Sensitive Re-Roofing Project Necessitates Durable System, Flawless Execution

The 250,000-square-foot Pepper River data center project would pose challenges including a tight schedule and difficult weather conditions. Utah Tile and Roofing Inc.

Utah Tile and Roofing Inc. prides itself in its ability to tackle difficult projects. When Okland Construction approached the company to help prepare budgets for a bid on a roof replacement on a building that would become a data processing center, they immediately knew this one would fit the bill.

Founded in 1948 in Price, Utah, Utah Tile and Roofing (UTR) relocated to Salt Lake City in 1966. The company handles all types of commercial roofing projects, as well as waterproofing, sheet metal, and wall panels. The current owners are Paul and Andrew Seppi, who took over from their father, founder Herman Seppi, in 1977. According to J.C. Hill, vice president, the company continues to build a reputation for craftsmanship as it works on some of Utah’s iconic buildings. “We’ve done a lot of high-end work here in the state of Utah,” Hill says. “A lot of the architectural gems here locally have our fingerprints all over them. The higher-end, more difficult work is where we’ve found our niche.”

The Aligned Energy data facility known as Pepper River in West Jordan, Utah, would also have its challenges, including a tight schedule and difficult weather conditions. Approximately 250,000 square feet of existing roof would have to be removed and replaced, but the sensitive nature of the building would require not only a durable temporary roof to keep everything dry during construction, but a resilient, long-lasting finished roof to protect the equipment below. The answer was a hybrid roof system from Sika with a vapor barrier set in hot asphalt. It would be topped with insulation, a cover board, and an 80-mil Sarnafil PVC membrane.

The design for the roof system was developed by UTR in conjunction with the architect, roof consultant, general contractor, and the manufacturer. “The vapor barrier would be set in hot asphalt as a temporary roof. The insulation and the tapered insulation would also set in hot asphalt,” Hill says. “That gave them some redundancy, which is a term those tech guys like.”

Roof Removal

The building’s original gravel-surfaced built-up roof had been covered over at some point with a mechanically attached white TPO roof on one side and a mechanically attached black EPDM roof on the other.

“We had to keep the building watertight as we tore it off,” says Hill. “We put the temporary roof down and crews would do a nightly seal to keep everything watertight as they progressed across the building.”

The existing roof systems included the building’s original gravel-surfaced built-up roof. It was cut into sections and pried off the metal deck.

Work was done in sections, beginning on one half the roof and then finishing up on the other. The expansion joint in the center of the building was the dividing line.

The safety plan included a perimeter flag system, and those outside the warning line were tied off 100 percent of the time. A scaffold stair tower was built to provide safe access to and from the roof.

Debris from the tear-off was removed using chutes and dumpsters. First the roof membrane was sliced up into manageable sections, rolled up, and deposited into a dumpster, along with the cover board. Then the built-up roof was cut into 3-foot-by-3-foot squares and pried off the metal deck.

The deck was swept clean of debris and inspected. Some of the decking had to be replaced, including sections where skylights were eliminated. A 5/8-inch DensDeck cover board was then screwed down to the metal deck. The vapor barrier sheets were unrolled and allowed to relax in the hot sun, and then set in hot asphalt. “We were able to do about 2,000 or 2,500 square feet a day with the tear-off and dry in,” notes Hill.

One unusual obstacle was a Canadian goose that had set up her nest in the expansion joint. “We had to leave that section undisturbed while she was waiting for her chicks to hatch,” says Hill. “Actually, there was a pretty good-size section of the roof in the middle that we weren’t able to address until she left. Luckily there was plenty of roof to work in, and we didn’t want to disrupt her. Even after she left with her chicks, she would come back and chase the guys around every once in a while.”

After the temporary roof was installed, the existing parapet walls were raised. The durable temporary roof allowed carpenters other trades to work on the roof without excessive fear of damage. After the trades completed their work, the finished roof system was installed right over the temporary roof.

The PVC System

First a layer of polyiso insulation was set in hot asphalt. Next the tapered insulation layer was also set in hot asphalt, followed by another layer of insulation to achieve R-30. Half-inch DensDeck Prime was then set in low-rise adhesive and the white PVC membrane was fully adhered.

To provide the durability the project needed, a hybrid roof system from Sika was specified. It included a vapor barrier set in hot asphalt and an 80-mil Sarnafil PVC roof system.

“We actually had two crews for that phase: a hot crew and a single ply crew,” Hill states. “The hot crew would be laying the insulation out in front, and then the single-ply crew would lay the cover board in the low-rise foam and start fully adhering that membrane down. It took a coordinated effort with the guys we had out there to make sure that there was no asphalt contamination of the PVC membrane and that white roof remained clean.”

As work continued on the second half of the roof, cold weather set in. Due to the temperature limitations of the membrane adhesive, the decision was made to switch to a self-adhered membrane. “We were having production issues with the cold weather, and we went back to Sarnafil and they recommended putting the SA down,” notes Hill. “It was the first time we had ever installed the self-adhered membrane. It saved our production, and we were able to install nearly as much as we were doing in the better weather days.”

The last steps on the project included installing edge metal. “We did a Sarnafil high-wind edge detail with their clad metal and a pre-finished metal fascia plate over the top,” says Hill. “It gave the building a nice finishing touch from the ground and also from the roof side.”

Meeting the Challenges

The biggest challenge on the first phase of the project was the tight schedule. “We had to get that first phase operational so they could get the data hall up and running,” says Hill. “We had to get the first section dried in so the trades — electricians, drywallers, painters, and tech guys — could get in there and do their work.”

Work began in April of 2019 and wrapped up in December of the same year. After the first phase was completed, the weather posed the greatest difficulties. “The winter was quite heavy,” Hill says. “We had to remove snow quite often to be able to go back to work.”

In the last phase of the project, cold weather and heavy snow affected the schedule.

Hill credits the teamwork between all of the principals and the excellent craftsmanship of job foreman Rudolfo Garcia and his crew for the success of the project. He also cites durability of the temporary roof and the extra protection the hybrid system provides as critical components in the design. “With carpenters and steel guys working over that temporary roof, the typical peel-and-stick vapor barriers simply wouldn’t have been durable enough,” he says. “This building has to remain dry. That temporary roof with a cap sheet over the top of it could have been a completed system, so it gave them the backup that they needed. If there ever is a problem on the top layer with that single ply, there is still that temporary roof underneath to keep them dry.”

Utah Tile and Roofing received first place in the 2019 Sika Sarnafil Project of the Year Awards in the Low-Slope Re-Roof category. “The award is a testament to how good our guys in the field are,” Hill says. “Because we have such good field mechanics, we are able to take on these tougher projects that take more critical thinking and more experience. They are the best at what they do, the engine that drives this thing. They are the ones that make it happen.”

TEAM

Architect: HKS Inc., Salt Lake City, Utah, www.hksinc.com

General Contractor: Okland Construction, Salt Lake City, Utah, www.okland.com

Roofing Contractor: Utah Tile and Roofing Inc., Salt Lake City, Utah, www.utahtileandroofing.com

MATERIALS

Roof Membrane: Sarnafil G410 80-mil PVC, Sika, https://usa.sika.com/sarnafil/

Insulation: Sarnatherm ISO, Sika

Vapor Barrier: HA-87 SBS Ply Sheet, Sika

Cover Board: DensDeck Prime, Georgia-Pacific, www.buildgp.com

Dickies Arena Plaza Deck Extends the Experience

The Dickies Arena plaza deck hosts a variety of outdoor events and protects visitors and livestock in the exhibit space below. Photos: Trail Drive Management Corp.

Commemorative events to celebrate the grand opening of Dickies Arena in fall 2019 ranged from a ribbon cutting party to Monster Truck competitions, and performances by Twenty One Pilots, the Black Keys and the Harlem Globetrotters. The arena is home to the Fort Worth Stock Show and Rodeo and other sporting events.

Not all the action takes place under the domed roof, however. The Dickies Arena plaza deck provides not only breathtaking views of the Fort Worth skyline, but offers a high level of functionality, strength and performance to protect visitors and livestock.

According to Bill Shaw, operations manager at Dickies Arena, the plaza is designed to serve as an extension of the rodeo, enabling visitors to watch the livestock from above. Ten-to-12-foot windows built into the plaza deck provide a view of the 100,000 square foot warm-up area where animals work with their handlers before barrel racing and other rodeo events. A roadhouse tent hosts musicians for plaza deck performances held following the rodeo. And instead of a conventional courtyard, Dickies Arena boasts a “cork yard” wine and food space.

Functionality Fuses With Performance

From lush green spaces that provide a scenic vantage point for taking in the iconic Fort Worth skyline and views of nearby barns and stables to fire lanes for emergency vehicles and concert equipment deliveries, Dickies Arena requires a plaza deck that can deliver outstanding strength. And in Fort Worth’s unpredictable weather, it must also successfully manage storm water runoff. The insulation used in the roof — Owens Corning Foamular extruded polystyrene (XPS) — is key to delivering compressive strength and storm water management performance. But the team specifying insulation for this unique landmark encountered some unusual challenges.

Exhibit areas underneath the plaza deck can be configured to house livestock. During rodeos, a warm-up area for horses is set up underneath the pavilion.

With a plaza deck encircling the main arena of about 140,000 feet, the size, scale and slope of the Dickies Arena plaza deck all presented challenges for the insulation team, beginning with the estimating process. The plaza’s design required a blend of tapered, flat filler, and reverse tapered installation.

Each phase was broken into three layers. The reverse taper layer brings the slope of the roof back to a flat slope. The flat fill section raises the height of the roof without adding the weight that concrete would have contributed to the plaza. A traditionally sloped area above the slab and pavers directs water back to the drainage assemblies located in the top layer of the roof. These layers had to be carefully calculated for many sections around the jobsite that changed in priority as construction surged ahead of schedule.

All the calculations required an experienced team who could coordinate and collaborate in real time. Sunbelt Building Services LLC was the insulation distributor on-site and team members’ experience in the roofing industry proved to be an invaluable asset. As Sunbelt prepared the drawings, Owens Corning calculated the insulation estimates by computer and by hand to ensure accuracy, piece by piece, and then Sunbelt reviewed them again. “You’ll never get the correct material count if you don’t know how the roof is sloping, where the drains are located and how to interpret the structural architectural drawings,” says Darrell Evans, project manager at Sunbelt Services. The result of the estimating process showed the collaboration and teamwork were successful. The estimated insulation for one of the first phases was within two pieces of the material used on the jobsite.

Managing Storm Water

Based on the “sandwich” of the roof design, Dickies Arena required two sets of drains sloping in different directions, according to Eric Nelson, AIA, RID, CCCA, and vice president at HKS, the architect of record for Dickies Arena.

The plaza deck had to be designed to withstand heavy stresses including emergency vehicles and equipment deliveries. Owens Corning Foamular extruded polystyrene insulation was specified for its compressive strength and storm water management performance.

The structure has one set of drains at the lowest level, where TREMproof 6100, a waterproofing membrane from Tremco, was hot-mopped into place over the concrete slab. On top of the waterproofing layer is the insulation and filter fabric, as well as the sand bed, Hanover pavers, and planters with trees. Slot drains at the top level collect surface water, and the drains at the lower level collect any water that works its way through that system. Extensive modeling was helpful in determining not only the placement of drains but precisely how much insulation should be used — and its depth and location — in various parts of the plaza deck.

Given all the activity taking place on the plaza roof, material weight was a huge consideration when selecting the roofing insulation. Emergency vehicles must be able to navigate the fire lanes that encircle the deck. Semi-truck trailers need to unload concert equipment and staging. From a building material perspective, the plaza deck supports 5 inches of concrete in addition to the weight of the insulation, with reverse tapering depths varying from 3 to 5 inches. In some areas, the plaza deck’s insulation is 12 to 13 inches deep.

While the project was originally specified to require 100-psi insulation, the team evaluated the Dickies Arena design structure and determined its design would allow weight to be distributed in a way that could be effectively managed by a 60-psi insulation. This exercise in value engineering revealed the lighter compressive strength XPS could deliver required strength and offer better economics. The plaza can support weight loads of 25,000 pounds.

Logistics Require a Team Effort

With the estimating complete and materials specified, supply chain management became an area of focus. Owens Corning worked with its manufacturing plants across the nation to coordinate logistics involved with production of XPS product and delivery to the jobsite.

A best practice on any construction project is to ensure products are not left unprotected and exposed to the elements, so communication and jobsite staging were coordinated between Owens Corning, Sunbelt and various contractors on the job. As XPS continues to expand slightly after manufacturing, the insulation was “aged” for 30 days after it came off the line. Owens Corning production plant teams, product managers and sales managers worked with a dedicated purchase order processor and a team of 20 to manage the plaza deck insulation project through to completion.

This detail from architect of record HKS Inc. shows the “sandwich” design of the plaza roof, which required slot drains at the surface and drains in the underlying slab. Image: HKS Inc.

On the jobsite, tapered pieces were sent up the slope and cut into specific rectangular sizes. Easily cut with a knife, structurally sound XPS isn’t prone to breaking into messy pieces and avoids random materials blowing away from the construction site. Given the sunny and windy climate in Fort Worth, the contractor kept exposed materials protected from sunlight and glued loose pieces together with a product that would not harm the insulation. Ordering the right amount of the right products at the right time was essential when considering up to 700 people were working on the project during peak construction periods.

The effect of the plaza deck gracing Dickies Arena can be summarized by modifying a common statement about Texas: “Everything is bigger and better in Texas.”

About the author: Tiffany Coppock, AIA, NCARB, CSI, CDT, LEED AP, ASTM, RCI, EDAC is the Commercial Building Systems Specialist at Owens Corning where she provides leadership in building science, system development, testing, and documentation.  

TEAM

Architect of Record: HKS Inc., Dallas, Texas, www.hksinc.com

Plaza Deck Installer: Sunbelt Building Services LLC, Dallas, Texas, www.sunbeltllc.com

MATERIALS

Waterproofing Membrane: TREMproof 6100, Tremco, www.tremcosealants.com

Insulation: Foamular 600, Owens Corning, www.owenscorning.com

Brick Pavers: Hanover, www.hanoverpavers.com

Talented Team Designs and Installs Multiple Roof Systems for Dickies Arena

Dickies Arena in Fort Worth, Texas, hosts the Fort Worth Stock Show and Rodeo as well as concerts and sporting events. Photos: Trail Drive Management Corp.

The new Dickies Arena in Fort Worth, Texas, was designed to echo the iconic Will Rogers Memorial Center, a historic landmark built in 1934. The site of the Fort Worth Stock Show and Rodeo as well as other concerts and sporting events, Dickies Arena was designed to provide a modern entertainment experience and configurable event spaces that would stand the test of time. The multiple roof systems on the project — including the plaza deck surrounding the arena — were essential in delivering on these goals.

Dickies Arena features a domed main roof with a cupola at the top that pays homage to its historic neighbor. “One of the major themes, especially of the dome roof structure itself, was to have a kind of throwback to the original Will Rogers Center, which is still there,” says Eric Nelson, AIA, RID, CCCA, vice president at HKS, the architect of record for Dickies Arena. “The Will Rogers Center was one of the first buildings of its type to have a long-span steel truss roof system. We used that existing structure as the inspiration for the roof structure inside the arena. We have these very thin, elegant looking trusses that are very art deco.”

The new structure’s domed roof is surrounded by low-slope roofs and complemented by two towers topped with metal roofs. Dickies Arena also features a pavilion with a standing seam metal roof, which sits on a plaza deck that serves as an outdoor event space as well as a giant roof system covering exhibit space and areas for housing rodeo livestock. The venue is also designed to provide excellent acoustics for concerts and features luxurious millwork and finishes throughout to provide a touch of elegance. “I like to say that it’s a rodeo arena, but it’s designed like an opera house,” Nelson says.

It took an experienced team of design and construction professionals to envision and execute the project, including HKS, the architect of record; David M. Schwartz Architects, the design architect; The Beck Group, the general contractor; Jeff Eubank Roofing Co., Inc., the roof system installer; and Sunbelt Building Services LLC, the insulation distributor and installer of the plaza deck.

The Dome

The roof system specified for the dome featured an 80-mil PVC system with decorative ribs manufactured by Sika Sarnafil. “The roof system is one that we use pretty regularly on our large sports projects, the Feltback PVC,” notes Nelson. “It’s a lot more durable than other single-ply roof membranes, so we really like it a lot. Dickies Arena is an arena that wasn’t just built for the next 20 years; it’s meant to be there for the next 100 years, so we wanted to make sure we used nothing but the highest-quality materials, especially with all of the hailstorms that we can get out there in Fort Worth.”

The pavilion has a Fabral double-lock standing seam roof system.

The roof system installer, Jeff Eubank Roofing Co., Inc. of Fort Worth, Texas, tackled the dome roof first, followed by the low-slope sections and the metal roofs. Work on the dome roof began in July of 2018. “The project progressed pretty quickly,” says Jeff Eubank, vice president of Jeff Eubank Roofing Co. “The dome in and of itself was like two different projects. The top half of the dome is pretty workable and walkable, and the bottom 40 percent of the dome is almost vertical.”

The Sarnafil Decor system was installed over an Epic acoustical deck, which posed some logistical and safety challenges. “We had to engineer special anchors because a typical tie-off anchor could not be used,” Eubank explains. “Before we could set foot on the job, we had to engineer special tie-off anchors which nested into the acoustical deck.”

Eubank and a structural engineer worked with Epic Deck to construct anchor points that would meet requirements for fall arrest. The half-inch aluminum, F-shaped anchors were designed to rest in the flutes of the acoustical deck and featured a ring provide a tie-off point. They were set in place using a crane.

Safety concerns included the Texas weather. “Our biggest challenge came with the heat,” says Eubank. “Summers in North Texas are brutal enough, but at the end of last summer, a high pressure system just stalled over Fort Worth. We were in the middle of a drought, with temperatures up to 110 degrees. You’re up on a deck with nowhere to hide, and with it was pushing 200 degrees up there. From a life safety standpoint, we ended up pushing the dome installation to night work.”

The main roof on the arena’s dome was topped with an 80-mil PVC system with decorative ribs manufactured by Sika Sarnafil.

Crews applied approximately 250,000 square feet of material on a near vertical application at night, with lighting provided by six tower cranes. The project required 100 percent tie-off of men and equipment.

The original plan for the dome was to work top to bottom, but as work began, the cupola was incomplete, so the safety and logistical plans had to be radically changed. “We ended up basically making two rings around the dome, doing the near-vertical portion — the bottom 30 or 40 percent — first,” Eubank says. “We moved up and did another 360-degree loop around the top half of the dome once the cupola was done.”

The roof system was installed over the acoustical deck and loose-laid filler. After a 5/8-inch DensDeck Prime substrate board was installed, crews mechanically fastened two layers of Sarnatherm polyiso and 1/4-inch DensDeck Prime. They adhered the Sarnafil G-410 20 Feltback membrane, which was produced in a custom color called Agreeable Gray.

After the membrane was installed, the PVC ribs were heat welded into place to give it the look of a standing seam roof. “We installed over 16 miles of custom-color Decor ribbing,” notes Eubank.

The Logo on the Roof

The dome roof also prominently features the Dickies Arena logo, which took some advance planning. “We left an area of the ribs out on the east side anticipating the logo up there,” Eubank says. “That’s in another custom color. Sarnafil ran the custom color and templated the letters. The logo is roughly 130 feet by 10 feet, so we received a giant D, a giant I, a giant C, and so forth. Once these things are installed, there is no pulling them up — your only option is to tear the roof off. So, imagine working with a 10-foot letter, 200 feet up in the air, on a slope, and making sure it’s level.”

Eubank Roofing came up with a plan to use a section of 60-mil PVC membrane as a backer sheet. “We laid out this big backer sheet in Agreeable Gray and stenciled all of the letters across it,” Eubank explains. “We took the backer sheet up, got it lasered and leveled, and installed the solid backer sheet on the dome. It already had the stencils on it, so we were able fall back and install the individual letters. We didn’t need to line them up — we just had to fill in the blanks.”

The last steps in the dome installation included installing ribs in a second custom color to go through the letters. Helicopters also brought in three large Dickies signs, which were placed atop concrete pedestals treated with a Sarnafil liquid membrane.

Flat Roofs and Metal Roofs

On the low-slope sections that surround the dome, the Sarnafil G-410 Feltback was installed over structural concrete and fully tapered polyiso. “There is a tremendous amount of masonry work on this project, and it is gorgeous,” Eubank notes. “It was important, though, on the low-slope portions to let the brick work and stone work wrap up before any roofing membranes were installed.”

The design of the arena echoes the iconic Will Rogers Center, which was the inspiration for the thin, elegant steel trusses.

A vapor barrier was installed over the structural concrete deck. After masonry work was completed, crews installed a fully tapered polyiso system in ribbons of OM Board adhesive, then adhered 1/4-inch DensDeck Prime and the 80-mil PVC membrane.

The complex also features two different metal roof systems from Fabral. On the north side of the building, the two towers were capped with a flat-seam panel. Down at the plaza level, the pavilion was topped with a double-lock standing seam roof system featuring Fabral 24-gauge Galvalume Power Seam panels.

According to Nelson, an area underneath the pavilion serves as a warm-up arena for horses during the rodeo, so the design was meant to evoke a rustic effect. “The cladding on that building is all quarter-inch steel with rivets on it,” Nelson points out. “Galvalume is finished to look like galvanized sheet steel, but it won’t tarnish or turn white or black like galvanized steel would — which is why they selected it — but it still has that kind of throwback look of a barn.”

Out of the Gate

Dickies Arena is now open to the public and is gearing up to host its first rodeo. The experienced team that built it has moved on to other projects, but they look back on their work on the new landmark venue with pride.

“I’m very proud of the people that I work with and the thought and care that they put into the project and the time that we take,” Eubank says. “A lot of our work is negotiated re-roofing, and I think that’s in large part because we take the time to think through a problem and come up with the best solution. I think that’s really highlighted here. You’ve got to take your time and do it right — and do it efficiently.”

Eubank commends the general contractor, H.C. Beck, for a smoothly operating jobsite. “The job was very well managed from a safety standpoint,” Eubank says. “The general contractor did a fabulous job of manipulating trade work and making sure no one was working overtop of anyone else.”

Nelson agrees, crediting the teamwork at every phase of the project for the successful outcome. “The partnership with David M. Schwartz as the design architect really worked very smoothly from our side,” Nelson says. “We worked very well with a talented team of consultants and who specialize in sports design. It’s a one-of-a-kind type of project.”

“My family has been in Fort Worth for five generations, and this is a project I’m just tickled to death about for the city,” says Eubank. “To be part of its install means a lot.”

TEAM

Architect of Record: HKS Inc., Dallas, Texas, www.hksinc.com

Design Architect: David M. Schwartz Architects, Washington, D.C., www.dmsas.com

General Contractor: The Beck Group, Dallas, Texas, www.beckgroup.com

Roofing Contractor: Jeff Eubank Roofing Co., Inc., Fort Worth, Texas, www.eubankroofing.com

MATERIALS

Dome Roof

Roof Membrane: Sarnafil G-410 20 Feltback PVC with Sarnafil Decor ribs, Sika Sarnafil, https://usa.sika.com/sarnafil

Acoustical Deck: Epic Metals, www.epicmetals.com

Cover Boards: 5/8-inch DensDeck Prime and 1/4-inch DensDeck Prime, Georgia-Pacific, www.buildgp.com

Low-Slope Roof

Roof Membrane: Sarnafil G-410 20 Feltback PVC, Sika Sarnafil

Cover Board: 1/4-inch DensDeck Prime, Georgia-Pacific

Metal Roof

Standing Seam Panel: 24-gauge Galvalume Power Seam, Fabral, www.fabral.com

Underlayment: Fabral HT, Fabral

Plaza Deck

Waterproofing Membrane: TREMproof 6100, Tremco, www.tremcosealants.com

Insulation: Foamular 600, Owens Corning, www.owenscorning.com

Brick Pavers: Hanover, www.hanoverpavers.com

PVC System Is the Answer for U.S. Bank Stadium Roof

U.S. Bank Stadium is topped with a PVC roof system that display’s the company’s logo. Photo: Johns Manville

When discussions began about the new U.S. Bank Stadium in Minneapolis, Minnesota, there was a request for an outdoor stadium. However, state and local government provided funding specifically for an indoor stadium that would be able to host major events like the professional football championship game and the college basketball championship game. As a result, a translucent roof and mobile front windows were designed to allow natural light to enter the stadium and to give fans a view of downtown Minneapolis. The mobile windows also allow fans to experience outdoor elements while providing protection from snow, rain and cold winter weather. The roof design was developed taking into consideration the budget and the region’s weather; it would be costly to make it retractable, and a sloped roof lends to a more secure option for snowy weather.

Challenging Task

Berwald Roofing Company Inc., headquartered in North St. Paul, Minnesota, installed an adhered PVC roof system manufactured by Johns Manville over the structure’s metal deck. In all, 280,000 square feet of grey 60-mil PVC were installed. The system also included a vapor barrier and two layers of 1.6-inch ENRGY 3, a rigid roof insulation board composed of a closed-cell polyisocyanurate foam core with fiberglass reinforced facers. Half-inch DensDeck Prime cover board from Georgia-Pacific was also installed.

The roofing portion of the project began in April 2015, with an aggressive completion deadline of November 1, 2015. The schedule and logistics on the project posed major hurdles. “Getting material 300 feet up to the roof was our biggest challenge,” says Berwald Roofing Senior Project Manager Steven Hegge. “A big part of that was scheduling time to share the cranes with the iron workers and general contractor.”

Another challenge was storing material during the installation due to the limited amount of space on the roof. “All the decking had to be installed as we went along, just before roof installation,” Hegge states. “We were on a very tight time schedule in this multiple-phase construction project.”

“The general contractor and Berwald Roofing have worked with Johns Manville on numerous stadium projects in the past and preferred to use JM PVC on this complicated stadium project,” notes Johns Manville sales rep Bob Deans. “This application is on a 3.75-inch to 12-inch slope on the north side of the building, which adds to the difficulty of installing a fully adhered PVC roof assembly.”

The Solution

Due to restricted loading space at the jobsite, materials arrived to Berwald’s yard directly from the manufacturer. They were then loaded on Berwald Roofing semi-trucks each day for delivery. Once they arrived at the site, they were immediately lifted to the roof via tower cranes and installed in the most efficient time frame, to meet the owners expected installation timeline.

The stadium seats approximately 65,000 people for most games. However, this space is built to be expandable to hold up to 73,000 attendees for special events such as the professional football championship game, which the stadium is scheduled to host on February 4, 2018, and for events like the college basketball championship game, which will be held there in 2019. U.S. Bank’s logo is prominently displayed on the rooftop. Charcoal grey 60-mil PVC membrane was cut to specification using a computerized cutter to create an exact replica of the U.S. Bank logo. Berwald Roofing then adhered the charcoal grey PVC on top of the grey 60 mil PVC membrane using JM PVC low-VOC membrane adhesive and then heat-welded the edges of material to finish the application of the logo.

TEAM

Architects: HKS Inc., www.hksinc.com; Studio Hive, www.studiohive.com; Studio Five; and Lawal Scott Erickson Architects Inc., http://lse-architects.com
General Contractor: Mortenson Construction, Minneapolis, Minnesota, www.mortenson.com
Roofing Contractor: Berwald Roofing Company Inc., North St. Paul, Minnesota, https://berwaldroofing.com

MATERIALS

Roof System: 60-mil PVC, Johns Manville, www.jm.com/roofing
Vapor Barrier: Johns Manville
Insulation: ENRGY 3® Insulation, Johns Manville
Cover Board: DensDeck Prime, Georgia-Pacific, www.gp.com