Used Container Floors: Soft Spots, Stains & When to Replace

The floor is the part of a used container that takes the most abuse. Forklifts drive in and out, heavy cargo shifts at sea, and rain blows in every time the doors open. It's also one of the most expensive parts to replace, so it's worth knowing how to judge one.

When you compare shipping containers for sale used, here's how to check the floor, what the common problems mean, and when a damaged floor is a deal-breaker.

How container floors are built

Most container floors are thick marine plywood or hardwood planks, usually about 28 mm (just over an inch) thick. They sit on steel cross members spaced along the length of the container and are screwed down from below.

Because containers travel internationally, their floors are often treated with pesticides to meet quarantine rules in importing countries. That's normal and rarely a problem for storage, but it matters if people will live or work inside.

What a good used floor looks like

• Solid underfoot everywhere, with no give
• Flat, without boards sticking up or sagging between cross members
• Dry, with no dark, wet or rotten patches
• Stains and scuffs that are cosmetic only

Expect plenty of marks. A used container floor will never look new, and that's fine.

Common problems and what they mean

Soft or spongy spots

If the floor flexes or feels springy when you step on it, the wood may be rotting or the layers separating. Check the area just inside the doors first. That's where forklifts and rain do the most damage.

Verdict: small soft areas can be repaired; widespread softness is a deal-breaker.

Delamination

Plywood floors are made of thin layers glued together. Water can make the layers separate, so you'll see edges lifting or peeling.

Verdict: minor delamination near the doors is common. Large areas will get worse.

Holes and broken boards

Look for holes, splits and broken sections, often near the doors or where something heavy was dropped.

Verdict: small holes can be patched or covered; large damage means a new section of floor.

Stains and smells

Oil, chemical or food stains come from previous cargo. Most are cosmetic, but strong smells can linger.

Verdict: fine for most storage, not ideal for offices, workshops or anything people spend time in.

Rusted cross members

If you can see under the container, check the steel beams that hold the floor up. Surface rust is normal; flaking or holed beams are a structural problem.

Verdict: serious corrosion here is a deal-breaker.

How to check a floor in five minutes

1. Walk the full length of the floor, slowly, in a zigzag.
2. Pay extra attention to the first few feet inside the doors.
3. Push down with your heel on any dark patch.
4. Look along the floor at a low angle for dips and lifted edges.
5. If you can see underneath, check the cross members for heavy rust.

If you're buying sight-unseen, ask for photos of the floor near the doors and down the middle, and ask the seller directly about soft spots.

Repair or replace?

For storage, many owners simply lay new plywood or rubber matting over a sound but worn floor.

Protecting the floor once it's yours

A few habits keep a container floor in good shape for years:

• Keep the doors closed in the rain. Water blowing in is the main cause of rot near the doors.
• Use a door mat or rubber threshold if you'll walk in and out often.
• Spread heavy loads on timber or steel plates instead of narrow feet or small wheels.
• Store things on pallets or shelves so air can move and spills can be cleaned.
• Vent the container to cut condensation, which drips onto the floor from the ceiling.
• Keep the container level and off wet ground so moisture doesn't creep up from below.

Floors for offices, workshops and homes

If people will spend time inside:

• Seal the floor with an epoxy or similar coating, or
• Lay a new subfloor over the old one, or
• Replace the floor entirely.

Starting with a new (one-trip) container gives you a clean floor and fewer surprises. See our custom and office conex page for fit-out options.

FAQ

What are shipping container floors made of?

Usually thick marine plywood or hardwood planks, about an inch thick, laid over steel cross members.

Are container floors treated with chemicals?

Often, yes. Many are treated with pesticides to meet international quarantine rules. Seal or cover the floor if people will work or live inside.

Can you replace a container floor?

Yes. Sections can be cut out and replaced, or the whole floor can be renewed. It's a sizeable job, so factor it into the price of a used container.

Is a stained floor a problem?

Usually not, unless it smells strongly or the stain hides rot. Check that the wood underneath is solid.