A key advantage of shipping containers is their toughness, stability, and longevity, which together we call strength. This strength is noticeably different from most conventional construction methods.
Depending on your design and intended usage, increased strength may not seem very important to you. But for many potential container-based homeowners, this strength is an important differentiator.
Imagine you go to the store to pick up some household cleaner. You see two choices: regular strength and extra strength. Which one do you buy?
If you’re like most people, you go for the extra strength. The same thing applies whether you’re buying products as varied as aspirin or batteries.
The thinking goes that if whatever you’re buying is good enough for professionals and commercial users that use the product every day and can’t afford for it not to work, it should be great for you.
The same applies for containers. In most cases, you aren’t going to be able to take advantage of all the strength they have, but you’ll still be glad you have it just in case.
Let’s get more specific on what increased strength actually means in a practical sense.
Toughness is the ability to withstand wear, damage, and poor conditions. On top of the unintentional wear you have on your container through day to day use, there is also the 24/7/365 assault from Mother Nature.
It should come as no surprise to hear that shipping containers are originally designed to carry valuable cargo through dangerous weather over extremely long distances. With that use-case in mind, they are made specifically to be durable and extremely tough so the high winds, swirling water, and rough weather do not damage the items inside the containers.
They are truly designed for some of the worst-case scenarios imaginable, and they are virtually indestructible (though they can certainly be scratched and dented). While at sea, shipping containers can be subjected to 100 mile an hour winds and 50+ foot waves.
This should give you peace of mind knowing that the building you have constructed can endure and keep you safe in extreme weather conditions, assuming proper engineering of the cutouts and foundations. Considering they are made for harsh conditions and to withstand extreme weather, they are more than tough enough to sit on land and be your shelter.
While toughness against Mother Nature implies resistance to weather, it can also deal with how your container deals with fauna. Some pests like woodcutter ants may try to eat your house, while others like crickets drive your crazy with noise or scare you to death like spiders.
Then you have slightly larger pests like squirrels and raccoons, who often try to find their way into houses in search of food or warmth.
Finally, homeowners in more rural area may have even larger animals like coyotes, bears, and moose to deal with.
Regardless of the type of animal, a properly built cargo container house is quiet resilient with its thick floor and strong metal walls and roof.
And let’s not forget that the properties that make container homes so impervious to unwanted animal intrusions also helps protect you from things like thieves and even inlaws! Just make sure to practice good security measures including but not limited to closing and locking doors.
Stability is a container’s capacity to endure adversity and resist change and outside forces. The most important way a container demonstrates its stability is through structural strength.
Per ISO standards, containers are designed to be heavily loaded and stacked nine units high. And one individual container can hold tens of thousands of pounds of material while only being supported at its four corners.
The typical homesite imposes less stress on containers than an open-ocean ship, and the typical container home weighs much less than a loaded container full of cargo.
For most residential and light-commercial purposes, containers are over-engineered. This excess structural capacity is what enables you to make small cuts for windows and doors while still usually having plenty of remaining structural strength.
Longevity is having a long duration of life. In the modern era where almost everything is disposable, it’s nice to find things that are designed to last.
In the article on sustainability, we talked about how upcycling shipping containers into homes gives them a second life. So the longevity we’re talking about here is actually over two life spans!
Nevertheless, a practical concern that most potential shipping container owners have is wondering how long their container home will last.
New containers are generally designed to last 20 to 30 years without much maintenance. If you buy a used container, they are typically sold around the 10 to 15- year mark, as that is when they become fully depreciated for tax accounting purposes.
This doesn’t mean they will turn to a pile of dust just a few years later. Rather, it means they may need some light attention and maintenance to keep extending their life.
When compared to most types of traditional construction, containers fare better on longevity.
The biggest problem you face with containers is rust and corrosion. However, the use of weathering steel means that the metal skin in containers resist deep corrosion and instead forms light surface rust that prevents further penetration. And that’s assuming the paint has worn off enough to let even that surface rust form (Hint: with proper maintenance and recoating, no rust should be forming anyway).
Of course, if you buy a used container with a lot of wear and tear and then don’t adequately prep and refurbish it, you may find yourself with a shorter lifespan than anticipated. In addition, environmental conditions can slow or accelerate the countdown on a container’s lifespan.
The initial strength of a container has been well-covered earlier in the article, but we now move forward to preserving that strength.
The first thing to consider is maintenance. A container can give you decades of faithful service, but like almost anything, it does require some maintenance.
Maintenance really begins when you first receive a container, especially if it’s used. Before you place it, modify it, and ultimately cover it up with insulation, cladding, and walls, you need to ensure there is no rust, holes, or missing paint.
In most cases, a little wire brushing or sanding and a few coats of paint will get things back in order. If you purchased an especially worn container, you may need to push out some dents, weld in some metal patches, and paint over problem areas. With this initial maintenance, you’ll set a good base to work off of.
Next is ongoing preventative maintenance. As you use your container over the coming years, make an effort to do a quick visual inspection whenever you get a chance. If at some point in the future you do see signs of peeling paint or rust, deal with them swiftly.
The other part of strength preservation has to do not with maintaining your container, but modifying it. The vast majority of container home designs include at least some level of modification to the corrugated metal siding.
While containers are overengineered enough to endure a few cutouts, this isn’t limitless. Eventually, you’ll remove enough metal to significantly affect the overall strength.
Knowing where that tipping point lies depends on the condition of your containers and more so on the design of your building. Perpendicular stacking, bridging, cantilevering, and large cut-outs all place large stresses on the structure and should really be evaluated by an engineer to see if additional steel is needed in order to supplement the strength of what’s left.
A more proactive, positive type of modification is possible as well. For instance, using a form of external cladding for your containers can add decades to its lifespan. A good cladding shields the container’s metal from moisture, sunlight, falling tree limbs, and other irritants. The less the metal has to ensure, the longer it should last.
The strength of containers is well documented and easy to understand. It might be a little stronger than you even need, but it should last a long time and give you peace of mind.
By understanding the three dimensions of strength, you can better appreciate how shipping container construction compares to some of the alternatives you may be considering and make the best decision for you.
What have we overlooked with regard to container strength? Let us know below in the comments.