The condition grade determines how long a container lasts. It also determines whether you can convert the unit, whether valuable equipment can be stored inside, and whether the visible cosmetics matter for your application.
The grade sections below run from the most worn grade to the cleanest.
Economy (No Certification)
The lowest grade we sell. A used container that has been retired from active shipping but has not been certified to a specific standard. Expect:
Surface rust on most external panels.
Paint chipping, faded original branding, evidence of multiple repaints.
Dents and dings on side walls and roof. None should be deep enough to compromise structural integrity.
Floor wear: original plywood with industrial residue, possible burn marks, possible patches.
Door hardware functional but stiff.
Best for: Rough storage on a working farm or jobsite, where appearance is not a factor and the unit will be locked and forgotten. Not recommended for storage of valuable, rust-sensitive, or moisture-sensitive contents without ventilation upgrades.
Photos to expect: Visible rust streaks, chipped paint, repaired patches. Doors open and close but show wear. The unit is unmistakably second-hand.
Wind and Water Tight (WWT)
WWT means the container has been inspected and certified to keep wind and water out. Specifically:
Door seals checked and confirmed weatherproof.
Roof inspected for holes, dents, and rust through-spots.
Floor inspected and confirmed structurally sound. May show wear but no rot, no holes, no soft spots.
Walls inspected and confirmed solid. Surface rust and cosmetic dings are acceptable.
Lock boxes and door hardware functional.
WWT is not the same as cargo worthy. WWT means the container keeps wind and rain out. Cargo worthy adds the structural certification needed for international ocean shipping.
Best for: General storage, contractor jobsite tools, farm equipment, household goods during a renovation, on-site materials during construction.
Photos to expect: External panels show some surface rust and cosmetic wear, but doors close cleanly, seals look intact, and the interior is dry. The unit looks used but functional.
Cargo Worthy (CW)
Cargo worthy is a structural certification, not just a cosmetic grade. A CW container has been inspected to the IICL (Institute of International Container Lessors) standard and certified safe for international ocean shipping. That means:
All structural members (corner castings, side and end frames, undercarriage) inspected and confirmed sound.
Walls, roof, and floor confirmed weatherproof and load-rated.
Door hardware tested.
The unit can be loaded onto a ship and sent across an ocean without further inspection.
For storage, CW works much like WWT; the difference is the certification for ocean shipping. Pricing sits between WWT and one-trip.
Best for: Buyers who plan to ship the container internationally at any point, buyers who want a documented certification for resale or insurance purposes, buyers who want better cosmetics than WWT without paying for one-trip.
Photos to expect: Cleaner overall appearance than WWT, with visible age but a more uniform exterior. Documentation accompanies the unit.
One-Trip (Sometimes Sold as Like-New)
A one-trip container has made a single ocean voyage, typically loaded from a manufacturing facility in Asia to a North American port. After unloading, the unit goes into the resale market essentially brand new. Specifically:
Original factory paint, with minor scuffs from the single shipping journey.
Floor in excellent condition, no industrial wear.
Doors and seals tight, lock boxes pristine.
Interior clean and dry, no residue.
Minor cosmetic marks consistent with one ocean trip and one truck transfer.
One-trip carries the longest warranty on the scale. For any conversion project, any food-adjacent storage, any high-visibility placement, or any clean-finish workshop or office build, one-trip is the practical starting point.
Best for: Conversion projects (offices, workshops, tap rooms, tiny homes), food-adjacent or sensitive storage, customer-facing placement, and anyone who wants the cleanest grade.
Photos to expect: Factory paint, sharp graphics, clean interior. Looks like a new container with light handling marks.
Warranty by Grade
Container One's warranty depends on the grade:
Grade
Warranty
One-Trip
10 year structural and 10 year no-leak
Cargo Worthy
5 year structural and 5 year no-leak
Wind and Water Tight
5 year structural and 5 year no-leak
Economy
1 year against roof leaks
Ask about warranty terms for a refrigerated unit before you buy.
The IICL Standard, Briefly
The Institute of International Container Lessors maintains the inspection standard used to certify cargo worthy containers. IICL inspectors check structural members, weatherproofing, door function, and floor integrity against a published criteria set.
How to Choose for Your Use Case
The match between use case and grade:
Use Case
Recommended Grade
Construction jobsite tools and materials
WWT
Farm or ranch equipment storage
Economy or WWT
Household goods during renovation
WWT
Office, workshop, tap-room conversion
One-trip
Tiny home or container home build
One-trip
Long-term acreage storage
WWT
Insurance-grade documentation needed
Cargo worthy
Customer-facing placement (retail, hospitality)
One-trip
Inspecting Before You Buy
Whatever grade you select, the visual checklist is the same:
Floor. Walk it. Listen for soft spots. Look for water staining or rot. A damaged floor is costly to repair after delivery.
Door seals. Look for daylight around the closed doors from inside while a second person stays outside with the doors unlatched. Daylight means a gap in the seal.
Roof. If you can climb up safely, check for dents that pool water, rust through-spots, and obvious patches.
Corner castings. The eight corner blocks should be intact and free of major damage. They carry the entire load when the unit is lifted or stacked.
Side walls. Look for bulges, deep dents, and heavy rust patches. Surface rust is normal; structural rust is not.
Use this checklist when the container arrives.
Delivery and Grade in North Carolina
Containers are supplied and delivered by Container One, dispatched from the depot at Charlotte and, for Raleigh, from the depot at Norfolk, Virginia.
Delivery timing depends on location, payment, weather, container availability and site access; Container One's Delivery/Dispatch department schedules the date after payment is received and the site is reviewed. Delivery areas across North Carolina:
The Charlotte region, inside and outside I-485, including Mecklenburg, Union, Cabarrus, Gaston and Iredell counties
The Triad and the Triangle, from Greensboro and Winston-Salem across to Raleigh, Durham and Chapel Hill
The Sandhills and the Cape Fear, from Fayetteville and Southern Pines down to Wilmington and the Brunswick County beaches
Frequently Asked Questions About Container Grades
Cargo worthy means the container has been inspected and certified as fit to be loaded and shipped again on an ocean vessel, so it carries survey paperwork as well as sound steel. Wind and water tight means it is dry, structurally sound and serviceable for storage, without that shipping certification. For a box that is going to sit on your North Carolina property and hold your belongings, wind and water tight does the same job for less money. Pay for cargo worthy when you need the certification itself, for example when the container is going to travel again.
Wind and water tight suits storage on a farm, a job site or a business yard, and it carries a 5 year warranty. Cargo worthy also carries 5 years and adds the shipping certification. If the box will sit where customers, neighbors or a homeowner association can see it, a one-trip container looks close to new and carries a 10 year structural and no-leak warranty. Economy is the budget grade with a 1 year no-roof-leak warranty, and it suits storage without insulation. Whichever you choose, set it level on blocks or timbers and keep the roof clear of leaf litter under the Carolina hardwood canopy.
Warranty runs by grade. One-trip units carry a 10 year structural and no-leak warranty. Cargo worthy and wind and water tight units carry 5 years. Economy units carry a 1 year no-roof-leak warranty. Refrigerated units are inspected and tested before delivery. Ask about their warranty terms before you buy.
Walk it before the driver leaves. Open and close both doors and watch the gaskets seat. Step inside, pull the doors to, and look for daylight at the seams and along the roof line. Check that the floor is dry and sound underfoot. Look at the roof from a ladder or a truck bed if you safely can, because standing water and debris are what start a leak years later, and a Carolina hardwood canopy drops leaves on the roof. On the coast and the sounds, look specifically at the door gaskets and at any place the paint is thin. If something is wrong, it is far easier to resolve while the truck is still in your driveway.
It depends on what the box has to do. For dry storage behind a barn in Duplin County, no, wind and water tight does the job and the money is better spent on a gravel pad. For a container that will be seen from a street in a covenanted neighborhood in Cary or Ballantyne, or that you plan to insulate, finish and condition, yes, because straight walls, sound seals and a 10 year structural and no-leak warranty are worth paying for before you spend on closed cell foam and framing. The test is whether appearance or a future conversion is part of the plan.