A Force of Nature

Library Reroof Following Intense Storm in Phoenix, Arizona

by John Plescia, CEO, Star Roofing Inc.

 

One Saturday evening in 2017, an intense weather phenomenon known as a microburst lifted the entire roof structure off of the Burton Barr Central Library in Phoenix, Arizona. Thankfully, the roofing system used on the library, including the membrane and pavers, was designed to lift, yet remain mechanically stable, as a way to adapt to the stresses put on the structure during extreme weather conditions.

Unfortunately, the stress of the storm led to a broken sprinkler system located under the roof on the top side of the metal deck. Water rained down from a raised fifth floor, which allowed it to spread further through the building. Upon initial evaluation it was believed that 50% of the building had water damage. The immediate goal was to temporarily protect the roof from potential rain, since the weatherproof membrane had been disturbed, but not the roof structure, and to dry out the moisture inside the building.

Star Roofing Emergency Services, Phoenix, was brought into the project by BRYCON Construction Company, Chandler, Arizona. A crew of Star Roofing contractors spent the weekend performing roof repairs to mitigate further interior damage. Star Roofing’s estimating and operations departments worked with BRYCON Construction and the City of Phoenix to put together reroof specification and budget pricing to install a completely new roof.

The existing roof system consisted of loose-laid EPDM over two layers of 4″ ISO insulation on a steel deck. Ballast consisted of 1-1/2″-thick interlocking pavers, with a complete removal of the existing system required. In all, 23 semi-truck loads of insulation, 6-1/2 tons of rubber, and 255 tons of concrete pavers were removed. Star Roofing was able to recycle 100% of the pavers at CEMEX USA in Phoenix, where they grind the concrete pavers and use the material in making new concrete. The EPDM and the roof insulation were also recycled through Nationwide Foam Recycling.

Access, as well as a roof height of 92’, provided challenges, especially in the roof removal process. During this process, 34,000 pavers, each weighing 15 pounds, were placed in small trash bins 45 at a time, as this was the maximum weight per bin that Star’s crane could handle with the angle of the building. The replacement of the damaged sprinkler system also presented a unique situation for the repair team. Because of possible litigation, the sprinkler system piping was marked, disassembled, and lowered to the ground. The system was then reassembled in the parking lot for inspection by the City of Phoenix and their consultants.

The new roof system is 5/8″ gypsum board mechanically fastened with gray colored screws, which had to be kept in a straight line to match the underside of the exposed metal deck. A self-adhered vapor barrier was installed over the gypsum board. Next, one layer of 3″ ISO and two layers of 2-1/2″ ISO insulation, all set in adhesive, were installed. Additional taper was also installed to provide slope.

A special installation was required at the perimeter to protect against another wind occurrence. Four layers of 5/8″ gypsum board and two layers of 2-1/2″ ISO insulation, all secured with adhesive, were installed 18’ in from the roof edge. The entire area then received a Sarnafil® 72 mil. FleeceBACK PVC membrane that was fully adhered and carries a 25-year warranty.

The project progressed smoothly and was completed on schedule by Star Roofing Emergency Services. Not only did Burton Barr Central Library save on repair costs by recycling their used materials, the environment also benefited from their sustainability goals by keeping a large amount of roofing materials out of the landfill.

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