A Gaylord – the large octagonal or rectangular bulk box used for loose parts and resin – usually sits directly on a pallet, and a sheet of corrugated plastic underneath is a common addition. Whether it does anything depends on what problem you are trying to solve, because it solves two of the three people expect.
What it genuinely does
It bridges the pallet gaps. A Gaylord with a part-full bottom panel will bulge downward into the space between pallet boards. A sheet underneath spreads that load across the boards and stops the bulge. This is the real benefit and it is worth having.
It keeps the box off a wet or dirty floor. If pallets sit on a yard or a wash-down floor, a sheet is a barrier. Cheap, effective, and the reason most people put one there in the first place.
What it does not do
Make the box stackable, or add meaningful structural strength. A sheet under a Gaylord is not carrying the load – the pallet is. If the box is failing, the sheet is not the fix.
It also does not stop a box that is already over-loaded from bulging. A sheet bridges a gap; it does not contain pressure. If the sidewalls are bowing, the problem is fill weight or box specification, and adding a sheet just hides the symptom for a while.
Thickness: less than you think
Because the sheet is supported by the pallet boards and is only bridging short gaps, a mid-range thickness is usually enough. Going thicker adds cost and stiffness you cannot use, and it makes the sheet harder to handle and more likely to be skipped by whoever is building the pallet.
The exception is a pallet with wide gaps or missing boards. Then the sheet is spanning further and thickness starts to matter. What to check is set out in what GSM means for PP corrugated sheet.
The thing that actually fails
The sheet gets chewed at the edges by the pallet truck. Fork tips catch it, it gets dragged, and after a few loops it is cracked halfway across and doing nothing.
Cut the sheet to the pallet footprint rather than letting it overhang. An overhanging sheet is a handle for anyone and anything to grab, and trimming it to size costs nothing.
Where it causes a problem
On a smooth concrete floor, a PP sheet under a loaded Gaylord reduces friction more than people expect. If the pallet then gets moved with a powered truck, the whole assembly can slide rather than the truck stopping. It is an occasional issue rather than a common one, but if your floors are smooth and your loads are heavy, it is worth knowing about.
How long one lasts
In a loop where pallets are built and broken down indoors, a sheet under a Gaylord survives a long time – it is not doing much structural work. In a yard, with pallets built outside and moved by truck, expect to replace them, because the edges go first and the sheet is only useful while it is whole.
Keep a few spares. A sheet that has cracked halfway is worse than no sheet, because it looks like protection and gives none.
What we can do
We supply PP corrugated sheet cut to pallet footprint so there is no overhang to catch. Tell us your pallet size and what the box carries – and if a sheet is not going to solve your problem, we will tell you that rather than sell you one.