What Is a Standing Seam Metal Roof Panel?
Standing seam metal roof panels are the core component of a metal roofing system. Unlike corrugated metal panels that use exposed fasteners, standing seam panels conceal all the fasteners underneath the seams where two panels meet. Those seams run vertically up the roof and sit elevated above the panel surface.
What You Need to Know
Standing seam panels are not all the same. The specs you choose determine how the roof performs, how long it lasts, and what it costs. Here are the decisions that matter:
Material. Most panels are Galvalume, a steel coated in aluminum and zinc. If the home is within a mile of coastal or brackish water, aluminum or copper are better choices because they handle corrosion better. They cost more but they are the right call in that environment.
Gauge (thickness). Panels typically come in 29g, 26g, or 24g. Thicker is more durable. 24g is the standard for residential work. 29g is too thin and will oil can and dent easily from everyday weather.
Width. Panels range from 16 to 21 inches wide. Narrower panels create more seams and a busier look. A 16 to 17 inch panel is standard for residential. Wider panels are more common on commercial buildings.
Seam method. Snap-lock panels interlock like a lego and are faster to install. Mechanically seamed panels use a machine to crimp the seams, which creates a tighter, more waterproof connection. Mechanically seamed panels can be used on very low slope roofs down to a 0.5/12 pitch where snap-lock cannot.
Fastening. Panels can be fastened with a fixed nail strip or floating clips. Floating clips allow the panels to expand and contract with temperature changes throughout the year. In the mid-Atlantic region with its range of hot and cold seasons, floating clips are the right choice. A fixed nail strip gives the panels nowhere to go.
Oil canning. This is a visual waviness that can appear on the flat surface of metal panels. It can result from thin gauge panels, uneven decking, or a roof that was not built to allow for natural expansion and contraction. Striated or ribbed panels help reduce the appearance. Matter also installs a foam backer rod behind every panel to fill air gaps between the panel and the decking, which helps prevent oil canning even on surfaces that are not perfectly flat.
What Matter Roofing & Construction uses. Englert panels, Galvalume, 24g, 17 or 21 inch width, mechanically seamed, floating clips, and foam backer rod on every panel. (Alterations are accepted upon request)
Why You Need to Know
A metal roof costs two to three times more than a shingle roof. If the panel spec is wrong, you pay premium price for a roof that performs like a budget one.
Exposed fastener panels (corrugated metal) are not appropriate for habitable buildings. The screws get wet with every rain, rust out over time, and eventually leak into the property. Concealed fastener panels like standing seam exist specifically to solve that problem.
Floating clips versus a fixed nail strip is one of the most critical decisions in the system. Without the ability to expand and contract, panels will stress the fastening points over time. In a climate like Maryland with real seasonal extremes, that movement adds up.
29g panels will oil can and dent. 24g costs more but holds its shape and its finish far longer.
View Standing Seam Metal Roof Panel on Our Job-Site
We completed this Standing Seam Metal Roof Installation in Monkton, MD. Click here to view the job photos in our portfolio.
We completed this Standing Seam Metal Roof Installation in Havre de Grace, MD. Click here to view this job in our portfolio.
Bottom Line
The panel you select determines almost every other decision in the system. The seam method, the fastening style, the gauge. Getting the panel spec right is where a metal roof is won or lost.
Frequently Asked Questions
What is the difference between standing seam and corrugated metal roofing?
Standing seam panels conceal all fasteners underneath elevated seams that run vertically up the roof. Corrugated panels use exposed fasteners that get wet every time it rains, rust out over time, and eventually leak. Standing seam is the appropriate choice for habitable buildings.
What gauge metal panel should I use for a residential roof?
24g is the standard for residential work. It is the most durable option commonly used for metal roofing and holds its shape and finish far longer than thinner options. 29g is too thin for residential use and will oil can and dent easily from everyday weather.
What is oil canning on a metal roof and how do you prevent it?
Oil canning is a visual waviness that appears on the flat surface of metal panels. It is caused by thin gauge panels, uneven decking, or panels that have no room to expand and contract naturally. Using 24g panels, floating clips, striated panels, and a foam backer rod behind each panel all help prevent it.
What is the difference between snap-lock and mechanically seamed panels?
Snap-lock panels interlock like a lego and are faster to install. Mechanically seamed panels use a machine to crimp the seams together for a tighter, more waterproof connection. Mechanically seamed panels can also be used on very low slope roofs down to a 0.5/12 pitch where snap-lock cannot.
Why do floating clips matter on a standing seam roof?
Floating clips allow the panels to expand and contract naturally with temperature changes throughout the year. A fixed nail strip locks the panels in place with no room to move. In the mid-Atlantic region where temperatures swing between extremes, panels fastened with a fixed nail strip will stress the fastening points over time.