How should I prepare my shipping container for winter?

Shipping containers are designed to keep everything inside safe from the environment, such as sun, snow, wind, and even rodents.

However, there are a few things to consider as the seasons change....

Condensation
Condensation is often one of the first things people experience inside a container. It can be a big problem, especially in winter. 

With minus 20 outside and the sun shining, the outside of the container is warming up. When the sun heats the steel no longer matches the temperature inside the container. That is when condensation builds up.

If there is a temperature change between the air inside and outside the container, water droplets will appear. Instead of condensation building up on the outside of the container like a water glass, it will appear on the inside, called container rain.

Container rain occurs when water droplets appear on the container walls and ceiling and drip onto the floor or anything stored inside. This rain can lead to big problems in the future, such as mold, mildew and rust.

Make sure the items you’re packing are adequately sealed and aren’t damp. During the winter, unexpected moisture can cause things to warp or crack. During the spring thaw, humidity can attract pests and mold. Store items in vacuum-sealed bags or dry boxes, and include desiccants to protect contents from moisture throughout the season. 

Ventilation
Condensation is a big issue in wintertime and colder climates, but it can happen anytime of the year and in other climates as well—especially humid ones. So no matter where you live, if condensation could be an issue, you need to install vents. Vents can be installed on the end walls, container doors, or sidewalls. For optimal airflow, install two vents diagonally so that interior air can equilibrate with the outside temperature.

Container Frozen to the Ground
When a container is positioned directly on the ground without blocks underneath the corner posts, it might sink into the ground. Once it sinks into the ground and the ground freezes, your container is now frozen to the ground and can be nearly impossible to winch it out (if needed). If you plan to move your container during winter, ensure you have placed blocks beneath the corner posts so it's easier to move when you need to.

Roof Damage
Another way to prepare for winter is to check your container for damage, such as rust or pinholes. During the winter, we sometimes get inches of snow at a time, and what you don’t want is for a large amount of snow to concave the container ceiling and cause irreparable damage to your container or items inside. Before winter hits, do a walk around of your container—especially the roof— and check for damages. See if there are any areas that hold water or places that are starting to cave in. Push out any dents holding water and silicone or caulk pinholes where the sun is creeping in.

Rodents
Another problem that can cause issues during winter are rodents looking for shelter. They could sneak under your shipping container through the forklift pockets, or mice/birds could nest in the corner castings. Although shipping containers are rodent-free and they won’t be able to gnaw their way into the container, animals such as skunks, foxes, rats, and rabbits can still make the underside of the container their home during winter. These animals can create health hazards and other problems over time. To reduce the risk, consider the following steps:

• Place blocks or cribbing under the corner posts to elevate the container and reduce sheltered space beneath it.
• Inspect the forklift pockets and corner castings regularly and clear out any nesting material.
• Seal any gaps around the base of the container with weather-resistant materials to discourage animals from sheltering underneath.
• Contact a pest control professional if rodents are already present.

Maintain moving parts 
Monitor the door hinges and locking rods regularly. Follow these steps to keep moving parts functional throughout winter:

1. Rinse joints and door hinges with water and soap to clear mud and debris.
2. Apply WD-40 or another suitable lubricant to all joints and door hardware.
3. Open and close the doors periodically to prevent joints from fusing together.

Remove this line:  and soap. WD-40 or other lubricants can be applied to joints and doors to help with functionality. 

Check that container is sealed
Inspect all walls and door seals for cracks or gaps. Any opening that disrupts humidity control or airflow can cause sudden environmental changes inside the container, increasing the risk of condensation, mold, or rust. Seal any openings you find with silicone or caulk to maintain a stable interior environment.