Thickness questions usually arrive as “what gauge do your panels come in”, which is the wrong way round. The right three inputs are the span the panel has to bridge, the load it carries, and whether that load is spread across the face or concentrated on a small footprint. Given those, thickness follows. Without them, any number is a guess.
Span first
Span is the distance between supports with nothing under the panel. On a pallet with full deck boards, the span is the gap between boards – small, and almost any panel will do. On a pallet with missing boards or a load bearing only on the stringers, the span is the stringer spacing, and that is a different problem entirely.
Deflection goes up with roughly the cube of span. Doubling the unsupported distance increases sag by a factor of about eight. This is why a thickness that worked on one pallet type fails on another – the pallet changed, not the load.
Then the load, and how it is applied
Total weight matters less than weight per point. A hundred kilograms spread evenly across a panel is an easy problem. The same hundred kilograms resting on four feet is a hard one, because the panel has to resist being punched locally as well as bending globally.
Tell a supplier both. “Two hundred kilos on a euro pallet” is not enough to size from; “two hundred kilos on four feet of fifty millimetres square” is.
Temperature and time
Two factors that get left out. Polypropylene creeps under sustained load, and faster at higher temperature. A panel that is loaded and left for weeks in a warm container will sag more than one loaded for an hour. If your panels sit under load for long periods, or travel hot, say so – it changes the answer by a thickness step.
Reading a spec sheet honestly
Panels are sold by thickness and by grammage, and sometimes by a compressive strength figure. Compressive strength is measured through the thickness and tells you almost nothing about spanning. If you are choosing a topper, you want a bending or flexural figure, and a supplier who cannot give one is not going to help you size it.
Also worth knowing: two panels of identical thickness from different makers are not equivalent. Core cell size and face thickness both vary, and both matter more than the overall dimension on the label.
A rough starting point
We deliberately avoid publishing a table, because it gets used without the caveats and then panels get ordered wrongly. As an orientation only: light layer work on a continuous deck is a thin panel; spanning a stringer gap with a distributed load needs something in the middle of the range; concentrated loads or long spans need the thick end. Beyond that it is a calculation, and we will do it for you.
If you are weighing honeycomb against a cheaper sheet, honeycomb versus corrugated sheet for pallet liners covers when the extra thickness is wasted money.
What we can do
We supply PP honeycomb panels across a range of thicknesses and will size one from your span, load and dwell time. Send us those three and a sketch if you have one. If the calculation says corrugated sheet will do, we will tell you that instead.