Updated on January 11th, 2021
Corrugated metal roofing and its close cousin, ribbed roofing, offer the original style of corrugated (iron) steel roofs. At an average cost of $4.00 to $8.00 per square foot installed, corrugated metal is priced somewhat similarly to asphalt shingles, especially at the low end, and yet it’s far more durable, energy efficient, and with proper maintenance can last far longer than asphalt shingles.
What Exactly Is Corrugated and Ribbed Metal Paneling?
Sheet metal coil (typically galvanized steel or aluminum) gets fed into a roll-forming machine that shapes the metal sheet into the curvy U-shaped, wavy pattern — the primary variation for corrugated metal roof and wall panels.
Corrugation gives metal panels considerable structural strength, which makes it possible to use these otherwise thin sheet metal panels for building envelope applications, such as roofing and cladding. Check out the video below to see how it’s made:
Old School Corrugated Steel Panels
During the height of the Industrial Age, steel became relatively cheap and abundant. Metal was viewed as the kind of material that offers an economically viable way to cover large agricultural and industrial buildings. Back then, the corrugated steel panels were often non-coated, but that was not a problem since there were plenty of spare steel roof and wall panels to replace any corroded ones.
As steel corrodes, it develops visible rust. When the old steel panels would get too unsightly, or worse develop holes resulting in leaks, they would get replaced with the shiny new pieces.
Today, corrugated metal panels are often chosen because of their old school appearance and relatively low cost.
Most modern corrugated steel panels are normally coated with a metallic (zinc) finish to prevent oxidation and corrosion, and thus made to last for decades.
G-60 vs. G-90 Galvanized Steel Panels and their Paint Finishes
Steel panel coating process is referred to as galvanizing. There are two types of galvanized steel panels: G-60 and G-90 steel panels. G-60 refers to the low-end, lower quality and lower cost galvanized steel, while G-90 is the higher-end, thicker and longer lasting grade of galvanized steel.
G-90 steel panels are also normally finished with a higher-end paint finish such as Kynar 500 as opposed to the cheaper acrylic paints normally used for the low-end G-60 steel panels.
Note: G-90 (26 or 24 gauge) steel panels finished with Kynar 500 paint can be used in residential applications, while G-60 (29 gauge) steel panels should only be used for sheds, garages, and on lower-end agricultural or industrial applications.
Corrugated Metal Panels vs. Crimped or Ribbed Metal Roofs
Corrugated metal panels are not the same as crimped or ribbed metal panel. Corrugated metal refers strictly to the U-shaped, or sometimes V-shaped panel sheets.
The rustic appearance of corrugated metal panels hearkens to the simpler time, or way of life. However, the main benefits of corrugated metal panels are their cost-effectiveness, durability, and a wide range of available colors and paint finishes.
Installation and Options
Corrugated metal panels tend to be between 2 and 3 feet wide and come in varying lengths such as 8 ft. and 12 ft. long metal panel sheets. When covering a roof, metal panels form overlaps along their curves. The panels are then fastened together with metal screws that penetrate not just the two panels, but into the roofing deck or substrate.
Obviously, the metal panels themselves will shed water, given the proper slope of the roof, as metal is not a porous material. Yet, with the panel overlaps, a seam is formed and to prevent water leaking into or through that tiny gap, caulk is used.
Covering the entire roof with corrugated metal panels can go rather quickly, especially on a simple gable roof, once the installer has all the necessary tools, experience, and help from others.
Both corrugated and ribbed metal panels can make for a fairly simple DIY roofing project when covering a small shed or garage, as explained in this guide from DoItYourself.com.
However, the installation process can be quite grueling and tedious on larger projects, especially for the less experienced, which is why larger projects would almost always benefit from getting a professional installation, like all roofing projects. And since the cost is not too high, it would be best to go with the insured and certified professionals, providing warranties on their products and workmanship.
When it comes to options, it’s really about the actual material and its thickness or gauge, paint finish and the color options. Steel is still the primary material option.
In today’s world it is routinely coated or labeled as galvanized steel. Sometimes, you’ll see it as Galvalume steel (zinc and aluminum metallic finish). — Both coating options offer a layer of protection that will take a decade or two to sacrifice themselves before the steel is exposed. Thus, rusting is no longer a problem for at least 20 years from the time the roof is installed.
Aluminum is another metal option for corrugated panels. The costs are virtually the same as (coated) steel. Stainless steel (which is an alloy of steel and chromium) is also an option, but stainless steel is more expensive.
Stainless steel corrugated panels are highly corrosive resistant and will provide a shinier appearance than normal steel products.
Typically, the products are sold in a 26 or 29 gauge. The smaller the gauge number, the thicker the material. And the thicker the material, the more durable it is. Though thickness does add a little more to the labor intensity, and hence cost.
Note: You should aim for a minimum of 26-gauge steel when evaluating residential steel roofing options.
Color options are virtually unlimited. This references the painted finish. The DIY approach to painting such metal panels is there, but it is likely way more expensive than going with a factory finish.
The factory process feeds metal panels through the metal mill and coats it evenly in short order. Using superior paint pigments, it also shields the product with yet another layer of supreme protection.
If going with a professional contractor, they’ll probably have brochures of different color options that they carry (usually 10 to 40 options). Customized color options are also available, but usually at a premium cost, as they aren’t massively produced.
Keep in Mind that corrugated metal panels aren’t just for roofs. Chances are good that your roofer will have some left-over material (unless otherwise noted in the contract or specifically discussed) that you might find use for as siding in an exterior shed, or even in interior projects. Take a gander at the picture below for some ideas on how the panels can be used indoors.
via Bridger Steel