of Chagrin Falls; roofing manufacturer Tremco Roofing and Building Maintenance, headquartered in Beachwood; and roofing contractor Warren Roofing & Insulating Co., located in Walton Hills. After comprehensive testing revealed that more than 90 percent of the roof could be restored, they developed a plan to clean, repair and completely restore the 170,000-square-foot main roof of Quicken Loans Arena using a liquid-applied system from Tremco Roofing.

John Vetrovsky of Warren Roofing and Joe Slattery of Tremco Roofing shared their insights on the project with Roofing magazine. Both men were brought in during the planning stages of the project and saw it through to completion. “We were helping to budget the project with Adam Bradley and Osborn Engineering,” notes Vetrovsky. “They were asking about a few different systems, and the Tremco system was the best fit for the project.”

Warren Roofing has served the greater Cleveland and Akron area since 1922, and Tremco’s roots in northeast Ohio go back to 1928. Warren Roofing served as the general contractor and roofing contractor on the project. The scope of work included updates to the lightning protection system, the safety cable system, and the heat trace system used to melt snow in the gutters.

Repairing the Existing Roof

The existing system was the structure’s original roof. It was 24 years old, and consisted of a mechanically attached hypalon membrane over two layers of polyisocyanurate insulation totaling 3 inches. The roof membrane was showing some wear, and sections had sustained damage from an interesting source: fireworks from nearby Progressive Field, home of the Cleveland Indians, launched after the Indians hit home runs. After the damage was detected, the team changed the direction the fireworks were launched, and the problem ended.

Crews from Tremco Roofing cleaned the roof using the company’s RoofTec system, which recaptures the water and returns it to a truck to be filtered. Photos: Tremco Roofing and Building Maintenance

Despite the damage, visual analysis and a nuclear roof moisture test using a Troxler meter confirmed the roof was an excellent candidate for restoration. “There was some wet insulation and warped insulation, and we marked off those areas that had to be replaced,” notes Slattery. “It was a small fraction of the total job.”

Crews from Warren Roofing removed and replaced the damaged insulation, cutting through the membrane all the way down to the existing 6-mil vapor barrier on the deck. “All of that insulation had to be stair-stepped back so we could properly lap in the new material,” Vetrovsky says. “We got rid of all of the damaged insulation, and we repaired the vapor barrier. Then we staggered the two new layers of insulation, matching the existing thickness.”

Where possible, the existing membrane was pulled back and glued into place. In sections where new membrane was needed, crews adhered pieces of EPDM.

The plan specified adding the fasteners in the existing roof and any repaired sections before the coating system was applied. Tremco Roofing conducted uplift testing through Trinity ERD to ensure the results met or exceeded the specified design. “There was a significant upgrade to the fastening,” Vetrovsky says. “Because of the shape of the building, the perimeter enhancement was probably the greatest I’ve ever seen.”

Screws and 3-inch plates were used. In the field, the minimum was 4 feet on center, 12 inches apart. In the perimeter, fasteners were installed 2 feet on center, 8 inches apart. “It worked out nicely because the fastening ended up in the middle of the sheet, and now the sheet has fasteners that are original at the seam, and a foot or two over, there is a row of new fasteners,” notes Vetrovsky.

Cleaning Up

Prior to the fasteners being installed, the membrane was cleaned by crews from Tremco Roofing using the company’s RoofTec system. “We cleaned the membrane no more than 30 days ahead of what Warren Roofing was doing,” notes Slattery. “We had to mobilize at least three times to clean the roof so the time elapsed would never be more than 30 days.”

The three-step restoration process consists of a primer, a base coat with a fiberglass mat embedded in it, and a topcoat. Here, crews embed the fiberglass mat in the base coat. Photos: Tremco Roofing and Building Maintenance

The cleaning solution is applied using a custom-designed tool that looks like a floor polisher. It has a 2-foot diameter head that spins to clean the surface and a vacuum that recaptures the water, which is returned via hoses to a truck so contaminated waste water, environmental pollutants and high-pH cleaning solvents can be filtered out. “All of that water goes back into the sanitary system after it’s filtered,” Slattery explains. “It does not go into the sewer system.”

“It’s very fast, it’s very effective, and it’s very efficient because you can easily see the areas that have been cleaned,” notes Vetrovsky. “With power washing, you don’t have any way to filter the water.”

The biggest challenge on the cleaning portion of the project was the arena’s sheer size. Approximately 500 feet of hoses were needed to supply water and return it to the truck for filtering.

Cleaning of the substrate is a crucial step, according to Vetrovsky. “The system really does a nice job cleaning the membrane, and that is the key to any restoration project,” he says. “You’re only as good as the surface you’re applying it to.”

Applying the New Roof System

After the sections were cleaned, crews installed the liquid-applied AlphaGuard MT system. The three-step process consists of a primer, a base coat with a fiberglass mat embedded in it, and a topcoat. In this case, the primer was applied with rollers. “The area that we primed each morning was the section we would apply the first coat of AlphaGuard MT with the fiberglass mat that afternoon,” Vetrovsky says. “We did not prime ahead. We didn’t want to take the chance of dust adhering to the primer.”

The top coat was applied with both rollers and spray equipment. Photos: Tremco Roofing and Building Maintenance

Care had to be taken with the schedule to complete the work efficiently. “Once the base coat is on, you have 72 hours to apply the top coat,” Vetrovsky explains. “We would install the base coat and the fiberglass mat for two to three days to get a big enough area. The topcoat would go on faster because you’re not embedding any mesh into it. You really had to always keep an eye on the future weather to make sure you could get the topcoat on within the 72 hours.”

The topcoat was applied with both rollers and spray equipment. After the topcoat was applied, crews installed a second coat with sand embedded in it as a wear surface. Because of the roof’s curved surface, walk pads were not feasible, so the sand was used to provide additional traction for any workers conducting ongoing maintenance.

The sand was broadcast by hand and back-rolled into the coating to maintain a uniform appearance. “Part of this project was to make sure the sand looks uniform when it is visible from a blimp overhead,” notes Vetrovsky. “That was a difficult task, but the guys did a great job.”

The roof features three different finish colors, which were custom designed to match the roof’s original color scheme. The main roof is light gray, with black under the large LED sign. The sections over the wings are white, as are the 2-foot-wide stripes.

“They wanted black under the new LED sign so it would really show the letters nice and clear, even during the day,” says Vetrovsky. “We also put the white stripes back to match the roof’s original appearance. That was a challenge, to keep everything straight. It’s hard to chalk lines on a curve, but it came out nice. Everything matches what the original roof looks like.”

Penetrations for the sign included round posts that held the rails about 2-1/2 feet above the roof level. The liquid-applied membrane made coping with details easy, according to Vetrovsky. “The liquid membrane makes the flashing details all one piece with the roof system,” he says. “We removed the existing boot flashings so that we could seal directly to the conduit or steel posts.”

Gutters, Lightning Protection and Safety Systems

The large commercial gutters also needed to be refurbished. The gutters were 4 feet deep and 4 feet wide, and were outfitted with a cable snowmelt system, which had to be removed. “The gutters had a lot of damaged insulation, so material in the gutter sections was 100 percent torn off,” notes Vetrovsky.

After the roof surface was cleaned, the restoration system was applied. The three step process consists of a primer, a base coat with a fiberglass mat embedded in it, and a topcoat. Photos: Tremco Roofing and Building Maintenance

In the gutters, tapered insulation was installed, and a cover board — DensDeck from Georgia-Pacific — was added for increased durability. New EPDM membrane was installed and cleaned prior to the three-step coating application. New heat trace cable was also installed.

The lightning protection system also required repair, and close coordination with the subcontractors was critical. “The existing lightning protection had to be removed to apply the new roof system, but we couldn’t remove it 100 percent, because we still had to have an active lightning protection system for the building,” says Vetrovsky. “We rearranged the lightning system and installed new stanchions to try to eliminate as many horizontal lines as we could.”

During construction, key to the safety plan was a perimeter barrier system, which was installed by workers who were 100 percent tied off. After the system was in place, workers inside the barricades did not need to wear personal fall arrest systems. “The entire perimeter had a barricade system put on before any material was even loaded,” Vetrovsky says. The company makes its own barricade sections, which are anchored to the parapet walls and gravel stop edges and feature a downward leg for added support.

As part of the project, crews also installed permanent safety equipment. “There was an existing tie-off system out there, but it was not a certified system and we couldn’t use it,” Vetrovsky says. “We brought that to the owner’s attention and replaced it with a new certified tie-off system manufactured by Guardian Safety.”

Challenging Schedule

Progressive Field and the Quicken Loans Arena are right next to each other, and logistics and scheduling around the stadiums was difficult. Work began in 2016 and finished in 2017, and the demanding schedule was made even more difficult when both the Indians and the Cavaliers made deep runs into the playoffs. In 2016, the Cavs became NBA Champions. But it was the Indians making it to the 2016 World Series that posed bigger logistical problems for the re-roofing project.

The restored roof recreates the original color scheme, which features three different custom colors. The main roof is light gray, with black under the large LED sign, while the sections over the wings stripes are white. Photos: Tremco Roofing and Building Maintenance

“The first part of the schedule was the most difficult, as we had the get the black coating on the roof under the sign prior to the playoffs,” Vetrovsky says. The sign covered approximately 30,000 square feet of roof area, and it was difficult to access the roof surface beneath it. “Crews had to work on their hands and knees to apply the coating beneath the steel framing. That was towards the fall, when the weather started changing, and one of the biggest hurdles was just getting the roof dry in the morning. It got colder and colder as we got down to the wire, but we made our deadline for the work under the sign.”

The staging area was also limited, and the crane could only lift material to one section of the roof. Some material had to be moved by hand some 2,000 feet. “It was an awfully long walk from one end of that roof to the other,” Vetrovsky recalls.

Concerts and other events held during the construction cycle made the schedule even more challenging. “The most notable event was probably the Republican National Convention, which totally shut the site down for more than a week because of security,” notes Slattery.

Concerts usually necessitated loading in the early morning and clearing the staging area by 8 a.m., but usually work could continue during the day. “We had to do a lot of coordination to make sure we had what we needed to work the entire day and also not go against our commitment to the owner that we would not work past certain hours,” Vetrovsky says. “Many of the special events started after 7 p.m., so we would be long gone by then.”

Championship Caliber

The project was wrapped up earlier this year. Vetrovsky and Slattery agree that the system chosen was a great fit for this project for several reasons. With restoration, there is less noise, less disruption, and less equipment than with a re-roofing project, and the roof has a warranty for the next 20 years. The process also limits negative impact on the environment by preventing removal and disposal of the old roof system.

“The weight was also a factor,” notes Vetrovsky. “With the existing structure, there wasn’t a lot of room for a different type of roof system with heavy cover boards. This roof system was perfect because it doesn’t add a lot of weight.”

The coating also minimized installation time, notes Slattery. “The disruption of a roof replacement in a hospitality setting like that, where they need 250 days of revenue stream, restoration becomes a real attractive option,” he says. “I can’t think of one day where we really disrupted anything.”

Vetrovsky points to his talented crews as the key to meeting tough schedules with top-quality production “What we can offer is skilled labor,” he says. “We’re a union contractor and our guys are well trained. The harder, the better for us. We can handle projects that most other contractors won’t even put a number to — this project being one of those.”

He credits Adam Livingston, a third-generation foreman for Warren Roofing, for his work on the project.  “With his experience and attention to detail, we were able to complete this project on time, meet the expectations of the client and Tremco, and match the unique aesthetic requirements of the roof,” says Vetrovsky. “We have a lot of great employees who take pride in their work. Take all of that together, that’s why we can be successful on projects like the Quicken Loans Arena.”

The Cavaliers taking the NBA Championship during the project only added to the excitement. “It’s a great feather in our cap,” notes Slattery. “Restoration is a growing segment of the market. Instead of letting the clock run out on these roofs, if you catch them at the right time, it can be a phenomenal way to keep costs down and it’s good for the environment because it’s not adding waste to landfills.” 

TEAM

Architect: Osborn Engineering, Cleveland, Ohio, www.osborn-eng.com
Roof Consultant: Adam Bradley Enterprises, Chagrin Falls, Ohio, www.adambradleyinc.com
General Contractor: Warren Roofing & Insulating Co., Walton Hills, Ohio, www.warrenroofing.com

MATERIALS

Roof Cleaning System: RoofTec, Tremco Roofing, www.tremcoroofing.com
Roof Restoration System: AlphaGuard MT, Tremco Roofing

Research Centers Provide Valuable Information About Roof Performance

The Insurance Institute for Business and Home Safety Research Center evaluates construction materials and systems in its state-of-the-art testing laboratories. Photos: Insurance Institute for Business and Home Safety.

Until early October of this past year, Chester County, South Carolina, was home to a small, single-story house, similar to thousands of houses across the United States, but unique in almost every way.

What made this small structure one of a kind? The house sat inside the large test chamber at the Insurance Institute for Business and Home Safety (IBHS) Research Center, dwarfed by the six-story chamber’s cavernous interior. The house was built, in fact, to be destroyed.

On Oct. 5, the staff of the IBHS Research Center focused the test chamber’s intense destructive wind power, generated by 105 super-sized fans, on the small structure. Prior to the test, the center had digitized the wind record of an actual storm, and the wind speeds produced by the fans were varied accordingly. In the case of the simulated storm in early October, wind speeds were increased in three phases, up to 120 miles an hour. The house experienced significant damage to its walls and interior, and the garage door was ripped off. But the roof, built to IBHS’ recommended standards, held firm.

The IBHS research facility, which opened in 2010 and is funded by property insurers, evaluates various residential and commercial construction materials and systems. The lab is the only lab in the world that can unleash the power of highly realistic windstorms, wind-driven rain, hailstorms and wildfire ember storms on full-scale one- and two-story residential and commercial buildings in a controlled, repeatable fashion.

The mission of IBHS is to reduce the social and economic effects of natural disasters. And much of its research, like its attack on this small house last October, has focused, at least in part, on the resilience of roofs. As IBHS President and CEO Julie Rochman has noted, “The roof is your first line of defense against anything Mother Nature inflicts … and during a bad storm your roof endures fierce pressure from wind, rain, and flying debris.”

Educating the Industry

In May of 2017, the EPDM Roofing Association (ERA) launched a microsite to help educate the construction industry about the increasing need for resilience in the built environment, and the contributions that EPDM roofing membrane can make to a

IBHS conducts hail research in the Laboratory Building for Small Tests, where hailstones of various sizes are recreated and propelled against roof samples. Photos: Insurance Institute for Business and Home Safety.

resilient system. That effort came in response to the increasing number of extreme weather events. Since last May when ERA first launched its resilience microsite, the pattern of extreme weather has continued unabated, in the form of wildfires throughout the west which were exacerbated by extreme heat, and Hurricanes Harvey and Irma which left devastating floods and wind damage in their wake.

For more than a decade, ERA leadership has supported research about factors that contribute to the resilience of EPDM as a membrane, and how it best functions in various roofing systems. More recently, ERA has invested in site-visits to leading research organizations that generate science-based data about resiliency in building systems, first to Oak Ridge National Laboratories, near Knoxville, Tennessee, and then to the National Research Energy Laboratories (NREL) in Golden, Colorado. Given the complementary goals of ERA and IBHS to help support the creation of truly resilient buildings, ERA leadership welcomed the opportunity to visit the South Carolina research facility.

Analyzing Hail Damage

The hail research at IBHS was of special interest to ERA, given ERA’s research that has consistently shown that EPDM membrane offers exceptionally strong resistance against hail damage. Based on field and test data sponsored by ERA, EPDM roof membranes outperform other roof systems in terms of hail protection. In 2007, ERA conducted tests which showed that EPDM roofing membranes did not suffer membrane damage and avoided leaking problems endemic to other roofing surfaces in similar circumstances. Of the 81 targets installed for that research over different surfaces, 76 did not fail when impacted with hail ice balls up to three inches in diameter. Perhaps most importantly, the impact resistance of both field-aged and heat-aged membranes in this test also clearly demonstrated that EPDM retains the bulk of its impact resistance as it ages.

The IBHS Research Center’s super-sized fans can recreate winds to measure their effects on full-scale one- and two-story residential and commercial buildings. Photos: Insurance Institute for Business and Home Safety.

Using this ERA-generated research as a starting point, ERA leadership travelled to IBHS with specific questions in mind, including: What has IBHS research revealed about the impact of hail on various types of roofing membranes and systems? Does the IBHS research reinforce or contradict ERA’s findings? What are the next questions to be asked about the damage that hail can do, and are resilient systems cost-effective?

Hail research at IBHS is conducted in the Laboratory Building for Small Tests, a compact structure with equipment appropriate to replicate large hailstones and hurl them at roof samples. As part of its research, IBHS has worked with the National Weather Service to assess the geographic locations threatened by hail. Individual storms have long been recognized as creating widespread and expensive destruction, but is hail a threat that is confined to just a few specific geographic areas of the country?

In fact, more than 75 percent of the cities in the United States experience at least one hailstorm a year, and the risk extends across the country to all areas east of the Rockies. Annually, hail losses reach more than 1 billion dollars. The IBHS has identified the factors that contribute to the extent of hailstorm damage, with the impact resistance of roofing materials being one of the most critical factors, along with hailstone size, density and hardness. Likewise, the roof is one of the components most vulnerable to hail. Analysis of property damage resulting from a hailstorm in Dallas-Fort Worth in 2011 found that roof losses accounted for 75 percent of property damage in the area, and more than 90 percent of damage payouts.

In their efforts to replicate the true nature of hail, the staff at IBHS has conducted extensive fieldwork, and travelled widely around the United States to gather actual hailstones immediately after a storm. Over the last five years, the IBHS hail team has collected more than 3,500 hailstones, focusing on their dimensions, mass and compressive stress. The stones range from .04 inches in diameter to well over four inches. In addition, IBHS has conducted three-D scans of more than one hundred stones to further educate themselves about the true nature of hailstones, and how they contribute to the overall damage inflicted by hailstorms.

The research findings of IBHS reinforce or complement those of ERA. IBHS has found that unsupported roofing materials perform poorly and ballasted low-slope roofs perform especially well in hailstorms because they disperse energy. IBHS recommends that builders use systems that have impact resistance approval, including their own fortified standard. While IBHS found that newer roofing membranes perform better than older membranes, ERA studies found that new, heat-aged and field-aged EPDM membranes all offered a high degree of hail resistance, demonstrating that EPDM retains the bulk of its impact resistance as it ages.

Both organizations stress that resilient roofing systems in new and retrofitted construction can make good financial sense. According to Julie Rochman of IBHS, “We are really going to continue focusing on moving our culture from one that is focused on post-disaster response and recovery to pre-disaster investment and loss-mitigation … we’re going to be very focused on getting the roofs right in this country.”

For the members of ERA, “getting the roof right” has long been a dominant focus of their businesses. Now, in the face of increasingly frequent and extreme weather events, getting the roof right means gathering up-to-the-minute research about resilient systems, and putting that research to work to create resilient roofs.

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.

Cool Roofs in Northern Climates Provide More Bang for the Buck Than We Thought

Electricity demand in Washington, D.C., plotted against daily high temperature. Source: Weather Underground, PJM Interconnection (PJME).

(Figure 1) Electricity demand in Washington, D.C., plotted against daily high temperature. Source: Weather Underground, PJM Interconnection (PJME).

The energy savings from cool, reflective, roofs have long made them the go-to roof choice in warmer and temperate climates here in the United States. Both ASHRAE and the International Energy Conservation Code have included roof surface reflectivity requirements for a number of years. About half of all new flat roofs installed in the country are highly reflective and in some product categories white options outsell dark ones by a substantial margin. It is hard to argue with the notion that, where it is warm, the roofs should be white. While the building-level impacts of cool roofs in cool climates has been covered in the past, very little has been written about the broader economic benefits of cooler buildings and cities. When we include the economic impacts of factors like improved health, air quality, and energy savings, the case for cool roofs in cool climates looks even better.

The Benefits of Cool Roofs Go Way Beyond the Building

The building-level impacts of cool roofs are a central part of the discussion about whether they should be used in cold climates. However, it is also important to recognize the substantial co-benefits that come from installing cool roofs in terms of healthier and more comfortable people, improved productivity, better air quality, and increased economic prosperity. While the economic benefits of cool roofs are substantial, they may not always be fully included in a building owner’s roof buying decision.

How much cooler could our cities become if we added more reflective roofs? In a comprehensive review on this topic, Santamouris 2012 found that when a global increase of the city’s albedo is considered, the expected mean decrease of the average ambient temperature is close to 0.5°F (0.3°C) per 0.1 increase in reflectivity, while the corresponding average decrease of the peak ambient temperature is close to 1.6°F (0.9°C). The cooling impact of reflective roofs in certain neighborhoods could be significantly better, though. A study of Chicago by Notre Dame University found that installing reflective roofs cooled city surfaces by around 3.5 to 5.5°F (2-3°C), but surfaces in the downtown core cooled by 12.5 to 14.5°F (7-8°C).

Cool Cities Are Energy Savers

We have started to better understand and quantify the impact in cities that are able to get a degree or two of cooling. The most obvious benefit is that cooler cities demand less energy on hot days. The graph in Figure 1 plots electricity demand in

Lowering the temperature of cities can bring a multitude of benefits. Source: Global Cool Cities Alliance.

(Figure 2) Lowering the temperature of cities can bring a multitude of benefits. Source: Global Cool Cities Alliance.

Washington, D.C., against the maximum temperature every day for 5 years (2010–2015). The graph’s shape looks very similar to plots from other cities with high penetrations of air conditioning units. Demand for electricity climbs rapidly above about 80°F. When the maximum temperature is 90°F, the city requires 21 percent more electricity, on average, than on 80°F days. At 95°F, demand has spiked by nearly 40 percent over the 80°F baseline. Charges for peak electricity demand are a major expense for commercial and industrial building operators and, in seventeen states, for homeowners as well. Further, peaking demand is often met by less efficient, more expensive, and dirtier power plants that worsen air quality. At worst, peak demand can cause productivity-killing service interruptions or brownouts.

Cooler Cities Are Healthier Places

Heat is a potent but silent killer. On average, heat kills more people than any other natural disaster, and heat-related deaths tend to be underreported. In 2015, Scientific American reported that 9 out of the 10 deadliest heat events in history have occurred since 2000 and have led to nearly 130,000 deaths. Cities on dangerously hot days experience 7 percent to 14 percent spikes in mortality from all causes.

Heat stress and stroke are only the tip of the pyramid of heat health impacts. Heat puts significant additional stress on people already suffering from diseases of the heart, lungs, kidneys, and/or diabetes. A recent study finds that every 1.5°F increase in temperatures will kill 5.4 more people per 100,000 people every year.

Installing cool roofs or vegetation can lead to a meaningful reduction in heat deaths by making the daytime weather conditions more tolerable. There are a number of studies estimating the impact of increasing urban reflectivity and vegetative cover on weather conditions. Kalkstein 2012 and Vanos 2013 looked at past heat waves in 4 U.S. cities and modeled the impact of increasing reflectivity by 0.1 (the estimated equivalent of switching about 25 percent of roofs from dark to light colors) and vegetative cover by 10 percent. Though the sample sizes are too small to draw sweeping conclusions, the studies found that cities making these modest changes could shift weather into less dangerous conditions and reduce mortality by 6 percent to 7 percent.

Cooler Cities Are Engines of Economic Growth

The health, air quality, and energy benefits of modest increases in urban roof reflectivity could generate billions of dollars of

An infrared scan of Sacramento, Calif., shows the range of surface temperatures in the area. Source: Lawrence Berkeley National Laboratories.

(Figure 3) An infrared scan of Sacramento, Calif., shows the range of surface temperatures in the area. Source: Lawrence Berkeley National Laboratories.

economic prosperity for our cities. A study of 1,700 cities published in the Journal Nature Climate Change found that changing only 20 percent of a city’s roofs and half of its pavement to cool options could save up to 12 times what they cost to install and maintain, and reduce air temperatures by about 1.5°F (0.8°C). For the average city, such an outcome would generate over a $1 billion in net economic benefits. Best of all, adding cool roofs to between 20 and 30 percent of urban buildings is a very realistic target if existing urban heat island mitigation policy best practices are adopted.

Cool Roof Performance in Cold Climates: In Brief

As positive as cool roofs are for cities in cool climates, they first have to be a high-performing choice for the building itself. What do we know about net energy savings in cool climates with higher heating load? This question was the subject of “There is Evidence Cool Roofs Provide Benefits to Buildings in Climate Zones 4-8” in the November/December 2016 issue of Roofing that summarized the newest science and field studies that show that reflective roofs provide net energy benefits and favorable heat flux impacts on roofs in cold climates. In short, the newest research from Columbia, Princeton and others demonstrates that the size of the “winter heating penalty” is significantly less than many had thought and shows net reductions in annual energy use when cool roofs are used, even with roof insulation levels as high as R48.

Real Cool Roofs in Cold Climates: The Target Survey

It is not just the science that supports the use of reflective roofs in cold climates. The strong and steady growth of cool roofing in northern markets over the last decade or two is also a good indication that reflective roofs are a high-performance option in those areas. For almost 20 years, Target Corporation has installed reflective PVC membranes on nearly all of its stores in the

Studies estimate that modest increases in urban roof reflectivity could generate billions of dollars of economic prosperity for cities. Pictured here is the roof on the Cricket Club in Toronto. Photo: Steve Pataki

Studies estimate that modest increases in urban roof reflectivity could generate billions of dollars of economic prosperity for cities. Pictured here is the roof on the Cricket Club in Toronto. Photo: Steve Pataki

United States and Canada. The membranes are usually installed over a steel deck with no vapor retarder. Target and manufacturer Sika Corporation undertook a field study of 26 roofs on randomly chosen stores located in ASHRAE Climate Zones 4-6 including Connecticut, Illinois, Massachusetts, Michigan, Minnesota, New York, Washington, and Wisconsin. The roofs were 10-14 years old at the time of the survey. None of the 51 total roof sample cuts were made across these roofs showed signs of condensation damage. A more detailed accounting of the study by representatives of Target Corporation and Sika Sarnafil published in Building Enclosure includes this important paragraph from authors Michael Fenner, Michael DiPietro and Stanley Graveline:

“Specific operational and other costs are confidential information and cannot be disclosed. However, it can be stated unequivocally that although the magnitude varies, Target has experienced net energy savings from the use of cool roofs in all but the most extreme climates. Although the savings in northern states are clearly less than those achieved in southern locations, experience over approximately two decades has validated the ongoing use of cool roofs across the entire real estate portfolio. Even in climates with lengthy heating seasons, overall cooling costs exceed heating costs in Target’s facilities.”

It is increasingly clear that installing cool roofs is the definition of “doing well by doing good.” Even in cold areas, a properly built roof system with a reflective surface is a high-performance option that delivers value for building owners while making hugely positive contributions to the neighborhoods and cities they occupy.