R-panel and Ag Panel are both very popular metal wall and roof panels; however, because of their similarity, there is often confusion as to which panel may be best for a particular application.
Both panels are manufactured by tens, if not hundreds, of companies, and it is important to know that not all panels are created equal because there are different levels of quality and performance. Just as facial tissues range from aloe-infused options for extra comfort to lower-quality tissues that feel like sandpaper on your nose, R-Panels and Ag Panels differ in performance because of the steel substrate and paint system used. Therefore, end-users need to take care and ask questions about the panels to ensure quality and performance are in sync with long-term end-user expectations.
What are R Panel and Ag Panel?
Ag Panel is a slang term for one of the most popular exposed fastener metal roofing and siding profiles in the construction industry. Post-frame (aka pole barn) buildings and residential metal roofing represent the two largest construction segments for Ag Panel usage.
While specifications and details may vary slightly, the drawings below show the most popular Ag Panel profile in use today. The distinguishing feature of this popular Ag Panel is ¾” tall major ribs that are spaced 9” on-center.
What is an R-Panel?
R-Panel is a multi-use exposed fastener metal wall and roof panel that was originally designed for use in pre-engineered metal buildings. However, since its inception, R-Panel has expanded into many other areas, such as residential metal roofing.
The drawings below showcase the distinguishing characteristics of an R-Panel. Note that major ribs are 1.25” tall and spaced 12” on center.
Where Are R-Panel and Ag Panel Used?
Both R-Panel and Ag Panel are great multi-purpose panels used in a wide variety of applications, including walls and roofs on commercial and residential projects. In engineered buildings, these panels are the industry standard in two different segments. R-Panel is the industry-standard panel for the pre-engineered metal building industry, while Ag Panel is the industry-standard panel for the post-frame industry. The reason for the difference goes back many decades, which we will address in the next sections.
Is R-Panel Stronger Than Ag Panel?
Traditionally, R-Panel is commonly manufactured in 26 gauge, while Ag Panel is commonly manufactured in 29 gauge. However, gauge options can vary by product and manufacturer. Gauge is referred to on a numerical scale, with larger numbers equating to thinner steel; therefore, 26 gauge is thicker than 29 gauge. Panels may also be available in different gauges to meet specific engineering requirements on projects.
To better understand R-Panel and Ag Panel differences, let’s take a look at how metal buildings and post-frame buildings are different.
Metal buildings are supported with steel structural and substructural members, while post-frame buildings are supported with wood structural and substructural members.
To reduce the amount of framing material required, it is desirable to spread the framing as far apart as possible. R-panel’s thicker 26-gauge steel in combination with the taller major ribs enhances the strength and load-bearing characteristics of the panel and therefore can span greater spacing between framing members. In some climates, sub-structural spacing on pre-engineered metal buildings can be as much as 5' on center. Roof framing on post frame buildings is typically spaced 2’ on center. This narrower gap on a post frame building means a lighter gauge panel with less robust major ribs is sufficient for the required engineering. Hence, an Ag Panel is the standard for post frame buildings.
If panels are being installed over open framing with greater on-center spans, R-Panel is most likely a better option. If panels are installed over a solid deck, such as in residential metal roofing applications, the difference in strength has less impact. While a 26 gauge R-Panel is still stronger than a 29 gauge Ag Panel, fastening attachment patterns can help make up the difference in strength to ensure engineering requirements are met.
Especially in the Southwest, R-Panel is also used extensively for residential applications. End uses include residential metal roofing and buildings that combine both work and living spaces. These applications are becoming more popular and are commonly referred to as a barndominium or shouse. Although your contractor has flexibility, the most common practice is to use an R-Panel if the structure is a pre-engineered metal building and use an Ag-Panel if the structure is a post-frame building.
What Is the Difference in Appearance Between R-Panel and Ag Panel?
Like many things in life, beauty is in the eye of the beholder. That analogy also applies to R-Panel and Ag Panel. As shown earlier, here are the major differences.
Ag Panel- R-Panel major rib height is 1.25” while Ag Panel major rib height is .75”
- R-Panel has major ribs 12” on center, while Ag Panel has major ribs 9” on center
Take a look at the drawings above and imagine them side by side on a building. Aesthetically, the panel profile is the difference between the two panel types, which is why the final decision often comes down to personal preference. Some people prefer the bold appearance of an R-Panel, especially in Texas and the Southwest where “bold is beautiful,” while others prefer the more subtle appearance of an Ag Panel.
Trim, or flashings, is another aesthetic difference. Flashings are the components that tie in or connect the metal panels together and are installed at the intersections and terminations of metal panels to seal the roof and prevent water from entering the building envelope. Many homeowners prefer smaller flashings so the roof itself gets more visual emphasis rather than the flashings. In other words, flashings should blend in rather than stand out. In this case, an Ag Panel is preferable because the ¾” rib height uses smaller flashings than an R-panel with the 1.25” rib height.
The rake on a building runs from the eave to the ridge along the roofline. Shown below is a drawing and installation detail of a rake, or gable, flashing for an Ag-Panel. Because the rake flashing covers the metal panel on the roof, the flashing is designed accordingly. Therefore, since an R-Panel rib is taller and wider than an Ag-Panel rib, the flashing is also larger.
Does R-Panel Cost More Than Ag Panel?
Traditionally, R-Panel costs approximately 15-20% more than Ag Panel. The primary reason for the price difference is the gauge, or thickness, of the steel. R-Panel is commonly manufactured in 26 gauge, while Ag Panel is commonly manufactured in 29 gauge.
In addition to the gauge difference, the larger R-Panel major ribs require more steel to manufacture than Ag Panel, which also contributes to the cost difference.
How Do You Choose Between R-Panel and Ag Panel?
To sum it up, consider a few factors when choosing between R-Panel and Ag Panel.
- What is the construction method? If it is a pre-engineered metal building, R-Panel is standard, while Ag-Panel is standard for post-frame buildings.
- What are the spanning and engineering requirements? If panels are being installed over open framing, R-Panels offer more strength than Ag-Panels. If panels are being installed over solid decking, the difference in strength can be equalized with fastening patterns.
- What is your aesthetic preference? Is bold beautiful, like R-Panel, or is subtle superb, like Ag-Panel?
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