What "PBR" means
PBR stands for purlin bearing rib. It's the R-panel profile with one extra detail: a small leg on the panel edge that sits on the purlin under the side lap. That leg supports the overlap where two panels meet, so the lap doesn't sag between purlins, and screws through the lap clamp against something solid. On a metal building with open purlins, that's the version you want. Over a solid deck, PBR and R-panel behave about the same.
Typical PBR specs
| Spec | Typical published value | Why it matters |
|---|---|---|
| Coverage | 36 in per panel | Fewer side laps than narrower panels |
| Major ribs | About 1-1/4 in tall, 12 in on center | Stiffness between purlins and water capacity |
| Minimum slope | Commonly 1:12; some panels publish 1/2:12 with lap sealant | Below the panel's minimum, water backs up at laps |
| Fastening | Exposed screws with sealing washers, plus stitch screws at side laps | Washers are the long-term wear item |
| Gauge we install | 24 or 26 | Span, hail and foot traffic (we don't install 29) |
| Ratings to look for | UL 580 uplift class, UL 2218 impact class, UL 790 fire, as listed for the exact panel | Ratings belong to a specific panel and assembly, not to "PBR" in general |
Values vary by manufacturer. We confirm the published data for the exact panel before we quote it.
PBR vs. R-panel vs. standing seam
| PBR | R-panel (no bearing leg) | Standing seam | |
|---|---|---|---|
| Best over | Open purlins on metal buildings | Solid deck, walls, light framing | Low slopes, long runs, buildings where looks or leaks matter most |
| Fasteners | Exposed | Exposed | Hidden under the seam on clips |
| Thermal movement | Fixed by screws; long runs work the holes | Same | Clips let panels float |
| Cost | Lower | Lower | Higher |
More detail: commercial R-panel, mechanically seamed standing seam, and R-panel and PBR for homes and barns.
How a PBR roof goes on right
- Insulation first: on open framing, faced blanket insulation is draped over the purlins, often with thermal spacer blocks so the panel doesn't crush it. That's what keeps a metal building from dripping condensation on cool mornings.
- Lay direction: panels are laid so side laps face away from the prevailing wind where possible.
- Side laps: the bearing leg goes under the next panel, with sealant tape on low slopes, then stitch screws through the lap.
- Purlin screws: set to seat the washer, not flatten it, in the pattern the panel maker publishes for the building's wind exposure.
- Closures and trim: foam closures at eaves and ridge, then eave, rake, ridge and high-side trim.
- Light panels: matched to the PBR profile and lapped and sealed like a steel panel.
Panels formed to length, not spliced
Shipped panels are limited by trucks and handling, so long roof runs often get an end lap halfway down, and end laps are a classic leak point on low slopes. We form PBR on our own roll formers to the measured length of each run, so most runs go on in one piece. See panels roll-formed to length.
Texas weather and PBR
- Hail: thicker steel dents less, and some PBR panels carry a UL 2218 Class 4 listing. Light panels are usually the first casualty. See commercial hail claims.
- Wind: uplift is resisted by the screw pattern, especially at eaves, rakes and corners. Texas Department of Insurance windstorm evaluations matter most on the coast; in North Texas we follow the panel's published fastening for the building's exposure.
- Sun and heat: washers dry out before panels do. A PBR roof should be checked about once a year and after hail or high wind.
Re-roofing an old PBR building
| Condition | What we usually recommend |
|---|---|
| Panels sound, leaks at screws and laps | Re-screw with new, slightly larger fasteners; seal laps and trim |
| Panels sound, finish chalking or lightly rusted | Restoration coating after fastener and lap repairs |
| Panels rusted through or badly hail-damaged | Retrofit over the old roof, or tear-off and new PBR |
| Chronic lap leaks on a very low slope | Consider standing seam on a retrofit frame |
We have hands-on experience with coating systems from American WeatherStar, EpoxyFlex, Carlisle and Tropical Roofing Products. Every inspection comes with a free digital photo report, so you see what we see.
Finishes
PBR comes in bare Galvalume and in painted finishes, usually SMP (silicone-modified polyester) or PVDF (Kynar-type). PVDF holds color longer and costs more. Whatever you choose, the finish and gauge should be written on the quote. See colors and finishes and 26 vs. 24 gauge.
Where we install it
Warehouses, mini storage, church gyms and outbuildings, shops and ag buildings and barndos, across Wise County, Fort Worth and the rest of DFW. Local pages: Fort Worth warehouses, Decatur metal buildings, Bridgeport shops.
We're certified with GAF, CertainTeed, Owens Corning, Atlas, Johns Manville, Carlisle, Tropical Roofing Products, Mule-Hide and Enviroshake. We offer same-day response in almost every case, and we answer leak and storm calls 24/7 at (817) 733-9228. We've done commercial jobs from about $1,000 repairs to multi-million-dollar projects, and owner Blake Snow brings 30 years of large commercial and industrial project experience, including casino properties (Imperial Palace, Boomtown, Casino Magic and Hard Rock).
Commercial warranty: a workmanship warranty from 10 years up to lifetime, depending on the job, plus both 10-year and 20-year NDL (no-dollar-limit) manufacturer warranties (the price depends on which NDL term you choose). Manufacturer coverage depends on the product and brand, and on the project qualifying for that manufacturer's program. We put the exact warranty for your roof in writing.
Certified, with 30 years installing every major roofing brand, a family roofing business going back 75 years, and over $80 million in completed roofing projects. 5.0 stars on Google at all three of our offices.
Request a free inspection or call (817) 733-9228. Small repairs are welcome too.
