Are Shipping Containers Waterproof?

Shipping containers play a big role in the international trade. They are used to transport goods between oceans in the cheapest and safest way possible, which begs the question, “Are shipping containers waterproof?”

In this article, we are going to look into the construction and materials used to make shipping containers. In this way, we can determine how and why the goods stay safe inside while being shipped across the seas.

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What Is a Shipping Container?

A shipping container is a very strong kind of container suitable for storage, shipment, and handling. They vary in sizes from universal corrugated boxes to huge steel shipment boxes. In the international shipment language, it is also called the intermodal freight container and is intended to be transported between different modes of transportation without having to unload or reload.

Types of Shipping Containers

Shipping containers come in different types that vary in size, structure, construction, and materials. Here are the different types of shipping containers that are commonly used today:

  1. Dry Storage Container. As the name implies, dry storage containers are used to transport dry goods and products. They come in three sizes (10 feet, 20 feet, 40 feet) and different standard dimensions as defined by the ISO.
  2. Open Top Container. For products with great height, the open top container is used to accommodate them. The top cover is convertible and can be removed to fit huge product sizes.
  3. Tunnel Container. Doors on both ends of this container make it easy to load and unload the products being shipped.
  4. Open Side Storage Container. One side of this shipping container can be used as doors. Hence, the opening side is much wider compared to the typical containers. Open side storage container has more room for loading goods of different sizes.
  5. Refrigerated ISO Container. For perishable goods like fruits, vegetables, and meats, this type of container is the most appropriate. Refrigerated ISO container is equipped with a low temperature-controlled environment to preserve the goods over long distances.
  6. Thermal Container. For goods that need a higher temperature setting, the thermal or insulated container can transport them. This type of container is built with regulated temperature control.
  7. Special Purpose Container. This is not your typical kind of container because it is custom-made for specific purposes. The materials and construction used to build it depend on the purpose it caters to. Special purpose container is usually used for transporting weapons, and security is the top priority.

What Are Shipping Containers Made Of?

Most shipping containers are made of steel because this material is highly durable, withstands movements, and can be stacked without getting damaged, hence protecting the goods inside. It also resists corrosion from the salty composition and gusty waves of the sea. Because of the high durability of shipping containers, they are also turned into storage rooms and container houses.

Shipping containers are made of complex construction as explained in the following paragraphs:

  1. The walls are made of 8×3-foot sheets of steel, which are processed to turn into walls. Each sheet is prepared for fabrication. During the fabrication process, the sheet is flattened, sandblasted, and stamped. The process also corrugates the sheet, which adds to its strength.
  2. After the fabrication, the sheets are welded together to form wall panels. It takes 7 to 14 sheets to form one wall panel, which generally measures 20 to 40 feet in length.
  3. The sub-floor of the shipping container is made of square steel beams. Then, the cross rails and the two long side rails are welded together every 1.5 to 2 feet. Ultimately, this structure is covered with plywood flooring.
  4. In order to build the wall frame, big corner posts are welded to the subfloor frame, and the door components are mounted. The doors are also built from hinged steel and suspended from an I-beam, which is then fitted to the corner posts. The back wall is also constructed to the frame to build two side wall panels.
  5. The welds are sanded to eliminate uneven corners and jags. The entire container goes through sandblasting, priming, and other various processes to prepare it for painting. Shipping containers are painted in different colors, but usually red or yellow color.
  6. The final process in manufacturing shipping containers is the addition of floor onto the subfloor frame. Strong plywood floor is usually added out of a sequence of panels.
  7. After the construction, shipping containers are painted with identification marks such as the company who owns it, serial number, and the kinds of goods being transported through the container.

Waterproofing and Testing

After constructing the entire shipping container, the process is not yet complete. The bottom is then sprayed with a waterproof sealant. Once the sealant dries off, the next process is soaking the container in water.

Each side and part of the container is examined for defects or leakages. If and when there is no leakage or defect, the container is sent to the intended location or company.

All the processes of constructing shipping containers are impressive. Imagine a good number of sheets welded together into a huge, durable box. A brand new 20-foot container usually cost around $4,000, but second-hand containers can be bought at a lower price.

Are Shipping Containers Waterproof?

Shipping containers are made of a combination of durable steel, fiber-reinforced polymer, and aluminum with waterproof coating. Steel is an excellent material used to make stackable containers. They are also designed with a closed top and hinged doors as well as ribbed walls on the top and bottom sides. All the parts are welded to the corners and rails to ensure a sealed and tight enclosure.

Shipping containers are stored in the deck of the shipping vessels where they are exposed to elements like water, wind, and movement. Because of this condition, shipping containers have strong rubber door covers to keep the elements out. This gives them the watertight construction that prevents the elements from getting in and liquid goods to get locked inside.


So, are shipping containers waterproof? Yes, they are. In fact, they are even watertight to prevent not just the water but also the winds and other elements from getting in, hence safeguarding the goods being shipped.

With the ultimately durable materials and construction, shipping containers play a huge part in international trade. The processes that the strong materials go through are impressive and effective in putting the pieces together to form watertight, waterproof quality.

Today, shipping containers are transformed into houses and offices because of their impressive structure and quality. Advantages such as low cost, high durability, and waterproof feature are of the major consideration.

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If you're looking for the best container home designs, look no further!

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