How Are Sea Containers Made and From What Materials?
How Sea Containers Are Made, and What All the Names Mean
Sea container, shipping container, conex, sea can, ISO container: people use all of these for the same steel box. Here is how one is built, and why that construction makes it such good storage on land.
One Box, Many Names
- Sea container / sea can: named for its job, carrying cargo across the ocean.
- Shipping container: the most common general term.
- Conex: from CONEX (“Container Express”), a U.S. Army container system from the 1950s. See conex boxes in Maryland.
- ISO container: built to International Organization for Standardization sizes, so it fits ships, trains and trucks worldwide.
How a Sea Container Is Built
- Steel panels: sheets of weathering (Corten) steel are corrugated into ridged panels, which adds strength without adding much weight.
- Floor frame: steel cross-members are welded to the bottom side rails to carry heavy loads.
- Walls and roof: the corrugated panels are welded to the corner posts and frame.
- Corner castings: reinforced steel fittings at all eight corners let containers be lifted, locked down and stacked.
- Paint: the box is blasted, primed and painted to resist salt air.
- Floor: thick marine-grade plywood is bolted to the cross-members.
- Doors and seals: cargo doors with locking bars and rubber gaskets keep weather out.
Why That Matters for Storage
The same build that survives ocean storms makes a container secure, weather-resistant storage on your property. For the details of size and weight, see our guides to shipping container sizes and 20′ conex weight, or browse our shop.
