After buying a shipping container online, you’ll go through a series of expected events – have it scheduled for delivery, and have it arrive via either a tilt-bed or flat-bed truck to your desired destination. There is one aspect of delivery that people don’t often consider though: where to place their container, and if the foundation is sufficient.
If you’re only using a shipping container for a brief period of time, you can leave it where it’s offloaded. For instance, if you’re buying shipping containers to pack up your house’s belongings and then transporting them to your new house within the span of a weekend. As long as the surface is flat, level, and solid, the shipping container’s temporary resting spot should be fine.
However, if you’re hoping to keep your shipping container in the same location for a matter of weeks, months, or even years, then placing your shipping container on a proper foundation is essential.
Read ahead to find out why foundations are an essential consideration for shipping container placement and what types of foundations are most ideal for shipping container placement.
Why Is a Foundation So Important for a Shipping Container?
Prevent Your Container from Sinking
First and foremost, a foundation prevents a shipping container from sinking deeper into the earth. After all, a shipping container is very heavy. An empty 20ft shipping container weighs 5,181 lbs, while an empty 40ft shipping container weighs 8,267 lbs. As expected, that weight only increases the moment that you add cargo or other materials inside. For example, if you converted your shipping container into a pool and filled it with water, it could hold over 5,000 gallons of water inside of it — that’s over 41,000 lbs.
Many don’t consider that the ground may not be able to support the weight of the shipping container. Unless the ground is rock-solid, the bottom of your container could sink over time. Your area’s soil type can exacerbate this problem. For example, some areas of the country have soil with a lot of clay in it. Clay is wet and soft. It also swells and contracts with changes in temperature and precipitation, which can pull the bottom of the container down. Before placing your container on the ground, be sure to assess what type of soil your land is made up of.
Keep Your Container Level
It’s important to keep your shipping container perfectly level so the container’s structural elements don’t shift and warp over time. To achieve this, choosing the right foundation plays a huge role.
Shifting and warping will cause serious structural problems. If the main door’s frame shifts, it will be difficult to open and close the doors properly. The floor, walls, and roof could become uneven. If shipping containers have been converted into a multi-level house, shifting can cause the separate levels to become uneven. Any windows and doors installed in the building might not open and close properly. In worst case scenario, your container home could lose structural stability and require intensive renovations to restore its integrity.
Minimize Container Corrosion
A proper foundation can also minimize corrosion on the base of the shipping container. How? Certain types of foundations will raise the bottom of your container off the ground, which prevents groundwater from touching the bottom and creating rust. Other types of foundations can create a thick barrier between the shipping container and the ground, which should prevent groundwater from touching the base of the container.
Corrosion can affect the durability of your shipping container, and severe corrosion makes it easier for your container walls to take on damage and spring leaks.
How Do You Choose a Foundation for Your Shipping Container?
The answer to this question is that it depends on how long you expect to keep your shipping container in that location. If you’re keeping your shipping container in a single spot for several weeks, you can use a short-term solution. If you’re planning on keeping your shipping container in that location permanently, you will need a long-term one.
You’ll also need to consider factors like your area’s soil type, the local climate, and your budget. Talk to a professional contractor or structural engineer to get a better idea about which foundation is right for your shipping container plans.
The Best Short-Term Foundations for Shipping Containers
If your shipping container is not going to stay in the location forever and in a matter of weeks or months, you’re going to move it, you’ll want to look into a temporary foundation.
One of the temporary foundations for shipping containers is called blocking. Blocking is when you prop your shipping container on top of a foundation of concrete blocks. The weight of the shipping container should keep the concrete foundation blocks firmly in place. Try not to stack too many concrete blocks on top of each other. The higher you stack your foundation blocks beneath your shipping container, the less sturdy the foundation will be.
Another solution you could try is resting your shipping container on a series of railroad ties. Railroad ties are rectangular pieces of wood used to support the rails along railway tracks and are used to keep shipping containers off of the ground.
Cement blocks and railroad ties will raise your shipping container off the ground, which will prevent water from pooling around the bottom and causing corrosion. The foundation styles can also make moving your shipping container a little easier when you no longer need it to be in that location. The materials aren’t attached to the container, so the container can be picked up with a forklift or crane without difficulty.
The Best Long-Term Foundations for Shipping Containers
If your shipping container is going to stay in the same spot long term, you’ll want to rest it on a foundation that will keep it level and away from groundwater permanently.
Long-term foundation options are especially important when you’re building a shipping container house. You should never use a short-term foundation option on a shipping container house. A short-term foundation can’t offer long-term support, and when used longer than intended, can result in shipping container damage that could prove costly. You might also find that your local zoning regulations only allow shipping container houses that are on permanent foundations. Houses without these foundations will be considered zoning violations.
Concrete Slab Foundation
A concrete slab foundation is a thick barrier between the bottom of your shipping container and the ground, which can protect it from corrosion, water intrusion, and pest infestation. This will be one of the more expensive foundation options for a shipping container.
Concrete Strip Foundation
Another long-term solution is a concrete strip foundation (also known as a trench foundation). It is made of a series of sunken concrete walls instead of one full slab. One of the biggest advantages of this foundation style for shipping container homes is that it leaves room for utility lines and plumbing to go beneath the house.
A pile foundation is made up of solid steel piles (cylindrical tubes) that are driven deep into the ground and capped with concrete. It is an ideal foundation style for shipping container homes in regions with softer soil.
A pier foundation is a very popular foundation for shipping container homes and other permanent structures. It is very similar to a pile foundation. Cylindrical concrete piers (often reinforced with steel) are placed into the ground until they rest on compact soil. Each pier supports a shipping container corner, and sometimes its middle points for stronger weight distribution.
Don’t risk cutting corners when choosing a foundation for your shipping container. By following the steps outlined, you can ensure that your container has a solid foundation that is level, removed from groundwater, and properly anchored. Taking the time to plan and execute a proper foundation will increase the lifespan of your shipping container, whether you are using it for storage, as a home, or for any other purpose.