Container homes have an innate strength of carrying tens of thousands of pounds in itself, as well as up to nine fully loaded stacked upon one another. As they are meant to endure long trips overseas, they are designed to ensure all its contents remain dry, intact and dust free. However, one must be cautious of all the chemicals the container either transported or was treated with in order to contain the goods well. One must also undergo regular maintenance of the container to ensure it is free of rust, prolonging its life.
Its Innate Strength and Build
Shipping containers have been designed to withstand extreme, harsh weather conditions. One of which is being overly exposed to saltwater and storms for weeks or months.
“They’re probably one of those durable products on the planet,… Container homes are designed to have up to 60,000 pounds on the inside, and up to 400,000 pounds stacked on top of them.” (Container Homes Are Becoming the New Norm — Here’s Why | NextAdvisor with TIME) (1)
Naturally, steel is stronger than wood. Weathering steel (or corten steel), is a low-alloy steel that has even more features in resiliency, delaying corrosion. These containers are so designed that you can stack multiple units, heavily filled to the brim up to nine stacks high! (2)
These steel walls are welded so well together to ensure the container is airtight, watertight and fireproof to ensure all its contents remain dry and intact. It must be able to ensure and keep out dust, dirt, rain and ice, dust among many other factors such as tornadoes, hurricanes and big movement on the ship. Specifically, they are designed to handle over 50 foot high seawaves and strong winds of 100 miles per hour.
For the exact specifications of a shipping container’s build, here is a summary from The Structural Strength of Shipping Containers (2)
Walls: The walls of a shipping container, made of 14-gauge steel, consist of a series of 0.075-inch corrugated sheet metal panels that are welded together.
Supports: Each structure is supported by 7-gauge tubular steel top/bottom side rails and end frames, which hold the container together and add strength to the walls.
Roof: die-stamp corrugated sheets to keep elements out.
Bottom: The container bottom features 3-4-millimeter-thick cross members, which have recesses to allow lifting via a straddle carrier.
Floor: The floor is 28 millimeters thick and has 19-ply treated plywood secured to the cross members.
Their stacking and load carrying ability are as per ISO standards. Each container can carry tens of thousands of pounds at its four corners, in which lies the structure’s strength.
Containers are meant to last around 20 to 30 years with little repair and maintenance. Used shipping containers to be recycled as homes are often sold out after their 10 to 15 year of use. This is when they have reached their peak as shipping containers can still be economically used as a great home. (2)
However, they may slightly be too strong, chemically. Remember they have to preserve goods, keeping away vermin, pests and being fireproof. This is to ensure they render top performance being first and foremost a great shipping container before it is a home. This leads to having them lined with very strong chemicals that can be damaging to our health. One of which is Radaleum FHP-60, which is also odorless and hard to detect. Make absolutely certain the container has been stripped of all chemicals and professionally washed before moving into it as a home. (1)
They are also very secure structures, meaning their doors and walls are made of heavy duty metal. This makes it difficult for thieves to break into, as well as pests and rodents to enter. They are designed to be fire-resistant as previously mentioned, which can be a pro and con. These are safety features you’ll get with any shipping container whether brand new or used. (2)
Residential homes, not being out for months at sea nor being filled to the brim in weight definitely take a much lighter load than what containers were initially meant for. Therefore, ten years off its life should still give ample strength for a home. This will however require some maintenance to ensure they remain strong.
How To Keep Them Strong
Firstly, where you’re placing your container home is crucial to its longevity. Sites prone to flooding and tornadoes for example will pose a higher risk than others. If this is the case, it is always good practice to elevate your container off the ground and securely fasten them to a foundation system. (1)
More on that with our piece on Foundations for Container Homes.
Despite being made of weathering steel, shipping containers are still prone to rust and corrosion. Weathering steel will however prevent the process of deep corrosion for a while and form a rust on the surface that is easier to fix than one deep inside.
Before you treat, insulate and clad your container, make sure that your container is free of rust. Ensure there are no holes and patches of rust anywhere. In this case rust can be removed with some sanding, wire brushing and some coats of paint to keep it protected. This is a great start but you need to keep an eye out for regular maintenance should you see some resurface. (3)
If you’re planning on creating fantastical house shapes like a cantilevered balcony or staggered container volumes, it’s best to consult a structural engineer. They need to evaluate whether or not the container’s strength can handle the shift of weight and stress.
Yes containers are very strong but note we’ve taken its prime years of strength out, as well as reduced its structural durability by cutting out holes for our doors and windows. Engineers will check if additional support and bracing is needed for the design to happen.
Another way you can strengthen your container home is by adding an exterior shell or cladding that can protect the metal box from moisture damage, sun exposure, debris, harsh weather and other harmful factors. This prolongs the container’s life as the metal doesn’t have to handle as much at a time. (3)
You can also check out our piece on if Shipping Container Homes Make Good Storm Shelters!
How Strong are Container Homes as an Economic Concept?
The incoming generation continually struggles financially. Seeing as their income will not match living costs as inflation rises, many have given up the dream of owning a home of their own. Therefore, many millennials have pivoted into owning non-conventional or traditional housing options such as manufactured homes, mobile homes, tiny homes and container homes. (1)
“Eighty six percent of Americans said they would buy a tiny home as their first home, according to a survey conducted in late 2020 by Investment Property Exchange Services (IPX 1031). Among those who were surveyed, 65% said that affordability was a factor. With the cost of homes skyrocketing, mortgage rates rising and wage stagnation, this trend is likely to continue.” – Container Homes Are Becoming the New Norm
- Container Homes Are Becoming the New Norm — Here’s Why | NextAdvisor with TIME
- The Structural Strength of Shipping Containers (highplainsholdingcompany.com)
- Shipping Container Strength: Why it Matters – Discover Containers