Which panel? Start with the profile pages
This page covers the fastening system all exposed-fastener profiles share. For the panels themselves, see R-panel, PBR panel (R-panel with a purlin-bearing leg at the side lap), corrugated, and R-panel and PBR for homes, barns and shops.
Exposed fastener vs. standing seam
| Exposed fastener (R-panel, PBR, corrugated) | Standing seam | |
|---|---|---|
| How it's attached | Screws through the panel face on every purlin | Hidden clips under a raised seam; no holes through the weather surface |
| Thermal movement | Panel is pinned, so expansion and contraction work on every screw hole | Clips let the panel slide as it heats and cools |
| Minimum slope (2021 IBC 1507.4.2) | 3:12 with plain laps; 1/2:12 with applied lap sealant | 1/4:12 |
| Upkeep | Inspect screws and laps; plan a re-screw over the roof's life | Very little; check flashings and penetrations |
| Up-front cost | Lowest of any metal roof | Higher, for a longer service life with less upkeep |
| Best for | Shops, barns, warehouses, storage, ag and many commercial metal buildings | Homes, offices, retail, churches, long runs and low slopes |
Both are good roofs. On a visible roof, or a building below 3:12 where every lap would need sealant, we usually price standing seam or mechanically seamed standing seam next to the exposed-fastener option so you can see the difference.
How a good exposed-fastener roof is fastened
- The pattern comes from the panel maker's drawing, not habit. Most R-panel and PBR profiles are fastened in the flat beside the major rib, where the washer seats on solid steel; some corrugated profiles are fastened through the crown. We follow the manufacturer's pattern for that profile and wind zone.
- Driven square and snug. An overdriven screw flattens and splits the washer; an underdriven one never seals. Both leak within a few summers. Crews use depth-setting drivers, and we spot-check.
- The right screw for the structure: self-drilling screws for steel purlins and wood screws for wood, long enough to hold, with sealing washers and a coating rated for outdoor exposure.
- Side laps stitched. Stitch screws close the side lap between purlins so it can't open up in wind.
- End laps avoided. Because we roll-form each run to its measured length, most buildings get one-piece panels eave to ridge and no end laps. Where a lap is unavoidable, it is sealed with butyl tape and fastened as the manufacturer specifies.
- Closures at the eave and ridge. Foam or metal closures keep wasps, birds and wind-driven rain out of the ribs.
Why exposed-fastener roofs leak, and the fix for each
| What we find | Why | Fix |
|---|---|---|
| Cracked or shrunken washers | UV and heat age the rubber | Re-screw with oversize screws and new washers |
| Wallowed-out holes | Thermal movement working a pinned panel | Oversize screws; on a worn roof, a retrofit |
| Rust at laps | Water held in the lap | Clean, treat and seal, or replace the panel |
| Missed screws | Screw missed the purlin | Remove, seal the hole, re-fasten into structure |
| Leaks at curbs and pipe boots | Flashings not tied into the rib pattern | New boots or curbs flashed to the profile |
| Hail dents | Impact | Dents alone may be cosmetic; we document and you decide with your insurer |
We walk the roof, fly a drone for photos of areas that are hard to reach safely, and run drone thermal (infrared) scans that help show where water has gotten under the surface. Every inspection comes with a free digital photo report, so you see what we see.
Re-screw, coat, retrofit or replace
- Re-screw: panels sound, washers failing. The cheapest fix that actually stops leaks.
- Re-screw and coat: panels sound but rusting at laps and fasteners. See metal roof coatings and the acrylic or silicone spec pages.
- Retrofit: new panels over the old roof on sub-framing, with insulation space if you want it. See metal retrofits.
- Tear off and replace: new 24- or 26-gauge panels formed to length, or a switch to standing seam.
Bidder checklist for an exposed-fastener roof
- Gauge (24 or 26) and paint system, in writing
- Panel profile, and whether panels are one-piece or end-lapped
- Screw type, length and spacing, following the manufacturer's pattern
- Side-lap stitch screws, and lap sealant where the slope needs it
- Closures, ridge, trim and flashing details named
- Insulation and condensation control on enclosed buildings (see shops and barndominiums)
- Permit, if the city requires one, and who pulls it
Code sections and product standards are summarized in plain English from the published documents. Your building official and the manufacturer's current specification have the final word.
We're certified with GAF, CertainTeed, Owens Corning, Atlas, Johns Manville, Carlisle, Tropical Roofing Products, Mule-Hide and Enviroshake, and many other roof manufacturers. Our workmanship warranty runs from 10 years up to lifetime, depending on the job.
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.
