20ft used containers
The common choice for site and general storage, and the easiest size to place on a constrained yard.
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Wind and Watertight (WWT) Containers Explained
Weather-resistant used containers intended primarily for static storage — what WWT means, what it does not guarantee, and when cargo worthy may be more appropriate.
Updated
What wind and watertight means
Wind and watertight means the container is intended to keep normal wind and rain from entering through the shell, doors and seals while it is used as a stationary container.
It does not, by itself, state that the container is currently suitable or certified for international cargo transport.
The frame holds, the panels are intact, the doors close against their seals, and rain stays outside. That is the whole of what the description covers, and for a container that will be placed once and stay there it is usually the whole of what matters.
What it deliberately does not address is sea carriage. That omission is the point rather than a gap: by leaving out a capability a stationary container never uses, WWT is normally the best value on the market for storage. Seller usage of these terms does vary, so it is worth confirming what a particular seller means by it.
Is WWT right for you?
One question decides it in most cases: will the container stand still, or will it travel as freight equipment?
WWT is usually appropriate when
- The container will remain stationary once placed
- The main use is storage
- Weather resistance is what matters
- Cosmetic wear is acceptable
- Cargo certification is not required
- You want the most sound steel for the money
Consider another condition when
- The container will travel as freight equipment
- Valid CSC status is required for the intended use
- Appearance is especially important
- A recent-production unit is preferred
- A defined inspection standard is required
Where WWT works well
The common thread is that the container is placed once and stays there.
Site storage
Construction tools, materials and plant, secured on site and out of the weather.
Agriculture
Farm equipment, feed, supplies and machinery, where a hard-standing yard is the site.
Workshop and static conversion
Stores, workshops and conversions that stay where they are put and need no certification.
General storage
Anywhere weather resistance matters more than cargo capability — which is most storage.
WWT does not mean cargo worthy
A WWT condition description alone does not establish that the container is acceptable for international freight transport.
If the container will be used as cargo equipment, confirm the structural condition required for that use, the CSC status of the specific unit, and any carrier or terminal requirements that apply — before purchase rather than at a gate. The price difference to a cargo worthy unit is usually smaller than the cost of establishing this late.
WWT vs cargo worthy
The two describe different things rather than two rungs of one scale. Cargo worthy concerns structural suitability for carrying cargo; WWT concerns keeping weather out of a stationary container.
| Criterion | Wind & watertight | Cargo worthy |
|---|---|---|
| Primary purpose | Wind & watertightStatic storage | Cargo worthyCargo and transport |
| Weather resistance | Wind & watertightThe point of the description | Cargo worthyExpected of a serviceable unit |
| Structural cargo suitability | Wind & watertightNot implied | Cargo worthyThe primary consideration |
| CSC status | Wind & watertightNot implied — confirm per unit | Cargo worthyMust be confirmed for the intended movement |
| Cosmetic appearance | Wind & watertightVariable | Cargo worthyVariable |
| Typical buyer | Wind & watertightStorage buyer | Cargo worthyTransport or export buyer |
| Relative cost | Wind & watertightOften lower | Cargo worthyOften higher |
What to check on a WWT container
Condition varies unit by unit within any description, so these are the six things worth establishing for the use you have in mind.
Roof and side panels
Holes, severe perforation and any area where weather could enter. The roof is the hardest part to see and the most common place a problem is missed.
Doors
That the doors open and close adequately for the intended use, and that the locking gear operates.
Door seals
The condition of the gaskets and any visible gaps when the doors are closed.
Floor
General condition, damage, contamination and whether it suits what will be stored on it.
Interior
Visible signs of water ingress, holes and any significant damage not apparent from outside.
Repairs
Major visible repairs, and whether their extent or position affects the use you have planned.
Visible daylight through unintended openings can indicate a problem, and it is worth looking for. It is not, on its own, a complete technical assessment of weather resistance — no single informal check establishes the condition of a unit.
What an inspection looks at
Watertight ≠ condensation-free
This is the most common misunderstanding about WWT, and it is worth being precise about because it changes how you use the container.
A WWT container is intended to keep external rain out. Moisture can still form inside it, because warm humid air in contact with steel that has cooled below the dew point condenses onto the surface — sometimes called "container rain". That is a property of a sealed steel box in a changeable climate, not a defect in the container.
What WWT addresses
- External rain
- Shell, doors and seals
- Kept out
What it does not address
- Humid air inside
- Steel cools overnight
- Water condenses
- Interior moisture
Reducing moisture in storage
Ventilation
Allow moist air to escape where the contents and the site permit it.
Keep goods raised
Pallets or shelving keep stored items off a floor where moisture collects.
Avoid loading damp goods
Moisture brought in with the contents has to go somewhere, and it usually goes onto the steel.
Insulation and moisture control
For moisture-sensitive goods, consider insulation with a vapour barrier, or desiccants. What is appropriate depends on the goods.
WWT condition vs CSC status
These describe different things and neither establishes the other.
Wind & watertight
A description of intended condition: weather-resistant, for use as a stationary container. It is a trade description with no certifying body behind it, and seller usage varies.
CSC
A safety approval under an international convention, with its own inspection and validity framework, applying to freight containers used in international transport.
A WWT description does not confirm current CSC validity for any particular unit.
Read the CSC plate guideFrequently asked questions
Is wind and watertight good enough for storage?
For most storage, yes, and it is normally the right specification. You are buying sound steel that keeps weather out, without paying for sea-carriage capability a stationary container never uses.
Does WWT mean cargo worthy?
No. They describe different things: cargo worthy concerns structural suitability for carrying cargo, WWT concerns keeping weather out of a container that stays put. A unit described as WWT has not been assessed against the first of those. See cargo worthy containers.
Does a WWT container have a valid CSC plate?
The description does not say. A WWT unit may carry a plate that is current, one that has expired, or none at all. If a valid plate matters for your intended use, ask about the specific unit and get the answer in writing rather than inferring it from the condition description.
Can a WWT container be used for international shipping?
Not on the strength of the WWT description alone. Whether a particular unit is acceptable as freight equipment depends on its actual structural condition, its CSC status and the requirements of the carrier and terminal involved — all of which need confirming before purchase rather than at a gate.
Will my goods stay dry in a WWT container?
Dry from rain, yes — that is what the description covers. Condensation is a separate matter: humid air inside the container condenses onto steel that has cooled overnight, and no condition description prevents that. Ventilation, raised storage and, for sensitive goods, insulation or desiccants are what address it.
Can a WWT container have dents and rust?
Yes. Surface corrosion, dents and previous repairs are all normal on a used container and none of them is inconsistent with the description, provided the shell, doors and seals still keep weather out. If appearance matters, treat it as a separate requirement on the enquiry.
What should I check before buying a WWT container?
Roof and side panels for holes or heavy perforation, doors and locking gear for operation, the seals for gaps, the floor for damage and contamination, the interior for signs of water ingress, and the extent of any major repairs. Visible daylight through unintended openings is a useful signal but is not a complete assessment on its own.
Looking for a WWT container?
Tell us the size, quantity and destination and we will quote against suitable current stock.
40ft used containers
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Storage-focused options compared, including what changes when a unit will never move again.
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