Charles Martin Roofing installs both Standing Seam and R-Panel metal roofing.
Here’s a closer look at the two products to help you decide which one may be right for you.
Exposed Fastener System (R-Panel) vs. Concealed Fastening System (Standing Seam)
An exposed-fastener metal roofing system—often called corrugated metal roofing—uses panels that are fastened directly to the roof deck with screws driven through the face of the panel. Because the screw heads remain visible, the system is known as “exposed fastener.” These screws must be inspected regularly to ensure the washers are still sealed and the screws haven’t loosened or deteriorated.
A concealed-fastener system, by contrast, uses panels formed with vertical ribs along the edges. These panels overlap and interlock, and are secured to the roof deck using clips and fasteners that are completely hidden beneath the panels.
Each exposed screw relies on a rubber washer that compresses as the screw is tightened to create a watertight seal. A roof with exposed fasteners will have thousands of these penetrations, and every one of them is a potential leak point. Screws installed at an angle, overtightened, or under-tightened can compromise the seal. Over time, natural expansion and contraction of the metal can also cause screws to back out slightly, creating tiny gaps around the penetration.
Once exposed, these gaps allow rainwater to slowly work its way through the roof. A concealed fastener system eliminates this risk because its fasteners are protected beneath the panels, shielded from weather and UV exposure.
Long-Term Water Protection
Winner: Standing Seam
While both systems can perform well with proper maintenance, the exposed fasteners used in R-Panel roofing make it more vulnerable to long-term water intrusion.
Most Affordable
Winner: R-Panel
Cost is another major distinction between the two systems. R-Panel is one of the most affordable metal roofing options, while standing seam panels sit at the top of the pricing spectrum.
Standing seam roofing can cost twice as much—or even more—than R-Panel, making R-Panel the budget-friendly choice.