Packaging Reference Library · Wall Charts

Pallet Patterns Chart

How column stacking and interlocked stacking compare for box compression strength and load stability, and how overhang and gaps weaken a pallet load.

Ref PK-0209ASTM D642

Draft, open for review. Check every value against the governing standard and the manufacturer’s data before use.

What it is

A pallet pattern is the way boxes are arranged on each layer and how layers sit on each other. The two basic choices are column stacking, where each box sits squarely on the box below, and interlocked stacking, where layers are rotated or offset so boxes bridge the boxes below. Column stacks keep the box corners lined up, and the corners carry most of the load, so column stacking keeps more of each box's compression strength. Interlocked stacks tie the load together and are more stable, but they cost compression strength. ASTM D642 is the test method for box compression.

How to read it

Decide whether the load will be stacked high or stored long term. If so, compression comes first.
Decide whether the load will move a lot by forklift, truck or rail. If so, stability comes first.
Pick a pattern from the chart.
Use stretch wrap, tie sheets, corner boards or straps to add what the pattern lacks.

Pattern comparison

Pattern	How it looks	Compression strength	Stability	Notes
Column	Boxes stacked straight up, corners aligned	Highest	Lowest	Add wrap, tie sheets or corner boards
Interlocked (brick)	Each layer rotated or offset over the one below	Reduced, often a lot	High	Corners bridge gaps and lose support
Pinwheel	Boxes arranged around a center space, rotated per layer	Reduced	Good	Used when box size does not fill the pallet
Row or split row	Rows rotated between layers	Moderate	Moderate	Mixed approach
Column with tie sheets	Column stack with a sheet every few layers	High	Moderate to good	A common compromise

Key points

Overhang is the most damaging error. Box walls hanging past the pallet deck lose support and can lose a large share of their strength. Keep boxes on the deck.
Gaps between pallet deck boards let box bottoms sag. Use a pallet with good top-deck coverage or a slip sheet.
Misaligned columns, even by a small amount, reduce strength.
Humidity and time under load reduce box strength. Long-term storage needs a safety factor.
Box compression values come from ASTM D642 tests or the box maker's data. Use those, not rules of thumb, for design.

Common mistakes

Interlocking a load meant for high stacking in a warehouse.
Letting boxes overhang the pallet edge to fit more per layer.
Using a pallet with wide gaps under a column-stacked load.
Wrapping so tightly that the top box edges crush.
Changing box size without rechecking the pallet pattern.

Governing standards: ASTM D642 (compressive resistance of shipping containers); the box maker's compression data; customer and carrier pallet specifications.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.

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