Home | A Guide to Metal Roofing Panel Gauge
The gauge of a metal roof is the thickness of the roofing panels that are used. 22-guage is the thickest panel, while 29-guage is the thinnest. At Gravity Metal Roofing, we can answer all of your questions regarding the best gauge for your metal roof and help you make an informed decision for your home.
In the United States, using gauge as a measure of thickness has its roots in the industrial revolution. Measurements were based on a 1” thick steel plate so 1/20” became 20 gauge, 1/22” became 22-gauge, and so on. The bottom number of the fraction became an easy way to identify the gauge of the panel and was used as the gauge number.
As a homeowner, it’s important to know about the differences between the gauges, or thicknesses, of metal roofing panels so that you can select the best for your home’s needs. By choosing Gravity Metal Roofing for your metal roof installation, you’ll also have an industry expert guide you through the process of choosing the right gauge metal for your roofing project. There are several things to consider including budget, the structural demands on the roof, the location of the home, and the climate and weather patterns where the home is located.
There isn’t usually a noticeable difference in the appearance between the different panel gauges, but their different compositions can lead to some aesthetic changes. For example, thinner gauge metal panels, such as 29 gauge, are more prone to oil canning. Oil canning is a visible, wavy distortion that affects cold-rolled metal products. The rippling is noticeable in the flat areas of the metal panels.
Thicker gauge metal roofing panels will cost more than thinner gauge panels. It’s easy to assume that thicker panels are always better, but that isn’t necessarily the case. When it comes to metal roofing gauges the type of building construction will determine whether the added strength is necessary.
22-gauge metal panels are the thickest, measuring .0299”. The thickness of 22-gauge metal panels makes them durable against the elements and severe weather conditions. This is important if the structure lacks sheathing and the metal itself plays a structural role for the building. 22-gauge panels are the most expensive option since they are the thickest type.
24-gauge metal panels have a thickness of .0239”. 24-gauge panels maintain their appearance for the long-term and are resistant to extreme weather. In terms of price, these panels are also a more expensive choice.
26-gauge metal panels are .0179” and are the industry standard for most residential and commercial applications. It is thicker, lasts longer, is more structurally sound, and more resistant to dents than 29, while still being more affordable than 22 or 24 gauge. 26-gauge is also a good choice for an open frame structure. Consider 26-gauge panels when longevity and appearance are more important than price.
At .0149”, 29-gauge metal panels are the minimum thickness for a metal roof and more than adequate for most residential roof applications. Consider 29-gauge if cost is a priority. It is usually the least expensive option, but if you live in an area that often experiences hail you may consider a thicker gauge. 29-gauge metal is a good choice when you’re located in a mild climate that doesn’t experience snow, hail, or storm conditions often.
The thickness of your metal roof is best determined by the type of metal roofing panel and paint finish that you choose. The most commonly used gauges for residential roofing are 26 gauge and 24 gauge. The first choice you’ll need to make before you choose metal thickness is whether you want an exposed fastener system or a standing seam metal roof.
In an exposed fastener system, such as corrugated metal roofing, panels are perforated by thousands of screws to adhere to the substrate. Each screw, or perforation in the metal is a weak point that can potentially lead to leaks and rust at a later date. If you want a more rustic look, this is the right roof for you. Exposed fastener systems give you the flexibility to choose 29, 26, or 24 gauge roof metal.
Standing seam metal roofing systems typically cost more because the roof consists of a concealed fastener system using clips that do not perforate the metal. The concealed fastener system makes this the most weathertight roofing panel, and it is typically only available in 24 gauge or heavier.
Another choice that will affect the metal thickness you choose for your roof is the paint. SMP and PVDF are paints typically used for metal roofing. SMP is generally used for agricultural and rural settings. It is a good paint but does not retain its color the way that PVDF does. PVDF is one of the best paint finishes and it is not available in light gauge steel. PVDF coatings are only available for 24 gauge or heavier in a great selection of vibrant colors, matte finishes, and designer paint finishes. PVDF holds its color integrity the longest and bright colors should only be purchased in PVDF.
Installation is another factor when choosing metal thickness. When a metal roofing panel is installed over a wood substrate, the strength of the panel is of less concern because it doesn’t have to reach from support to support. Most metal roofing that is attached to a wood substrate is 29, 26, or 24 gauge. Although 29 gauge panels are available, keep in mind that they are the thinnest panels. This means that they are most easily damaged during hailstorms, have lesser snow loads, and are more prone to wind lift. Also, if your construction requires long panel lengths, there’s a greater risk that 29 gauge can be damaged by thermal expansion and contraction.
When metal roofing is attached to a solid wood substrate, 26 gauge material can provide good value but if you live in an area that experiences high winds, a 24 gauge panel would be a better choice. And remember, if you want all the benefits and color retention of PVDF paint, they you will most certainly need to choose 24 gauge steel.
If your metal roof panels will be installed over metal purlins, the strength of the panel is paramount. This is because the metal panels need to span the distance between the purlins while also handling the load and wind uplift. 29 gauge metal isn’t typically used for this application because it simply isn’t strong enough. The further the distance that the metal roofing has to span between purlins, the stronger and heavier the gauge needs to be. The appropriate gauge range is as light as 26 gauge to as heavy as 20 gauge. If you have a short span of four feet or less, a lighter gauge such as 26 is appropriate. If the span length reaches between four and six feet, 24 gauge may work. For spans that are longer than six feet, you definitely need heavier gauge steel, 22 or thicker may be required.
No matter the type of metal roof you choose, metal panels that are manufactured from heavier gauge steel will be heavier, stronger, have additional wind resistance, handle foot traffic better, and make for a longer lasting roof.
Just to recap, choosing a metal roof for your home is a great choice. First, you’ll need to choose the panel type, then determine the gauge of steel, and finally choose the paint system and color for your roof.
Ultimately, your choice of metal panel, steel gauge, and paint system will be determined by your priorities for your home and the type of metal roofing system you choose. At Gravity Metal Roofing, we are proud to offer high quality metal panels and fabricated components to meet the needs of discerning homeowners. Call us at (844) 352-7663 to discuss your metal roofing project.
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