The Top & Underside of a Shipping Container

Have you ever wondered what the Roof or Underside of a Shipping Container look like? These two parts of a container may be rarely seen, but they are still important and like the rest of a container, they are highly engineered to provide value.

A Few Things to Know About Container Roofs


The roof of a Shipping Container has corrugations or “bumped up” portions every 6 inches. The purpose of this design for the roof is to give the Container more strength and to shed water from the roof to the sides of the Container.


You will notice that each Shipping Container has a unique Serial Number consisting of 4 Letters and 7 Numbers. Many Simple Box Containers start with the prefix of GSBU, followed by 7 digits. The Unit Number is located in many places on the Shipping Container (Door, Wall, etc.) as well as on the Roof of the Container.


As with the walls of a container, ISO Shipping Container Roof panels are made of Corten Steel, which is a special steel blend that enables it to form a water-resistant layer of rust when it is dented or scratched.

A Few Things to Know About the Underside of a Container


The floor of a shipping container is made of steel cross-membranes and thick marine-grade plywood. The plywood used for newer containers is often eco-friendly bamboo that is cross-hatched for added strength.


The underside of a shipping container is sealed with a thick water-proof coating. The sealant is one part primer and two parts bitumen (otherwise known as asphalt). A new shipping container seals up so tightly that it can often be submerged in water and even float without the contents inside getting wet!


Most newer containers have “fork pockets” on the sides to be used for lifting with a heavy-duty forklift. The forklift pockets are located 6′ 8″ apart from each other, based on the center point of the shipping container.

The container roof and floor condition are just two areas to focus on when choosing your own shipping container. We also suggest you consider the doors, walls, and locking hardware to make sure that your container suits your needs and your budget.

The Simple Box Difference

One thing that sets Simple Box apart from most other Container Companies in the area (Seattle, Portland, Bellingham, etc.) is that we invite you to come to our Storage yard and let you choose your own container.

Another thing that sets us apart is the condition of the Shipping Containers we offer: cargo-worthy or better unless otherwise specified. If you are anything like us, you don’t like surprises unless they better than you had expected. That’s why we specifically only offer Cargo-worthy containers, which is a higher grade than Wind and Water Tight (WWT).

Ready For a Container?

If you would like to come by any one of our Shipping Container locations near you, just come on by! Or you can give us a call or text us and we’ll be happy to send photos, video, or even FaceTime with you in order to help you choose the best container for your situation.


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