Many options are available to building owners faced with choosing a new roof. Consequently, finding the right roofing system to meet the building’s longevity, durability, and aesthetic goals is essential. Two options available to building owners for new construction and retrofits are R-Panel roofing and standing seam roofing.
R-Panel is a generic industry term used for a metal roof or wall panel with ribs 1 1/4" tall spaced at 12" on-center. This panel style offers a 36" wide coverage and attaches to the building substructure with exposed fasteners.
Initially, R-Panel profiles were used almost exclusively in the pre-engineered metal building industry. Over time, however, R-Panel has also become quite popular for residential roofing, especially in the southwest.
It is essential to realize that tens, if not hundreds, of different companies manufacture R-Panel. While they all produce a product that matches the basic specifications above, the quality levels can be anything but similar.
Two common differences to consider involve the panel gauge and paint system. At McElroy Metal, we're proud to offer our R-Panel in 26 & 24 gauge and two different paint systems. We recommend our Kynar 500® paint system for projects with long-term performance requirements; however, we also provide a silicone-modified polyester system (SMP) for cost-sensitive projects. If you aren't familiar with the differences, you can learn more about the paint systems here.
Beyond paint systems and panel gauges, the quality of the actual roll-forming equipment can vary greatly. While it might not seem obvious, tooling quality affects everything from panel appearance to ease of installation and performance.
Some smaller roll-formers (often called regional roll-formers) produce R-Panel from tooling that doesn’t offer the necessary panel length and width control. Still, others struggle to match the crispness of the panel ribs that other, more high-end manufacturers provide.
Bottom line: Unfortunately, not all R-Panels are created equal. Consequently, it’s essential to ask questions regarding panel thickness, paint systems, and tooling quality before selecting a manufacturer for R-Panel products.
Standing seam metal roofs are typically installed vertically and run from eave to ridge. Standing seam systems feature a raised interlocking seam that connects adjoining panels and is popular in commercial, residential, and industrial settings.
Standing seam systems are installed with hidden clips and fasteners, eliminating visible fasteners that are more prone to leaking over time. As a result, some standing seam systems often offer what is called a weathertightness warranty. These warranties are designed to assure building owners that their building will remain leak-free for a specified period, often 20 years.
In comparing the two systems, it’s essential to realize that R-Panel is widely available, often offers a shorter lead-time, and is more economical to purchase and install than standing seam systems. Part of the difference lies in the design differences between the panels.
R-Panel covers 3’ whereas standing seam products more often cover 16-18”, meaning it takes two standing seam panels to cover the duplicate square footage as one R-Panel. Two panels vs. one affect everything from panel production at the manufacturer to packaging, transportation, and even crew installation, so the difference in panel width is significant.
R-Panels also use exposed fasteners for attachment, whereas standing seam panels utilize clips and hidden fasteners. While that difference might seem minimal, it impacts cost. The clip is an additional cost to standing seam systems, but clipped systems also install more slowly than an exposed fastener panel like R-Panel.
Given the higher product and installation costs, you might wonder why any owner would choose standing seam products over an R-Panel style. The downside of R-Panels is that expansion and contraction can cause the fasteners to “slot” over time and wear away a bit of the metal. When this occurs, water can enter the building. Once this happens, owners choose to either replace the screws with an oversized fastener to cover the elongated hole or remove and replace the panels.
While that isn't an ideal situation from either a cost or maintenance perspective, it is essential to realize that expansion and contraction are functions of thermal cycling. Consequently, the phenomenon worsens in areas of the country that experience large temperature swings. It's also noteworthy that thermal cycling doesn't typically affect panels under 40' long. So for building owners with panels below 40' or those located in areas where temperature changes are minimal, it can be a non-issue.
Conversely, fasteners don't pierce standing seam panels during installation. Instead, a clip is commonly attached to the substructure, and the panels then engage with the clip. This clip allows for much more significant expansion and contraction than an R-Panel or any other exposed fastener panel can accommodate. Since there are no exposed fasteners in a standing seam roof system, thermal cycling (or expansion and contraction of the panels) doesn't limit the system's life expectancy.
While standing seam systems cost more to purchase and install, many owners find the enhanced durability, reduced likelihood of leaks, and minimal maintenance worth the extra cost.
Throughout this article, we’ve referred to R-Panel and standing seam panels as similar but different things. But that’s an unfair comparison. R-Panel is a specific panel type where the standing seam represents an entire product family.
While standing seam products are similar in their attachment method, there are numerous profiles and applications for standing seam panels. Although the different panel types can work on virtually any building that meets the required roof slope, there are certainly some more common products by industry segment.
Consequently, this product type has been a mainstay in the commercial/industrial and PEMB markets since the early 1960s. Given its trapezoidal shape, it is better suited to straight panel runs and projects without valley conditions. Consequently, weathertightness warranties may not be available for all projects with this panel type.
So which is the right product for your roof? Only you can decide that, but it’s essential to consider your appetite for ongoing maintenance vs. cost in your decision-making process. If cost is your predominant criterion, then R-Panels may be your best option.
However, if you’re interested in a longer-term solution with a lower likelihood of leaks, standing seam systems may be your best choice. If you’d like to discuss your specific project, contact us, we’re always here to help!