How to Specify an R-Panel Roofing Profile (Complete Technical Guide)

Learn how to specify an R-Panel profile including finished dimensions, coil width, thickness range, material grade and machine requirements.

Complete Engineering & Procurement Guide

R-Panel is one of the most common exposed-fastener roofing and wall cladding profiles used in:

United States
Canada
Industrial buildings
Commercial metal structures

Although similar to PBR, R-Panel typically:

Does NOT include a purlin bearing leg
Maintains 36” cover width
Uses 1¼” rib height
Uses 12” rib spacing

Specification must clearly define which variant is required.

1️⃣ Understanding What “R-Panel” Means

In most U.S. markets:

Standard R-Panel =

36” effective cover width (914 mm)
1¼” rib height (approx. 32 mm)
12” rib pitch (305 mm)
Major ribs with minor ribs between
No bearing leg extension

However, some suppliers blur the line between R-Panel and PBR.

Always confirm:

Whether bearing leg is included or not.

2️⃣ Standard Finished Dimensions (U.S. Reference)

Typical U.S. R-Panel:

Effective cover width: 36”
Overall width: ~38–39” formed
Rib height: 1¼” (32 mm)
Rib spacing: 12” centers
Minor ribs: 1 or 2 between majors

Always request full cross-sectional drawing before approval.

3️⃣ Metric & International Variations

Outside the USA:

1000 mm cover variants
900 mm cover versions
Rib heights from 25–40 mm
Different minor rib configurations

Never specify simply “R-Panel.”

Specify:

Exact cover width + rib geometry.

4️⃣ Typical Coil Width for R-Panel

For standard 36” cover R-Panel:

Typical developed coil width:

1040–1120 mm (approximate range)

Exact width depends on:

Bend angles
Bend radii
Thickness
Springback compensation

Metric 1000 mm cover versions:

Typically require 1150–1250 mm coil.

Developed width must be calculated — not estimated.

5️⃣ Thickness Range (Market Standards)

Common R-Panel thickness:

Residential:

29 gauge (~0.36–0.40 mm)

Commercial:

26 gauge (~0.45–0.50 mm)

Industrial:

24 gauge (~0.60 mm)

Heavy structural:

22 gauge (~0.75 mm)

Machine must be engineered for:

Maximum intended thickness at maximum grade.

6️⃣ Material Grade Selection

Common grades:

USA:

ASTM A653 Grade 33 (33 ksi)
ASTM A653 Grade 50 (50 ksi)

International:

G250
G350
G550 (less common but possible)

Higher grade increases:

Forming force
Springback
Motor torque
Shaft deflection

Never specify thickness without grade.

7️⃣ Coating Specification

Common coatings:

G60 / G90 galvanized
AZ50 / AZ55 Galvalume
Prepainted (SMP / PVDF)

Prepainted requires:

Polished roll tooling.

Galvalume may increase friction slightly.

Coating must be declared before tooling design.

8️⃣ Rib Geometry Considerations

1¼” (32 mm) rib height is typical.

Altering rib height changes:

Structural performance
Wind uplift resistance
Machine forming load

Minor rib design also affects:

Panel stiffness
Aesthetic appearance

Geometry must remain consistent with tested load tables.

9️⃣ Overlap & Fastener Detail

R-Panel uses exposed fasteners.

Specify:

Side lap configuration
Screw placement location
Minor rib alignment
Sealant compatibility

Overlap design affects water performance.

🔟 Wind & Code Compliance

In the USA:

R-Panel systems often require:

Wind uplift ratings under IBC.

Profile geometry must match:

Certified test sample.

Changing:

Rib height
Steel grade
Thickness

Can invalidate load rating.

1️⃣1️⃣ Machine Engineering Considerations

Typical R-Panel machine:

14–18 forming stands
70–85 mm shafts (depending on thickness & grade)
15–22 kW motor
Hydraulic stop cut standard
Flying shear for high-speed lines

Thicker or higher-grade steel requires:

Larger shafts and stronger motor.

1️⃣2️⃣ Production Speed

Typical speeds:

Standard line:
15–20 m/min

High-speed industrial:
30–40 m/min

Cutting system determines maximum production rate.

1️⃣3️⃣ Tolerance Requirements

Typical dimensional targets:

Width ±2 mm
Rib height ±1 mm
Length ±2 mm

Tolerance stability affects:

Overlap alignment
Aesthetic quality
Certification compliance

Machine rigidity influences consistency.

1️⃣4️⃣ Developed Width Reminder

Developed width must include:

All bend allowances
Thickness compensation
Springback correction

Wrong developed width causes:

Material waste
Production interruption
Incorrect effective cover

Calculation must be done from approved drawing.

1️⃣5️⃣ Export Market Considerations

Some countries request:

Metric cover widths
Different rib spacing
Higher rib height

Never assume U.S. R-Panel is universal.

Define market before specifying profile.

1️⃣6️⃣ Common Specification Mistakes

❌ Confusing R-Panel with PBR
❌ Not confirming bearing leg presence
❌ Ignoring developed width calculation
❌ Specifying gauge without grade
❌ Overlooking coating type
❌ Not confirming wind rating requirement

Most issues originate at specification stage.

1️⃣7️⃣ Final R-Panel Specification Checklist

Before tooling approval:

✔ Confirm effective cover width
✔ Confirm rib height & spacing
✔ Confirm minor rib detail
✔ Confirm thickness range
✔ Confirm steel grade
✔ Confirm coating
✔ Calculate developed width
✔ Confirm coil availability
✔ Confirm target speed
✔ Confirm compliance requirements

Then proceed to tooling design.

FAQ Section

Is R-Panel the same as PBR?

No — PBR includes bearing leg; R-Panel typically does not.

What is typical coil width?

Approximately 1040–1120 mm for 36” cover, but must be calculated.

Can I run 22 gauge on standard machine?

Only if machine capacity supports it.

Does grade matter for R-Panel?

Yes — Grade 50 requires more forming force than Grade 33.

Is 36” always standard?

In the U.S., yes. International markets vary.

Can I slightly adjust rib spacing?

Not without recalculating structural performance.