Stacking and securing the load

This is the part of packaging with the most leverage. The same boxes on the same pallet can arrive perfect or destroyed depending on how they were stacked, wrapped, and strapped. None of it takes special equipment, and most of it is free.

Choosing a stacking pattern

There are three ways to stack boxes on a pallet, and each trades stacking strength against sideways stability.

Two rules apply to all three patterns:

• Cube the load. A rectangular block of freight, square on all sides, is the most protected shape and the cheapest to ship.
• Never pyramid stack. Stepping the load in as it goes up leaves the top boxes exposed and unsupported, and it can increase the billable dimensions of the shipment, so you pay more for a worse result.

Overhang and underhang

The relationship between the footprint of your freight and the footprint of the pallet is worth getting exactly right.

See Measuring your freight for how overhang affects the dimensions on your quote.

Tie sheets and corner boards

These two cost very little and prevent a large share of load failures.

Tie sheets are flat sheets laid between layers of boxes, and at the top and bottom of the load. They increase stability, level out an uneven pallet deck, help lock the load to the pallet, and protect boxes from abrasion and soiling. They are especially valuable on column-stacked pallets, which is exactly where lateral stability is weakest. Single, double, or triple wall corrugated, solid fiber, plywood, and plastic composite all work, and how much they help depends on the quality of the sheet.

Corner boards run up the vertical corners of the load. They add stacking strength, hold the boxes in line, stop them shifting off the pallet, and protect the corners from the pressure of stretch film and strapping. Two details matter:

• Use full-length, single-piece corner boards. Short pieces stacked end to end lose most of their value as a load stabilizer.
• Where they end depends on the underhang. With less than an inch of underhang, run them all the way to the ground. With more than an inch, rest them on the top deck instead. Running them to the floor over a large underhang makes the stretch film roll up the load, which is exactly the opposite of what you want.

Honeycomb fiberboard corner boards are the exception worth knowing: they add stacking strength but do not properly protect against the forces from roping or strapping.

Applying stretch film

Stretch film has one job: keep the load contained and on the pallet. It is very good at that and very bad at everything else.

The details that decide whether the wrap actually holds:

• Use a machine if you have one. Getting a consistent pattern and consistent tension by hand is genuinely hard. Wrapping by hand means pulling the film taut before it touches the load, every single pass.
• Stretch the film. Most films are designed for at least 200 percent pre-stretch, and should be stretched to at least 80 percent of the supplier's recommended figure to actually stabilize the load. Film applied loose does almost nothing.
• Cling side inward. On most rolls the cling side is the inside face, and it needs to be against the load.
• Protect the corners. The tension between the box and the wrapper can collapse a corrugated corner, which takes the compression strength of the box with it. Corner boards prevent this.
• Consider stretch roping. Bunching the bottom few inches of film into a rope creates a concentrated band that anchors the film so it cannot ride up off the pallet, and it reduces tearing from ragged film edges. It concentrates a lot of force at one point though, so use corner boards with it.

Strapping the load to the pallet

Strapping, also called banding, is what holds the freight down onto the pallet deck. Material choice matters more than people expect.

Chocking

Straps stop vertical movement. They do not stop the freight sliding around on the pallet deck. Chocking does that: blocks fixed to the deck that physically prevent movement along both the length and the width of the pallet.

Chocking and strapping are a pair. Chock to stop sliding, strap to stop lifting, and use both if the freight is round, heavy, or does not sit flat.

Top frames

A top frame is a simple wooden structure, usually two layers of boards fastened face to face, laid on top of the load. It does two things: it spreads strapping force across the whole top of the load instead of letting the strap cut into it, and it stabilizes a load that would otherwise be loose.

Size it to the load. A top frame that is longer or wider than the base gets damaged itself and damages the freight beside it. A top frame that is too small lets the strapping bite into the load at its edges.