05/02/2016
Metal Roofs Last Forever??? Daily I hear the phrase that "Metal Roofs Last Forever". Yet, there is an entire industry based on just replacing and fixing metal roofs...huh? How is that possible? Are they replacing metal on the old airplane hangars or potato sheds from the 1950's? No, they are repairing recent and modern roofing installations. Here is a perfect example of 23 of 24 metal roofs purchased by a school district failing. Read the article at your own risk, it may change your paradigm... (courtesy of Oregon DJC)
Metal roof systems spur concern
By: Justin Carinci in Construction February 10, 2010
Keith Schaber, a roofing consultant, displays a model of a correctly built metal roof. When metal roofs fail, it’s usually because of design or installation problems, not the metal itself, Schaber said.
Often, however, warranties only cover the metal and paint, not the entire roof system.
Faced with the prospect of replacing asphalt-shingle roofs every 15 years, Oregon school district officials have looked for a longer-lasting material. Many have settled on metal roof systems.
And many of those roofs have failed. Roofing consultant Keith Schaber surveyed districts that built metal roof systems since 1998. Officials in 23 of the 24 districts who responded to the survey reported roof failures, Schaber said. They failed in different ways, he said, but never because of the metal itself.
“Of those that have failed, there has not been material failure involved,” Schaber said. “It’s been design or workmanship failures.”
Terry Thetford, facility manager for the Forest Grove School District, had worked successfully with metal roofing as a contractor. Still, he was skeptical of using metal on the Tom McCall West Upper Elementary School, finished in 2008.
The school has a very slight slope, gaining 6 inches per 12 feet. “It’s darn near flat,” Thetford said.
“You don’t find any contractor who will apply their (metal) roof to that low slope application.”
But the roof system manufacturer repeatedly reassured Thetford the system would work. “The manufacturer wanted to make the sale,” he said. “Their application was marginal and their specifications – that we followed throughout – were not correct.”
The system involved joining overlapping metal sheets with rivets and sealant tape. As the metal expanded and contracted, the rivets raked over the ice-and-water-shield underlayment.
The movement also created holes around the rivets themselves. “The first winter, we started having leaks,” Thetford said.
In Redmond, the application was different but the results were the same. Elton Gregory Middle School was built in 2006 and started experiencing leaks soon after, said Doug Snyder, the district’s chief operations officer.
“It’s been a painful lesson,” Snyder said. “Three years into it, we have a building that still leaks.”
Once the roof started leaking, Snyder found that the roofing supplier’s warranty didn’t help. “If you were putting on any other kind of roof, the supplier of the roof has a warranty that deals with the issues we’re talking about.
“When you boil the warranty down from the (metal roof) manufacturers, they’re not valid until you have two years of leak-free conditions.”
Such warranties are getting more attention as use of metal roofs increases, said Steve Olson, principal with Dull Olson Weekes Architects, which specializes in school projects. “The warranty for a metal roof is not written in the same way as it is for a built-up roof,” Olson said.
“Right now, the warranties cover the metal itself and the paint on the metal, but not necessarily the system itself.”
“One thing we’re taking more care with is how it’s designed and detailed in its drawings,” he said. “With metal systems, it’s important to have an expert in the field inspecting, somebody working for the owner or architect that’s an expert and does this every day and knows the details of how these go together and makes sure they’re installed properly.”