The Enemy: Moisture
Corrugated cardboard and moisture do not mix. A box stored in a humid environment loses compression strength, and a clean box can become a weak box just by sitting in the wrong spot.
The rules are simple: store boxes indoors, off the ground, and away from exterior walls where condensation can form.
Store Flat Whenever Possible
Knocked-down (flat) boxes take up far less space than erected boxes. They are also less likely to be damaged by accidental bumps. Keep bundles square and supported so they do not bow or take a set.
Mind the Temperature
Cool, dry, stable conditions are ideal. If you are storing boxes in a space without climate control, such as a garage, shed, or shipping container, be aware that temperature swings cause condensation.
In Portland this is particularly relevant during fall and winter, when damp air meets cold walls and floors.
Stacking Rules
If you must stack boxes, flat or erected, follow these guidelines:
- Keep stacks stable: Stack only as high as is safe to reach and to keep the pile square.
- Column stack, not brick stack: Align corners directly above each other for the most support.
- Use pallets: Do not stack boxes directly on a concrete floor. Concrete wicks moisture.
- No leaning: If a stack starts tilting, restack it. Leaning creates uneven pressure that crushes the bottom boxes.
Before You Buy
Storage matters before boxes reach you too. When a partner supplier follows up on your quote, it is reasonable to ask how the boxes were stored, and to check a delivery for any sign of moisture before putting boxes into use.