Pertaining to the small size of the container home, a basement could be a useful extra space to accommodate your needs. However, building a basement is not as simple and DIY friendly as the container home itself.
You can have a basement with a container home, but you cannot use another shipping container as a basement.
Figure 1-Basement in a container home- Source-(container home- https://icontainerhome.com/shipping-container-home-with-basement/)
Using a container as a basement is not a good idea for the following reasons:
- Even though the containers are very strong and sturdy, they are not designed for the constant push of dirt across the wall. It won’t be able to withstand the pressure.
- Constant exposure to surrounding moist soil can lead to early rusting that can further lead to leakage or worse- the collapse of the structure. It is true that containers are made of Corten steel. But Corten steel only delays corrosion and does not prevent it.
Best ways to build a basement for your container home.
When building a container home, it is normal to be tempted to use alternative cheaper methods to build a basement too. However, a basement has a lot more factors than an envelope built above the ground. Hence, it is important to be careful, or you could end up with serious damages to life and property and a lot of lost time and money.
The following are ways to build an effective and safe basement for your container home.
Conventional Concrete Basement
Building a basement for a container home is the same as building any regular basement. Just that the size would depend on the size of your container. Briefly explained, the process involves
- Digging a pit a little larger than the size of the basement, to facilitate workability,
- trenching with wooden panels/ from work to prevent soil from falling
- tying the reinforcement for the footing and the floor slab
- pouring concrete into the footing and floor
- formwork for reinforced concrete retaining walls
- tying reinforcement
- pouring concrete
- Once the concrete walls are completely cured, the formwork is removed, and waterproofing agents are applied on the outside of the wall
- Then filled with mud
- Roof slab.
- In the case of a shipping container, the base of your container will be the roof, so you just need to make some piers on the corners to attach the containers using steel plates
- Once the container is in place, the structure can be finished, and a staircase can be installed connecting the basement and container.
If you have plenty of construction suitable stone around your site and hold of some skilled masons, then this might be another strong option for you. Since concrete has taken over, stone foundations have become a thing of the past, but they have tremendous potential to give us strong basements if laid out correctly.
These are extremely durable, fight water penetration like a pro and can be built with locally available materials. Along with these qualities, the excellent compressive strength of stone contributes to the stone basements lasting for decades. There are various types of stone basement/ retaining walls.
The most common one is as follows.
Two walls (or wythes) of stone each 8 inches thick are built facing opposite directions with a 4-inch space in between. This space is filled with a liquid lime-based mortar and the stone wythes are pointed up and sealed.
Although these two are the strongest methods to build a basement, the whole process involves a lot of crucial steps. If you are looking at some alternative way, ensure all these factors are fulfilled in your alternative basement technique.
Many people have tried earthbag basements, concrete blocks, steel basement/bunkers and many other ways. It depends on your will and resources.
Factors to consider when building a basement:
- Retaining walls– strong enough to bear the constant load of soil against it throughout the life of your structure
- Waterproofing barrier– Constant exposure to moisture needs to be tackled carefully, as it has the potential to cause the failure of the structure.
- Ventilation- if you plan to build living spaces in the basement, ensure that you build it a little above ground and add small basement windows for light and ventilation in the basement
- Drainage-Building underground needs some figuring out in terms of drainage, especially if you are planning to have a bathroom underground.
Using a container as Basement/ Bunker
It is NOT recommended to use a shipping container as a basement, because the containers are not manufactured to withstand the constant pressure of the soil on its walls. The structural system of the containers lies on the corners, and not the walls.
However, if you have already bought the container or are in the mood for some experimentation, here are some points that could help you to carry out a safe endeavor.
1. Bury the Container in an Upside-Down Position
The floor of the container is designed to carry more load than the floor. Therefore, burying the container upside down might make it more effective to bear the load of the soil on top of it. It will also prevent the floor from warping when the container settles to the ground. This, however, doesn’t mean you refrain from providing extra structural support using strong steel bars.
2. Reinforce the roofs and sidewalls of the container
As mentioned above, the walls of the container are not strong enough to bear the constant push of soil from the sides. It needs serious structural bracing in order to function as a strong basement. If not done properly, it could cause the structure to collapse at any point, which could lead to loss of life and property.
Consult a structural engineer to carry out the appropriate bracing.
3. Waterproof coating /materials on the exterior of the container.
Even though the container is made of Corten steel which can delay corrosion, constant exposure to moisture underground can be fatal and cause the structure to collapse due to rusting. Hence, before burying the container, ensure to do all you can to keep the envelope away from the moisture by coating and covering it with waterproof layers.
Having a basement with your shipping container home could indeed be a boon, but it is not a DIY friendly project, and it needs some careful material and structural considerations. Also, it might add a significant sum to the cost of your construction.
So, if you have the resources, start digging. Good luck!