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Humidity during the summer months can be difficult for people, so it should be easy to consider what that same humidity could do to corrugated boxes. They don’t perform well after getting wet and having the wrong type of moisture in the air could start providing the same results. The amount of humidity in the air has a definite effect on the strength of corrugated boxes, so when moving or storing items in a high humidity region, using a stronger box, or moisture resistant adhesive (MRA) type box is recommended.

How do you know when humidity will start affecting the box?

The Handbook of Package Engineering has a chart explaining how relative humidity (RH) will affect a corrugated box based on stacking strength. The higher the RH percentage, the lower the stacking strength percentage. This must be considered when moving or storing items that will be in high humidity areas throughout the summer months.


What will happen if the boxes are stored improperly?

While corrugated boxes can be negatively affected by too much humidity, the same can be said for when there isn’t enough. Improperly stored boxes can result in boxes that swell or become distorted when there is too much moisture. For those boxes that don’t have enough, the boxes become dry, brittle and crumbly. Boxes should not be stored outside under any circumstances due to fluctuations in weather. Even if things are dry outside, the boxes can lose their appearance, looking dry and faded.


How to properly store corrugated boxes

Knowing how to properly store corrugated boxes will prolong their life cycle. Here are a few tips:

  • No direct floor contact—When boxes are stored directly on the floor, they can become contaminated with debris or become damaged. Putting them on a pallet and storing on shelves can help alleviate this. When using pallets, the surface should be smooth and free from protruding items to avoid puncturing the boxes. Storage racks are a good idea for properly storing boxes.
  • Use a climate-controlled facility—If you’re stacking boxes for storage or have boxes filled with items, using a climate-controlled area can help regulate the humidity and bypass the effects of the boxes becoming weak from too much moisture or dry and crumbly from not having enough.
  • Shape integrity—If boxes are not being used, they should be stored flat, making sure to keep it from being stored on its edge. Even when boxes are stored in this manner, it is important to be mindful of weight loads.


Caring for and properly storing corrugated boxes helps maintain their lifecycle and while protecting the items being stored. For more information on corrugated boxes and maintaining their integrity throughout the humid summer months, contact our team at Express Packaging today!