Pallet overhang: why loads should not hang past the pallet edge

Overhang is when any part of a unit load extends beyond the edge of the pallet deck. It is common, easy to prevent, and one of the most frequent causes of crushed boxes and damaged freight. This guide explains what overhang does, why receivers reject it, and how to design it out with the right pattern or pallet.

#What overhang does to boxes

A corrugated box carries most of its stacking load through its vertical walls and corners. When a box on the bottom layer overhangs the pallet, part of its bottom edge is not supported. The wall above that edge can bend inward or outward and buckle at a lower load than it would on full support.

Packaging research, including work at the Virginia Tech Center for Packaging and Unit Load Design, has shown that overhang reduces the compression strength of boxes on a pallet, and that even a small overhang has a measurable effect. The amount depends on how far the box overhangs, which walls overhang (corners are worst), the box construction and the product inside. Treat any overhang as a reduction in your stacking safety margin.

Overhang also affects the upper layers. If the bottom layer bulges or leans, every layer above it is out of column, which reduces strength further. See pallet stacking patterns.

#Other costs of overhang

#Overhang and truck counts

In a 53 ft trailer, 48 × 40 pallets loaded straight fit 13 rows at 48 in each (624 of about 630 in). Add 1 in of overhang at each end of every load and each row becomes 50 in: only 12 rows fit, and the trailer holds 24 pallets instead of 26. See pallets per truckload.

#Overhang and freight class

LTL carriers compute density from the shipment's outside dimensions. A 48 × 40 × 50 in load that overhangs 2 in on each side measures 52 × 44 × 50 in, about 19% more cubic feet at the same weight, which can push it into a higher freight class.

#Underhang

Underhang is when the load is smaller than the pallet. A small underhang, up to about 1 in on each edge, is normal and protects the boxes from edge damage. Large underhang:

• wastes pallet, truck and rack space;
• leaves exposed deckboard ends that snag;
• lets stretch wrap pull the top of the load inward;
• can mean you are paying for a pallet larger than you need.

#How to eliminate overhang

1. Change the pattern. Try mixed-orientation or pinwheel layers that fit inside the footprint. The cases per pallet calculator compares layouts.
2. Change the case. Small changes to case dimensions, often less than 1/2 in, can make a pattern fit. This is usually decided at packaging design, so involve the packaging engineer early. See unit load design.
3. Change the pallet. If the product footprint is fixed, specify a pallet to match it. A custom footprint costs little extra at volume. See how to spec a custom pallet.
4. Use a winged pallet. A winged pallet has a top deck that overhangs the stringers, which supports a wider load while keeping the base narrower. It is common for bagged goods.
5. Train and check. Overhang often comes from careless palletizing. A visual check at the stretch wrapper catches most of it.

#Who sets the overhang rules

There is no general law or industry standard that sets a maximum load overhang. The rules come from the people who receive and move the load:

• Retailers publish overhang limits in their vendor, routing or shipping guides, usually alongside height and weight limits, and often reject or charge back non-compliant loads. See the Amazon, Walmart and Costco pages, and always check the current guide.
• Carriers do not usually forbid overhang, but they bill on the measured dimensions and may decline claims for damage to overhanging freight.
• Warehouses and 3PLs set their own rules so loads fit their rack bays and conveyors.

If none of these applies, zero overhang is the safe design target.

#Load overhang vs pallet overhang on rack beams

Two different things are called overhang in a warehouse, and they are easy to confuse.

In selective racking, a 48 in deep pallet usually sits on a rack frame about 42 in deep, so the pallet extends about 3 in past the front beam and 3 in past the back beam. That overhang puts the pallet's bottom lead boards and stringer ends on the beams, which is how the rack is designed to support it. Pallets that are too short for the frame depth can fall through, and pallets that overhang too far can catch on the next bay or the flue space. See pallet racking and deflection.

#How to measure overhang

Place a straightedge or a level vertically against the pallet edge, at the lead board and at mid-length on each side. Measure from the straightedge to the furthest point of the load. Record the overhang on each of the four sides separately, and note whether it is the whole layer or a single bulging box. Stretch wrap can hide overhang, so check before wrapping or measure the wrapped load at its widest point, as the carrier will.

#A quick check at the stretch wrapper

Most overhang is created at the palletizing station and can be caught before the load leaves:

• Is every edge of every layer inside the pallet edge?
• Are the corner boxes square to the pallet corners?
• Is the load centered, not pushed to one side?
• Are the top layers level and not leaning?
• If a pattern cannot avoid overhang, has someone approved it?

A photo of the finished load at the wrapper is also useful evidence if a receiver disputes the condition of a shipment.

#Special cases

• Bagged goods such as cement, feed and seed spread when stacked. A winged pallet or a slightly larger pallet keeps the bags supported.
• Long products such as pipe, lumber and doors may overhang by design. They need a pallet or skid sized to the product, or dunnage and bracing to support the overhang.
• Retail displays on half and quarter pallets usually have strict no-overhang rules because they go straight onto the sales floor.

#Specifying the load and pallet together

On a pallet RFQ, give the unit load dimensions (length × width × height) and the pallet footprint, and state "no overhang" or the allowed overhang per side. If the pallet is custom, size it to the load footprint plus whatever underhang you want at the edges. You can set the footprint in the designer and put the load dimensions in the spec notes.