Tips for Buying a Used Conex Shipping Container (Portable Steel Storage Box)

Used Conex containers offer waterproof, weatherproof storage. Steel storage boxes work for portable offices and out buildings. Used cargo containers find a new life as oversize building blocks for shops, homes, and warehouses. It's no wonder these portable storage containers are in high demand. They're versatile and can be modified. They're secure. They don't require extensive ground prep or a foundation.

What to Look for When You Buy a Used Conex Container  Shipping / Storage Box

When you go to buy a used Conex, what do you look for so you get a good one? Here are tips for buying a secondhand shipping container storage box. They'll help you get the right container for your needs.

Insulated or Not?

In many areas of the country a non-insulated container will sweat with condensation inside from the change of temperature. This condensation may be the color of the paint on the ceiling, dripping on the very things you wanted to protect. The interior walls in an insulated container will usually be a nice stainless steel, verses painted or primered steel in the non-insulated version.

Check the Roof

Take a ladder with you to get up top of the used Conex, to check the roof. Look for rips, holes, and gashes. If you need to, you can usually fix leaks, but avoid them if you can.

How High?

Insulated Conex containers come in two heights, 8 ft. and 9 ft. You can expect the 8 ft. to have about 7 ft. 3 in. interior height, and the 9 ft. to have about 8 ft. 3 in. interior height. If you will be putting in lighting this extra headroom is really nice.


Insulated shipping containers will usually have slotted aluminum flooring for air circulation. If you don’t like it, you can overlay it with plywood flooring, but you will incur that cost. Non-insulated containers will usually have wooden flooring. This can sometimes be tricky patching. Either type of flooring should be free of nasty looking and smelling contaminants. Most all containers will need cleaning, but cleaning a flat wooden floor will be easier than cleaning between the aluminum slats. Removing 12-year-old dried molasses from between these slats can be a chore, and I would avoid if possible.


Full-size cargo containers are about 40 ft long, and half-size containers are about 20 ft long. The shorter containers cost about the same initially, and usually cost the same for delivery. Unless you absolutely don’t have the space, the larger is probably a better value. Most people will have no problem with the extra storage space.

The Doors

The double rear doors of a used Conex will seldom open and close easily, but they should work correctly. Look to see that they aren’t sprung out of square. Check to see that the insulated doors aren't rotting from the inside. Make sure the seals are in reasonable shape. Even if you plan to cut a walk through door into the side, you want the rear doors to close and seal well.


Who will deliver your container? Although considered a portable storage container, it takes a semi or heavy equipment to move them. Will the seller deliver it, or will you have to arrange a truck yourself, and which will be less expensive? Who will have more experience and do a better job of setting the container just where you want? Will taking the time to hire another trucking company save you $200 or $300? Although you have the room for the container, can a truck get in and drop it where you want it?

Will it be Legal?

Check the codes for your area. More and more counties, boroughs, parishes, townships, fire districts, and government entities are regulating buildings and storage units. Are there covenants on your land title that may be restrictive? Is it OK with your homeowners or community association? Just because the neighbor has a metal storage box in his yard, doesn’t make it legal. If you plan to modify your Conex, you may need a building permit.

Used Conex storage containers can last for years. Use these tips for buying a good used container. Do periodic maintenance on it, to prevent leaks and keep the doors working. Repair damage, so it doesn't get worse. You should get many years of service from your pre-owned steel shipping box.

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