See flat pans, striations and pencil ribs, with McElroy examples explaining oil canning and the choices that affect a metal roof’s appearance.
The lines between standing seams are a design choice. Compare flat pans, fine striations and raised stiffening ribs before ordering your roof. These details change appearance and can reduce visible waviness, but no option guarantees a perfectly flat-looking roof.
| Option | Appearance | Main tradeoff |
|---|---|---|
| Flat pan | Smooth area between raised seams | Clean look; waviness may be more noticeable |
| Striations | Gentle, repeated shallow waves | Breaks up reflections across the panel |
| Pencil ribs | Narrow raised lines within the pan | More visible lines; separates broad flat areas |
| Ribbed / plank profiles | Wider or more pronounced formed details | Stronger visual texture; availability varies |
See the panel shapes
Flat pan
McElroy illustration of a flat-pan Medallion-Lok panel.
Striations
McElroy illustration of a striated Maxima ADV panel.
Pencil ribs
McElroy illustration of a Medallion-Lok panel with pencil ribs.
These manufacturer renderings show the surface treatments, not identical panel systems. Rib shapes and placement vary by product and roll-forming tooling. Review an actual sample of the specified panel.
What oil canning looks like
The cover image is McElroy’s example of visible panel waviness. Light and viewing angle can make the same roof appear smoother or wavier. Oil canning is commonly an appearance issue; suspected installation deformation, leaks or loose attachments still need inspection.
| Factor | Ask about |
|---|---|
| Panel width | Narrower pans where appropriate |
| Surface treatment | Striations or ribs on the exact profile |
| Metal thickness | Gauge and material, without a no-waviness promise |
| Deck and framing | A flat, suitable support surface |
| Installation | Alignment, fastening and provision for thermal movement |
| Color and sunlight | A sample viewed outdoors at several angles |
Put the choice in writing
Specify the panel name, width, gauge, finish and pan treatment.
Approve a physical sample before fabrication.
Discuss oil-canning expectations before the order is placed.
Use only manufacturer-approved assembly details; do not improvise backer rods or fastening changes.
McElroy: oil canning explained
McElroy: pan conditions and oil-canning acknowledgement
Prepared by Barnes N’ Roofs. Reviewed September 18, 2026. Manufacturer examples are identified in captions and are not represented as our installations. Exact product availability and current written specifications control.