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Commercial Roof Lives Up to a Big Challenge

Article-Commercial Roof Lives Up to a Big Challenge

GAF Stanley Center roofing project image
Stringent standards and exacting specifications called for sustainable, high-performance products that would stand the test of time—and water.

A commercial project sporting sustainable, ultra-high-performance roofing materials provided Black Hawk Roof Co. with bragging rights for having installed a roof on one of only 30 buildings worldwide to have earned the Living Building Challenge recognition. 

Several years ago when Black Hawk senior project manager Mike Kerker received the specifications from which to bid for this project, he knew he’d have at least two big challenges: finding products that met the high standards of the Living Building Challenge, a program from the International Living Future Institute requiring buildings to generate more energy than they use; capture and treat all water (including stormwater, potable water and water used in the plumbing system) on-site; and be produced using only health-friendly materials, and finding those products during the pandemic. 

Kerker had to abide by the Red List of the “worst-in-class” materials, those that the institute says are known to pose serious health and ecosystem risks and should be phased out. To stay true to the specs and the desires of the owner, Kerker and his team won the bid by choosing products they’d never used but that came from a manufacturer that he has long worked closely with.  

Value alignment 

The Stanley Center for Peace and Security, located in Muscatine, Iowa, works to drive policy on climate change and nuclear weapons and the prevention of mass violence and other atrocities. President and CEO Keith Porter said that for its new headquarters, the Stanley Center team wanted to put their “core values into action in a decision-making process around a building …. The Living Building Challenge lined up with our values.”  

GAF’s products “fit the bill right away,” said Kerker, who ensured on the specs that the materials were preapproved for use in Living Building Challenge projects. He ultimately used only GAF products for the project, including GAF EverGuard Extreme TPO membrane, EnergyGuard NH HD polyiso cover board and EnergyGuard NH polyiso insulation. 

While pandemic supply issues proved to be a roadblock for many materials—“commercial contractors took the worst hit out of anybody in the industry,” Kerker said GAF got his firm the materials on deadline and Black Hawk completed the work in December 2022. 

Challenges conquered

Despite never having used these specific GAF products, Kerker said, application for the 100-square roof wasn’t difficult. But he was “thrown for a little bit of a loop” when he learned he had to use a mechanical fastening system rather than adhesives. Kerker typically prefers adhesives for aesthetic reasons.  

“But we saw that the mechanically fastened system would serve the purpose,” he said, “and by testing we saw it would have better uplifts (and) better wind speed warranties. It was a better system overall.”  

Black Hawk used a heat welding process to fuse the TPO over itself and essentially envelop the fasteners so none are exposed and won’t allow water access. 

The other tricky bit was dealing with the additional rainwater on the roof. A solar array was speced, held down with ballast weight, a majority directly on the TPO; it is cantilevered, and rainwater drains directly back onto the roof. The water is then diverted to drains and collected in cisterns to fulfill the Living Building Challenge requirement to reuse and repurpose rainwater. 

Any sheet could handle the rain load, but Kerker felt a premium-quality product “would hold up longer and better.”  

“And in an instance like this where you've got a solar array ballast system directly over it,” he said, “if you do have failures, it's going to be real pricey to repair. I know that the GAF Extreme has excellent puncture resistance, which is important for future maintenance on the solar arrays.” 

Kerker said the toughest hurdles on this project were the paperwork and checks and balances required to fulfill the Living Building Challenge requirements.  

“But I learned so much doing this project,” said Kerker, who grew up two blocks from this building. “We put down a good quality roof that we’re all proud to have our name on, and I’ve got bragging rights where I can say, ‘I’ve done one of these projects, and there are only 30 others (Living Building Challenge projects) in the world.’”  

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