How are 20 ft Containers Made?


Too often do we see those 20 ft containers in Auckland down by the waterfront. The question is, where exactly do they come from? ContainerCo is the ideal place for container hire and selling, but we also love informing our customers about the manufacturing process of shipping containers and side opening containers in NZ .

What Are They Made Of?

Over 60 years ago, the steel shipping container was invented, and it revolutionised international trade. The ability to have 20ft and 40 ft containers sit on ports stacked on one another allows for exponential growth in shipping and productivity.

Although you’d imagine shipping containers just to be made from steel, they contain several components to ensure their strength and durability during harsh weather conditions. The containers of today are typically made from Corten – weather and corrosion-resistant steel. Additionally, some containers come comprised of SPA-H steel – or superior atmospheric corrosion resistant).

Once each side, roof and door have come together, each of the eight corners has steel castings welded for reinforcement. This method ensures that the container is airtight and water-sealed. These crates are built to last.

The robust durability of shipping containers explains their interest in repurposing for storage units, warehouses, portable offices, and even tiny homes. With competitive prices, strength and durability, it’s no surprise that they’re growing more popular.

How Are They Made?

There is a five-step process by which containers are made – each reinforcing the structure to endure the harsh journey of travelling the seas.

1. Preparing the Steel Sheets

Before the box shape that we all know too well – the steel arrives as a large steel roll. Once the sheet is unrolled, it will be cut into necessary pieces, which will become the sides of the container. The sides will be moulded and bent into various shapes to maximise the protective potential.

2. Fortifying the Sheets

Here, the sheets are moulded into the corrugated panels that we all know too well. This will increase the durability and strength of the container.

3. Wall Panels and Frames are Welded

To receive durable status, the container will need to have each side adequately welded to the frame. A few simple welds can be completed to create the base of the container; from here, however, perfect alignment is needed.

Each side will need to be perfectly placed at the corners; otherwise, the whole structure is compromised.

4. Container Sealing

Upon the doors being completed (a separate process), they will then be attached to the container and coupled with wall panels. Here, the roof panel is placed on top and welded into place.

With the container now completely covered, the corner posts are to be aligned and added, thus improving the overall strength. Now waterproof, the corner posts also ensure the container can withstand impact – with force being spread throughout the frame.

5. Final Touches

After an inspector has checked off the quality, a final sandblast is undertaken. Lastly, a painting apparatus will apply both the base and top coats to the container.

Once all else is done, wooden flooring is installed within the container to give more support and durability for the storage. Once the floorboards are installed with screws into the cross-members, the container is complete.


At ContainerCo we have shipping containers NZ wide in a range of sizes and configurations. Depending on your needs, you can buy or hire on a short or long term basis. 

Whether it’s one container or 20 containers, everyone gets the same quality service at ContainerCo. We supply whatever shipping container you require to any location around New Zealand. Your container purchase or hire is backed by our full after-delivery support. 

We have 10,20 and 40ft shipping containers for both sale and hire. We also have a dedicated and highly specialised team of in-house engineers. Providing strong and durable shipping container modification solutions. This includes site offices, portable buildings, open-top shippingside opening containers, etc.

Contact us on 0508 73 28 73 or request a free online quote today!

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