Zinc rookie takes on challenge

One directive for construction of four new residence halls on the campus of Grinnell College in Grinnell, Iowa, was to use a roofing material that offered tremendous longevity.
“The board of directors charged us with finding a product that would last 50 years,” says Mark Godar, director of facilities management. To meet that objective, the design and construction team opted to specify approximately 15,000 square feet of pre-weathered blue-gray RHEINZINK titanium zinc roofing and façade panels on the four new buildings.
“Come back in 50 years and we’re convinced we’ll be as happy then as we are now,” Godar says. “We considered a number of material options for the roofs. Frankly, we weren’t familiar with RHEINZINK. We did a lot of research and found that it has been used extensively in Europe for years. RHEINZINK provided the longevity that we sought. And their director of technical services, Georg Koslowski, made an informative presentation in conjunction with the roofing contractor. The material clearly met our needs and we couldn’t be happier with the outcome.”
Finding the material is the easy part — now find a willing and able installer.
Enter roofing contractor Carl Poe, who had never before worked with RHEINZINK. “Other materials were considered but the architect specified RHEINZINK and it was definitely the right choice,” says Poe, the president of Poe Roofing & Sheet Metal in Montezuma, Iowa. “The job was complicated since every building had a variety of complex curves combined with vertical façades. One building had a barrel roof with eight flattop dormers. That’s a real challenge. The details were critical. The design also included an internal perimeter gutter system.
“It probably wasn’t the best first one to jump into. I’m not going to say it wasn’t scary when we were going through the bidding process, but I really have to credit Georg, he walked us through the whole thing. We were required to go through training and between Georg and his people, we came away pretty confident about the whole thing.”
RHEINZINK America provided technical training and certification for Poe and a five-person crew prior to beginning the job. “It was fairly intense, but it was very much needed,” Poe says. “It’s a different animal to work with. Some of the tools, we didn’t even know they were available, the tools the craftsmen use.”
Poe says one thing stressed over and over was that no caulk or rivets would be used during installation. After a week of training and six weeks of going over shop drawings, working out the details and making sure everyone was on the same page, the crew of Poe Roofing was ready to go. “That kind of attention to detail really paid off,” Poe says. “By then, everybody knew what they were doing.”
Koslowski also attended the first project meeting on-site and was “great to work with,” Poe says.
The project consisted of four separate buildings, including the main building with its barrel roof and eight dormers. The others had a 12:12 pitch with a half-barrel over the entryway. Poe says overall, the project went as well as could be expected.
“We started in the dead of winter, waiting until the brickies were done and we still finished up in August, before school started,” Poe says. During the wet spring, there were occasions when Poe’s four-wheel drive lift ended up stuck in the wet ground. A borrowed Caterpillar was called in to push the lift along the building.
Iowa winters provide some snow and plenty of cold and wind, which combine to add to the considerations when installing zinc. “Because of the molecular structure of zinc, the colder it is, the more it wants to crack as you’re shaping it,” Poe says. “We didn’t really have to fight too much with the cold. We formed the panels in the shop and took them to the worksite. We did have a heated trailer on site if we needed it.”
The long panels were transported to the site on a large, custom-built cradle and raised to the roof via crane or extendable forklift and installed.
So as not to crack the panels during installation, Poe’s crew did no seaming until July, “when it was nice and hot.” During the colder months, panels were installed, hand-crimped to the clips  — but not seamed.
“We made the panels in the shop on bad (weather) days and if it was decent, we were out at the site,” Poe says. “Because of the late start, we had some lulls. And it was a tight site to work at, it was tough on all the trades.”
Now that Poe has taken the zinc plunge, he won’t be afraid to jump in again. “We’ve done a couple of smaller jobs, nothing big,” Poe says. “We worked with RHEINZINK at the Omaha Performing Arts Center. It’s really not that big of a deal to get into. We’d like to do more. It’s just a matter of focusing on finding those jobs.”
In addition to learning how to work with an exotic metal, thereby expanding the capabilities of his business, Poe acquired an appreciation for the metal with a rich history in Europe.
“What sticks in my mind and I think in the minds of everyone who went through the training and worked on the project, is that if you’re using a product capable of lasting 150 to 250 years, obviously proper installation is real important,” Poe says. “You can’t take a product with those capabilities and use accessories that shorten its lifespan. Zinc moves more than steel, so you have to accommodate that movement; you can’t use a fastener that will restrict movement.”
For now, it is Poe’s signature zinc project. “I’m very pleased with how it turned out,” he says. “I have a great time taking people to the college to show them our work. It’s opened a lot of doors for us.”

William Rawn Associates Architects of Boston designed the project. 

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