One can anchor a shipping container to the ground by fastening the container’s corner castings onto its concrete foundations. One can use several methods to attach to the foundation, such as welding onto a steel plate, steel chain, or twist locks. All of which require steel embedded or bolted onto the concrete foundation. After which the steel fittings will then attach to the corner castings of the container.
First off, not all container homes may need to be anchored down. If you live in an area that isn’t prone to any natural disasters, chances are the weight of the container itself along with all your things in it can be enough to weigh it down.
However, it is better safe than sorry to have it anchored to your foundation. Anyway, this can be either permanently attached or removable to retain its portability. (1)
All anchoring systems make use of a concrete foundation. So you need to secure this first. If you haven’t wrapped your head around this yet, check out our article on shipping container home foundations!
The minimum foundation you’ll need to be poured is on the four corners of your container. This is to match the corner castings on the containers themselves, acting as attachment points. From here, stem the different ways you can anchor the container down. (2)
One can weld underneath the containers’ corners onto steel plates with long hooks in a J or L shape, that will be embedded into the concrete foundation while wet. You can also drill holes into your concrete after it has dried and cured, however, the measurements may need to be more precise, the metal rods will be straight (without hooks), and need epoxy or a good bonding agent. (1)
This method requires some planning ahead of time as you’ll implement some steps even before the concrete is poured. However, it is a highly solid and secure anchor to the foundation. (2)
This anchoring method is very common as it is the easiest way to secure your container home while maintaining its portability. Twist locks are a mechanism initially used for containers when shipping cargo and when needed to stack multiple containers. It can also be used to secure container homes over one storey.
Like the previous steel plate method, the steel plates are first bolted into the foundation through L or J hooks. Afterward, the container is placed on the plates, aligning the corner castings with the twist locks. Lastly, pull or turn to secure the container in its spot. (2, 3)
The image above shows a boltable dovetail twist lock on its own and locked into the corner casting of the shipping container. To attach the corners of the container, these need to be locked into to corner castings of concrete foundations. Additionally, you would need the following materials: steel plate, Hammer drill, 10 mil masonry bit, and 12 mills concrete anchor bolt. (4)
Just like the steel plate, you can choose between embedding the steel plates while the concrete cures, or waiting till it hardens and drilling the holes in after.
The twist lock mechanism must be securely attached to the foundation itself. Afterward, it just needs a flick of the lever to either fasten it onto the twist lock or unlatch the lock to move your container out. The downside to using twist locks is that the measurements must be precise for the container to fit exactly onto the corner fittings. Also, twist locks cannot be used anywhere else along the container except its corners. (1)
Ensure the chain is heavy-duty and has high-grade strength. Weave the chain through the container’s corner casting then attach it to a hook/rebar on the foundation. This method can be easier than twist locks. (2)
Bridge Fittings (for Multi-Unit Container Structures)
When combining containers side by side, use bridge fittings to stabilize them during any strong winds or seismic movement. This significantly helps container structures that will be stacked on one another and will prevent the containers from toppling. Bridge fittings also aid in the welding of edges together.
Other ideas one can engage in to anchor your home to the foundation will mainly need attaching my container to the corner castings. However, if you are considering using alternative methods, be sure to consult your local building professionals if this is secure enough.
- Shipping Container Foundations Guide – Discover Containers
- How to Secure a Shipping Container to the Ground (containerone.net)
- Six Practical Shipping Container Accessories (falconstructures.com)
- How to anchor a shipping container to concrete using a Boltable Dovetail twist lock – YouTube
- Anchors for Portable Buildings and Containers (americanearthanchors.com)