RhinoBond® and PowerGrip®, A Safe Bet for T-mobile Arena Roof
Life in the Fast Line
It may have seemed the odds were against Commercial Roofers, Inc. of Las Vegas when they were given the job of installing a roof over the new T-Mobile Arena in Las Vegas. Construction of the 20,000 seat arena, scheduled to open in April, 2016, was on a fast track schedule, and Commercial Roofers was expected to install 275,000 square feet of Johns Manville TPO membrane with R-30 isocyanurate insulation over a steel deck in just 45 days. Fortunately the roofing installers had an ace up their sleeve: the JM RhinoPlate Induction Fastening System based on RhinoBond technology from OMG Roofing Products of Agawam, Massachusetts.
RhinoBond, designed for use with thermoplastic PVC and TPO roofing systems, uses advanced induction welding technology to bond the membrane directly to specially coated plates that are used to secure the insulation to the deck, all without penetrating the roofing membrane. The result is a roofing system that requires 25 to 50 percent fewer fasteners and plates and up to 30% fewer membrane seams to weld on the roof.
“As with many construction projects, the roof of the arena was to be completed before the walls, so we were expected to maintain a very demanding schedule,” said Scott Howard, president of Commercial Roofers. “Fortunately, because it uses fewer fasteners and there are fewer seams to weld, the RhinoBond system allowed us to keep pace with the aggressive timeline.”
“The 45-day timeframe was extremely fast for a roof of this size,” said Michael Lee, senior associates of Curtain Wall Design Consulting (CDC), Inc. of Las Vegas. “RhinoBond is a lot faster to install than other fastening methods. For instance, if you are using adhesives you have to worry about cold temperatures, but RhinoBond isn’t affected by that.” Lee also mentioned that there are much fewer supplies to store and stage on the roof with the RhinoBond System.
“Commercial Roofers has installed more than 30 RhinoBond roofs with no failures, so we know it is a proven system that works,” Howard said. “Not only is it a very clean system, but also with RhinoBond the roofing crew doesn’t have the repetitive bending like you do with a mechanically attached system.
No Wind Uplift Gambles
The arena is insured by Factory Mutual (FM), so the roofing system had to comply with the FM-4470 standard. With RhinoBond the fastening points are spread out across the roof deck in a grid-pattern rather than concentrated in the seams of the membrane, so the wind uplift load is distributed more evenly. The result is less point loading on each fastener, enabling the system to achieve higher wind ratings with fewer fasteners, all while using full width rolls of membrane to reduce overall seam welding. The T-Mobile Arena was installed according to an FM I-90 Windstorm Classification Rating that required 20 fasteners and plates per square.
On top of the insulation, a 60 mil JM TPO membrane was installed. TPO membranes have become a very popular commercial roofing material in the past several years. JM differentiates its TPO by offering the industry’s highest thickness-over-scrim, with manufacturing standards that are more than 150% of the ASTM requirement; exceptional solar reflectance with an SRI of 101 that exceeds the EPA standard; and exceptional strength, with a 1,300 x 1,300 denier reinforcing scrim that provides better puncture and tear resistance for long-term performance.
There was another challenge facing Commercial Roofers: most of the roof is dome-shaped and was built and the roofing membrane was installed at a nearby location and then hoisted onto the arena after the roof was completed.
“That’s another advantage the RhinoBond System has over an adhered system,” Lee remarked. “When there is a dome and the roof is jacked up and temporarily shored, the steel structure under the roof will do some settling,” he explained. “A fully adhered system would be too rigid to allow for the settling, whereas the RhinoBond System is more flexible.” Fortunately, Commercial Roofers has a lot of experience installing arena roofs so the job wasn’t too complex for their crew, which ranged from six to 20 people.
“OMG Roofing Products’ field representative also helped by being very responsive to our needs, especially involving the equipment,” Howard pointed out. “OMG’s fast response really helped to make us more productive.” Lee echoed Howard’s sentiment about OMG field representatives. “The staff there really knows their products, and OMG even went to Factory Mutual to make sure the roof would comply with their wind-uplift requirements. In my opinion, OMG Roofing Products is in the top five percent of manufacturers in the roofing industry.”
A Winning Roof
: The final challenge was installing the large T-Mobile Arena sign on the roof. Each individual letter in the T-Mobile name is nearly 20-ft. long. The letters are backlit in T-Mobile’s signature magenta color, and are individually secured to the roof. For this part of the project, OMG Roofing Products’ PowerGrip and the larger PowerGrip Plus products were specified.
PowerGrips are designed to hold solar rack systems and other roof mounted equipment - such as giant letters - securely to the roof deck, all without having to core the roof down to the structural steel, and without having to create individual pitch pockets. Instead, PowerGrips are made of the same material that is on the roof, in this case JM TPO, and provide a secure connection directly to the roof deck or structural members. This takes the wind load off the membrane and places it onto the structural deck, where it belongs.
Installation involves locating where the fastener is going, driving the fastener into the metal deck underneath the insulation and membrane, sliding the PowerGrip over the fastener head, and hot air welding it in place. Since there is no need to cut open the roof down to the deck, most PowerGrips can be installed in less than 10 minutes.
“We had a crew of two-three guys working on the sign installation, and they had to install 200 PowerGrip Plus units and 250 PowerGrip units in just a few days,” Howard remarked. “The crew found the PowerGrips much easier and faster to install than other attachment methods, and the roof and the sign really look great.”
Thanks to the dedicated crew and to the OMG products that help to improve rooftop productivity and enhance roof system performance - the RhinoBond induction welding system and OMG PowerGrips - Commercial Roofers was able to complete the roof installation on time.
“They took this project very seriously and it was incredible how they not only did the installation quickly, but with quality. It’s hard to do both,” Lee commented.
“We like working with RhinoBond and PowerGrip because both are fast and yet gives us a quality application,” Howard commented. “RhinoBond was the choice for this project hands down, and the addition of the OMG PowerGrips for the signage was a no brainer for us too. We will continue to use these and other OMG Roofing Products again and again. They are winners in our book!” We wholeheartedly agree!