Three Sioux City Community School District Projects Are Part of Long-Term Plan

In 2017, Winkler Roofing crews re-roofed portions of two high schools and one elementary school. Shown here is an aerial photo of East High School. Photos: Mule-Hide Products Co. Inc.

For the Sioux City Community School District (SCCSD) in Sioux City, Iowa, the final dismissal bell of the school year marks more than the start of summer break for students and staff. It also signals the beginning of roofing season.

In addition to routine maintenance and repairs, each summer brings at least one major roofing project for the district and its 24 facilities. Existing roofs that have fallen out of warranty coverage are replaced. The district also has completed a steady stream of construction projects over the past 16 years, replacing aging schools to meet evolving needs.

District enrollment has increased by several hundred students over that timeframe and now stands at more than 14,500. SCCSD also has expanded its programming, creating specialty elementary schools focusing on STEM (science, technology, engineering and math), computer programming, environmental sciences, the arts, and dual-language education in English and Spanish. These specialties continue with middle school exploratory classes and eventually lead to the Sioux City Career Academy, which offers numerous education pathways to help students prepare for postsecondary education and careers.

Aerial view of West High School. Photos: Mule-Hide Products Co. Inc.

“Our facilities need to keep up with the curriculum and new technologies so we can provide the best possible learning environments for our students,” says SCCSD Director of Operations and Maintenance Brian Fahrendholz, adding that the facilities plan emphasizes both supporting student achievement and maintaining fiscal responsibility.

Winkler Roofing Inc. of Sioux City has been one of the district’s key partners in this process for more than 20 years, installing new or partial roofing systems on nearly every building in the district. The summer of 2017 saw its crews re-roof portions of two high schools and one elementary school, installing 335 squares of new TPO roof systems and removing 170 tons of ballast.

A crew of between six and nine professionals was on a jobsite at any given time. The three projects were completed in less than a month, beginning in late June and wrapping up in late July. And there was nothing on the punch list following the warranty inspections.

A Systematic Approach

In recent years, SCCSD has adopted a systematic, long-range-planning approach to roof system management, working with local architects to evaluate its facilities, identify and plan work that needs to be completed the following summer, and map out future projects. The three roofs replaced in 2017 were indicative of this approach.

TPO Bonding Adhesive is applied on the substrate and the back of TPO membrane. Photos: Mule-Hide Products Co. Inc.

Each of the roofs was between 15 and 20 years old and had begun to show signs of age. Their manufacturers’ warranties had also expired in recent years, making their replacement next up on the district’s roofing project schedule.

“We typically replace roofing systems within five years of the warranty expiration,” Fahrendholz explains. “It enables us to stay ahead of the maintenance issues that can begin cropping up.”

All three existing roofs had ballasted EPDM roofing systems. The re-roofing projects continued the district’s move toward TPO systems and, where possible, eliminating ballast. The three new roofing systems have 20-year, no-dollar-limit labor and material warranties.

SCCSD has several reasons for moving away from ballasted systems, according to Winkler Roofing President Jeff Winkler, P.E. In addition to reducing the roof’s weight and eliminating the cost of the ballast, unballasted roofs have a neater appearance and it is easier to monitor the membrane’s condition and find and repair any leaks. And, of course, when the time for re-roofing comes, there are no truckloads of ballast to remove and replace.

According to Winkler, SCCSD likes the durability of TPO membranes. “They like that the membrane is reinforced and that the seams are heat-welded, rather than seamed with primer and tape,” Winkler notes.

East High School Project

Re-roofing a 5,356-square-foot section at East High School entailed a complete tear-off of the existing ballasted EPDM roofing system and insulation down to the steel roof deck. The Winkler Roofing team then installed a new system topped with Mule-Hide TPO with CLEAN Film from Mule-Hide Products Co. It was the first time Winkler Roofing had installed the prodcut.

At East High School, polyisocyanurate insulation is installed using 3-inch galvalume plates and drill point fasteners. Photos: Mule-Hide Products Co. Inc.

Three layers of polyisocyanurate insulation were mechanically fastened with screws and plates to enhance the building’s energy efficiency. The 60-mil TPO membrane was then fully adhered using TPO Bonding Adhesive from Mule-Hide Products.

The last step in any well-done TPO project is removing the dirt and scuffs that are inevitably left behind during installation, notes Winkler. That step is eliminated with this product; the crew simply removes the protective film covering the membrane to reveal a clean roof that is ready for inspection.

“The material is more expensive than regular TPO membranes, but there is the potential to make up for that in reduced labor costs,” Winkler notes.

The biggest benefit would be seen on roofs that have fewer penetrations, according to Winkler. Installing the membrane around penetrations requires removing a portion of the protective film, he explains. Because those areas are then exposed to scuffs and dirt, crews must go back and clean them by hand.

West High School Project

Meticulous detail work was key to the successful replacement of a 18,056-square-foot section of the roof at West High School. There were nearly four dozen penetrations in the roof, from 4-inch pipes to HVAC equipment measuring 8 feet by 12 feet. Many of the chimney stacks also were in spots that were awkward for the crew to work around.

Winkler Roofing crew members prepare to install a TPO walkway pad. Photos: Mule-Hide Products Co. Inc.

It was all in a day’s work for the Winkler Roofing team. “The quality of our detail work is one of the things we take pride in,” Winkler says. “The keys are good leadership, both on and off the roof, and a well-seasoned crew. My foreman, Absalon Quezada, is a master of solving the toughest of details and coordinating a well-orchestrated crew.”

The roof’s existing concrete deck made a mechanically attached system uneconomical, so a new ballasted system was specified. The existing ballast had deteriorated to the point that, if reused, it could puncture the new roofing membrane. So, all 100 tons of it, along with the existing EPDM membrane, were removed and disposed of. The pieces of stainless steel cap metal along the perimeter were removed and numbered in sequence for reinstallation later. Sections of water-damaged insulation were removed and replaced.

An additional layer of polyisocyanurate insulation was loose-layered over the entire roof to improve energy efficiency, followed by a new loose-layered 60-mil white TPO membrane. New ballast was then installed.

Details such as this pipe boot were installed using a hot-air welder. Photos: Mule-Hide Products Co. Inc.

The crew navigated a challenging site while depositing the new ballast on the roof of the one-story building. The site offered only one feasible parking spot for the seven dump trucks that would deliver the rock, and that was on a lawn, just on the other side of two large trees. Crews carefully noted the location of sprinklers for the in-ground irrigation system to avoid driving over them, and shut the system down for several days in advance of the delivery to minimize ruts caused by the trucks’ tires. The trees’ trunks were spaced less than 20 feet apart and the canopies have grown together, leaving only small tunnel to feed the conveyor through. Crews kept the conveyor low as they extended it through the branches, then brought it to roof height by repeatedly raising it and the backing the truck up.

Riverside Elementary School Project

At Riverside Elementary School, a 7,314-square-foot section of roof was replaced with a 60-mil, fully attached TPO system.

The existing EPDM membrane, ballast and edge metal flashings were removed and disposed of. Crews removed and replaced any water-damaged insulation, added an additional layer of polyisocyanurate insulation throughout to increase the building’s energy efficiency, and mechanically attached the insulation to the steel roof deck using screws and plates. The white TPO membrane was then installed using bonding adhesive, and new edge metal flashings were added.

Straight A’s on the Report Card

The new roofs received top grades on their inspection report cards.

At East High School, crews installed Mule-Hide TPO with CLEAN Film from Mule-Hide Products Co. The last step in the installation process is removing the protective film covering the membrane. Photos: Mule-Hide Products Co. Inc.

When Mule-Hide Products Co. Territory Manager Jake Rowell inspected the roofs, there were no items on his, or the district’s, punch list. The only remaining task — which was completed during the inspection — was covering the seams on the West High School roof with ballast; they had intentionally been left exposed for easy inspection. In fact, that was the only “to-do list” item Rowell noted during inspections of 11 Winkler Roofing projects that week.

“The quality of their work is phenomenal,” Rowell says. “The crews take pride in their work. They don’t just throw a project together and move on. They check their work to make sure it’s done right before I see it and before the customer sees it.”

THE TEAM

Roofing Contractor: Winkler Roofing Inc., Sioux City, Iowa
Architect: FEH DESIGN, Sioux City, Iowa, www.fehdesign.com
Roofing Materials Distributor: ABC Supply Co. Inc., www.abcsupply.com
Decorative Sheet Metal: Interstate Mechanical Corp., Sioux City, Iowa, www.interstatemechanicalcorp.com

MATERIALS

TPO Membrane Roof Systems: Mule-Hide Products Co. Inc., www.mulehide.com

Metal Roof and Wall Panels Capture the Spirit of Shakespearean Theater

The Otto M. Budig Theater is the home of the Cincinnati Shakespeare Company. The new theater was designed by GBBN Architects in Cincinnati. Photos: Petersen Aluminum Corp

For many new arenas and theaters, the sheer size and scope of the project can pose the biggest hurdles. At the new Otto M. Budig Theater, home of the Cincinnati Shakespeare Company, the problem was the reverse. The intimate theater was shoehorned into an existing space up against an adjacent building, so logistics were tight. But that didn’t mean the roof system couldn’t be striking. Designed by GBBN Architects in Cincinnati, the building’s exterior features daring angles and multi-colored metal roof and wall panels that combine to help capture the spirit of the Shakespearean theater.

Matt Gennett, senior project manager and vice president of Tecta America Zero Company in Cincinnati, oversaw the roofing portion of the new construction project in the Over the Rhine section of Cincinnati on the corner of Elm Street and 12th Street. “This building was plugged in downtown, and they fit everything in real tight,” he says.

Approximately 5,400 square feet of PAC-CLAD 7/8-inch, 24-gauge Corrugated Panels from Petersen Aluminum Corp. were installed on the metal roofs and walls. Tecta America Zero Company installed the metal roof systems, as well as a TPO roof manufactured by Carlisle SynTec over the main structure and mechanical well. Work began in January of 2017 and the roofing portion of the project was wrapped up in late August.

The Metal Roof System

The building features two different metal roof systems. The roof on the Elm Street side is comprised of three intersecting triangle-shaped sections in two colors, Champagne Metallic and Custom Metallic Bronze. “There were several unique angles on the roof,” Gennett explains. “On the top, there was a second metal roof, a shed roof that went down to the 12th Street side.”

The theater’s roof and walls feature approximately 5,400 square feet of PAC-CLAD 7/8-inch Corrugated Panels from Petersen Aluminum Corp. in two colors. The wall panels are perforated. Photos: Petersen Aluminum Corp.

The metal roof systems were installed over a 2-inch layer of polyisocyanurate insulation and a 2-1/2-inch nail base from Hunter Panels, H-Shield NB. The nail base is a composite panel with a closed-cell polyisocyanurate foam core, a fiber-reinforced facer on one side and, in this case, 7⁄16-inch oriented strand board (OSB) on the other. The nail base was topped with Carlisle WIP 300 HT waterproofing underlayment to dry in the roof.

Crews also installed two rows of snow guards on the metal roof using the S-5! CorruBracket. “The snow guard was a little different,” Gennett says. “It was specifically designed for a corrugated roof.”

The TPO Roof System

The main roof and mechanical well were covered with the TPO roof system, which totaled approximately 8,300 square feet. After Carlisle VapAir Seal725 TR self-adhering air and vapor barrier was applied to the metal deck, crews installed two layers of 2-inch iso. Tapered insulation was applied over the top to ensure proper drainage. The insulation was covered with a 1/2-inch sheetrock and the 60-mil TPO was fully adhered.

Two large smoke hatches manufactured by Bilco were installed over the stage area. The ACDSH smoke hatches measured 66 inches by 144 inches, and are designed for theaters, concert halls and other interior applications that require limiting noise intrusion.

The Installation

The initial focus was to get the roof dried in so work could progress inside the building. The jobsite conditions posed a few challenges. The structure abutted an existing building, and the space was tight. The schedule necessitated multiple trips to the site, which can be a budget-buster on a small project. “We had a lot of trips in and out to accommodate the schedule and get everything dried in so they could meet the interior schedule,” notes Gennett. “We were sort of on call. We made three or four trips out to roof this small project, so it took a lot of coordination because it was completed in pieces.”

Crews tackled the TPO roof sections first. The mechanical well section provided several challenges. Changes in the mechanical well layout necessitated moving some curbs and making adjustments to the tapered insulation. “They were trying to get lot of equipment into a small space,” Gennett explains. “We had to make sure we could get the water to the low spots and route it around all of that equipment. That was probably the biggest challenge on the project.”

Staging material was also problematic, as traffic was heavy and parking space was at a premium. Material was loaded by a crane, which had to be set up in the street. “It’s a postage stamp of a site,” says Gennett. “This is a main thoroughfare, and there is a school right across the street. We had to work around school hours, and we couldn’t be working when the busses were coming in. We usually came in after school started, around 8 a.m., to load materials.”

When it came time to load the metal panels, the cramped jobsite actually paid off. “It was very convenient,” Gennett recalls. “We were able to load the panels onto the adjacent roof and just hand them over. We had a nice staging area for cutting, so all in all it wasn’t bad.”

The corrugated panels were installed with matching edge metal. “It’s not a complicated panel to install, and they look really nice,” Gennett notes. “On the Elm Street side, to the right of the valley was one color, and to the left was another, so we had to match the color with our coping. There were some interesting transitions with our metal. We also had to really pay attention to how the siding was being installed so we could match the metal to the siding and follow the transitions from color to color.”

The perforated wall panels were installed by ProCLAD Inc. of Noblesville, Indiana. “Once the walls were done, we came in and did the transition metal,” Gennett says. “We just had to make sure everything lined up perfectly.”

Planning Ahead

Ensuring a safe jobsite was the top priority for Tecta America Zero and Messer Construction, the general contractor on the project. “Both Messer Construction and Tecta America take safety very seriously. That’s why we’re good partners,” Gennett says. “We had PPE, high-visibility clothing, hard hats, safety glasses for the whole project. All of the guys were required to have their OSHA 10. Anyone outside of the safety barriers had to be tied off 100 percent of the time.”

Planning ahead was the key to establishing the safety plan and meeting the schedule while ensuring a top-quality installation. “This job had a lot of in and out, which is tough in the roofing business,” Gennett says. “But we planned ahead, we made sure everything was ready for us when we mobilized, and we did a good job of coordinating with the other trades. It took a lot of meetings and discussions — just good project management.”

Gennett credits the successful installation to a great team effort between everyone involved, including the general contractor, the subcontractors, and the manufacturers. “We pride ourselves on our great, skilled crews and our great field project management,” he says. “Our superintendents are there every day checking the work and making sure the guys have everything they need. Messer Construction is great to work with, and obviously having the manufacturer involved the project and doing their inspections as well helps ensure the quality meets everyone’s standards and holds the warranty.”

The theater is now another exciting venue in the Over the Rhine neighborhood. “It is really cool spot,” Gennett says. “It’s an up-and-coming neighborhood that’s grown in leaps and bounds in the last seven years. There is a ton going on in Cincinnati. It’s just another part of the city that makes it really fun to go downtown.”

TEAM

Architect: GBBN Architects, Cincinnati, Ohio, www.gbbn.com
General Contractor: Messer Construction, Cincinnati, Ohio, www.messer.com
Roofing Contractor: Tecta America Zero Company, Cincinnati, Ohio, www.tectaamerica.com
Wall Panel Installer: ProCLAD Inc., Noblesville, Indiana, www.procladinc.com

MATERIALS

Metal Roof:
Roof Panels: PAC-CLAD 7/8-inch Corrugated Panels, Petersen Aluminum Corp., www.pac-clad.com
Wall Panels: PAC-CLAD 7/8-inch Corrugated Panels, Petersen Aluminum Corp.
Nail Base: H-Shield NB, Hunter Panels, www.HunterPanels.com
Snow Guards: CorruBracket, S-5!, www.S-5.com
Waterproofing Underlayment: Carlisle WIP 300 HT, Carlisle SynTec, www.CarlisleSyntec.com

TPO Roof:
Membrane: 60-mil grey TPO, Carlisle SynTec
Waterproofing Underlayment: Carlisle WIP 300 HT, Carlisle SynTec
Smoke Hatches: ACDSH Acoustical Smoke Hatch, The Bilco Co., www.Bilco.com

Plate Marking Tool Designed to Increase Installation Efficiency

OMG Roofing Products introduces a plate marking tool designed to help roofers improve rooftop productivity by quickly locating and marking RhinoBond Plates installed under thermoplastic membranes.  

The new RhinoBond Plate Marking Tool is lightweight, simple-to-use and easy-to-maneuver. Simply roll the marking tool over a row of installed RhinoBond Plates. Every time it passes over a properly installed plate, the tool leaves a temporary mark on the surface of the membrane to identify the plate location. Plate marks are made with standard blue construction crayons and typically fade away within a few weeks.

The plate marking tool is compatible with all thermoplastic membranes regardless of type or thickness. In addition, the tool’s handle is reversible for quick direction changes, and lays flat for rolling under rooftop pipes and raised equipment such as air handling units. Other benefits of the new system include powerful sweeper magnets mounted on the front and back of the chassis that pick-up any metal debris on the roof. The tool is provided in a protective carrying case for easy handling and storage.

The RhinoBond System is designed for use with TPO and PVC roofing membranes. The System uses advanced induction welding technology to bond roofing membranes directly to specially coated plates that secure the insulation to the deck. The result is a roofing system with improved wind performance that requires fewer fasteners, plates, and seams, and zero penetrations of the new membrane.

For more information, visit OMGRoofing.com.

School Board’s Kite-Shaped Building Reflects Location’s History

The roof design for the Homewood Board of Education Central

The roof design for the Homewood Board of Education Central Office was inspired by the site, which is known as Kite Hill. Photos: Petersen Aluminum Corp.

The new home for the Homewood Board of Education Central Office in Alabama is a 14,500-square-foot modern structure that marks the first phase of a long-term development plan on a 24-acre site in Homewood, Ala., a suburb of Birmingham.

The contemporary structure was designed by Williams Blackstock Architects in Birmingham. “The roof design was inspired by the site, which is known as Kite Hill,” says architect Kyle Kirkwood. “It’s a spot where kids and parents come to fly kites. The roof, which slopes in two different directions and is kite-like in its appearance, is representative of the popular site.”

The building was conceived as a “garden pavilion” integrated within the site, intended to mediate between public and private property, and man-made and natural materials. The structure is nestled into a line of pine trees with a cantilevered roof extending just beyond the pines.

The design incorporates approximately 24,000 square feet of Petersen’s PAC-CLAD material in four different profiles. The main roof includes 16,000 square feet of Petersen’s Snap-Clad panels up to 60 feet long. The design also incorporates an interior application of the Flush panels by integrating them into the lobby area. In addition, 7,000 square feet of Flush panels were used in soffit applications. The panels were manufactured at Petersen’s Acworth, Ga., plant.

The roof design was complex, Kirkwood notes. “Since the roof slopes in two directions, we had an interesting valley situation where we had to coordinate the orientation of the seams,” Kirkwood said.

Challenging Installation

The roof also features two rectangular low-slope sections that were covered with a TPO system manufactured by Firestone Building Products. The roof systems were installed by Quality Architectural Metal & Roofing in Birmingham, which specializes in commercial roofing, primarily architectural metal and single-ply projects.

The building is nestled into a line of pine tree

The building is nestled into a line of pine trees near the edge of the site, adjacent to a residential area. The cantilevered roof was designed to help the structure blend in with the location and mediate between public and private property. Photos: Petersen Aluminum Corp.

Eddie Still, Quality Architectural Metal & Roofing’s vice president, helped prepare the budget for Brasfield and Gorrie, the construction manager on the project, so Still was prepared to go when his bid was accepted. “It was a job that consisted of a large portion of metal and a smaller portion of TPO,” he says. “Since we do both things, we were a good fit.”

The installation was made event tougher by the logistics of the site, according to Still. “The design of the metal roof was unusual, to say the least,” he says. “It had a valley that cut through it, and the panels were sloped in two directions. That’s not normally the case.”

The biggest obstacle was posed by the building’s location on a hill near the edge of the property line, immediately adjacent to a residential neighborhood. “The Snap-Clad panels were approximately 60 feet long, which isn’t a problem if you have the equipment to handle them,” Still notes. “It does pose a problem logistically when it comes to getting them into a tight area, and we definitely had that.”

Panels were trailered in and hoisted to the roof by a crane. “Once the panels were up there, the installation was fairly easy,” Still says. “The roof didn’t have a lot of changes in elevation or different plateaus built into it. The only quirky thing was that valley, and once you had that squared away, you were good to go.”

Coordinating penetrations with members of plumbing and HVAC trades is critical, according to Still. “On the metal roofs, we always stress that you’re trying to present an aesthetic picture for the building, so you want to minimize the penetrations so it looks cleaner,” he says. “You have to coordinate on site so if you have a plumbing exhaust stack, it comes up in the center of the pan and not on the seam.”

The metal roof incorporates approximately 24,000

The metal roof incorporates approximately 24,000 square feet of Petersen’s PAC-CLAD material in four different profiles. In addition, 7,000 square feet of Flush panels were used in soffit applications. Photos: Petersen Aluminum Corp.

A small section of metal roof near the entryway was made up of mechanically seamed panels. “The reason we used Tite-Loc panels on that portion of the roof was because of the low slope,” Still says. “We used the same width panel, so it looks identical, but the seams are different. They are designed to work on systems with slopes as low as ½:12.”

Quality Architectural Metal & Roofing also installed the Firestone self-adhered TPO roof system on two low-slope sections of the roof, totaling approximately 3,000 square feet.

Still looks back on the completed project with pride. “Our niche would be a building like this one, which has TPO or some other membrane roofing and metal,” he says. “We’ve been in business 33 years. We have a well-deserved reputation for the type of work we do. In the bid market things are price driven, so more often than not, price is the determining factor. But in larger projects and work that’s negotiated, the G.C. is going to opt to choose people to solicit pricing from who have a history of doing successful projects with them.”

TEAM

Architect: Williams Blackstock Architects, Birmingham, Ala., Wba-architects.com
Construction Manager: Brasfield and Gorrie, Birmingham, Brasfieldgorrie.com
General Contractor: WAR Construction Inc., Tuscaloosa, Ala., Warconstruction.com
Roofing Contractor: Quality Architectural Metal & Roofing Inc., Birmingham, Qualityarch.com
Metal Roof System Manufacturer: Petersen Aluminum Corp., Pac-Clad.com
Low-Slope Roof Manufacturer: Firestone Building Products, FirestoneBPCO.com

North Carolina Middle School Generates More Energy Than It Uses

Sandy Grove Middle School in Hoke County, N.C.

Sandy Grove Middle School in Hoke County, N.C., was designed to be an energy-positive building. It generates 40 percent more energy than it consumes. Photo: Mathew Carbone Photography

When Robbie Ferris first presented the idea of a school building that generates more energy than it uses, people were skeptical. Now he can point to Sandy Grove Middle School in Hoke County, N.C., as proof that a high-performance school building can go well beyond net zero and generate 40 percent more energy than it consumes.

Ferris is the president of SfL+a Architects and manager at Firstfloor, a development company that specializes in public-private partnerships and design-build-operate agreements. “We designed the building, we own it and we lease it to the school district,” he says. “We monitor all of the systems remotely. One of the reasons we do that is because when you put really high-performance systems in buildings, you have to make sure they are operating at peak efficiency. It can take time to make sure everything is optimized.”

Three years after completion, Sandy Grove Middle School is outperforming its energy models, and the building continues to win accolades. It recently received Energy Star 100 Certification and has been recognized as the nation’s most energy positive school.

“Sandy Grove Middle School is a perfect example of a high-performance facility,” says Ferris. “With the public-private lease-back model, everyone wins. The students receive a quality school, it fits in to the school system budget, and it is energy efficient to help both total cost and our environment.”

The building’s systems were designed to be as energy-efficient as possible, and that includes the roof, which features an array of photovoltaic (PV) panels to generate electricity. “We wanted a roof that would last 30 years,” Ferris notes. “We’ve had a tremendous amount of success with TPOs, and metal roofs as well. This particular client wanted a metal roof look from the front, but they were very open to a membrane roof on other parts of the building. We made the decision to put the metal roof on the front of the building and a TPO on the wings at the back of the building.”

On this project, the warranties were important considerations, along with durability and energy efficiency. SfL+a specified a standing seam metal roof system manufactured by Dimensional Metals Inc. and a TPO system manufactured by GenFlex. “Obviously, if you’re putting a couple of million dollars’ worth of solar panels on your roof, you want to make sure you have a roof that is going to be problem free.”

A Smooth Installation

The installation was a challenging one, but everything went smoothly, notes Aaron Thomas, president and CEO of Metcon Inc. Headquartered in Pembroke, N.C., Metcon is a full-service general contractor that specializes in energy positive commercial buildings, so it was perfectly suited to serve as the construction manager on the project.

Photovoltaic panels were installed

Photovoltaic panels were installed on both the standing seam metal roof and the TPO system. The systems on the low-slope roof sections are fully ballasted, and both sections were installed without penetrating the roof system. Photo: SfL+a Architects

Thomas and Ryan Parker, senior project manager with Metcon, coordinated the work of subcontractors on the job, including the Youngsville, N.C. branch of Eastern Corp., which installed the TPO and metal roofs, and PowerSecure, the solar installer on the project, based in Wake Forest, N.C.

The roof systems covered 85,000 square feet, and Sharp PV panels were installed on both the metal roof and the TPO system. Solar panels were also installed on freestanding structures called “solar trees.” Each solar tree is 20 feet tall, 25 feet wide and weighs 3,200 pounds.

“The TPO roof system was upgraded to an 80-mil product due to solar panels being added to the roof,” Parker notes. “It was 100 percent ballasted on the low-slope sections, with slip sheets being used below the racking on the TPO roof.”

On the metal roof, clips manufactured by S-5! were used to affix the solar racking to the seams. “There are no penetrations for the frames, and penetrations for the electrical wiring went through vertical walls, not the roof,” Parker says. “There were no penetrations anywhere in the roof system, which made all of the warranties that much easier to keep intact.”

The biggest challenges on the project, according to Parker, were coordinating the different scopes of work and ensuring all of the manufacturers’ warranty considerations were met. “We had two different kinds of roofs, both coupled with solar panels,” Parker says. “Like any rooftop with photovoltaic products, there had to be special attention paid to the warranties of all parties involved. Both Genflex and DMI were closely involved in coordinating details to ensure that the owner achieved a great roof free of defects.”

The building’s systems were designed for energy efficiency

The building’s systems were designed for energy efficiency, and the roof features an array of photovoltaic panels to generate electricity. Photo: Mathew Carbone Photography

One key was developing a detailed schedule and keeping everyone on it. “We would meet once a week and huddle up on how it was progressing and what else needed to be done,” Parker recalls. “We found that by using a collaborative submittal sharing platform, all of the varying parts and pieces could be checked by all parties to ensure compatibility.”

There were multiple safety concerns associated with combining solar panels to the roofing system, so everyone had to be on the same page. “The roofing subcontractor and the solar subcontractor performed a joint safety plan that utilized common tie off points,” Parker notes. “The job had zero lost time.”

“Everyone coordinated their work and it was a great team effort,” Ferris says. “It was one of the smoothest jobs I’ve ever seen. We have not had a single leak on that project—not a single problem.”

Proof Positive

For Ferris, the greatest obstacle on energy-positive projects convincing members of the public and governmental agencies of the benefits. “The biggest challenges had nothing to do with construction; they had to do with just doing something new and different,” he says. “The toughest challenge was getting the school board, the county commissioners, the public and the review agencies on board. It took a very long time—and lots of meetings.”

Photo: SfL+a Architects

Now Ferris can point to Sandy Grove as an example of just how a high-performance school building can pay huge dividends. “As soon as you see it in real life, you’re on board,” he says. “It’s very exciting for people to see it. If we can get people to the school, they’ll walk away convinced it is the right thing to do.”

With Sandy Grove, the school district has a 30-year lease with an option to purchase. Ferris believes the lease model is the perfect solution for educators. “We’re responsible for any problems for the life of the lease,” he says. “If a problem does come up, we usually know about it before the school does because we monitor the systems remotely online.”

“In their world, buildings are a distraction from educating kids,” Ferris concludes. “This is one building that is not a distraction.”

TEAM

Building Owner: Firstfloor, Inc., Winston-Salem, N.C., Firstfloor.biz
Architect: SfL+a Architects, Raleigh, N.C., Sfla.biz
Construction Manager: Metcon Inc., Pembroke, N.C., Metconus.com
Roofing Contractor: Eastern Corp., Youngsville, N.C.
Photovoltaic Panel Installer: PowerSecure, Wake Forest, N.C., Powersecure.com
Metal Roof System Manufacturer: Dimensional Metals Inc., DMImetals.com
TPO Roof System Manufacturer: GenFlex Roofing Systems, GenFlex.com

Self-Adhered TPO Membrane Offers Easy Installation With No VOCs

UltraPly TPO SA Firestone Building Products offers UltraPly TPO SA with Secure Bond Technology, a self-adhering membrane with a factory-applied, pressure-sensitive adhesive. Designed to be the next generation in fully adhered roof system application, Secure Bond Technology ensures adhesion coverage across the membrane, establishing one of the strongest bonds possible. According to the company, this advanced technology not only significantly improves installation speed over traditional fully adhered applications, but allows installation in temperatures as low as 20 degrees Fahrenheit. With no Volatile Organic Compounds (VOCs), UltraPly TPO SA with Secure Bond Technology is safe for the contractor, building occupants and the environment. 

Hot-Air Welding Under Changing Environmental Conditions

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

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

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

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

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

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

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

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

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

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

Reality Check

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

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

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

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

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

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

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

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

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

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

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

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

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TPO System Delivers Energy Efficiency for Company Headquarters

TurnKey Corrections constructed a new 115,000-square-foot in facility in River Falls, Wis.

TurnKey Corrections constructed a new 115,000-square-foot in facility in River Falls, Wis.

If you want it done right, do it yourself. Company owners Todd Westby and Tim Westby take a hands-on approach to running TurnKey Corrections, the River Falls, Wisconsin-based company that provides commissary and jail management services to county corrections facilities nationwide. The Westby brothers also take pride in the fact that TurnKey manufactures the kiosks it provides to its clients and develops and owns the proprietary software used to run them.

So, it’s perhaps not surprising that, when building the company’s new headquarters, Todd Westby, the company’s CEO, founder and general manager, served as the general contractor. Or that he had definite ideas regarding the roofing system that would be installed. Or that he was more than willing to get his hands dirty during the installation process.

Founded in 1998, TurnKey Corrections helps corrections facilities streamline and lower the cost of delivering a variety services to inmates, including commissary, email and email-to-text communication, video visitation, law library access, and paperless intra-facility communication and documentation. Following several years of robust growth, the company had outgrown its three existing buildings. So, it constructed a new 115,000-square-foot facility to bring all operations, including 50,000 square feet of office space and a 65,000 square-foot warehouse where commissary items are stored prior to shipment to corrections facilities, under a single roof and accommodate future success.

“We wanted to be involved in the project from beginning to end so we knew what we were getting and how it was built,” Todd Westby says of the decision to keep construction management in-house. “We wanted to know about anything and everything that was being built for the company in this building.”

In planning the project, Westby initially set two key criteria for the roofing system: that the building would be made watertight as quickly as possible so concrete slab pours and other interior work could be completed, and that the roof would be covered by a warranty of at least 20 years. The design-build firm’s initial plans called for a ballasted EPDM roofing system, but Rex Greenwald, president of roofing contractor TEREX Roofing & Sheet Metal LLC of Minneapolis, suggested a white TPO system, noting that it would meet the quick installation and warranty goals while also enhancing the building’s energy efficiency. Westby was intrigued and, after some research, agreed to the recommendation. In addition to helping reduce cooling costs during summer months, the reflective surface would allow a blanket of snow to remain on the roof during winter months to provide additional insulation.

The TPO roofing system was constructed over a 22-gauge metal fabricated roof deck.

The TPO roofing system was constructed over a 22-gauge metal fabricated roof deck.

The Roof System

The TPO roofing system included a 22-gauge metal fabricated roof deck; two 2.5-inch-thick layers of Poly ISO insulation from Mule-Hide Products Co., with tapered insulation saddles and crickets to aid drainage; and 811 squares of 60-mil white TPO membrane from Mule-Hide Products Co. The insulation and membrane were mechanically attached using the RhinoBond System from OMG Roofing Products. Cast iron roof drains, designed and installed by a plumber, were used rather than scuppers and downspouts—a practice that the TEREX team strongly recommends to prevent freezing during the cold Upper Midwest winters. Walkways lead to the mechanical units, protecting the membrane from damage when maintenance personnel need to access the equipment.

The TEREX team finds the RhinoBond System to be the most efficient and economical attachment method for TPO systems. Specially coated metal plates are used to fasten the insulation to the roof deck and then an electromagnetic welder is used to attach the membrane to the plates. The membrane is not penetrated, eliminating a potential entry point for moisture. And while other mechanical attachment methods require the crew to seam as they go, the RhinoBond System allows them to lay the entire membrane (a task which must be completed in good weather conditions) at once and go back later to induction weld the seams and plates, which can be done when Mother Nature is slightly less cooperative.

Greenwald estimates that the switch from the originally specified ballasted EPDM system to the TPO roofing system and RhinoBond System shaved at least 10 percent off the installation time and reduced the roof weight by 10 pounds per square foot.

Having Westby on-site as the general contractor also sped up the project considerably, Greenwald notes. “He was a huge asset to all of the subcontractors,” he explains. “We could get construction questions answered quickly and could talk through issues and procedures on a timely basis.”

And the most memorable moment in the project for Greenwald was seeing Westby working side-by-side with his crew. “One day we had a delivery truck show up, and Todd jumped on the forklift and helped us unload the truck.”

As sought from the project’s outset, the roofing system is backed by a 20-year, no-dollar-limit labor and material warranty.

With one winter of use in the rearview mirror, the roofing system has exceeded Westby’s expectations. Warehouse space was doubled, but heating costs have been cut in half. The 10-unit heating system also is able to keep the warehouse a uniform temperature, without the cold spots that were common in the old building.

“It really is a beautiful, very efficient and organized-looking roof,” Greenwald says.

Virginia Tech Study Measures the Impact of Membranes on the Surrounding Environment

Equipment tripods are set up to hold air temperature and EMT temperature sensors.

Equipment tripods are set up to hold air temperature and EMT temperature sensors.

For much of the past decade, the debate over when and where to install reflective roofing has been guided by two basic assumptions: first, since white roofs reflect heat and reduce air conditioning costs, they should be used in hot climates. Second, since black membranes absorb heat, they should be used in cool-to-colder climates to reduce heating costs. This reasoning has been broadly accepted and even adopted in one of the most influential industry standards, ASHRAE 90.1, which requires reflective roofing on commercial projects in the warm-weather portions of the United States, Climate Zones 1–3.

But as reflective membranes have become more widely used, there has been a growing awareness that the choice of roof color is not simply a matter of black or white. Questions continue to be debated not only about the performance and durability of the different types of membranes, but on the impact of other key components of the roof system, including insulation and proper ventilation. The issue of possible condensation in cooler or even cold climates is garnering more attention. Given these emerging concerns, the roofing community is beginning to ask for more detailed, science-based information about the impact of reflective roofing.

One recent area of inquiry is centering on the impact of “the thermal effects of roof color on the neighboring built environment.” In other words, when heat is reflected off of a roofing surface, how does it affect the equipment and any other structures on that roof, and how might the reflected heat be impacting the walls and windows of neighboring buildings? Put another way, where does the reflected heat go?

THE STUDY

To help answer those questions, the Center for High Performance Environments at Virginia Tech, supported by the RCI Foundation and with building materials donated by Carlisle Construction Materials, designed and implemented a study to compare temperatures on the surface and in the air above black EPDM and white TPO membranes. In addition, the study compared temperatures on opaque and glazed wall surfaces adjacent to the black EPDM and white TPO, and at electrical metallic tubing (EMT) above them.

Specifically, the Virginia Tech study was designed to answer the following questions:

  • What is the effect of roof membrane reflectivity on air temperatures at various heights above the roof surface?
  • What is the effect of roof membrane reflectivity on temperatures of EMT at various heights above the roof surface?
  • What is the effect of roof membrane reflectivity on temperatures of opaque wall surfaces adjacent and perpendicular to them?
  • What is the effect of roof membrane reflectivity on temperatures of glazed wall surfaces adjacent and perpendicular to the roof surface?

To initiate the study, the Virginia Tech team needed to find an existing roof structure with the appropriate neighboring surfaces. They found a perfect location for the research right in their own backyard. The roof of the Virginia-Maryland College of Veterinary Medicine at Virginia Tech was selected as the site of the experiment because it had both opaque and glazed wall areas adjacent to a low-slope roof. In addition, it featured safe roof access.

In order to carry out the study, 1.5 mm of reinforced white TPO and 1.5 mm of non-reinforced black EPDM from the same manufacturer were positioned on the roof site. A 12-by-6-meter overlay of each membrane was installed adjacent to the opaque wall and a 6-by-6-meter overlay of each was installed next to the glazed wall. At each “location of interest”—on the EPDM, on the TPO, and next to the opaque and glazed walls—the researchers installed temperature sensors. These sensors were placed at four heights (8, 14, 23, and 86 centimeters), and additional sensors were embedded on the roof surface itself in the TPO and EPDM. Using these sensors, temperatures were recorded on bright, sunny days with little or no wind. The researchers controlled for as many variables as possible, taking temperature readings from the sensors on and above the EPDM and TPO on the same days, at the same time, and under the same atmospheric conditions.

The roof of the Virginia-Maryland College of Veterinary Medicine at Virginia Tech is the site of the experiment because it has opaque and glazed wall areas adjacent to a low-slope roof.

The roof of the Virginia-Maryland College of Veterinary Medicine at Virginia Tech is the site of the experiment because it has opaque and glazed wall areas adjacent to a low-slope roof.

THE RESULTS

The output from the sensors showed that at the surface of the roof, the black membrane was significantly hotter than the white membrane, and remained hotter at the measuring points of 8 cm and 14 cm (just over 3 inches and 5.5 inches, respectively). However, the air temperature differences at the sensors 23 centimeters (about 9 inches) and 86 centimeters (just under three feet) above the surface of the roof were not statistically significant. In other words, at the site the air temperature just above the white roof was cooler, but beginning at about 9 inches above the roof surface, there was no difference in the temperature above the white and black membranes.

On the precast concrete panel adjacent to the TPO and EPDM, temperatures were warmer next to the TPO than adjacent to the EPDM, leading the study authors to hypothesize that the TPO reflected more heat energy onto the wall than did the EPDM. Exterior glazing surface temperatures were found to be approximately 2 degrees Celsius hotter adjacent to the TPO overlay as compared to the EPDM overlay.

Elizabeth Grant led the team that designed and implemented the study. She says her findings show that you need to take the entire environment into account when designing a roof system. “You need to think about what’s happening on top of the roof,” she says. “Is it adjacent to a wall? Is it adjacent to windows? Is it going to reflect heat into those spaces?”

Samir Ibrahim, director of design services at Carlisle SynTec, believes the study results will help frame additional research. “These findings are an important reminder that the full impact of reflective roofing on a building and on surrounding buildings is not fully understood,” he says. “Additional research and joint studies, covering different climatic conditions, are certainly warranted to broaden the knowledge and understanding of the true impact on the built-environment.”

OMG RhinoBond Projects Are Being Completed Across Europe

OMG Roofing’s RhinoBond System has left marks across Europe with more than 125 completed projects and more in the pipeline. Collectively, these projects represent more than 300,000 square meters (3.2 million square feet) of single-ply roofing.

“In last two years, the RhinoBond System has started to take off across Europe, as more roofing contractors have seen the roof performance benefits that the system can offer,” states Web Shaffer, vice president of marketing for OMG Roofing Products. “We have completed projects across Europe and we are expanding to new countries in the region, most recently, into South East Europe.”

RhinoBond is a method for installing thermoplastic and now also clean EPDM membrane. The system consists of a stand-up induction welding tool and magnetic cooling clamps. Contractors install roofing insulation using fasteners and specially coated plates designed specifically for the type of membrane being installed – PVC, TPO or Clean EPDM. Each plate is then bonded to the roof membrane installed over the top with the RhinoBond plate welding tool. The result is a roofing system that can provide wind performance with fewer fasteners, fewer membrane seams and zero penetrations of the new membrane.

The RhinoBond System is approved for use in Europe by many roof system providers, including Bauder, Carlisle/Hertalan, Danosa, Fatra, FDT, Firestone, GAF, IcoPal, IKO, Renolit, Sika, Siplast, and Soprema/Flag.

Headquartered in Agawam, Mass., OMG Roofing Products is a supplier of commercial roofing products including specialty fasteners, insulation adhesives, roof drains, pipe supports, emergency roof repair tape as well as productivity tools such as RhinoBond. The company’s focus is delivering products and services that improve contractor productivity and enhance roof system performance. For additional information, please contact OMG Roofing Products at (413)789-0252 or visit the OMG Roofing website.