Developing Roof Systems That Prevent Energy Loss

A fully-adhered membrane will prevent fluttering and minimize energy loss. Photos: Hutchinson Design Group

Several millennia ago, early man — and the wife and kids — decided that life in a cave was a little dark, damp and confining, and started thinking about a better place to live. This led, eventually, to the need for a roof. Sod was the obvious first choice for a roofing material — abundant supply, close at hand, pretty simple to install, providing good insulation — but not very waterproof and very prone to catching fire in dry weather. Whether that caveman knew he had installed the first “green roof” is unknown.

Fast-forward to the multiple choices that we now have to shelter ourselves and the structures where we work, learn, shop and perform hundreds of other activities. In some ways, the challenges are the same as they were thousands of years ago: keep the occupants dry and comfortable and protect the systems in the building, although those systems are vastly more complex than they were for our ancestor emerging from his cave. A few other things have changed, as well, including the cost of energy for heating, cooling and running building systems. The challenge today is still to keep a building and its occupants protected from the outside elements. But an equally important challenge, given rising energy costs, is to keep energy expenses from literally going through the roof.

Insulation should be installed in multiple layers with the joints staggered.

Roofing contractors are meeting this challenge by paying increased attention to places in a roofing system that might allow penetration of air, either escaping from the inside or penetrating from the outside. To get an update on state-of-the art thinking, we talked to one of the most knowledge people who study this problem.

André Desjarlais is the Program Manager of the Building Envelopes Research Program at Oak Ridge National Laboratory. He has spent the majority of his professional career “developing novel building envelope technologies and assessing their market viability.” Much of his recent focus has been on developing systems that will prevent energy loss. Roof color has been extensively discussed related to energy use, with general agreement that reflective roofs save energy in warm to hot climates, and dark membranes are the most economical choice in cool to cold climates. However, there are a broad variety of other factors that influence the efficiency of a roofing system.

Proper installation of the insulation is key to meeting code requirements and preventing air leakage.

For instance, referring to low-slope roofing, Desjarlais points out that adequate insulation, defined by recent building codes, is essential to ensure an effective roofing system. “If we are in a jurisdiction that has adopted the most recent versions of the energy code, IECC 2015, we’ve really done a good job of increasing our insulation levels. Hooray for us — we have finally acknowledged that energy is important and we are mandating reasonable amounts of insulation to be put in commercial roofing.” Experts also note that it is important to install insulation in multiple layers and stagger the insulation joint. Studies have shown that up to 10 percent of the insulation’s R-Value is lost due to joints in the insulation.

Assuming the roof color is appropriate to the specific climate where it is being used, and insulation levels meet the latest codes, then other potential energy losses, specifically air flow or air leakage, become important. Desjarlais says the connection between the membrane and the perimeter of the building requires special attention. “How do we attach the membrane to the perimeter of the building and how do we make that connection continuous with the air barrier system of the walls?” Desjarlais says it is critical to avoid creating a path or paths for air to flow around the membrane and into the perimeter. “We need to have a continuous air barrier system, so the issue is how do you connect the wall and the roof system together?” He points out that this task can be most challenging during a retrofit to replace the roof since the parameters of the job may not include repair on the adjacent walls. Nonetheless, the connection still needs to be made securely.

The connection between the membrane and the perimeter of the building requires special attention. There should be no voids in the insulation at the perimeter.

It’s also important, Desjarlais continues, to note that there are several ways for air to either penetrate or escape from a building. “Air leakage” refers to air that starts on one side of the roof and gets to the other side, so it can start from the inside of the building and work its way outdoors, or start from the outside of the building and work its way in. Either way, there is energy loss.

Another kind of energy loss is “air intrusion.” This occurs when air that starts inside the building works its way through the roofing system but doesn’t make it to the outside, instead looping back to the interior. This is likely to be a problem when single-ply membranes are mechanically attached. When wind flows over the surface of the roof and the membrane billows slightly, it creates a void, and that void needs to be filled. The air that fills the void is coming from the interior of the building. So as the roof flutters, it is pumping air into and out of the roofing system. The air can also be carrying moisture that can condense under the roofing membrane.

If you are in a cold climate, the warm air from the interior of the building is chilled by its contact with the cold roofing membrane; if it is summer, the air becomes warmer. Either way, the air needs to be reconditioned when it returns to the interior of the building, driving up energy costs. [Click here, for a video showing the impact of “fluttering” on a roofing system, and the preferred alternative of a fully adhered system.

If fluttering is a potential problem, Desjarlais says, some kind of control should be put on the interior side of the roof, to make it hard for the air to flow to the underside of the membrane. This also extends the service life of the roof, preventing the wear and tear on the roofing membrane that can occur with fluttering.

There’s no doubt that creating an energy-efficient roofing system demands an investment in time and resources. But some currently available roofing membranes are setting new records for durability: EPDM, for instance, if properly maintained and installed, is projected to last up to 40 years. A well-designed, well-installed roofing system that prevents energy loss over four decades could provide invaluable protection against rising energy costs and a volatile energy market.

About the Author: Louisa Hart is the director of communications for the Washington-based EPDM Roofing Association (ERA). For more information, visit www.epdmroofs.org.

Designing Thermally Efficient Roof Systems

Photo 1. Designing and installing thermal insulation in two layers with offset and staggered joints prevents vertical heat loss through the insulation butt joints. Images: Hutchinson Design Group Ltd.

“Energy efficiency,” “energy conservation,” and “reduction of energy use” are terms that are often used interchangeably, but do they mean the same thing? Let’s look at some definitions courtesy of Messrs. Merriam and Webster, along with my interpretation and comment:

· Energy efficiency: Preventing the wasteful use of a particular resource. (Funny thing, though — when you type in “energy efficiency” in search engines, you sometimes get the definition for “energy conservation.”

· Energy conservation: The total energy of an isolated system remains constant irrespective of whatever internal changes may take place, with energy disappearing in one form reappearing in another. (Think internal condensation due to air leaking, reducing thermal R-value of the system.)

· Reduction: The action of making a specific item (in this case energy use) smaller or less in amount. (Think cost savings.)

· Conservation: Prevention of the wasteful use of a resource.

So, looking at this article’s title, what does “designing a thermally efficient roof system” imply?

Photo 2. Rigid insulation is often cut short of penetrations, in this case the roof curb. To prevent heat loss around the perimeter of the curb, the void has been sprayed with spray polyurethane foam insulation. Open joints in the insulation have also been filled with spray foam insulation. Note too, the vapor retarder beyond the insulation.

I conducted an informal survey of architects, building managers, roof consultants and building owners in Chicago, and they revealed that the goals of a thermally efficient roof system include:

  • Ensuring energy efficiency, thus preventing the wasteful use of energy.
  • Reducing energy use, thus conserving a resource.
  • Being energy conservative so that outside forces do not reduce the energy-saving capabilities of the roof system.

Unfortunately, I would hazard a guess and say that most new roof systems being designed do not achieve energy conservation.

Why is this important? The past decade has seen the world building committee strive to ensure the energy efficiency of our built environment.

A building’s roof is often the most effective part of the envelope in conserving energy. The roof system, if designed properly, can mitigate energy loss or gain and allow the building’s mechanical systems to function properly for occupant comfort.

Photo 3. Rigid insulation is often not tight to perimeter walls or roof edges. Here the roofing crew is spraying polyurethane foam insulation into the void to seal it from air and heat transfer. Once the foam rises it will be trimmed flush with the surface of the insulation.

Energy conservation is increasingly being viewed as an important performance objective for governmental, educational, commercial and industrial construction. Interest in the conservation of energy is high and is being actively discussed at all levels of the building industry, including federal and local governments; bodies that govern codes and standards; and trade organizations.

As with many systems, it is the details that are the difference between success and failure on the roof. This article will be based on the author’s 35 years of roof system design and in-field empirical experience and will review key design elements in the detailing of energy-conserving roof systems. Best design and detail practices for roofing to achieve energy conservation will be delineated, in-field examples reviewed and details provided.  

Advocacy for Improvement

In the past decade, American codes and standard associations have increased the required thermal values every updating cycle. They have realized the importance of energy conservation and the value of an effective thermal layer at the roof plane. They have done this by prescribing thermal R-values by various climatic zones defined by the American Society of Heating and Air-Conditioning Engineers, now better known by its acronym ASHRAE. Additionally, two layers of insulation with offset joints are now prescribed in the IECC (International Energy Conservation Code). Furthermore, the American Institute of Architects (AIA) has also realized the importance of conserving energy and defined an energy conservation goal called the 2030 Challenge, in which they challenge architects, owners and builders to achieve “zero energy” consuming buildings by 2030.

These codes, standards and laudable goals have gone a long way to improving energy conservation, but they are short on the details that are needed to achieve the vision.

Energy Conservation Is More Than Insulation

Roofs are systems and act as a whole. Thus, a holistic view of the system needs to be undertaken to achieve a greater good. Roof system parameters such as the following need to be considered:

  • Air and/or vapor barriers and their transitions at walls, penetrations and various roof edges.
  • Multiple layers of insulation with offset joints.
  • Preventing open voids in the thermal layers at perimeters and penetrations.
  • Protection of the thermal layer from physical damage above and warm moist air from below.
Photo 4. The mechanical fasteners below the roof membrane used to secure the insulation conduct heat through them to the fastening plate. The resultant heat loss can be observed in heavy frost and snowfall.

Air intrusion into the roof system from the interior can have extremely detrimental consequences. In fact, Oak Ridge National Laboratory research has found that air leakage is the most important aspect in reducing energy consumption. Interior air is most often conditioned, and when it moves into a roof system, especially in the northern two-thirds of the country where the potential for condensation exists, the results can include wet insulation, deteriorating insulation facers, mold growth and rendering the roof system vulnerable to wind uplift. Preventing air intrusion into the roof system from the interior of the building needs to be considered in the design when energy efficiency is a goal. Thus, vapor retarders should be considered for many reasons, as they add quality and resiliency to the roof system (refer to my September/October 2014 Roofing article, “Vapor Retarders: You Must Prevent Air and Vapor Transport from a Building’s Interior into the Roof System”). The transition of the roof vapor/air barrier and the wall air barrier should be detailed and the contractors responsible for sealing and terminations noted on the details.

One layer of insulation results in joints that are often open or could open over time, allowing heat to move from the interior to the exterior — a thermal short. Energy high to energy low is a law of physics that can be severe. Thus, the International Code Council now prescribes two layers of insulation with offset joints. (See Photo 1.)

When rigid insulation is cut to conform around penetrations, roof edges and rooftop items, the cuts in the insulation are often rough. This results in voids, often from the top surface of the roof down to the roof deck. With the penetration at the roof deck also being rough, heat loss can be substantial. Thus, we specify and require that these gaps be filled with spray foam insulation. (See Photos 2 and 3.)

Insulation Material Characteristics and Energy Conservation

In addition to the system components’ influence on energy loss, the insulation material characteristics should also be considered. The main insulation type in the United States is polyisocyanurate. Specifiers need to know the various material characteristics in order to specify the correct material. Characteristics to consider are:

Photo 5. Heat loss through the single layer insulation and the mechanical fasteners was so great that it melted the snow, and when temperatures dropped to well below freezing, the melted snow froze. This is a great visual to understand the high loss of heat through mechanical fasteners.
  • Density: 18, 20, 22 or 25 psi; nominal or minimum.
  • Facer type: Fiber reinforced paper or coated fiberglass.
  • Dimensional stability: Will the material change with influences from moisture, heat or foot traffic.
  • Thermal R-value.

In Europe, a popular insulation is mineral wool, which is high in fire resistance, but as with polyisocyanurate, knowledge of physical characteristic is required:

  • Density: If you don’t specify the density of the insulation board, you get 18 psi nominal. Options include 18, 20 and 25 psi; the higher number is more dimensionally stable. We specify 25 psi minimum.
  • Protection required: Cover board or integral cover board.
  • Thermal R-value.

Protecting the Thermal Layer

It is not uncommon for unknowledgeable roof system designers or builders looking to reduce costs to omit or remove the cover board. The cover board, in addition to providing an enhanced surface for the roof cover adhesion, provides a protective layer on the top of the insulation, preventing physical damage to the insulation from construction activities, owner foot traffic and acts of God.

The underside of the thermal layers should be protected as well from the effects of interior building air infiltration. An effective air barrier or vapor retarder, in which all the penetrations, terminations, transitions and material laps are detailed and sealed, performs this feat. If a fire rating is required, the use of gypsum and gypsum-based boards on roof decks such as steel, wood, cementitious wood fiber can help achieve the rating required.

Insulation Attachment and Energy Efficiency

The method in which the insulation is attached to the roof deck can influence the energy-saving potential of the roof system in a major way. This fact is just not acknowledged, as I see some mechanically attached systems being described as energy efficient when they are far from it. Attaching the insulation with asphalt and/or full cover spray polyurethane adhesive can — when properly installed — provide a nearly monolithic thermal layer from roof deck to roof membrane as intended by the codes.

Figure 1. Roof details should be drawn large with all components delineated. Air and vapor retarders should be clearly shown and noted and any special instructions called out. Project-specific roof assembly details go a long way to moving toward ensuring energy conservation is achieved. Here the air and vapor retarder are highlighted and definitively delineated. Voids at perimeters are called out to be filled with spray foam and methods of attachment are noted.

Another very popular method of attaching insulation to the roof deck and each other is the use of bead polyurethane foam adhesive. The beads are typically applied at 6 inches (15.24 cm), 8 inches (20.32 cm), 9 inches (22.86 cm) or 12 inches (30.48 cm).

The insulation needs to be compressed into the beads and weighted to ensure the board does not rise up off the foam. Even when well compressed and installed, there will be a ±3/16-inch void between the compressed beads, as full compression of the adhesive is not possible. This void allows air transport, which can be very detrimental if the air is laden with moisture in cold regions. The linear void below the insulation also interrupts the vertical thermal insulation section.

The most detrimental method of insulation attachment in regard to energy loss is when the insulation is mechanically fastened with the fasteners below the roof cover. Thermal bridging takes place from the conditioned interior to the exterior along the steel fastener. This can readily be observed on roofs with heavy frost and light snowfall, as the metal stress plates below the roof cover transfer heat from the interior to the membrane, which in turn melts the frost or snow above. (See Photo 4.)

The thermal values of roofs are compromised even more when a mechanically attached roof cover is installed. The volume of mechanical fasteners increases, as does the heat loss, which is not insignificant. Singh, Gulati, Srinivasan, and Bhandari in their study “Three-Dimensional Heat Transfer Analysis of Metal Fasteners in Roofing Assemblies”found an effective drop in thermal value of up to 48 percent when mechanical fasteners are used to attach roof covers. (See Photo 5). This research would suggest that for these types of roof systems, in order to meet the code-required effective thermal R-value, the designer needs to increase the required thermal R-value by 50 percent.

Recommendations to Increase Energy Savings

Code and standard bodies as well as governments around the world all agree that energy conservation is a laudable goal. Energy loss through the roof can be substantial, and an obvious location to focus on to prevent energy loss and thus create energy savings. The thermal layer works 24 hours a day, 7 days a week, 52 weeks a year. Compromises in the thermal layer will affect the performance of the insulation and decrease energy savings for years to come. Attention to installation methods and detailing transitions at roof edges, penetrations, walls and drains needs to be given in order to optimize the energy conservation potential of the roof system.

Based on empirical field observation of roof installations and forensic investigations, the following recommendations are made to increase the energy-saving potential of roof systems.

  • Vapor and air barriers are often required or beneficial and should be specifically detailed at laps, penetrations, terminations and transitions to wall air barriers. (See Figure 1.) Call out on the drawings the contractor responsible for material termination so that this is clearly understood.
  • The thermal layer (consisting of multiple layers of insulation) needs to be continuous without breaks or voids. Seal all voids at penetrations and perimeters with closed cell polyurethane sealant.
  • Design insulation layers to be a minimum of two with offset joints.
  • Select quality insulation materials. For polyisocyanurate, that would mean coated fiberglass facers. For mineral wool, that would mean high density.
  • Attach insulation layers to the roof deck in a manner to eliminate thermal breaks. If mechanically fastening the insulation, the fasteners should be covered with another layer of insulation, cover board or both.
  • Design roof covers that do not require mechanical fasteners below the membrane as an attachment method.
  • Protect the thermal layer on top with cover boards and below with appropriate air and vapor barriers.

Saving limited fossil fuels and reducing carbon emissions is a worldwide goal. Designing and installing roof systems with a well thought out, detailed and executed thermal layer will move the building industry to a higher plane. Are you ready for the challenge?

About the author: Thomas W. Hutchinson, AIA, FRCI, RRC, CRP, CSI, is a principal of Hutchinson Design Group Ltd. in Barrington, Illinois. For more information, visit www.hutchinsondesigngroup.com.

Community Service Initiative Celebrates America’s Heroes

Habitat for Humanity identifies veterans who are in need of a new roof, and Owens Corning donates the materials. Platinum Preferred Contractors donate their team members’ labor to install the roofing systems. Photos: Owens Corning Roofing

Combine the expertise of a global humanitarian organization with roofing system materials donated by a manufacturer. Add the generosity and community-minded spirit of roofing contractors across the nation. Apply the parties’ collective efforts to honor and protect unsung heroes. What is the outcome? For veterans served by the Owens Corning Roof Deployment Project, the results are safer, more comfortable homes. This article shares the story of how one manufacturer connected its relationship with Habitat for Humanity with the expertise of roofing contractors already active in community service to create an integrated program serving American heroes.

An Idea Is Born and Contractors Collaborate

As the grandson of a veteran who proudly served under General Patton in World War II, Brad Beldon, CEO of Beldon Roofing in San Antonio, Texas, has long respected the service and sacrifice of America’s veterans. In fact, his grandfather’s selfless service inspired Beldon Roofing Company to develop a strong legacy of community outreach. When Brad broached the concept of a community service initiative honoring veterans during a Platinum Contractors Advisory Board meeting in San Antonio, his idea was met with broad enthusiasm. Beldon Roofing completed the first “trial project” which served as a model for the national Roof Deployment Project.

Leveraging the humanitarian spirit of Platinum Preferred Contractors across the nation, the Owens Corning Roof Deployment Project is a multi-stakeholder initiative bringing together Habitat for Humanity, members of the Owens Corning Platinum Preferred Contractor Network and the Owens Corning Foundation to support American veterans. The program fuses Habitat for Humanity’s experience building and restoring homes with the expertise of the network’s members to provide veterans with new roof systems. Each partner in the program plays a distinct role. Habitat identifies veterans who are in need of a new roof but are unable to replace the roofs themselves. Owens Corning donates the roofing system materials including underlayment, shingles and other materials needed to replace roofs in disrepair. Platinum Preferred Contractors donate their team members’ labor to specify materials and install the roofing systems.

Since its inception in Spring 2016, the National Roof Deployment Project has installed nearly 60 roofs, and the program’s momentum continues to grow. The practice of giving back is a time-honored tradition for Platinum Preferred Contractors. Owens Corning Contractor Network Leader Jason Lewinski says the program builds upon Platinum Contractors’ rich history of giving back to their communities. “When we rolled the program out at our Platinum national conference in San Antonio, we saw lots of hands go up and heard contractors say loud and clear, ‘I’m ready and willing to participate,’” said Lewinski. “Not one contractor has ever said, ‘this is new to us’ – as many of our contractors are already so community-minded. And many of them don’t stop at the roof. They often want to provide gutters, soffit, fascia, siding or whatever it takes to make the needed repairs.”

Platinum Contractor Tripp Atkinson, owner of ContractingPRO in Memphis, Tennessee, is a good example of a roofer who is also a community servant. He and his team have donated roofing and siding labor for Brinkley Heights Urban Academy, a Christian missionary organization serving at-risk youth. In addition to ministering to the kids, feeding them or just listening to the kids, ContractingPRO finds opportunities to apply its remodeling expertise to the distressed homes of these under-served youth. Remarking on his involvement in the Roof Deployment Project, Atkinson says, “We’re not just putting on roofs, but giving back in a way that is changing lives and helping these veterans enjoy their homes more.” He adds that community service provides an opportunity for his team to make a difference that extends beyond the business. “It’s very important for us to be part of something that is bigger than ourselves and our company,” he said.

Contractors Give Back to America’s Heroes and Communities

The National Roof Deployment Project’s focus on supporting veterans has been especially appealing to contractors, notes Matt Schroder, communications leader at Owens Corning. “Many contractors have shared that they either served in the military or have close members of their family who are active service members,” Schroder said. He added that the Roof Deployment Project has also opened up opportunities for Owens Corning to partner with veteran-focused organizations such as Purple Heart Homes.

The Owens Corning Roof Deployment Project brings together Habitat for Humanity, members of the Owens Corning Platinum Preferred Contractor Network, and the Owens Corning Foundation to support American veterans. Photos: Owens Corning Roofing

Jon Sabo, owner of RoofRoof in Charlotte, North Carolina, is a good example of a Platinum Preferred Contractor who can relate to the program as a veteran. “As a former Marine myself, I’m personally honored that we’re able to partner with Owens Corning and Habitat to relieve a big stress,” said Sabo, following the donation of a new roof to a veteran. “One of our core values has always been to give back to the communities we serve, and we jumped at the opportunity to be able to give back to someone right in our own back yard.”

Military members’ time away from home can mean maintenance on the home front is neglected. Nick Yadron, owner of M&M Remodeling Services in Crete, Illinois, says that the Roof Deployment Project is an opportunity to say thank you to veterans and help their families. “We all see so much value in this program as a way to say thank you to our veterans. All the Platinum Contractors were really excited when the program was announced a few years ago,” Yadron says.

While he is active in the Chicagoland area, Yadron’s commitment to service goes much further. In 2013 and 2016, he traveled to India on a mission trip where he helped a team establish water wells and build schools. Closer to home, M&M supports Habitat for Humanity. Over the years, his company has also “adopted” a family experiencing hard times and provided new windows, siding and gutters.

Employee and Community Engagement

Even those not directly impacted by the Roof Deployment Project are engaged by the program. According to Don Rettig, Director of Community Relations and President of the Owens Corning Foundation, the Roof Deployment Project has resonated with both Owens Corning employees and the communities served by Platinum Contractors. Rettig says one welcome outcome of the project is the amount of conversation on Owens Corning internal communication channels and social media. “We’re always excited to see our people take pride in our community engagement,” Rettig says. “This partnership with our contractors to help our nation’s veterans has certainly been well received.”

“We know from surveys that some 93 percent of our people appreciate working for a company that provides opportunities to be involved in supporting the local community,” Rettig notes.

Communities have also taken notice of the contractors and veterans involved in the program. In multiple local markets, media outlets ranging from broadcast television stations to daily newspapers and online news sites have shone the spotlight on this program. In several markets, media have come out more than once to report live from veterans’ homes as contractors replaced a roof. “We’ve seen TV stations return to neighborhoods to produce stories about additional projects — even in the same market,” Schroder says.

Making an Impact

A November 6, 2017 article in The New York Times noted an emerging trend in corporate philanthropy is the desire by companies to show both customers and employees that their interests extend beyond making profits, and that companies today are determined to show an impact. As the National Roof Deployment Project illustrates, when roofing contractors, communities, and corporations align with non-profits to engage in service, the results can literally make an impact, one shingle at a time.

North Carolina Legislative Building Restoration Poses Unique Challenges

The North Carolina State Legislative Building was the site of a renovation project that included asbestos abatement in the interior and a complete restoration of the building’s roof systems.

The North Carolina State Legislative Building was the site of a renovation project that included asbestos abatement in the interior and a complete restoration of the building’s roof systems. Photos: SkySite Images

Some of the variables that can make a project difficult include a variety of complex, interconnected systems, unique design elements, and a tight schedule. These challenges are heightened on a highly visible, historic building, where the goal of keeping the design historically accurate must be balanced with making improvements to the structure and functionality of the systems. All of these elements and more were in play during the restoration of the one-of-a-kind roof on the North Carolina State Legislative Building in Raleigh, North Carolina. It took a talented team of design, engineering, and roofing professionals to bring the project to a successful conclusion.

Originally designed by architect Edward Durell Stone, the building has been the home of the state legislature since 1963, but water intrusion under its copper pyramids and at windows and doors on the promenade level precipitated a complete restoration project. Renovation work conducted in 2016 and 2017 included asbestos abatement in the interior and a complete restoration of the building’s roof systems.

The roofing phase of the project included removing and replacing the metal roof systems on the five copper-clad pyramids, as well as re-roofing the low-slope sections adjacent to the pyramids with a two-ply modified bitumen system. A liquid-applied waterproofing system was installed in the planter areas and under the pavers in the promenade section. The project also involved the removal and replacement of windows, doors, and skylights, as well as repairing and coating the concrete surfaces at the perimeter of the roof.

The design of the quilted flat lock copper panel system involved 17 different panel profiles. A false batten was added after the panels were in place.

The design of the quilted flat lock copper panel system involved 17 different panel profiles. A false batten was added after the panels were in place. Photos: SkySite Images

Companies involved in the project included Raymond Engineering, headquartered in Raleigh, North Carolina, which provided engineering and architectural services; Owens Roofing Inc., also located in Raleigh, which served as the general contractor on the roofing phase of the project and installed the low-slope systems; and The Century Slate Company, headquartered in Durham, North Carolina, which removed and replaced the copper roofs on the five pyramids.

Some of the key players in the project shared their insights with Roofing, including John Willers, a senior engineer with Raymond Engineering; Bert Owens, president of Owens Roofing; and Mike Tenoever, president of Century Slate.

“This is an iconic state building with a unique roof system which the owner and designer required to be aesthetically replicated,” Tenoever notes. “At the same time, some functionality and technical improvements were incorporated. This is a very high-profile project with a lot of complexity, particularly given the schedule. There were a lot of details compressed into a very short period of time.”

Design and Pre-Construction

Raymond Engineering conducted testing on the existing roofs and specified systems designed to match the originals and provide some necessary improvements, including added insulation and ventilation under the pyramids. Willers worked closely with Jason Mobraten, the senior architect on the project. “We provided the engineering and architectural services, beginning with design and then assisting with bidding and managing the construction phase of this project,” says Willers. “We engineered the copper roof, all of the detailing for the modified asphalt roof, and the detailing for the drainage, the pavers, and the sealants for the promenade.”

Crews from Owens Roofing removed the existing plants, media and drainage system from four 42-foot-by-42-foot fixed planters with skylights. After the substrate was cleaned and primed, a liquid-applied waterproofing system was installed.

Crews from Owens Roofing removed the existing plants, media and drainage system from four 42-foot-by-42-foot fixed planters with skylights. After the substrate was cleaned and primed, a liquid-applied waterproofing system was installed. Photos: SkySite Images

The schedule was an obvious challenge, as the majority of the work had to be completed while the legislature was in recess, and there were substantial financial penalties that would come into play if the work was not completed on time. “The client also required that the asbestos abatement be completed before re-roofing the copper-clad pyramids to avoid the risk of dislodging the asbestos-containing textured ceiling finish. However, doing the work in two phases allowed the asbestos contractor to get started while the rest of the job was designed and bid,” Willers states.

The building houses legislators’ offices, and it was open and occupied during construction, with the exception of the areas undergoing asbestos abatement. The schedule had to be carefully adjusted as the job progressed. “In addition to our role in monitoring the technical aspects of the construction, we closely monitored the construction phasing and sequencing, as it was directly driven by the schedule of the state legislature,” Willers notes. “We had to take a lot of care in developing the schedule and monitoring it.”

Willers and Mobraten knew that the details on this project would be crucial. “There were previously some issues where the copper and the low-slope membrane roofs met,” Willers says. “We detailed that very carefully so that we had redundancy in keeping that watertight.”

Extensive mock-ups of the copper pyramids were constructed and tested to ensure the quilted pattern could be exactly replicated while avoiding the leaks that plagued the existing structure.

Photos: SkySite Images

Photos: SkySite Images

As designers looked for ways to improve construction, they explored the design and construction of the quilted panels. “From a design standpoint, we wondered why we had this odd diamond-shaped pattern,” Willers recalls. “After we played with the dimensions a bit, we realized that if you fly over the building, from above all of those diamond sections look like squares.”

The key was to replicate the design with its false battens while avoiding leaks. “We were concerned about how to detail out the joining of the copper sheets that formed the diamond-shaped panels,” Willers says. “What had been done was susceptible to windblown rain getting in. We did two things differently: the little clips that supported these battens were secured by forming the clips with hooks that would be integral with the single-locked seams and soldering the clips to the top surface of the copper panels. Previously they were held in place by pop rivets, which went through the copper.”

The Secrets of the Pyramids

Century Slate was well prepared to tackle the copper roofing on the project. The company has been in business more than 20 years, and it specializes in historic restoration projects including slate, tile, wood, copper and other historical metals.

Crews from Century Slate removed the existing copper panels. The copper was salvaged and recycled.

Crews from Century Slate removed the existing copper panels. The copper was salvaged and recycled. Photos: SkySite Images

Tenoever knew the design of the original quilted flat lock copper panel system needed to be replicated exactly. “There were 17 different panel profiles, each within a very particular location within the roof’s quilted pattern,” Tenoever notes. “Proper placement of each different profile was essential to the whole system working correctly and looking like the original.”

The first step was to remove the existing copper roofs. “We tore off the entire system down to the deck,” Tenoever explains. “We then installed a semi permeable a vapor barrier, insulation, and a vapor retarder.”

Along with added insulation and Carlisle WIP 300HT self-adhering underlayment, crews also installed a vented nail base from Hunter Panels. “The Hunter Cool-Vent is a vented nail base that gets screwed down,” Tenoever says. “The goal was to have a breathable air cavity. All of the hip caps are actually vented to allow the air to get out.”

With the addition of the insulation and nail base, the roof was built up approximately 6 inches from the previous configuration. This added height necessitated changes in the custom flashing at the base of the pyramids but did not change the configuration of the copper panels.

In all, 22,500 square feet of copper panels fabricated by K&M Sheet Metal in Durham were installed. Each of the 17 different panels was labeled with a letter code. “When they were out at the site, we could just grab an A panel or a B panel, as needed, and bring them to that layout,” Tenoever explains. “Four of the pyramids were the same, and the center one was different, as that was the one that had skylights built into it.”

The areas between the pyramids were covered with a two-ply modified bitumen roofing system. Photos: SkySite Images

The panels feature flat-lock clips that were screwed down to the nail base. “It’s a typical flat seam panel system, and the panels interlock together,” says Tenoever. “You can see the batten panel above it, which is an aesthetic feature. The battens and the clips that held them were amazingly intricate, for what they were. They were cut out with a CNC machine and soldered onto the copper panels prior to installation. Later we came back and installed the batten system over the top.”

Century Slate built new curbs in the center pyramid for the new skylights, which were manufactured by Wasco. “The skylights were one of the last things to go on,” says Tenoever. “They were custom made because even though they look square, there isn’t a square angle on them.”

Custom copper flashings were installed at the bases. “One of the trickier parts for us probably would have been the tie-in of the modified roof, because Owens Roofing had to do their bit, and we were also replacing all of the wood blocking and everything all along the bottom edge before we could put our flashing on,” Tenoever recalls. “It took a lot of coordination between the two trades, but it all worked out.”

The Low-Slope Roof Systems

Owens Roofing served as the general contractor on the project and installed the low-slope roof systems. The company was established in 1986 in Raleigh, and focuses on commercial and institutional buildings, almost exclusively re-roofing. Much of its work is on historic buildings, so Owens was confident he could execute the project and complete it on schedule.

A scaffolding system offered secure roof access, but material had to be loaded and removed from one access point, so logistics had to be carefully mapped out.

A scaffolding system offered secure roof access, but material had to be loaded and removed from one access point, so logistics had to be carefully mapped out. Photos: SkySite Images

Crews from Owens Roofing installed 18,900 square feet of modified bitumen roofing from Soprema over concrete decks, including the areas between the pyramids. Tapered polyiso and half-inch DEXcell cover board from National Gypsum were installed using Duotack adhesive, followed by the two plies of modified bitumen membrane.

A liquid waterproofing system from Sika was specified for the large planter areas. Crews from Owens Roofing removed the existing plants, media and drainage system from four 42-foot-by-42-foot fixed planters with skylights. After the substrate had been cleaned and primed, the Sika RoofPro system was installed.

“Once it’s cleaned and primed, it’s pretty simple,” says Owens. “The product is one part, and you don’t even have to mix it. We applied it with rollers on this project. You embed fabric sheets in the system and then topcoat it. It was a cold-weather job, but fortunately we caught a break last winter in that it wasn’t as cold as usual, and we didn’t miss as much time as we might have.”

The 30,000-square-foot promenade section was originally covered by white granite pavers native to North Carolina. The old pavers were removed and replaced over a new roof system, which was comprised of modified bitumen sheets beneath the liquid-applied waterproofing system. “The concrete deck was primed and a modified bitumen base ply heat welded to the deck,” Owens explains. “This surface was primed in preparation for the Roof Pro system, which was then installed.”

Innovative Roof Services of Raleigh was called in to conduct a high-voltage electrical testing to ensure there were no voids in the system before the pavers were re-installed. The pavers had originally been set in a bed of mortar, and they had to be removed and cleaned, which revealed a problem. “When we took the pavers up, we found out that they ranged between 1-1/8 and 1-3/4 inches thick,” Owens notes. “That wasn’t a problem when they were set in a bed of mortar, but over extruded polystyrene, they would have been all up and down. We put in a change order and had the pavers set in a bed of sand on top of one layer polystyrene.” The sand was adjusted by hand to ensure the pavers were level. New pavers were added to replace those broken over the years.

On the roof’s concrete eyebrows, damaged areas of concrete were repaired, joints were sealed, and a cold-applied waterproofing system from Sika Sarnafil was used to cover 8,800 square feet of concrete.

Numerous Challenges

Important considerations on the project included safety and logistics, as well as the tight schedule. Safety was paramount, and a third-party safety monitor was on the site to ensure the safety plan was designed and executed properly. During the time between when the original skylights were removed and when their replacements installed, the voids in the roof deck needed to be cordoned off and covered according to OSHA regulations. Personal fall arrest systems were used on the pyramids and outside of the safety perimeter, which was marked with flags. “With the promenade, you had a wide concrete eyebrow, so it made it easier to set up the safety lines and keep everyone safely away from the edge,” Owens notes.

This aerial photo taken before the restoration project shows the copper roofs with their green patina. Photos: SkySite Images

“Safety is a key concern as on all jobs, but this one in particular was highly visible out the windows of the nearby Department of Labor,” Owens continues. “We were paid a courtesy visit and agreed with them that an on-site safety meeting conducted by their personnel might be useful. The owner allowed us use of one of their auditoriums and we had a very productive half-day meeting for all trades. Every week we had a meeting with a state construction monitor.”

A scaffolding system was set up that offered secure roof access, but there was only one point for loading and unloading material, so logistics at the site were a concern. “We had to use wheelbarrows and roof carts to transport materials back and forth to the scaffolding tower,” Tenoever notes. “Between the removal of the original roof and the installation of the multiple layers of the new roof system, over 150,000 square feet of roofing materials were moved by hand over an average distance of approximately 200 feet.”

Loading and unloading added another wrinkle to the complicated schedule. “The schedule was based on when the legislature was scheduled to come back to town—not how long the job was supposed to take,” Owens says. “We were all concerned with the ambitious time frame and $1,000 a day liquidated damages included with this job.”

Willers cited excellent communication as one of the keys to completing the project on time. “Fortunately, the project managers for the general contractor and other trades were highly organized individuals,” Willers says. “Regular site meetings were detailed and thorough. Although setbacks did occur, communication kept the ball rolling.”

The roof system on the building’s iconic copper clad pyramids was removed and carefully recreated, matching the original design while adding a vented cavity and increasing the thermal insulation. Photos: SkySite Images

A Unique Experience

Copper removed from the existing roof was salvaged and recycled, notes Willers, with the exception of a few pieces that

were cut into the shape of the state of North Carolina to serve as mementos of the unique project. “We’re very proud of the design and the outcome—and the assistance we got from all of the contractors involved,” Willers says. “We had some pretty heavy rains after the project was completed, including some high winds, and there were no leaks.”

Tenoever also looks back on the project with pride. “A one-of-a-kind roof system was custom built and delivered on schedule and with the owner and designer’s praises,” he says. “Taking something so amazing and restoring it to the beauty it originally had—we all get a kick out of that.”

TEAM

Design and Engineering Services: Raymond Engineering, Raleigh, North Carolina, RaymondLLC.com
General Contractor: Owens Roofing Inc., Raleigh, North Carolina
Metal Roofing Contractor: The Century Slate Company, Durham, North Carolina, CenturySlate.com
Leak Testing: Innovative Roof Services, LLC, Raleigh, North Carolina, IRS-LLC.net

MATERIALS

Metal Roof System
Copper: 20-ounce copper sheet metal
Vented Nail Base: Hunter Cool-Vent, Hunter Panels, HunterPanels.com
Underlayment: Carlisle WIP 300HT, Carlisle, Carlislewipproducts.com
Skylights: Wasco Skylights, Wascoskylights.com

Modified Bitumen Membrane Roof System

Membrane: Sopralene Flam 180 and Sopralene Flam 180 FR GR, Soprema, Soprema.us
Adhesive: Duotack, Soprema
Insulation: Sopra-Iso, Soprema
Cover Board: DEXcell, National Gypsum, NationalGypsum.com

Waterproofing System

Liquid Applied Membrane: RoofPro 641, Sika Corp., USA.Sika.com
Reinforcing Fabric: Reemat, Sika Corp.
Primer: Sikalastic EP Primer/Sealer
Extruded Polystyrene Insulation: Foamular 604, Owens Corning, OwensCorning.com

Roofing Torch Program Reduces Fire Hazards During Modified Bitumen Application

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

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

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

Background

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

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

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

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

Safety Specifics

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

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

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

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

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

Certa Works

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

Photo: NRCA

NRCA Announces June 4-10 is National Roofing Week

The roof is an important component of every structure, yet it often is taken for granted until it falls to disrepair. To raise awareness of the significance of roofs to every home and business, the National Roofing Contractors Association (NRCA) has announced National Roofing Week will take place June 4-10.

National Roofing Week also promotes the good deeds of the roofing industry and stresses the value of professional roofing contractors and the importance of making informed decisions about maintaining or replacing a roof system. During National Roofing Week, NRCA encourages its members to participate by engaging in their communities and informing the public about the role roofs and professional roofing contractors play in every community.

NRCA also will be sharing its members’ stories through its various social media outlets, its Roof Scoop blog and “Professional Roofing” magazine. Members throughout the U.S. are encouraged to share their stories of charitable giving, crew and staff appreciation, and roofing projects with NRCA.

“Professional roofing contractors play a role in every community, and National Roofing Week provides the roofing industry the opportunity to demonstrate the importance of the work we do,” says NRCA Chairman of the Board Dennis Conway. “I look forward to sharing the roofing industry’s stories of professional excellence and charitable giving during National Roofing Week.”

In addition, NRCA members are encouraged to promote the importance of what a roof does by encouraging children to participate in NRCA’s 2017 Children’s Art Contest sponsored by A.C.T. Metal Deck Supply and the International Roofing Expo (IRE). The contest is open to children in grades 1-8 whose relatives work for NRCA member companies (all NRCA member companies are eligible). Entries will be accepted until April 14.

ARMA Names Winners of 2017 QARC Awards Program

The Washington, D.C.-based Asphalt Roofing Manufacturers Association (ARMA) has named three winners of its annual Quality Asphalt Roofing Case-Study (QARC) Awards Program. The program seeks contractors who choose asphalt roofing and install beautiful and high-performing systems. This year, a stunning home in North Carolina, a commercial building in Florida and a firehouse in Washington state have been chosen as winners.

Chapel Hill Roofing Co. received the Gold QARC Award for its residential project titled The Triangle Home. The North Carolina-based contractor installed a full asphalt roofing system to fit the home’s complex architecture and the homeowner’s desire for a range of color options, protection from the elements and algae resistance at an affordable price.

The Silver Award was given to Advanced Roofing Inc., Fort Lauderdale, Fla., for the second year in a row. Its completion of a 49,955-square-foot roof on the Broward County Addiction Recovery Center’s Stephen R. Booher Building impressed judges with its intricacy. The new high-performance roof system provides weatherproof protection for the building’s residents.

Cascade Roofing Co., Burlington, Wash., was honored with the Bronze QARC Award for its steep-slope installation on the Burlington Fire Department firehouse. The building needed a new roof and required a product that had visual appeal, wind resistance and algae resistance. Cascade Roofing installed a full asphalt roofing system, including a synthetic underlayment and an ice and water shield on the leading edges.

ARMA received a record 40 submissions this year. These projects demonstrated the range of colors and designs that asphalt roofing can achieve, its ability to meet challenging project requirements and to provide reliability in tough climates. Each year, these projects are judged by a panel of roofing industry experts from trade associations, architecture firms and the media. Judges score projects based on their use of asphalt roofing technology to provide curb appeal, durability and value.

“As the QARC Awards Program has expanded over the last seven years, it has grown increasingly challenging for our judges to choose from the numerous excellent projects we receive,” notes Reed Hitchcock, ARMA’s executive vice president. “This year, it came down to identifying which projects demonstrated how contractors use asphalt roofing to solve key challenges for building owners and to provide peace of mind with a protective roof system.”

For more information about the QARC awards projects, visit the web page.

RoofPoint Administration Transfers to Roofing Industry Alliance for Progress

The Roofing Industry Alliance for Progress announces the administration of RoofPoint has been transferred to the Alliance. RoofPoint is a voluntary, consensus-based green building rating system that provides a means for building owners and designers to select nonresidential roof systems based on long-term energy and environmental benefits.

Originally developed by the Center for Environmental Innovation in Roofing and co-sponsored by the Alliance, RoofPoint is a roofing-specific version of a green building rating system that promotes an environmentally responsible built environment.

“The increasing need for energy efficient and environmentally friendly roof systems makes RoofPoint an important component of our industry,” says Alliance president, James T. Patterson C.P.M of CentiMark Corporation, Canonsburg, Pa. “We are pleased to have the opportunity to manage RoofPoint, and to continue the essential role it plays in promoting environmentally sustainable buildings.”

To ensure a smooth transfer of RoofPoint to the Alliance, a task force has been established to examine RoofPoint’s data and determine next steps.

Task force members are Rob Therrien, president of The Melanson Co. Inc., Keene, N.H.; Helene Hardy-Pierce, vice president of technical services, codes and industry relations for GAF, Parsippany, N.J.; Brian Whelan, senior vice president of Sika Sarnifil Inc., Lyndhurst, N.J.; Jim Barr, president of Barr Roofing Co., Abilene, Texas; and Mark Graham, vice president of technical services for the National Roofing Contractor Association (NRCA), Rosemont, Ill.

The task force will present its recommendations to the Alliance Board of Trustees during its Nov. 17 meeting in Chicago.