If you’ve gotten to this page in this issue, chances are you’re doing what you can to keep up with the latest innovations, designs and styles of architectural metal roofing. Good for you and, just as importantly, your clients. It’s important for you to understand and appreciate the ever-improving long-lasting capabilities as well as the increasing number of aesthetically pleasing options evolving within the metal roofing industry.
Innovation ensures the best roofing material for architectural projects is still metal
Installed properly, metal roofing can offer a watertight system capable of enduring the harshest of elements for decades, all with little maintenance, while providing an attractive appearance.
Metal Roofing Options
Selecting metal as a roofing option opens the door to a growing lineup of design choices. Many early standing seam panels were designed for low-slope applications over open framing—aesthetics were rarely a consideration. With an increasing use of metal roofing in commercial and residential applications and therefore, steeper slopes, aesthetics have become a concern. Architects had a choice between less attractive structural standing seam systems or visually attractive non-structural standing seam systems that had to be installed over solid decks. Fortunately, the industry’s evolution offers architects a wide array of standing seam systems that are both structural and aesthetically pleasing.
It’s important to understand the capabilities of the profile you’re working with.
Structural panels are designed to be installed over open framing on slopes as low as 1/4-inch per foot. Watertightness is required because these systems do not have underlayments as secondary waterproofing.
Non-structural panels are designed to be installed on a solid deck. Most are water shedding (as opposed to watertight) so they should be installed on slopes of at least 3 inches per foot and require secondary waterproofing underneath. These systems include early-generation standing seam systems that utilize separate batten caps. Standing seam systems that feature a fastening flange are popular today and are also nonstructural panels.
Metal tile and metal shingles are designed to replicate the look of clay or concrete tiles and asphalt or shake shingles, while providing the benefits of metal—a lightweight, easy to install and durable product.
Vertical leg standing seam systems are very popular today. These systems are both structural and aesthetically pleasing. These systems feature a seam that is engaged onsite with portable seamers that connect panels together. While vertical leg standing seam systems are designed to have the capability to be installed over open framing, they also are commonly installed over solid decking.
While these are structural systems with excellent watertightness capabilities, specifiers and contractors often install synthetic underlayments over the solid deck. It is also a common practice to use high-temp peel-and-stick underlayments at critical details such as valleys and along the eaves. The underlayments provide an extra layer of protection against leaks and peace-of-mind for all stakeholders.
Installed properly, metal roofing can offer a watertight system capable of enduring the harshest of elements for decades, all with little maintenance, while providing an attractive appearance.
Innovations
One of the more recent game-changing innovations is the symmetrical standing seam panel. Symmetrical standing seam systems do not have male and female seams, like vertical-leg products, but are comprised of panels with matching left and right seams. The panels are joined with a mechanically seamed cap. The panels are non-directional, meaning they can be installed left to right, right to left, or even from the center out.
One former drawback of metal roofing has been the cost of replacement when panels were damaged. Before symmetrical standing seam roofing, if a couple of panels were damaged, it often required the tear-off of those panels and all the panels that were initially installed after them. With a symmetrical standing seam system, the caps adjacent to the damaged panels can be stripped off, which allows for the removal of only the damaged panels. New panels can then be installed and capped. That can be a financial game changer on a replacement project, where a panel or several panels are damaged by flying or falling debris caused by storms or other accidents.
One question that comes up about the replacement of symmetrical standing seam metal roofing panels is color matching. Today’s PVDF coatings hold their color and resist chalking and fading much better than the previous generation of coatings.
Design Specifications
Metal roofing can successfully overcome design challenges as part of a durable and aesthetically pleasing system. It’s important to work through the details—valleys, internal gutters, penetrations, transitions and curbs—anything that could cause a problem … translation: a leak or failure.
It’s important that design teams consult with the metal roofing manufacturer for warranted detail requirements for a particular roof panel system before proceeding with the installation.
Many manufacturers offer factory-formed eave notching that reduce costly secondary fabrication and/or field cutting. Factory-formed eave notching also improves aesthetics due to consistent cuts, rather than via hand snips.
Curved metal roofs are also gaining in popularity and many manufacturers offer roofing profiles that can be curved in the factory or on-site. Curved metal roofing allows architects greater design flexibility and another way to accent their projects.
Conclusion
Metal roofing manufacturers are happy to help with questions on design or any of their products or systems. When you specify any product, you have certain expectations and are likely making promises based on those expectations.
Ken Gieseke is the vice president of marketing at McElroy Metal, Bossier City, La. More information can be found at www.mcelroymetal.com.