Complete Buying Guide: How to Choose a Used 20-Foot Shipping Container (Dry)

Why choose a used 20-foot shipping container?

A used 20-foot Dry shipping container is a robust and economical solution for many needs: static storage, site office, workshop, or even cargo transport. Its popularity stems from a rare balance between compactness, volumetric capacity, and acquisition cost. A new model often costs two to three times more, while a refurbished container guaranteed Wind & Watertight offers reliable sealing for a fraction of the price. In addition, ISO standardization ensures universal compatibility with handling and transport equipment.

This guide walks you step by step through choosing a used 20-foot container. We will cover dimensions, materials, inspection points to watch, possible uses, regulatory aspects, and maintenance tips. The goal is to help you make an informed decision, whether you are a professional or an individual.

Technical specifications of a 20-foot Dry container

Standard dimensions and interior volume

A 20-foot Dry container complies with ISO 668. Its external dimensions are constant: approximately 6.058 m long, 2.438 m wide, and 2.591 m high. These measurements are identical from one manufacturer to another, allowing it to be stacked, tiered, or transported on any suitable ship, train, or truck. The usable interior volume is about 33 m³, with a floor area of about 13.8 m². Maximum payload is around 28 tonnes, but it depends on the container's exact tare weight, which varies by manufacturer and condition. Empty weight (tare) is generally between 2.2 and 2.4 tonnes.

Materials and construction

The structure is based on a Corten steel frame, also known as weathering steel. This steel contains alloying elements such as copper, chromium, and nickel that allow it to develop a protective oxide layer on the surface, slowing corrosion. It has been the standard material for shipping container construction for decades. The side walls are made of corrugated steel sheets, which provide rigidity and impact resistance. The roof is also corrugated steel, and the floor is 28 mm thick marine plywood, treated to resist moisture and heavy loads. This floor is fixed to metal cross members welded to the frame. The rear doors are double doors equipped with container locking bars and rubber sealing gaskets. These gaskets are checked during refurbishment: they must be flexible and free of tears to ensure airtight and watertight sealing.

Criteria for choosing a used 20-foot container

Structural condition

When buying a used container, structural condition is paramount. Check for perforating corrosion on the walls, roof, or frame. Traces of surface rust are normal and can be treated, but holes or heavily thinned areas compromise sealing and strength. Carefully inspect the corners, welds, and bottom cross members. A refurbished container guaranteed Wind & Watertight has been checked on these points.

Floor

The marine plywood floor must be sound, hard, with no soft spots or rot. Make sure it is properly screwed to the cross members. A warped or infested floor can lead to moisture and safety problems. If you plan to store heavy loads, check flatness and strength.

Doors and gaskets

The doors must open and close without forcing. The rubber gaskets must be intact, flexible, and free of tears. A simple test is to close the doors and check that no light passes between the gaskets and the frame. Worn or poorly fitted gaskets impair sealing and can let in water and pests.

CSC plate and history

The CSC plate (Convention for Safe Containers) is a mandatory international certification for any container used in maritime transport. It must be legible and valid. For static use, it is not essential, but it demonstrates the container's compliance. Ask for information about the container's history: has it carried hazardous or odorous materials? A container that held chemicals may give off persistent odors.

Different uses of a 20-foot Dry container

Static storage

The most common use is storage. On private land, a construction site, a company parking lot, or an industrial area, it serves as a secure space for equipment, tools, spare parts, archives, or seasonal goods. Its robust design and padlock locking (not included) make it an economical alternative to traditional storage facilities.

Export and transport

After refurbishment, a used 20-foot container can go back to sea to transport goods, provided its CSC plate is valid and its structural condition allows it. It is then subject to international maritime transport rules.

Conversion into office, workshop, or living space

The 20-foot container is frequently converted into a site office, technical room, changing room, workshop, or even modular housing. Its rigid structure and standard dimensions make it easy to install openings (doors, windows), partitions, insulation, and electrical systems. However, these conversions must comply with local construction rules, particularly regarding planning permission or prior declaration if the container is permanently installed.

Regulations and urban planning

CSC Convention

As a transport unit, a container must comply with the International Convention for Safe Containers (CSC), which entered into force in 1977. This convention requires that each container bear a CSC plate indicating its manufacturing date, maximum payload, tare, and periodic inspection dates. For use in international maritime or land transport, the plate must be valid.

Urban planning

Placing a container on private land may be considered a construction if it is fixed to the ground and intended to last. In that case, a prior declaration of works or a building permit may be required, depending on the surface area and nature of the project. Rules vary by municipality and zone (urban, agricultural, protected). It is therefore essential to check with the local planning department before any permanent installation. For temporary use (construction site), authorization may also be necessary if the container remains in place for more than a few months.

Transport and delivery

Transporting a 20-foot container is regulated. It can be transported on a container truck, train, or ship. For road transport, the container must be securely lashed to a suitable chassis, and the total weight (container plus load) must not exceed the legal gross vehicle weight (GVW) limits, i.e., 44 tonnes for a standard road combination. Exceptional transport may be necessary if dimensions or weight exceed regulatory thresholds. It is also important to follow safety rules for lifting: a 20-foot container is handled by its four corner castings using spreaders or suitable slings. Never lift a container by its walls or roof.

Care and maintenance

Maintenance of a shipping container is limited but regular. It is recommended to visually inspect the structure at least once a year, paying particular attention to areas exposed to moisture: lower walls, corners, door surrounds. Dirt and debris should be removed from the roof to prevent water pooling. If paint chips appear, touching up with a suitable anti-rust paint helps prevent corrosion. Door gaskets can be cleaned and possibly treated with a rubber care product to prolong their flexibility. Inside, it is advisable to ventilate the container regularly to avoid condensation, especially if it is used to store moisture-sensitive materials. Adding a moisture absorber or passive ventilation can help.

To complete, a container placed directly on the ground can suffer from capillary moisture. It is better to place it on blocks, treated wooden beams, or concrete slabs to create a ventilated air gap under the floor. This simple precaution considerably reduces the risk of corrosion of the undercarriage and rotting of the plywood. Monitor welds and corners: corner castings can accumulate dirt and moisture; annual cleaning and visual inspection help detect any early rust. If necessary, localized anti-rust treatment is sufficient. Corrugated walls can trap dirt in their recesses; cleaning with a water jet (without high pressure directed at the gaskets) followed by natural drying is recommended once or twice a year. For containers exposed at the seaside, salt air accelerates corrosion; in that case, a six-month inspection is more prudent.

Comparison with other container types

Comparing the 20-foot Dry container with other sizes and types helps make the right choice. The standard 40-foot container offers double the volume (about 67 m³) for a floor area of about 28 m². It is more suitable for bulk storage or transporting large volumes, but it is heavier, bulkier, and requires more land. The 40-foot High Cube (HC) adds about 30 cm of interior height, which is useful for storing tall loads or fitting out a living space with a better sense of volume. The 10-foot container, rarer, is compact and fits into tight spaces, but its volume is limited (about 16 m³). The Open Top container has a removable or opening roof, convenient for loading bulky items from above (machines, long materials). The Flat Rack container, without side walls or roof, is designed for out-of-gauge loads. The Reefer container is a refrigerated container with a cooling unit, intended for perishable goods; it is more expensive and requires a power supply. The 20-foot Dry container remains the most versatile and economical for general use. It is also the easiest to resell, as demand is constant.

Preparation before use

Before using your container, a thorough cleaning is often necessary: sweeping, possible washing, drying. Check that the floor does not give off odors (containers that have carried odorous products may retain smells). A coat of paint on the floor can help protect it and make cleaning easier. If you want to insulate the container, several solutions exist: rigid insulation panels (polyurethane, extruded polystyrene), mineral wool with vapor barrier, or spray foam. Insulation must be installed leaving a gap to avoid condensation between the insulation and the metal wall. For office use, ventilation, lighting, and power supply must be provided. These installations must comply with current electrical standards. For residential use, the rules are stricter (building permit, compliance, sanitation). It is advisable to call in professionals for major conversions.

Recommended accessories and equipment

To get the most out of your 20-foot container, certain accessories are often useful. A high-security padlock, ideally protected by an anti-theft box, strengthens protection against theft. Passive ventilation grilles, installed on the walls, help limit condensation without compromising sealing. For storage, metal shelving or industrial racks optimize vertical space. LED lighting on battery or mains-connected makes work easier. If the container is used as a workshop, a workbench and wall storage are practical. Finally, an additional floor covering (rubber mat, OSB panels) protects the original floor and improves comfort.

Environmental impact and circular economy

Buying a used container is part of a circular economy approach. Rather than manufacturing a new container, an existing unit is reused, which saves steel, energy, and resources needed for production. The lifespan of a shipping container is long: well maintained, it can serve for decades. At end of life, Corten steel is recyclable. Choosing used therefore reduces carbon footprint while achieving substantial savings. For companies concerned about their environmental impact, it is an additional argument in favor of the second-hand container.

Common mistakes to avoid when buying

Several mistakes are common among used container buyers. The first is relying only on photos without inspecting the container or requesting a detailed report. The second is neglecting the condition of the floor, often hidden by goods. The third is forgetting to check the CSC plate and inspection dates. Some buyers also underestimate the cost of transport and handling, which can represent a significant part of the total budget. Finally, not checking urban planning rules before installation can lead to administrative complications. Take the time to ask the seller questions and obtain written guarantees on sealing.

Conclusion

Choosing a used 20-foot shipping container requires considering several factors: structural condition, sealing, compliance, but also your specific storage or fitting needs. A refurbished container guaranteed Wind & Watertight, such as the one offered by Transport Hosni Conteneur at €1,350.00 excl. VAT, offers excellent value for money. Do not hesitate to ask for detailed photos, visit the container if possible, and check local planning rules. With minimal maintenance, your container will serve you for many years.