What Are Shipping Containers Made Of?

Shipping containers play a huge part in our world. From ensuring cargo safely makes its way from port to port across oceans to their more recent second life as modular buildings, these inherently tough boxes suit many uses across a range of sectors and industries. But what are shipping containers made of?

Well, shipping containers are mainly made from steel for their walls, roof and frame, with plywood or bamboo floors. Rubber gaskets and locking bars seal doors against the weather, while specialist containers, such as refrigerated units or COSHH models, add further insulation, protective linings and robust security features too.

In this detailed guide from the experts at ModCon Cabins, we’re taking a closer look at the materials used and how they’re beneficial for a whole range of shipping container conversions. Let’s begin.

What Material Are Shipping Containers Made Of?

Shipping containers are made from a range of materials across their different parts and core structure. Here are just some of the main ingredients used in the fabrication of standard containers.

Corten Steel

One of the most common questions we hear is, ‘What metal are shipping containers made of?’ The answer is steel, but not just any type. Many containers are built from Corten steel, also known as weathering steel. This alloy is used for the corrugated walls, roof, corner posts and structural frame.

Corten steel is popular because it forms a protective rust layer when exposed to the elements, which prevents deeper corrosion and makes containers exceptionally durable, even in harsh ocean environments. Containers are generally painted too, giving them a protective skin over the steel.

Flooring

The actual base of a shipping container is made from the same steel as the rest of the structure, but the internal flooring will often be a different material. Most containers use marine-grade plywood flooring, strengthened and treated to handle heavy loads while resisting pests and moisture.

Increasingly, bamboo is used as a sustainable alternative, offering excellent strength and a distinctive finish. In some specialist situations and alternative container types, steel flooring can be added for extra load-bearing strength or for hygiene reasons, especially in food-related uses.

Doors and Seals

Security is a major concern, so container doors are manufactured as panels that use the same steel as the rest of the unit, with reinforced locking bars. These bars are sometimes galvanised to give them an extra layer of protection, securing the doors firmly in place and keeping out both the weather and any would-be burglars during transit and storage.

Rubber gaskets also line the edges of the doors, creating a watertight seal that protects the contents from the rain and salt spray associated with crossing the world's oceans time and time again.

 

Types of Containers and Their Materials 

Standard Dry Containers

Standard dry freight shipping containers are the most common type, and are built with corrugated steel walls, roofs and frames, with plywood or bamboo flooring.

Designed for strength and security, ISO-standardised containers are ideal for cargo and storage, and provide the perfect blueprint for many shipping container conversions, from classrooms and offices to workshops and welfare units.

Refrigerated (Reefer) Containers

Refrigerated containers, or reefers, build on the standard steel structure with thick polyurethane foam insulation and an internal lining of aluminium or stainless panels. This combination locks in temperature and makes cleaning easier.

They’re essential for safely transporting food, medicines, and other temperature-sensitive goods where durability, hygiene and reliability are non-negotiable.

COSHH Containers

Control of Substances Hazardous to Health, or COSHH containers, also known as chemstores, are usually converted steel shipping containers fitted with reinforced floors, secure ventilation and anti-spill bunded bases.

They’re designed to safely store hazardous materials, and at ModCon, we often adapt these further with shelving, electrics or climate control to suit specific customer needs. 

What Are Shipping Containers Made Of? | FAQs

How durable are shipping containers? 

Shipping units like these are built to last. Thanks to their robust steel structure, many remain in use for 20 to 25 years, often even longer if they’re maintained properly. This is also a direct factor in why they are increasingly used as buildings, including as construction offices, healthcare units and as education facilities.

Their durability is a direct answer to our original question: what are shipping containers made of? Their high-strength steel walls and frames resist weathering, and when combined with robust flooring and seals that protect against moisture and pests, their usefulness across a range of industries becomes vast.

How thick is the steel on a shipping container?

The steel used in container walls and roofs is typically between 1.6mm and 2mm thick, while the doors usually range from 2.5mm to 3mm in thickness. Frames and corner posts are even thicker, as they take the strain of stacking and heavy lifting. This is why what metal shipping containers are made of is so important.

What other shipping container solutions do you offer? 

At ModCon, we don’t just sell containers, we completely transform them. Across numerous sectors and applications, including as retail containers, stylish container homes and even robust, portable workshop units, our experts craft containers into the ideal solutions for your problems.

Whether you’re looking for a standard 10ft container or 20ft container as a starting point, or something a bit more unique, each of our modules can be fully tailored with insulation, electrics, plumbing and fit-outs.

We hope this blog post thoroughly answered the question, ‘What material are shipping containers made of?’ If you have any further questions or are ready to talk to our team about a modern, modular solution for your business, get in touch with us today.