A metal roof can be designed correctly, manufactured correctly, and delivered correctly. But if it is not installed correctly, none of that matters. In this episode of Building with Metal, we sit down with McElroy Metal's Weathertightness Warranty team to discuss what separates a good metal roof installation from a great one.
From contractor training and roof inspections to common installation mistakes and warranty requirements, we explore the critical role proper installation plays in long-term roof performance. Whether you're a contractor, architect, consultant, or building owner, this episode offers practical insights into delivering metal roofing systems that perform as intended for decades to come.
"We like to say that a metal roof panel is never gonna leak, but it's the holes that we put in it that cause us problems." Lane Osbon
"Every time you try to wrap a flashing around something, at every corner, there will be a pinhole." Lane Osbon
"One of the things about doing it wrong is it costs the contractor three times as much for the same condition. Because you've got to pay somebody to do it the first time, and if you have to go back and redo it, you gotta pay somebody to tear it apart, you gotta pay somebody to put it back together." Lane Osbon
In 30 seconds
A weathertight warranty is McElroy's guarantee that a standing seam roof keeps weather out for up to 25 years. Only standing seam products qualify, because the factory-applied sealant in the seam can be inspected and verified.
Most warranty problems trace back to penetrations and curbs. McElroy requires welded aluminum or welded stainless steel curbs, because wrapped sheet metal flashing leaves a pinhole at every corner that opens and closes as the metal moves.
Certified installers and approved details decide the outcome. Getting one detail wrong costs a contractor about three times the original price, and certification stays with the company that paid for the class.
A metal roof can be designed perfectly and manufactured perfectly. If it goes on wrong, none of that matters.
That is the case, Lane Osbon makes. He is McElroy Metal's senior technical specialist in the Weathertightness Warranty Department, with 19 years at the company and 32 years in the field before that. He spends his days looking at what works on a roof and what fails.
The panel itself is rarely the problem. “We like to say that a metal roof panel is never gonna leak, but it's the holes that we put in it that cause us problems,” Osbon says. Pipe penetrations and curb penetrations break up a continuous panel, and that is where leaks start.
A weathertight warranty is a guarantee from the manufacturer to the building owner that the roof system will keep weather out of the building for an extended period, once it is installed correctly. If something goes wrong later, the owner has someone to call. McElroy backs that for up to 25 years.
It does not apply to every product. McElroy issues weathertight warranties on standing seam products only. Those panels get factory-applied sealant injected into the seam, so the lapped seam is fully sealed for the length of the panel. Through-fastened roofs are different. There is no way to guarantee every fastener goes in right, and inspecting every fastener on an exposed roof would take forever. So those roofs are not covered.
One of the biggest misconceptions Osbon hears is that every warranty is the same. They are not, and the language inside them is not either.
McElroy offers two basic types. A joint warranty is held by the installer and the manufacturer together. The installer is responsible for the roof for the first 24 consecutive months, then McElroy carries it for the rest of the term. A single-source warranty gives the owner one place to go: McElroy investigates, decides whether it is a McElroy issue, and handles what needs handling. Each type also carries different liability limits, which set how much McElroy will pay out.
Getting to a warranty takes real work on McElroy's side. The process starts before the product is even bought, with a pre-approval review of the roof plan. The team checks for places where water cannot drain, since water cannot pond on a metal roof. Then the installer submits detailed drawings, McElroy verifies the details meet warranty requirements, and only after install does an inspector go look at the actual roof.
The area that most often blocks a warranty is the same one that gives contractors headaches: curbs and penetrations.
A lot of companies wrap sheet metal flashing up a curb. McElroy does not allow that under a weathertight warranty. The requirement is a welded aluminum or welded stainless steel curb. The reason is simple. “Every time you try to wrap a flashing around something, at every corner, there will be a pinhole,” Osbon says. Metal is always moving as the temperature changes, so those pinholes open and close over time.
Welded aluminum and welded stainless also resist corrosion. You can weld galvanized, but the heat burns the coating off the edges, and the recoat does not last. Corrosion then attacks the panel's paint and coatings, which voids those warranties too. No pinholes, no corrosion.
McElroy's installer class teaches the parts, pieces, and components of its systems, how they go together, and what inspectors look for. There is hands-on work on two products and coverage of every standing seam system, plus a certification test at the end.
There is a paperwork reason too. Many commercial specs require an installer approved by the manufacturer. The only way McElroy can document that approval is if the installer has passed the class. Anybody can buy the metal. Certification is what McElroy can put on paper.
Certification belongs to the company that paid for the class, not the individual. If a certified installer leaves, the certification stays behind, and the company has to send someone new. The warranties require a certified installer on the project while the metal is going down, and Osbon says he can usually tell from the install whether a certified person was there, because there are fewer problems.
The class is not free, and it pulls a person out of the field for a couple of days. The payback is bigger. “One of the things about doing it wrong is it costs the contractor three times as much for the same condition,” Osbon says. You pay to do it once, then to tear it apart, then to put it back together.
Safety comes first. The contractor has to provide safe access, and inspectors will not do anything unsafe to reach a steep roof.
From there, the inspector usually starts at the eave and works up, carrying the set of approved details to the job site. They check the eave, then the ridge, looking at outside closures, ridge trim attachment, fastener spacing, and whether the lap joints are sealed with no voids. They check the rake, the Z closures, and the valley, including whether the panel ends are sealed into the valley. Then they look at every penetration and curb. They photograph everything, good and bad, and turn it into a report that the contractor signs off on after corrections. The final warranty cannot be issued until all corrections are made and all invoices are paid.
One small thing makes a real difference in the field: the details have to be on the roof. Osbon has lost count of how many times he has asked an installer for the approved details and heard “what details?” or been told they are down in the truck. Tablets help here, since the approved plans stay on the roof and do not blow away.
Asked for a single tip, Osbon keeps it plain. “Know the product and know what's required to install it properly.” Do that, and the job goes better, and the problems shrink over the life of the roof.
The path from good to great is not complicated. Know your product, build a relationship with your manufacturer, and get trained by them. McElroy's team is on the phone with contractors every day for exactly that reason.
McElroy Metal manufactures metal roofing and siding products for residential, commercial, agricultural, and industrial applications. Headquartered in Bossier City, Louisiana, with plants and service centers across the U.S., McElroy supplies contractors, architects, designers, and building owners with metal panel systems, accessories, and the engineering expertise to use them well.