What an Ohio winter does to a pallet stack

The three mechanisms

Absorption

Untreated wood is hygroscopic. An uncovered pallet in December is taking on water through end grain, through the notch cuts, and through every split. Moisture content climbs well past the equilibrium it reached in a warehouse, and wood loses stiffness as it wets — an important point for anyone planning to rack it later.

Freeze-thaw

Water in a split expands when it freezes. The split gets wider. It takes on more water. Ohio gives us dozens of freeze-thaw cycles between December and March, and each one works the existing damage a little further open.

Spring mold

Wood that spent the winter wet meets March temperatures and grows mold. This is not a cosmetic problem for anyone shipping food, beverage or pharmaceutical product — it is an audit failure, and it travels into the building on the next pallet somebody reuses.

What it costs, concretely

A stack of standard-footprint cores in sound condition has a real per-core value. Overwintered uncovered, three things happen to that number.

• Some proportion drops from a resaleable grade to repair-only.

• Some proportion leaves the recoverable stream entirely on mold or rot, and becomes a grinding cost rather than an asset.

• The whole load weighs more, which matters if anyone is paying freight by weight.

We assess condition at collection, in daylight, with your person present. That is deliberately not a system where a spring load is quietly repriced after the fact — but it does mean a spring load is honestly worth less than the same pallets were in October.

The prevention, in order of effect

• Remove it before winter. By far the largest effect. A scheduled collection that keeps the stack small means there is nothing to overwinter.

• Get it under cover. A roof, a trailer, or even a properly secured tarp over a well-formed stack. Half-covered is close to useless; water runs in.

• Get it off the ground. Bottom pallets sitting in mud wick moisture upward and are almost always the first write-off. Runners, a hard standing, or a couple of sacrificial pallets underneath.

• Stack it square. A leaning pile holds water in every horizontal gap. A square stack sheds it.

• Keep broken ones separate. They soak up water fastest and they contaminate the assessment of the whole load.

The other winter problem: your building

Bringing wet pallets indoors is its own issue. A wet pallet in a heated warehouse releases moisture into shrink-wrapped loads, and the mold grows inside the wrap where nobody sees it until the customer does.

If you must bring pallets in from an outdoor stack in winter, break the bands, let them stand and dry, and inspect before use. It is a nuisance and it is a great deal cheaper than a customer complaint about a moldy pallet under their finished goods.

More on the wider storage question in warehouse pallet storage and fire code.