Frequently Asked Questions

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Shipping containers are sturdy, weather-resistant, and very versatile. They’re used for everything from mobile offices to backyard workshops, and when it comes to storage, few options offer more value for your money. But just because they’re built to last doesn’t mean you can store anything inside and expect it to be safe. In fact, there are quite a few things you really shouldn’t store in a shipping container—unless you want to deal with damage, safety hazards, or legal trouble.

1. Perishable Food

Shipping containers are designed for strength and security, not climate control. If you’re thinking of using one to store fresh produce, dairy, meat, or other perishable goods, think again. Without proper refrigeration (which standard containers don’t provide), food can spoil fast—especially in warm or humid conditions. Even canned or dry goods can spoil in fluctuating temperatures, making a climate-controlled space the better choice.

2. Hazardous Materials

Shipping containers might seem like a good place to store paint, gas cans, or cleaning chemicals, but most hazardous materials are a no-go. Not only are many of them flammable, but when sealed in a steel box with little ventilation, the risk of combustion or toxic fumes goes way up. Storing items like propane tanks, fuel, pesticides, or industrial solvents can also violate local fire codes or environmental regulations. If you’re unsure whether something is classified as hazardous, check the label—or better yet, play it safe and store it elsewhere.

3. Live Animals or Plants

This one might sound obvious, but you’d be surprised. Some folks have used containers as temporary shelters for chickens, goats, or even dogs. Others try turning them into greenhouses. But unless the container is retrofitted with ventilation, lighting, and temperature control, it’s a bad idea. Containers heat up quickly in the sun and can become dangerously cold in winter. That’s no environment for anything living. Without fresh air, light, or stable temperatures, both animals and plants are likely to suffer or die.

4. Firearms and Ammunition

If you’re considering using a shipping container to store guns, you’ll want to check local regulations. Gun laws vary widely from place to place. Even if it’s technically legal in your area, conditions inside a container can make ammunition prone to degradation or even dangerous instability.

5. Electronics and Appliances

Unless the shipping container is climate-controlled, you’re better off storing sensitive electronics in a more stable environment.

6. Items Prone to Melting or Warping

Vinyl records, candles, oil-based art supplies, and plastic containers are all sensitive to heat. If your shipping container sits in the sun, interior temperatures can soar. Anything that melts, warps, or loses shape should be stored in a place with better temperature control.

Shipping containers are built to survive saltwater spray, rough handling, and long hauls across the globe—so it makes sense that they’re made from some of the toughest materials out there. If you’ve ever wondered exactly what a shipping container is made from, here’s your answer.: The Primary Material: Corten Steel Most shipping containers are made from Corten steel, also known as weathering steel. This isn’t your average metal. Corten steel was designed to handle extreme conditions, especially those found at sea. When exposed to the elements, it forms a stable, protective rust-like layer that actually slows down further corrosion. That’s right—the rust helps prevent more rust.

This self-protecting property is what makes Corten steel so ideal for shipping containers. It stands up to salt air, moisture, and temperature swings without the need for constant repainting or upkeep.

Framework and Reinforcements While the walls and roof are usually made from corrugated Corten panels, the frame is a different story. The structural integrity of a container depends on its corner posts, rails, and cross members—all of which need to carry massive loads, often stacked many units high.

These parts are built from high-tensile steel for added strength. The corner castings (the square fittings at each corner of the container) are solid steel blocks that make it possible to lock containers together for stacking or secure them during transit. They’re also the points where cranes grab onto the container when lifting it on and off a ship, railcar, or truck.

The bottom cross members, which support the container floor, are made from I-beam or box-section steel. These help distribute weight evenly and keep the container from sagging under heavy loads.

Shipping Container Flooring

Shipping container floors are made from marine-grade plywood. The floors are supported by steel cross members and usually measure just over 1 inch thick. They’re designed to handle forklifts, pallets, and anything else you store inside.

Some newer shipping containers may use bamboo-based plywood as a more sustainable alternative. Bamboo is incredibly strong and grows faster than hardwoods, making it a popular choice for environmentally conscious manufacturers.

Doors, Seals, and Hardware

The doors at the end of a shipping container are made from steel panels with heavy-duty bars. Each door is fitted with rubber gaskets that create a watertight seal when closed. This helps keep the inside dry and secure, no matter what’s happening outside.

The hinges, locking rods, and cam keepers are all made of galvanized or stainless steel. These parts need to stay operational even after years of exposure to saltwater and grime, so durability is key. Roofs and Walls: Corrugated for a Reason

The roof and side walls of a shipping container are made from corrugated steel panels. The corrugation isn’t just for looks—it adds rigidity and helps the container maintain its shape under stress.

The thickness of these panels is usually between 1.5mm and 2.0mm. That might not sound like much, but when you factor in the corrugated design and the strength of Corten steel, it’s more than enough to protect against dents, impacts, and heavy stacking.

Paint and Coatings After a shipping container is assembled, it’s coated in primer and marine-grade paint. This helps add another layer of defense against rust and corrosion. Most containers are sprayed with epoxy or polyurethane coatings, which stand up to UV rays, chemicals, and moisture.

These coatings are designed to last up to 15 years without needing to be repainted, but if a container is going to be used for storage or converted into a building, repainting is often one of the first steps in the customization process.

So, what are shipping containers made out of? At their core, they’re a carefully engineered mix of Corten steel, marine-grade wood, galvanized hardware, and weather-resistant coatings. These materials combine to create a product that’s strong, secure, and ready to take on just about anything the world throws at it.

Whether you’re in logistics, construction, or looking to convert a shipping container into a home or office, it’s worth understanding what makes them so durable. Steel Construction: The Foundation of Strength

Shipping containers are made from a special type of steel known as corten steel, or weathering steel. It’s not just any steel—it’s engineered to form a protective layer of rust that actually helps shield it from further corrosion. Sounds counterintuitive, right? But that self-protecting rust layer prevents deeper damage and keeps the structure intact.

Corten steel is also extremely strong, allowing containers to carry heavy loads without bending or buckling. A standard 20-foot container can handle over 60,000 pounds of cargo. That kind of load capacity doesn’t come from average materials—it comes from decades of engineering refinement. Surviving the Elements

Shipping containers face extreme temperature swings, moisture, salt, and even physical impacts during transit. Yet they remain in use, year after year. How?

Their design includes thick corrugated walls that absorb shock and resist deformation. The floor is typically made of marine-grade plywood set into steel cross-members, which can take abuse from forklifts and heavy cargo. Doors are fitted with rubber gaskets to keep water and dust out, while corner castings and locking mechanisms are designed to withstand thousands of stacking cycles and crane lifts. Low Maintenance, High Payoff

One of the most overlooked aspects of shipping container durability is how little maintenance they require. Sure, a fresh coat of paint helps prevent rust and keeps them looking clean, but beyond that, there’s not much to worry about. Inspections are simple, and any minor repairs—like fixing a dent or re-welding a seam—are quick and inexpensive.

That’s a big reason shipping containers have found a second life in construction and architecture. Builders love materials that don’t need constant care, and shipping containers fit the bill perfectly. They don’t rot, they don’t warp, and they’re pest-proof. Rigorous Standards

Shipping containers are subjected to a rigorous set of international standards (ISO 1496-1, to be exact). That means every container, whether it’s crossing the Atlantic or being used as a pop-up store, has passed stress tests that simulate real-world conditions. We're talking about pressure loads, impact resistance, and even being dropped or twisted while fully loaded.

The uniform size and shape also make them ideal for stacking—up to nine containers high on a ship—which adds to the structural demands during design. All of this ensures that containers are not just strong in theory, but in practice, year after year. A Lifespan Measured in Decades

On average, a shipping container used for cargo transport lasts around 10 to 15 years in active rotation. After that, it’s often retired—not because it’s worn out, but because international regulations or cosmetic wear make it less appealing to shipping companies. Many of these "retired" containers still have 20 to 30 years of usable life left in them when repurposed.

Converted into homes, offices, storage units, or mobile clinics, these containers can easily reach a 40-year lifespan with minimal upkeep. That kind of longevity makes them one of the most cost-effective and sustainable building materials on the market. Real-World Examples of Durability

You’ll find shipping containers serving long after their seafaring days are over. In disaster zones, they’re turned into quick-response shelters. In remote areas, they’re transformed into modular clinics or classrooms. Even in urban environments, shipping containers have been stacked and customized into sleek residential complexes or co-working spaces.

What’s more telling than a shipping container surviving a hurricane? There are documented cases of shipping containers being recovered after tsunamis and earthquakes—battered, but still structurally sound. Not many building materials can claim that kind of toughness.

The resilience of shipping containers is the result of decades of design evolution, material innovation, and relentless performance testing. Whether they’re hauling goods across oceans or standing strong as an off-grid home, shipping containers have earned their reputation for durability.

In a world that’s constantly looking for ways to build faster, cheaper, and stronger, shipping containers deliver on all three. They’re more than steel boxes—they’re the future of functional, lasting design.

Let’s take a behind-the-scenes look at how shipping containers are constructed — from raw materials to fully welded, weatherproof units ready for your storage needs. It All Starts With a Sheet of Steel

The backbone of any shipping container is corten steel, also known as weathering steel. This material is specially formulated to resist corrosion.

Large steel sheets are first unrolled and flattened in the factory. These sheets are then cut to size based on the type of container being built. Once cut, they’re fed into massive press machines that bend and rib the panels. These ridges aren’t just for show — they provide extra strength and prevent warping. Welding the Skeleton

With the side panels formed, construction moves to the container’s framework. This involves creating the floor frame, corner posts, and roof rails. The floor beams are typically made of heavy-duty I-beams or C-channels. Workers then weld the side panels, roof, and wall panels onto this steel skeleton.

The welding process is fully automated in most modern shipping container factories. Robotic arms make quick work of creating airtight seals and solid joints. Quality control is strict, with regular testing to ensure each weld meets international ISO standards. Any crack or imperfection could lead to water damage or structural failure, so precision is everything. The Floor: Tougher Than It Looks

Shipping container floors take a beating — forklifts, pallets, and thousands of pounds of goods roll across them daily. That’s why the floors are designed to be both strong and easy to maintain.

Most containers use marine-grade plywood for the flooring, usually made from tropical hardwoods like bamboo or keruing. The plywood is fitted into the steel base and bolted down securely. Shipping Container Doors

Each door is constructed from corrugated steel and fitted with locking rods, gaskets, and cam keepers. The locking mechanism is made from galvanized steel, and precision engineering ensures that the container can be opened and closed even in freezing or extreme heat conditions. Rubber gaskets line the edges to make sure everything inside stays dry, no matter what’s going on outside. Painting and Protective Coating

Once the shipping container has been fully welded and assembled, it’s time for finishing touches. First, every container is sandblasted to remove any surface impurities. This ensures that paint will stick evenly and prevent rust from forming beneath the surface.

The next step is priming and painting, using industrial-grade coatings designed to resist corrosion, UV rays, and chemical exposure. Final Touches and Inspection

Before a shipping container can leave the factory, it undergoes rigorous quality checks. This includes water-tightness tests, where the container is sprayed or submerged to ensure there are no leaks. Dimensions are double-checked, and doors are opened and closed repeatedly to test for proper alignment.

If a container is being made for a specific use — like a refrigerated unit (reefer) or modified into a tiny home or mobile office — this is the stage when extras like insulation, electrical wiring, or interior fittings are installed.

Once all inspections are complete, the containers are stacked, labeled, and shipped to ports around the world. From there, they might head to China’s Pearl River Delta, the Port of Los Angeles, or a construction site in the Midwest.

What started as a few steel sheets in a factory is now ready to carry tens of thousands of pounds across oceans and continents. The entire process, from raw materials to finished product, can take just a few days thanks to modern automation and streamlined manufacturing.

Understanding how shipping containers are built isn’t just for engineers or logistics pros. Whether you’re a business owner thinking of using containers for storage, a designer dreaming up your next shipping container home, or are are just curious about supply chains, knowing what goes into these steel boxes gives you a greater appreciation for their strength, versatility, and reliability.

Tornadoes are one of nature’s most destructive forces. With their swirling winds and unpredictable paths, they can toss cars, rip roofs off houses, and flatten entire buildings. But what about something as massive and heavy as a shipping container? Can a tornado really pick one up and throw it around? The short answer: yes, under the right conditions, it’s possible. Let’s break down how and why. How Much Does a Shipping Container Weigh?

Before diving into the power of tornadoes, it’s important to understand how much a shipping container weighs. A standard 20-foot container weighs about 5,000 pounds empty. A 40-foot container can weigh more than 8,000 pounds. Add cargo, and you’re easily looking at 30,000 to 70,000 pounds, depending on what’s inside.

These containers are designed to carry heavy loads across oceans and withstand rough handling. They're built with corrugated steel panels, reinforced corners, and heavy-duty flooring. On the ground, they sit low and flat, which gives them a stable base — especially when loaded. The Strength of a Tornado

Tornadoes are rated on the Enhanced Fujita (EF) scale, which ranks them from EF0 to EF5 based on estimated wind speeds and resulting damage. Here’s a quick look at what that means in terms of wind:

EF0: 65–85 mph

EF1: 86–110 mph

EF2: 111–135 mph

EF3: 136–165 mph

EF4: 166–200 mph

EF5: Over 200 mph

An EF0 tornado might knock down tree limbs or damage a few shingles. But once you get into EF2 territory and above, you're dealing with winds strong enough to flip vehicles and demolish buildings. At EF4 and EF5 levels, almost nothing is safe. So, Can a Tornado Lift a Shipping Container?

In lower-end tornadoes, it’s unlikely. A well-placed, empty shipping container might shift a few inches if the ground is slick or uneven, but it’s not going to go flying.

However, once wind speeds climb above 130 mph — which you’ll see in EF2 and higher — the game changes. If the container is empty, unsecured, and sitting on a flat surface, it can absolutely be pushed, flipped, or even picked up. There are reports of shipping containers being tossed hundreds of feet by EF4 and EF5 tornadoes.

Even loaded shipping containers aren’t immune. If the wind gets underneath one — particularly if it’s sitting on blocks or not flush with the ground — it can create enough lift to break contact with the surface. And if the container isn’t anchored or held down by its weight alone, it could tip or slide. What Makes a Container Vulnerable?

Several factors determine how likely it is for a tornado to move or lift a container:

Is it empty or full? A fully loaded shipping container is significantly harder to move. But an empty one, especially a 20-footer, is relatively light in tornado terms.

Is it anchored? Shipping containers that are bolted to a foundation stand a better chance of staying in place.

Is it elevated? Shipping containers sitting on supports or piers are more susceptible to wind getting underneath them, which increases the risk of tipping or lifting.

Is it exposed? A shipping container tucked between buildings or behind a windbreak is more protected than one sitting out in the open field.

Real-World Examples

In past tornado events, there have been confirmed cases of shipping containers being tossed by the wind. After a tornado hit Joplin, Missouri in 2011, recovery teams reported seeing containers that had been rolled or thrown across lots. In rural Oklahoma and Kansas, shipping containers have been flipped or blown into fields following high-wind events.

One reason shipping containers sometimes get moved even when they seem too heavy is that tornadoes create powerful pressure differentials. When wind whips around a solid object, the high-speed airflow on one side and low pressure on the other can generate lift — much like an airplane wing, but on a much more chaotic scale. Can You Make a Container Tornado-Resistant?

To reduce the risk, you can take a few steps:

Anchor It: The best defense is bolting the container to a reinforced concrete pad. This will keep it from sliding or tipping.

Add Weight: Gravel, sandbags, or even large water tanks can increase the total mass.

Reduce Exposure: Place your shipping container next to a windbreak, such as a berm, wall, or another building. Reducing direct wind exposure can dramatically lower the risk of movement.

Seal Openings: Tornadoes often tear things apart by exploiting weak points. If doors or vents are left open, wind can enter the container, increasing internal pressure and making lift-off more likely.

Shipping Container Bolt Down Bracket - USA Containers Shipping Container Bolt Down Bracket from USA Containers

So, can a tornado pick up a shipping container? Yes, particularly if it's empty, unsecured, and in the path of a powerful storm. While these containers are rugged and heavy, tornadoes are on another level when it comes to raw energy. If you live in a tornado-prone area and use shipping containers on your property, it’s worth taking some simple precautions to keep them grounded.

So how much can you fit in a shipping container? The answer is—quite a lot. Here’s a breakdown of how much can fit in each size, from furniture to wine bottles. 40 Foot Standard Height Container or 40 Foot High Cube

Double the length means double the capacity—and way more flexibility:

Household Goods: Holds a 2–3 bedroom home, including larger furniture and more boxes (400–600).

Vehicles: Two standard cars or an SUV and extra items.

Pallets: Up to 20 standard pallets.

Whether you're hauling a house full of furniture or fulfilling a major retail shipment, these shipping containers have you covered. Tips for Maximizing Space in Your Shipping Container

Smart packing can make a world of difference in maximizing the space available:

Efficient Packing: Disassemble large furniture and use same-size boxes when possible.

Weight Distribution: Keep heavier items on the floor and spread the weight evenly across the base.

Stack Strategically: Consider getting a high cube to make the most of vertical space.

Protection Matters: Wrap items in blankets, use cushioning, and strap loads down to avoid damage in transit.

Once you understand the size and capacity of shipping containers, you’ll see just how useful they can be for everything from storing inventory to moving your family’s belongings to your new home.