Corrugated board is a sandwich: a wavy fluted sheet glued between flat liners. Single wall has one flute and two liners. Double wall has two flutes and three liners, usually with different flute profiles paired together. That structural difference is the whole comparison, and everything below follows from it.
The structural difference in numbers
| Board | Build | Approximate caliper |
|---|---|---|
| E flute single wall | 1 flute, 2 liners | About 1/16 in |
| B flute single wall | 1 flute, 2 liners | About 1/8 in |
| C flute single wall | 1 flute, 2 liners | About 3/16 in |
| EB double wall | 2 flutes, 3 liners | About 3/16 in |
| BC double wall | 2 flutes, 3 liners | About 5/16 in |
These are the published industry flute profiles, given as a reference rather than an iBox stock list. The finished caliper on your job is confirmed on the quote.
What double wall actually buys you
Three things, in order of how often they matter.
- Stacking. A box under a pallet load carries most of that load through its four vertical corners. More board in the corner posts means more of the stack it can hold without bulging.
- Puncture and edge resistance. Heavy dense contents and rough handling both attack the edges first, and a second flute layer is a second line of defence.
- Repeat handling. Boxes that get moved several times, or that are stored for months in a humid space, lose stiffness. Starting stiffer means ending usable.
What it costs you
More board, more weight, more freight, and less internal space. That last one catches people out. If your internal cavity is fixed by the product, moving from single wall C to BC double wall adds roughly a quarter of an inch to each external dimension, which can be enough to break a pallet pattern that used to tile cleanly. Recheck the footprint against the 48 x 40 in deck whenever you change board.
There is a print consideration too. Coarse flutes can telegraph faintly through the liner on a heavily printed panel, an effect known as washboarding. If the box is retail facing and needs a clean solid, a fine flute single wall or an EB double wall usually looks better than a coarse double wall.
A straightforward way to decide
| If this is true | Start with |
|---|---|
| Light contents, one courier leg, no stacking | Single wall |
| Retail facing with heavy print coverage | Single wall, fine flute |
| Palletised, stacked more than two high | Double wall |
| Heavy or dense contents | Double wall |
| Long transit, sea freight, multiple handling points | Double wall |
| Long term storage in an unconditioned space | Double wall, and ask about a coating |
A note on ratings
You will see board described with test values. Those describe a board specification, and the right way to use them is to state the performance you need and let the spec answer it, rather than assuming a number is a guarantee for your particular pack. Tell your supplier the weight, the stack height and the transit route, and ask what board they recommend for it.
Ordering
Both grades start at 100 boxes, from about $0.48 per unit at bulk volumes, confirmed on your written quote. The cutting die, the printing plates, design support, US shipping and a digital proof are included, so switching board grade does not mean re-tooling. Turnaround is stated per product in three lanes, rush (expedited production plus air freight), standard (air) and cost saver (sea), from about 7 business days of production plus 2 to 5 days for delivery. Production runs from West Chicago in the US and Guangzhou in China.
Send the contents weight, the stack height and the transit route and we will recommend a board. Start at request a quote, browse the range on the corrugated boxes page, or see how caliper feeds into sizing on regular slotted box dimensions.
