Understanding Fluted Panel Profiles
Fluted and corrugated panels differ from flat ACM — they span farther, but require strict fastening and movement allowances. As GC, confirm subcontractor shop drawings include span charts, fastening details, and fire compliance certificates.
- 7/8” Corrugated Panels: Span up to 1.5 m (24 ga) or 2.0 m (22 ga). Valley fastening at 300 mm O.C., ridge fastening avoided.
- 1.5” Mechanical Seam Panels: Concealed clips at 600 mm O.C., allow thermal movement.
- 2” Standing Seam Panels: Span up to 3.0 m. Two-piece clips allow structural attachment and movement.
Installation Considerations — GC Oversight Points
- Thermal Movement: Fixed points at mid-span, sliding clips every 600 mm, expansion joints at 9 m max.
- Oil Canning Prevention: Require tension-leveled coil, ribs/striations on flats, max 400 mm flat width.
- Fastening Patterns: Ends: 150–200 mm O.C.; intermediates: 300–400 mm O.C.; laps: double fastener rows with sealant tape.
GC Action: Require fastening patterns in submittals and QC logs during installation.
Metal Siding Systems
- Horizontal: Starter strip at base, 2 mm tolerance on course exposures, trims allow movement.
- Vertical: Base flashing min 100 mm up wall with hemmed edge. Top closures vented.
- Insulated Composite Panels: Tongue-and-groove joints with concealed fasteners. Expansion gaps of 3 mm at 20°C. Confirm OBC fire compliance.
Fastener Requirements for Metal Panels
- Screw Specs: #12 min, SS 304 (standard), SS 316 (coastal), EPDM washers, painted heads.
- Pull-Out Values (working loads, 3:1 safety factor): 16 ga = 630 lbs; 14 ga = 780 lbs; 12 ga = 950 lbs; 19 mm plywood = 320 lbs.
- Edge Distances: ≥3× dia from edge; ≥10× dia spacing; ≤25 mm from ribs; ≥50 mm from corners.
GC Checklist for Fluted and Metal Panels
- Span tables and fastening patterns included in submittals
- Pull-out test results provided for substrates
- NFPA 285/OBC compliance confirmed for insulated panels
- Thermal expansion allowances verified in QC reports
- Fastener torque logs reviewed during installation
- Oil-canning prevention measures documented
