Main Material: Corten Steel
The exterior walls, roof, doors, and frame of a shipping container are made from corten steel, also known as weathering steel.
Corten steel is designed to form a protective outer layer of rust when exposed to moisture. This rust layer seals the surface and slows further corrosion, making containers ideal for marine and outdoor environments.
Why Corten Steel Is Used
- High strength-to-weight ratio
- Excellent resistance to corrosion
- Long service life in harsh climates
- Minimal maintenance requirements
Container Frame and Structure
The container's structural frame is also steel and includes reinforced beams and corner castings. These components allow containers to be lifted, stacked, and secured during transport.
The frame is engineered to support heavy loads and withstand being stacked several containers high on ships or in storage yards.
Walls, Roof, and Doors
The walls and roof are made from corrugated steel panels. The corrugation adds rigidity and strength while keeping the container relatively lightweight.
Container doors are also steel and include heavy-duty locking bars and seals to keep the contents secure and protected from the elements.
Container Flooring
The floor of a shipping container is typically made from marine-grade plywood or bamboo flooring laid over steel cross members.
- Designed to support heavy point loads
- Treated to resist moisture and pests
- Durable enough for forklifts and pallet jacks
Some older containers may have floors treated with preservatives, while newer containers often use more environmentally friendly materials.
Paint and Protective Coatings
Shipping containers are coated with specialized marine-grade paint systems designed to resist corrosion, salt air, UV exposure, and abrasion.
These coatings help extend the life of the container and protect the underlying steel from environmental damage.
Additional Materials and Components
In addition to steel and wood, shipping containers include:
- Rubber door gaskets for watertight sealing
- Steel locking bars and hinges
- Vent covers for airflow
- Steel corner fittings for lifting and securing
Why Material Choice Matters
The materials used in shipping containers are the reason they can survive years of exposure to ocean salt, extreme temperatures, heavy handling, and constant movement.
This durability also makes shipping containers popular for storage, construction, and conversion projects well beyond their original shipping purpose.
Bottom Line
Shipping containers are made primarily from corten steel, with steel frames, corrugated steel panels, marine-grade flooring, and protective coatings. These materials work together to create a strong, weather-resistant, and long-lasting structure suitable for global transport and long-term use.