01Why corners carry everything
A corrugated box in a stack is a column, and like any column its strength is concentrated at the vertical edges. The flat panels contribute relatively little. Somewhere between 60% and 70% of a case's top-to-bottom compression strength lives in its four corners.
Now hang that corner over the edge of a pallet. The strongest part of the box is standing on air, and the load path has to detour through the panel — the weak part — to reach the deck. That is what overhang costs you, and it is why the loss is so much larger than the fraction of area unsupported would suggest.
| Overhang | Compression strength lost | Practical effect |
|---|---|---|
| 0 in | 0% | Design intent |
| 0.5 in | ~10% | Usually tolerable |
| 1 in | ~20% | Visible corner crush on lower tiers |
| 2 in | ~32% | Load failure risk in transit |
| 3 in | ~43% | Do not ship |
02It compounds down the stack
The tier that suffers is the bottom one, and the bottom tier is carrying every tier above it. So the strength loss and the load concentration land in the same place, which is why overhang damage is nearly always found at the base of the load.
Add double-stacking in a trailer and the bottom tier of the lower pallet is carrying two full loads with a third of its designed strength removed. That is the configuration where a shipment arrives as a heap.
“We spent eight months blaming the carrier. It was an inch and a half of overhang on a case pattern nobody had reviewed since 2019.”
03Three fixes, cheapest first
1. Change the case tile
Often the pattern, not the pallet, is what pushes product over the edge. A different tie-and-high arrangement can bring the load inside the deck footprint with no change to anything you buy. Cost: an hour of somebody's attention.
2. Add a top cap or corner boards
Corner boards under the strapping redistribute strap tension away from the case corner and add vertical stiffness where you have lost it. At $0.35 to $0.90 each, four of them cost less than two dollars and routinely protect several hundred dollars of product. A top cap protects the top tier from the pallet above it.
3. Change the pallet footprint
The proper fix, and the expensive one. A custom footprint sized to the case tile eliminates overhang at source. Minimum run is 500 units and lead time is 8 to 14 working days, so it is a planned change rather than a fix for next Tuesday.
04How to check it in five minutes
- Go to the dock and find a wrapped, loaded pallet.
- Look along each of the four edges at eye level. Product should not be visible past the deck.
- If it is, measure the worst side with a tape.
- Check the bottom tier of the load for corner crush. If it is there, you have your answer.
- Repeat on three different SKUs — overhang is usually product-specific, not universal.
Most operations that do this find at least one SKU with an inch or more, and most of those have a damage history nobody had connected to it.
