One of the most essential elements of a shipping container is its foundation. By the name itself, it is the “foundation” upon which the rest of your container storage is built, which is why it is so important. However, many people still wonder whether it is necessary to put a shipping container on a foundation- and we are here to answer that question and many more!
Specifically, we will be tackling what foundation you need for shipping container storage so you can plan out your next project with all the knowledge you need going forward.
Why is it necessary to have a container foundation?
Whether you are constructing a container pool, a container house, or simply storing an empty container on your land, you must support it properly and securely. The ground beneath you may appear even and stable, yet it is often uneven, unstable, and unpredictable. The passage of water, fluctuating temperatures, the decomposition of organic matter, and the development of adjacent plants can all cause the earth to rise, sink, or slide. Typically, months or even years are required to observe the cumulative visual consequences of these changes.
But do not be deceived by playing the long game. Unless you construct your container home on solid rock, it is likely that the ground may eventually impact its location and level. Even if you already have a foundation, don’t think it will be easy to construct the right type of foundation in the correct manner.
A well-constructed foundation offers a sturdy, secure basis for your building, ensuring its weight is uniformly distributed across a sufficient amount of ground. A foundation can prevent costly future aesthetic, functional, and structural problems. And in the worst-case situation, like a flood or cyclone, a solid foundation ensures that your container will remain in place.
Choosing the right place for your containers
Is the proposed location suitable for container delivery? Regardless of what you intend to use the container for, whether it’s a long-term onsite storage solution, a workshop, or to pack your home when moving, there are a number of factors to consider when evaluating the site:
- Do you have sufficient space?
The first and most significant consideration is whether or not the space can fit a container. Shipping containers are substantial, and there are numerous preparations to be made prior to delivery. Ensure that your preferred location has sufficient space for it. The positioning of the container is crucial; from where will it be opened? Do the doors have sufficient space to open fully? Consider these concerns if you intend to purchase or rent a storage container. Remember that containers are available in several sizes, including 8ft, 10ft, 20ft, and 40ft.
- Is the landscape in order?
The next consideration is the area where the container will be placed. Before placing your container, it is crucial to ensure that the ground is flat. Using a level checker, you may determine whether or not your plot is level. However, if there is rubbish and rocks on the plot, they must be removed. Everything that could damage a smooth surface must be eliminated. Small crevices and inclines may harbour insects and produce dampness.
This may require the assistance of machines. It may be necessary to rent an excavator if you do not already own one, but the expense will be worthwhile in the long run. Precaution is the best treatment. Suppose you utilise your cargo container as an office on a level dirt surface. Enter the left stage, heavy rains. All that water will certainly cause some of the earth to shift, and as a result, your office will also shift slightly, causing the entire structure to tilt.
- Vehicle Access
Consider not only the footprint of the container when selecting a location for the container but also the truck’s ability to enter the site to transport the container. The delivery truck will also require sufficient space to drop off the package. Another delivery method will be required if the truck cannot access the location.
- Footings
A container can be placed directly on level ground or on foundations to keep it off. You can use wooden beams, poured concrete footings, or a concrete slab to secure your container to the ground. Wooden Beam Footings are the most straightforward and cheap alternative available.
When using wooden beam footings, we recommend creating a gravel bed underneath the wood to aid with drainage, keep the beams dry and prevent premature wood rot. Concrete foundations are appropriate when the shipping container will remain in the exact location for an extended period of time. You can pour concrete in each corner at the same level and unload the container on top of the footings.
Different types of foundations for shipping containers
There are a variety of shipping container foundations available, each with its own functionality and composition. We will be classifying them according to their estimated service life:
- Temporary Foundations
This is the easiest and cheapest approach but also the most dangerous.
They keep your container level off the ground to prevent corrosion but allow it to move freely.
- Permanent Foundations
The conventional form of foundation. Once constructed, they cannot be moved without significant machinery and demolition.
Below, we will discuss the common types of shipping container foundations and their respective service life categorization.
Temporary
1. Wooden Beams
A wood beam foundation consists of just laying the shipping container on top of several huge wood pieces. Generally, the container is placed on railway ties, though different timbers and lumber might be utilised. The chemical treatment and size of railway ties allow them to withstand prolonged ground contact and disperse the weight over a vast region.
2. Gravel Foundation
A compacted gravel bed may appear similar to setting your container directly on the ground. By placing a container on gravel, water can drain away, preventing the bottom frame rails from coming into contact with wet soil. This helps prevent corrosion and rust.
Additionally, gravel settles less than added fill dirt, so the container will remain level until it is relocated to a permanent position. However, a gravel base might be considered for more permanent placement with good container anchoring—an important note on the type of gravel used to construct a gravel bed foundation.
You should seek out the crushed stone with jagged edges that interlock for increased strength. Standard gravel, consisting primarily of river gravel, is typically smooth and significantly weaker than foundation material.
3. Concrete Block Foundation
This foundation type may appear similar to some of the following alternatives at first glance, but it belongs to a different category. Here, we’re discussing installing a container atop concrete blocks placed directly on the ground. Whether you buy premade blocks and stack them or construct your own in forms on-site, the outcome is identical. Since the blocks are neither bonded to nor implanted in the earth, only their weight holds them in place. Even while the use of concrete may give the impression that this form of foundation is permanent, it is evidently not.
Permanent
1. Pile Foundations
Pile foundations, also known as friction piles or driven piles, are utilised when the soil near the ground has a low bearing capability. They are extended, slender foundation members that rely primarily on the friction of the surrounding soil’s skin. However, piles may also derive strength from end bearing if they reach a lower soil layer with more bearing capacity.
Several materials, including wood, steel, and concrete, are used to construct piles. Pile drivers are often used to push or hammer down into the soil, regardless of the material. Alternately, piles can be cast in situ, which means the concrete is poured into a hole drilled in the ground.
When with a Franki pile, this requires typically digging a hole, temporarily filling it with a steel casing, and then pouring concrete as the container is removed.
(The Franki piling system is a method for driving cast-in-place concrete (Franki) piles with an extended base.)
Due to the need for costly, specialised equipment, piles are often reserved for larger commercial projects and are not DIY-friendly. The exception to this rule is the much smaller pin piles described in the preceding section. One of the most popular locations to see heaps is by the coast. If you’ve seen a beach pier or a structure built on poles above the water, you’ve witnessed piles.
Piles stretch above the ground’s surface, and piles typically terminate below the soil’s surface. The pile is then capped with concrete to provide a hom*ogeneous bearing surface for the structure above. It might be challenging to identify a piling foundation once the building has progressed. Typically, only the concrete crowns are visible, as the piles are concealed beneath the dirt.
2. Pier Foundation
Similar to pile foundations, pier foundations are frequently confused with them. There are distinctions in form, function, and installation between the two:
- A pier is both broader and shorter than a pile.
- A dock’s primary mode of operation is end bearing, not skin friction.
- Placing wet concrete in an excavated hole is the typical method of constructing piers.
Most pier foundations are created by drilling a cylindrical hole in the soil and then pouring concrete (usually with reinforcing steel embedded). The objective of a pier foundation is to drill through layers of soil with a lesser load-bearing capability to reach strata with superior material capable of supporting a more significant load. Similar to piles, piers can extend above the ground and be used to elevate a structure. In this sense, they also serve as de facto columns, elevating your container without needing additional metal supports.
Piers are the most popular foundation for shipping containers, and we recommend them to the majority of our customers. They are generally affordable, simple to assemble, and economical. The two primary disadvantages of pier foundations for containers are the need for soil with high bearing capacity and the lack of uplift resistance of the piers. However, both of these disadvantages can be mitigated, as the following foundation type demonstrates.
3. Concrete Footing
A footing foundation, also known as an isolated spread footing or a bell footing, distributes isolated point loads over a broader area. The expanded cross-sectional area increases stability while decreasing ground pressure (thus, a lower bearing capacity soil can be used). Typically, footings are used in conjunction with concrete piers. Essentially, it entails expanding the dock’s base to press down on a broader area of the earth.
To construct a footing, you must excavate a hole sufficient for the width/diameter of the footing. Then, forms are constructed for the base and the column that rises above ground level. After the foundation and pier have been poured and the concrete has been set, the final footing is backfilled with dirt.
Due to this backfilling, it is impossible to determine whether a pier has a footing or is simply a straight pier after the fact. However, the backfilled earth has a purpose beyond aesthetics. A dock tied to a backfilled foundation provides significant uplift resistance, whether due to wind, flooding, or frost heave.
You may question why you would excavate a hole large enough for a footing if you’re going to backfill a significant amount of soil around the much smaller column. You could construct a traditional straight pier of the exact dimensions as the footing you intend to develop. The distinction is that a foundation will save a great deal of money on concrete because the pier above it has a smaller width.
4. Concrete Slab Foundation
Slab foundations, also known as slab-on-ground foundations, are well-known for traditionally built homes since they not only support the home’s structure but also provide a smooth concrete floor. This prohibits the installation of floor joists and a subfloor in your home. However, a shipping container already has a plywood subfloor installed, so this benefit is wasted.
In addition, a slab requires a great deal of more concrete, which incurs additional costs. Although you may not need to dig as deeply as for other types of foundations, you must dig. The edges of more substantial slabs are often thicker, where the most pressure is exerted. Therefore, an effective trench must be dug around the perimeter of your slab foundation.
In addition to the price, there are a number of specific aspects of slab foundations that may impact your container project. On the bright side, a slab prevents vermin and insects from entering the space beneath your container.
But this advantage might equally be a disadvantage. With a slab, all below-container utility lines must penetrate the slab, necessitating greater design and the inability to make adjustments later. Adding a sink, for instance, would be difficult and costly with a slab but relatively straightforward with piers.
Moreover, in northern climates, a slab will not be a suitable solution for frost heave. Getting the slab’s perimeter below frost depth will require extensive excavation; you may be better suited to constructing a concrete basem*nt instead.
5. Concrete Strip Foundation
Essentially, a strip foundation, also known as a trench foundation, is the result of placing a number of piers with footings adjacent to one another. The result is a linear footing that rests beneath a narrow, linear beam.
If desired, a strip foundation can encompass the whole circumference of your container, isolating the resulting crawlspace from the exterior. Or, you can support the container at each of its two short ends using two strip foundations.
Since a strip foundation contacts the ground along a line as opposed to a point, its ground contact area is significantly greater. Due to this, it functions effectively on soils with a lower bearing capacity, where a pier and footing would need to be very substantial
Conclusion
Now you understand why you need a foundation and how to choose the right one for your construction. With all the different types you can choose from, it is crucial to be aware of which foundation suits the allotted area you have for your shipping containers. Additionally, you must know how to mix cement for this type of foundation. Pay close attention to the instructions for laying in scorching and cold areas since this can make or break the foundation of your container. The next step is the delivery and installation of containers on the foundation.
If you still are unsure about who to help you transport your shipping containers to your site, then maybe it is time to consult professionals. If you need assistance with sea container storage in Bunbury, feel free to contact us at your convenience!
Our experienced team, combined with 40 years of industry knowledge, can assist with various transport requirements, including oversize, metropolitan, country, rail and interstate deliveries. We realise that as your business flourishes, your transport needs will grow, and Reef Group will need to increase the carrying capacity accordingly. We will monitor the requirements for your company so that no lag in the provision of service against the volume of work occurs, both by acquiring a new plant and using trusted sub-contractors as/and if required.
