By The Roofing Brief Team. Last reviewed: October 2026.
A PBR panel is an exposed-fastener metal roofing and siding panel with 36 inches of net coverage, a 1.25-inch rib height, and major ribs spaced 12 inches on center, per the MBCI PBR product page. The letters stand for Purlin Bearing Rib, the small return leg on the panel edge that makes it strong enough for roofing, not just walls. MBCI, Mueller, Metal Sales, McElroy Metal and Union Corrugating all roll the profile, and it is often sold under the names R-panel, PBR-panel, or R-PBR.
PBR sheet metal comes in 29 to 22 gauge steel, weighs 0.84 psf in 26 gauge on the Metal Sales PBR-Panel sell sheet (9-2023), and is cut to order in lengths from 5 ft up to 45 or 50 ft depending on the maker.
What does PBR stand for in metal roofing?
PBR stands for Purlin Bearing Rib. It describes a short leg formed into the underlapping edge of the panel that rests on the purlin or the panel beneath it. Mueller describes it as an extended leg on one side of the sheet that rests against the purlin or substrate beneath the lapping rib and holds the sheet stable as screws are applied. McElroy Metal calls the same feature a purlin bearing return.
The profile itself is often called an R-panel, a generic industry name used by manufacturers including MBCI, Ceco, and Union Corrugating. When you see PBR, R-PBR, or “R-panel with purlin bearing leg,” they refer to the same rib pattern with the added bearing rib. A panel labeled only R-panel usually lacks that leg, which Union Corrugating says the PBR adds to provide better support for roofing applications.
PBR panel dimensions
A standard PBR panel covers 36 inches wide, stands 1.25 inches tall at the major ribs, and repeats those ribs every 12 inches. Inland Buildings prices its PBR on a 38 1/4 in wide sheet that covers 36 in once lapped. Panels are roll-formed and cut to length on order: MBCI lists 5 ft to 50 ft and Metal Sales lists 5 ft to 45 ft, so a run often installs as a single sheet from eave to ridge. Because the 36 in, 1-1/4 in, 12 in profile is shared across these makers, trim generally interchanges, but confirm closures against the maker’s drawing.
| Spec | Standard PBR panel | Source |
|---|---|---|
| Net coverage width | 36 in | MBCI, Mueller, Metal Sales |
| Overall (pre-lap) width | 38 1/4 in | Inland Buildings panel chart |
| Major rib height | 1.25 in (1-1/4 in) | MBCI data sheet |
| Major rib spacing | 12 in on center | MBCI data sheet |
| Minor (stiffening) ribs | 2 per pan, 4 in apart | Inland and MBCI profile drawings |
| Gauges | 26 standard; 22, 24, 29 optional | MBCI data sheet (Rev D) |
| Weight | 0.84 psf (26 ga), 1.09 psf (24 ga), 1.43 psf (22 ga) | Metal Sales sell sheet |
| Length | 5 ft to 50 ft (MBCI); 5 ft to 45 ft (Metal Sales) | Maker pages |
| Fastener type | #12-14 XL self-drilling screw into steel, #10-14 XL wood screw into wood, 1/4-14 x 7/8 in stitch screw at side laps | Metal Sales sell sheet |
PBR panel specs by manufacturer
Every maker below rolls the same 36 in coverage and 1-1/4 in rib, but minimum slope, standard gauge, length and paint warranty differ. The minimum slope is the line most likely to decide which panel your roof can take, because Metal Sales, McElroy and Union Corrugating publish 1:12 while MBCI and Mueller publish 1/2:12.
| Maker and panel | Gauges | Minimum roof slope | Length | Ratings and warranty | Source |
|---|---|---|---|---|---|
| MBCI PBR | 26 std; 22, 24, 29 optional | 1/2:12 | 5 to 50 ft | UL 2218 Class 4; UL 580 Class 90; ASTM E1646 no uncontrolled water at 20 psf | MBCI PBR data sheet |
| Mueller PBR | 26 std; 22, 24 optional | 1/2:12 | Cut to order | Signature 200: 45-yr film, 30-yr chalk and fade; Signature 300: 45-yr film, 35-yr chalk and fade; Galvalume 40-yr limited | Mueller PBR page |
| Metal Sales PBR-Panel | 24 and 26 std | 1:12 | 5 to 45 ft | UL 2218 Class 4; UL 580 Class 90 (Construction #161); 45-yr paint finish warranty | Metal Sales sell sheet |
| McElroy R-Panel with PBR leg | 26 ga std | 1:12 with sealant; 3:12 without | Factory or onsite | UL 263 Class A; UL 580 Class 90; UL 2218 Class 4; PBR leg required on roofs | McElroy R-Panel page |
| Union Corrugating PBR | See maker | 1:12 recommended | Cut to order | Spans up to 5 ft; solid deck or open framing | Union Corrugating PBR page |
Metal Sales also publishes allowable loads for its PBR-Panel on 3 or more equal spans: at a 5 ft purlin spacing, 26 gauge carries 49 psf inward and 40 psf outward, 24 gauge carries 57 and 53 psf, and 22 gauge carries 76 and 80 psf. Those numbers are why 24 or 22 gauge shows up on long-span and high-wind jobs.
PBR panel vs R-panel: the difference is the leg
In any R panel vs PBR panel comparison, the two share the exact same 36-inch, 1.25-inch, 12-inch profile. The only structural difference is the purlin bearing leg on the PBR. McElroy Metal’s R-Panel page states the rule plainly: the PBR leg is required on roof panels and not required on wall panels.
The leg does three concrete jobs. It gives the underlapping sheet a bearing surface so the 1/4-14 x 7/8 in stitch screw at the side lap does not crush the seam, it supports the tape sealant Metal Sales specifies at roof side laps against wind-driven rain, and it holds the sheet stable as screws are driven, per Mueller. Skip the leg on a roof and the sidelap is clamped by the screw alone.
| Feature | PBR panel | R-panel (no leg) |
|---|---|---|
| Profile and coverage | 36 in, 1.25 in rib | 36 in, 1.25 in rib |
| Purlin bearing leg | Yes | No |
| Use on roofs | Yes; McElroy requires the leg on roof panels | Walls per McElroy; check the maker before using on a roof |
| Sidelap support | Metal-to-metal bearing | Screw-clamped only |
| Typical use | Metal building roofs, barns, walls | Wall cladding, liner |
PBR vs corrugated, U-panel, and 7.2 panel
PBR is the most common exposed-fastener rib for metal buildings, but it is not the only one. Corrugated has a rounded 7/8 in wave, U-panel (PBU at Inland and MBCI) runs a 3/4 in rib on the same 36 in coverage, and 7.2 panel uses a deeper rib spaced 7.2 in apart for longer spans. Choosing among them comes down to rib height, span capacity, and appearance rather than base material.
| Profile | Rib height | Coverage | Best fit |
|---|---|---|---|
| PBR / R-panel | 1.25 in | 36 in | Metal buildings, barns, light commercial |
| Corrugated (7/8 in) | 0.875 in | varies (24 to 36 in) | Agricultural, rustic, accent walls |
| U-panel (PBU) | 0.75 in | 36 in | Budget residential and shed roofs |
| 7.2 panel | 1.5 in | 36 in | Long spans, structural roof and wall |
For a wider walk through every rib pattern and metal type, see our guide to metal roofing profiles, and compare the rounded option directly in our corrugated roof panels breakdown. For the shorter 3/4 inch rib, see our master rib metal roof guide.
Gauge and finish options
PBR panels come in 29, 26, 24, and 22 gauge, and the number runs backward: a lower gauge is thicker steel. 26 gauge (about 0.0179 inch) is the standard on the MBCI, Mueller and Metal Sales sheets, 29 gauge is an MBCI option common on sheds and barns, and 24 or 22 gauge suits high-wind, high-snow, or commercial jobs. Our guide to the types of metal roof panels compares gauge across the other profiles.
- 29 gauge (about 0.0142 in): lightest and cheapest, fine for low-wind sheds and agricultural buildings.
- 26 gauge (about 0.0179 in): the default for residential and light-commercial roofing; 0.84 psf per Metal Sales.
- 24 gauge (about 0.0239 in): stiffer, better dent and oil-canning resistance, 1.09 psf; common on commercial spec.
- 22 gauge (about 0.0299 in): heaviest at 1.43 psf, used for the longest spans and severe wind or snow loads.
Finishes fall into three tiers: bare Galvalume (an aluminum-zinc coated steel), painted silicone-modified polyester (SMP, sold by Mueller as Signature 200), and PVDF (often sold as Kynar 500, or Signature 300 at Mueller and MBCI) for premium fade and chalk resistance. If you are weighing steel thickness, our 26 versus 29 gauge comparison covers where the extra thickness pays off. Readers shopping in Spanish will find the same gauge and price logic in our guide to lámina para techo: tipos, calibres y precios.
Can you use a PBR panel for roofing, and at what slope?
Yes. A true PBR panel with its purlin bearing leg is rated for roofing, which is the whole point of the profile. Mueller and Union Corrugating both state it installs over open framing (purlins) or a solid deck, and Metal Sales calls for a minimum 30# felt underlayment over a solid substrate. Exposed screws pass through the panel into the purlin or deck, with 1/4-14 x 7/8 in stitch screws at each side lap. This is a screw-down metal roof, so it moves and seals differently than a concealed-fastener standing seam.
Minimum roof slope for a lapped, exposed-fastener panel like PBR is 1/2:12 with applied lap sealant and 3:12 without it, per 2021 IRC Section R905.10.2 and the matching 2021 IBC Section 1507.4.2. The 1/4:12 minimum in those sections applies only to standing-seam systems, not to lapped panels. Several manufacturers publish a higher minimum than the code floor (1:12 for Metal Sales, McElroy and Union Corrugating), so confirm the panel maker’s published minimum before you order, because warranty coverage often depends on it. Western States Metal Roofing sizes field screws for 36 in R/PBR panels at 80 per square (100 square feet) on 24 in screw lines, plus side-lap screws equal to square footage divided by 3, then by 1.5.
For the install logic behind screw placement, see how many screws per square a metal roof needs, and read how the screw-down system compares to standing seam on lifespan and movement.
PBR panel cost in 2026
Exposed-fastener panels like PBR run about $1.50 to $2.00 per square foot in 26 gauge SMP and up to $3.40 to $4.00 in 22 gauge PVDF, per Western States Metal Roofing’s 2026 cost guide. Installed, exposed-fastener metal runs about $6 to $10 per square foot including fasteners, trim, and labor, per our 2026 roofing cost report. Western States puts installation at roughly 60% to 70% of the total roof cost, and says jobs under 500 square feet can cost double to triple per foot.
| Item | 2026 price | Source |
|---|---|---|
| Exposed-fastener panel, 26 ga SMP | $1.50 to $2.00 per sq ft | Western States |
| Exposed-fastener panel, 24 ga SMP | $1.75 to $2.00 per sq ft | Western States |
| Exposed-fastener panel, 24 ga PVDF | $2.30 to $2.65 per sq ft | Western States |
| Exposed-fastener panel, 22 ga PVDF | $3.40 to $4.00 per sq ft | Western States |
| Secondary (non-prime, no warranty) R-panel special | $2.75 per linear ft (about $0.92 per sq ft of coverage) | Steel Supply LP (Oct 20, 2026) |
| Eave or gable trim, exposed fastener | $2.50 to $4.00 per linear ft | Western States |
| Ridge cap, exposed fastener | $3.50 to $5.00 per linear ft | Western States |
| Installed, exposed-fastener metal | $6 to $10 per sq ft | Roofing Brief 2026 cost report |
Worked example for a 2,400 sq ft shop roof in 26 gauge SMP PBR: panels at $1.50 to $2.00 per sq ft come to $3,600 to $4,800; Western States’ rule of adding 25% of panel cost for exposed-fastener trim adds $900 to $1,200; and its screw formulas call for 1,920 field screws (24 squares x 80) plus about 533 side-lap screws (2,400 / 3 / 1.5). Freight and closures are quoted separately.
Who a PBR panel is right for
PBR panel is the low-cost roofing choice for a simple, rectangular building with purlins at 5 ft or less, the span Union Corrugating cites for its R family. It is engineered for metal buildings, barns, garages, shops, and light-commercial structures where a 1-1/4 in exposed rib and a $1.50 to $2.00 per sq ft panel price (26 ga SMP, Western States) matter more than the hidden-fastener look of standing seam. For a lower-rib panel on similar buildings, compare Tuff Rib metal roofing.
| If your roof is | Then | Rule source |
|---|---|---|
| Below 1/2:12 | Do not use PBR; use a standing-seam system (1/4:12 floor) | IRC R905.10.2 |
| 1/2:12 to under 1:12 | Only a panel listed at 1/2:12 (MBCI or Mueller PBR), with applied lap sealant | IRC R905.10.2; MBCI, Mueller |
| 1:12 to under 3:12 | Any of the five makers’ PBR, with lap sealant per IRC | IRC R905.10.2; Metal Sales, McElroy |
| 3:12 or steeper | PBR with or without lap sealant per IRC; follow the maker’s tape sealant detail | IRC R905.10.2 |
| Purlins spaced over 5 ft | Check the maker’s load table; step up to 24 or 22 gauge or a 7.2 panel | Union Corrugating; Metal Sales load table |
| A visible house roof where screws are a concern | Price a concealed-fastener panel instead | Editorial |
It is a weaker fit where appearance is the priority or the roof is steep and highly visible from the street, because the exposed screws and their EPDM washers are part of the look and need checking over the life of the roof; Western States names incorrect fastener installation as the single biggest cause of metal roof leaks. On those jobs a concealed-fastener panel is often worth the premium.
Frequently asked questions
What does PBR stand for on a metal panel?
PBR stands for Purlin Bearing Rib. It refers to a short leg formed into the panel’s underlapping edge that bears on the purlin or the panel below it. That leg carries the sidelap load metal-to-metal, which is why McElroy Metal requires it on roof panels but not on walls. The base profile is the same 36-inch, 1.25-inch R-panel shape.
What is the difference between a PBR panel and an R-panel?
They share the identical 36-inch coverage and 1.25-inch rib profile. The difference is the purlin bearing leg: a PBR panel has it, a plain R-panel does not. McElroy Metal requires the leg on roof panels and not on wall panels, and Union Corrugating says it provides better support for roofing applications.
What are the dimensions of a PBR panel?
A PBR panel covers 36 inches net from a sheet about 38 1/4 inches wide (Inland Buildings). The major ribs stand 1.25 inches tall and repeat every 12 inches on center, with two smaller stiffening ribs 4 inches apart in each flat. Lengths are cut to order from 5 ft to 45 ft (Metal Sales) or 50 ft (MBCI).
What gauge is a PBR panel?
PBR panels come in 29, 26, 24, and 22 gauge, where a lower number means thicker steel. 26 gauge is the standard at MBCI, Mueller and Metal Sales and weighs 0.84 psf; 29 gauge is an MBCI option for sheds and barns; and 24 or 22 gauge (1.09 and 1.43 psf) is used for commercial jobs and high wind or snow loads.
What is the minimum roof slope for a PBR panel?
Under 2021 IRC Section R905.10.2 and IBC Section 1507.4.2, a lapped exposed-fastener panel like PBR needs at least 1/2:12 with applied lap sealant and 3:12 without it; the 1/4:12 figure in those sections applies only to standing-seam systems. MBCI and Mueller list their PBR at 1/2:12, while Metal Sales, McElroy and Union Corrugating list 1:12, so confirm the published minimum for your panel before ordering.
How many screws does a PBR roof need per square?
Western States Metal Roofing sizes 36 in R/PBR panels at 80 field screws per square (100 square feet) on 24 in screw lines, plus side-lap stitch screws equal to the square footage divided by 3 and then by 1.5. Metal Sales specifies #12-14 XL self-drilling screws into steel, #10-14 XL wood screws into wood, and 1/4-14 x 7/8 in stitch screws at side laps.
Is a PBR panel good for a house?
A PBR panel can roof a house at a 26 gauge SMP panel price of about $1.50 to $2.00 per square foot (Western States, 2026), but it shows exposed fasteners and reads more utilitarian than a standing seam roof. It suits garages, shops, barns, and simple gable homes on a budget. Where a hidden-fastener look drives the decision, a concealed-fastener panel is often the better pick.