Offering a combination of performance, aesthetics and cost savings, metal roofing systems are a popular choice for a range of building projects from commercial to residential. However, within the family of metal roofing panels, the options are abundant. Choices include single skin, insulated, standing seam, curved, exposed fastener and concealed fastener systems, each offering different benefits for various roofing requirements.
Spring Fire Department Station No. 78 in Spring, Texas, features a mechanically field-seamed, vertical leg standing seam roof system with a 2-inch-tall slim rib using MBCI SuperLok panels in Medium Bronze.
When selecting a metal roofing system, factors to consider include desired performance capabilities and design criteria, as well as the climate conditions, roof slope, geometry and substrate of the project. For projects that require superior weather performance with aesthetic appeal, standing seam metal roof systems are one of the most durable and weather-tight roof systems available in the industry.
Why Specify a Standing Seam Metal Roof System?
Standing seam metal roofing is a concealed fastener roofing system which features vertical or trapezoidal legs with a flat space in between. Its concealed fastener design provides a clean, seek appearance while also ensuring that the fasteners aren’t exposed to the elements, which could cause them to fail over time. Since these panels are attached to the roof deck with clips, they’re free of any holes created from fasteners, which could allow moisture to seep through. Additionally, the fastener clips are designed to accommodate thermal roof expansion and contraction, as well as various thicknesses of fiberglass insulation. When properly installed, standing seam metal roof systems are an extremely effective and long-lasting material choice.
There are various styles of standing seam metal roof panels, including mechanically field-seamed and snap lock. These styles can be further delineated by seam shape or profile such as trapezoidal rib, vertical rib, square rib and tee rib. The choice of the rib profile, as well as the rib spacing is generally an aesthetic preference of the designer; however trapezoidal panels channel larger volumes of water and vertical rib panels are a popular choice in applications where the roof features details like hips and valleys. Knowing which panel style will best suit a given situation will help ensure a successful installation.
When specifying a standing seam metal roofing system, important criteria to consider are roof slope, roof run (distance from eave to ridge), weather conditions (such as ice or snow) and architectural features such as hips, valleys, dormers, parapet walls, etc.
The Spence Residence in Guntersville, Ala., features a snap-together standing seam roof system with a 1 3/4-inch-tall vertical rib using MBCI LokSeam panels in Slate Gray.
Popular Standing Seam Metal Roof Panels
Mechanically field seamed panels require a roof seamer to bend the panel edges and lock the sheets together, creating a standing seam. Double lock seam panels are folded twice with 180-degree seams and single lock seam panels are folded once with 90-degree seams. While the mechanically field-seamed process adds labor costs to the installation, these panels have a tighter seal providing greater wind and water resistance to withstand the most rigorous weather conditions. Double lock seam metal roof panels are often ideal for low-pitch roofs without hips and valleys where water runoff is slower, as well as in areas that experience heavy ice or snow.
One-piece snap interlock panels easily snap together to create a finished seam. The panel seam configuration allows the panels to lock together with factory mastic staying compressed, creating a watertight seal. By eliminating mechanical seals, snap-lock systems are often more cost effective and offer shorter installation times with lower labor costs. While these panel systems are preferable for roofs with steeper slopes, one-piece snap interlock metal roof panels provide effective weathertightness when installed in the correct application and design.
Two-piece snap interlock panels require a batten cap to be installed over the two connecting panels to create a weathertight seal. Typically, the clips used for this panel would secure the panel to the substrate and hold the batten cap on, keeping the factory applied sealant in compression. Two-piece snap interlock panels should be installed over a waterproof solid substrate on roof slopes 3:12 or greater. These panels are easier to install in complicated roof designs such as those seen in residential construction. With quicker installation times, this standing seam metal roof panel system is often an economical way to achieve an aesthetically pleasing roof.
Regardless of which roofing type you choose, standing seam metal roofing systems are a durable and energy-efficient alternative to standard roofing products. Engineered to withstand the elements, standing seam metal roof panels offer a long life expectancy and have fire and impact resistance ratings. Strong, sleek and attractive, standing seam metal roof panels offer a unique combination of form and function creating a high-performance roofing system that is both aesthetically pleasing and structurally sound.
Randy Tweedt is the technical service/warranties manager at Cornerstone Building Brands, Cary, N.C. For more information, visit www.cornerstonebuildingbrands.com.