Buying a used shipping container can be a cost-effective way to get secure, on-site storage or even portable workspace. Used containers are significantly cheaper than new ones but still offer years of service if you choose wisely.

However, not all used containers are equal, and it’s important to do your homework before parting with your money. Whether you’re a construction firm in need of site accommodation, a business looking for additional office space or an individual with a conversion project in mind, asking the right questions will help you avoid pitfalls and ensure you get a quality unit. Below we outline eight key questions (and why they matter) to guide your purchase.

1. What size shipping container do I need?

When buying a shipping container, one of the first things to consider is size. The most common lengths are 10ft, 20ft, and 40ft (roughly 3m, 6m, and 12m). Of these, 20ft and 40ft containers tend to offer the best value for money and are widely available on the used market. In comparison, 10ft containers are often cut down from larger units, making them relatively more expensive for the storage space provided.

Think carefully about your site and what you need the container for. A 40ft unit offers double the space of a 20ft, but it also requires more room for both placement and delivery. If your site is limited, a 20ft or even two 10fts might be more practical.

Also consider height. Standard containers are about 8.5ft tall inside, while high-cube containers add an extra foot of headroom — ideal for taller items or container conversions.

Whatever size you go for, make sure your site has enough space and access for delivery. Marking out the footprint in advance can help you visualise how the container will fit before committing to a purchase.

2. Is the container structurally sound and weatherproof?

When buying a shipping container, condition is key. Always check that the unit is structurally sound and wind and watertight (WWT) — meaning no holes, no daylight through the walls, and doors that seal properly. Surface rust, flaking paint and dents are normal for used containers and generally not an issue as long as the steel panels and roof are intact.

Make sure the wooden floor is solid and that hinges and locking bars move freely — seized doors are common on very old units. If possible, inspect the container in person or ask for detailed photos of the exact one you're buying. A professional repair (like a welded patch) is usually fine, but avoid containers with large areas of corrosion or unrepaired damage.

Reputable suppliers should guarantee the container is leak-free on delivery. It’s worth asking if it has been inspected for weatherproofing. Used containers are often graded — wind & watertight is sufficient for most storage needs, while export use may require a cargo-worthy (CSC plated) unit.

Whatever the intended use, make sure the container is fit for purpose and capable of keeping your items dry and secure in all weather.

3. Is the supplier reputable?

Choosing the right supplier is essential when purchasing a used shipping container. The market includes both reliable providers and those best avoided. To steer clear of scams or poor-quality units, stick with established companies like Willbox, which has over 25 years of experience in container sales and hire.

Ideally, buy from a supplier that owns and inspects its stock. This means they can guarantee quality, carry out repairs if needed, and ensure containers meet your expectations before delivery. Be cautious of brokers or private sellers on unverified platforms — red flags include no viewing options, upfront payment demands, or lack of proper documentation.

A trustworthy supplier will offer clear communication, recent photos or viewings, and a formal invoice. Ask how long they’ve been operating and if they can provide references or testimonials. A quick background check can save you a lot of hassle.

4. Can it be delivered to my site (and what will delivery cost)?

Delivery is a key part of the process, as containers are large and heavy — a 20ft unit weighs around 2.2 tonnes, and a 40ft over 3.5 tonnes. Specialist transport is essential, so always check the supplier can deliver to your location and ask for a clear quote, including delivery and VAT.

Containers are typically delivered by HIAB (crane-equipped) or tilt-bed trucks. Assess your site in advance: is there enough road width and turning space for a large vehicle? Is the ground level and firm? Are there low-hanging branches or power lines that might obstruct delivery?

HIABs can lift containers into tight or elevated spots, while tilt-beds need space in front to slide the unit off. Ask what offloading method will be used and confirm that ground-level placement is included.

Suppliers like Willbox may request site photos or measurements to ensure smooth delivery. Having someone on-site to direct the driver helps avoid delays or incorrect placement. A bit of planning upfront can save time, hassle, and unexpected costs.

5. Which type of container is right for my needs?

Shipping containers aren’t one-size-fits-all in terms of features – there are different types of containers designed for specific uses. Think about what you’ll be using the container for, as you may need something more specialised than a standard dry container:

• Standard Dry Container – This is the basic steel shipping container (usually 8ft 6in high) used for general storage. If you simply need secure, weatherproof space for tools, materials or furniture, a used 20ft or 40ft standard container will do the job. These are the most common and cost-effective units.
• High-Cube Container – As mentioned, high-cubes are taller (9ft 6in high). If you need to store extra tall equipment or want maximum cubic capacity, a high-cube 40ft could be ideal. They are very popular on construction sites for storing plant and machinery that might not fit in a standard height container.
• Refrigerated Container (Reefer) – If you need temperature-controlled storage (for example, for perishable goods, food/drink for site canteens, or temperature-sensitive materials), consider a used refrigerated container. These come with insulation and an integral cooling unit to keep the interior cold (or heated if needed). Ensure the refrigeration machinery is in working order or can be repaired if you buy an older used unit.
• Open-Side or Tunnel Containers – An open-side container has full-height side doors, useful for loading oversized items or accessing goods from the side. A tunnel container has doors at both ends (essentially a double-door container), handy for quickly getting to items without unloading everything. These types can be very convenient as storage units where frequent access is needed.
• Site Accommodation Units – If your need is more than storage – say you require an on-site office, canteen, drying room or toilet facility – you might actually need a purpose-built container conversion. Standard shipping containers can be converted into mobile offices or welfare units with windows, personnel doors, insulation, electrics, etc. Companies like Willbox offer used office containers, canteen/kitchen units, toilet/shower blocks and other accommodation containers ready-made, which can save you the trouble of converting one yourself. These are designed to meet on-site welfare standards and can be immediately put to use on a construction site or event.

As you can see, there’s a range of container types to choose from. It’s worth discussing your intended use with the supplier – they can guide you to the best option. 

For a look at the range of used containers and conversions on offer, you can browse the used containers for sale at Willbox.

6. Can the container be customised or upgraded to suit my needs?

Many suppliers can modify used containers before delivery to better suit your needs. Common customisations include:

• Security upgrades – Lock boxes (steel cowls around the padlock) deter theft and are often essential. Ask if one can be fitted if it’s not already included.
  
• Repainting – A fresh coat in your chosen colour improves appearance and adds protection, whether to match your site or display branding.
  
• Ventilation – For moisture-sensitive items, vents or moisture traps help prevent condensation. A simple plywood lining can also help.
  
• Shelving – Bolt-in racking systems improve organisation and make better use of space.
  
• Electrics and insulation – For workshops or site offices, ask about fitting lights, sockets, insulation, heating, and windows.

It’s easier and often cheaper to make these modifications before delivery. Companies like Willbox have in-house teams to customise containers quickly, while smaller resellers may outsource and add extra costs. Always check what’s possible and get a quote to ensure your container is ready to use from day one.

7. What maintenance will my used container require?

Used shipping containers are low-maintenance and can last 10+ years with minimal care. Here are a few tips to help extend their lifespan:

• Inspect regularly – Check for dents, damage, and debris on the roof. Clear off leaves or standing water to prevent rust, and inspect rubber door seals.
  
• Treat rust early – Surface rust is common and not a major issue if caught early. Wire brush any exposed steel and apply primer and paint, especially on door edges.
  
• Lubricate hinges – Apply grease or oil to hinges and locking rods yearly, especially in damp or cold weather, to keep doors operating smoothly.
  
• Control moisture inside – Use desiccant packs or vents to reduce condensation. Avoid storing damp items and open the doors occasionally for airflow.
  
• Use proper foundations – Place the container on level, solid ground or support at the corners to prevent twisting and ensure the doors stay aligned.
  

Containers are built to handle extreme conditions, but a little maintenance goes a long way. Your supplier can also provide upkeep advice tailored to your unit and site.

8. Can I inspect the container before purchase (or see photos)?

Always ask to see the exact container before committing. Reputable sellers will let you visit their depot or, at minimum, provide detailed photos showing all sides, the interior, roof, and doors. Some may even offer a video walk-around or live call if viewing in person isn’t practical.

If a seller only offers generic “sample images” or avoids showing the actual unit, that’s a red flag — they may not have the container in hand or it might not match the description.

Verifying the container’s condition builds trust and helps you avoid disappointment. Legitimate suppliers are transparent and confident in the quality of their stock — they’ll encourage inspections because they have nothing to hide.

Whether you view it in person or remotely, make sure you're comfortable with the unit's condition before paying. A quick check can make all the difference in securing a container that meets your expectations.

Choose Willbox for your container needs

Buying a used shipping container can be a smart investment for your business or project – provided you ask the right questions and buy from a trusted source. By covering the questions above, you’ll greatly increase the chances of a smooth purchase and a container that serves you well for years to come. Remember to consider size, check the condition, choose a reputable supplier, and ensure delivery and any custom needs are sorted in advance. With those bases covered, you can enjoy all the benefits of a steel storage container – from extra secure storage on a construction site to creative conversion projects – at a fraction of the cost of buying new.

If you’re ready to take the next step, we invite you to browse our used containers for sale at Willbox. We stock a wide range of used 10ft, 20ft, and 40ft containers which are available for quick delivery. Our team is happy to answer any further questions and help you find the perfect solution. Contact Willbox today or check out our quality used containers for sale to get started. Let us help you secure the ideal used container for your needs!