Container home flooring: keep, seal or replace the original floor

A standard dry container has a floor of thick plywood, typically about 28 mm (1 1/8 in), laid on steel cross members. It is strong enough to carry forklifts, but it was made for cargo, not for people. Before you lay a nice floor, decide what to do with the original one.

Why the original floor needs attention

To protect timber from insects during international transport, many container floors were treated with chemicals at the factory. The treatment is recorded on the data plate on the container door, but the plate does not tell you everything about the floor's history. The floor may also carry stains from previous cargo. For a home, that calls for caution.

Ask the seller about the floor and the container's history, and read the data plate. A one-trip container usually has a cleaner floor than one that has worked for many years — see buying a used container.

Option A: seal and cover

• Clean the floor and let it dry.
• Apply a sealing coat or lay a barrier membrane over the plywood.
• Build the new floor on top: battens, insulation, subfloor and finish.

This keeps the strong base and saves work, but raises the floor and lowers the ceiling.

Option B: replace

• Remove the old boards and expose the steel cross members.
• Treat the steel against rust.
• Lay a new subfloor rated for the loads, then insulation and finish.

More work, but you know exactly what is under your feet and you can keep the floor lower.

Insulating the floor

The floor loses heat through the steel frame. You can insulate from below — spray foam or boards between the cross members under the container — or inside, between battens on top of the plywood. Insulating from below keeps the ceiling height, which matters in a standard 2.59 m box. See how to insulate a container and container dimensions.

Finish floor ideas

• Laminate or engineered wood — warm, light and quick to lay on a flat subfloor.
• Vinyl planks — waterproof, good for kitchens and bathrooms.
• Tiles — for bathrooms; need a stiff subfloor and waterproofing.

In the UnedPod configurator you choose floor insulation and finish separately, see the full floor build-up in the section drawing and get the materials in the estimate.