Does My Shipping Container Home Need A Foundation - Shipping Container Foundation Facts
Deciding to live in a shipping container unit is a bold decision to downsize many things in your life. Less space in your home, a lower monthly payment on it (if any), smaller kitchen, smaller bedrooms, etc.… They get excited about container house plans and their container home design, but many people overlook the most important thing: the need of a foundation for a shipping container!
One of the most common questions we get asked about container builds is whether or not this home needs a foundation since it already has a base.
Do Shipping Container Houses Need Foundations?
The simple answer is yes. Without a foundation your house will likely shift, sink and raise as the ground moves. This is one of the most critical steps in building your home, because if you do not have a solid and sturdy foundation it can cause structural problems for your shipping container house, often leading to damage and major repair costs.
While not all of our customer use a concrete footing or foundation (some just place it on the ground directly), you will see why we recommend placing your home on some sort of foundation!
Having a foundation is necessary for your container house, however, not all foundation options are created equally. There are several factors that you need to understand when choosing the best foundation for your shipping container.
Factors That Determine Your Shipping Container Home Foundation Type
As mentioned above, there are a variety of factors and conditions that will determine what type of foundation you need to use for your shipping container house.
A few of the more important things you need to look at include:
SOIL TYPE – Soil is unpredictable. Rain, ground water, wind, erosion, earthquakes, these can all contribute to soil becoming unstable and then the risk of your home moving, whether it rises, sinks or slides. Most of the time we take soil for granted and see it as stable, however it can shift under the right conditions which would then cause a lot of potential problems for your home.
The soil that we typically see is called top soil, which may or may not be made up of all the same material. As you dig beneath the top soil you can come across a variety of different materials such as hard rock or soft clay, or even a combination.
With weight of your home distributed across the ground, settling will occur and the elements that we listed above can work its way into the deeper levels of soil and over time cause the home to shift due to the uneven material.
This can result in quite a few problems, such as doors and windows becoming out of square, which means they will not open or close correctly. A well-built and sturdy foundation provides a solid base and will secure the home distributing the weight of the home evenly. It also ensures that if erosion does occur your home will be well secured and safe.
COST – Let’s face it, the cost will always come into play when determining how to set up your new home. Some foundations such as steel piles will cost a lot more than a concrete pier-style foundation. Knowing your budget and the cost of each foundation type will certainly help you in choosing a foundation that is right for you.
You need to calculate the best and correct method to go with by meeting and consulting with a local qualified builder or local engineer. Soil type and how many containers you are planning on placing on your land will play a large factor here.
If you are building on a softer soil you will then need a deep foundation, such as pile foundations. If you are building on a harder soil you can then go with a minimal foundation choice. The reason for this is because the majority of the weight of the container will be evenly distributed onto the existing hard top soil.
Depending on some peoples budget they will do what is called ‘over-spec’ on their foundation, which means building a stronger foundation than what is required. There are a couple of reasons for that, from peace of mind or because they prefer a particular foundation that is more than what is required.
That decision will ultimately come down to cost, foundation design, and what the local building codes require structural.
COMFORT LEVEL – The foundation literally holds up your house and plays a huge role in its structural integrity. Some people tend to go the cautious route and install a much stronger foundation than they actually need.
This is perfectly fine but it is something to consider. What is your peace of mind worth? If cost isn’t an issue and you just want to make sure that your container is secure then you may go with the best, sturdiest foundation possible.
These are just a few of the factors that determine the type of foundation you will need for your container home. It is prudent to assess each factor before choosing the foundation for your building.
The Four Main Foundation Types For Shipping Container Houses
Unlike a traditional home, which is typically built on a concrete slab, there are four types of shipping container foundations to choose from when prepping your new shipping container home foundation needs.
What Footings Are Required For A Shipping Container?
They are: Slab, Pier, Strip, and Pile Driven. Each has different applications and situations where one is more appropriate over another one. Factors include budget, structural requirements depending on the type of home, size, etc., local soil type, and local building codes and requirements. We will look at the different foundation options, which one you should consider and why, and what to look for in your specific location where you are thinking of putting your new home.
We have assessed the various factors that will determine the type of foundation you choose, however, now we need to look at the 4 main foundations that exist for these container buildings.
The foundations can be classified as either shallow or deep foundations. A shallow foundation is laid close to the ground level, as much as a foot or two down from the top. Deep foundations can be laid at depths of up to 32 feet (10 meters).
Pier Foundation: A Concrete Block To Get Your Container Off The Ground!
To sum up what they are made of, they are concrete cubes which are reinforced with rebar (steel) within them, or a mesh of steel wires. The steel adds a lot of strength to the concrete for a very sturdy foundation.
Shipping container dwellings set on concrete piers usually will have a pier at each corner of the home. And if using 40-foot container an additional two piers are needed and are placed halfway down the length of each side of the home.
The best reason for going with a pier foundation is that because it will elevate the container off of the ground which allows for greater ventilation and will help prevent condensation from forming underneath the house.
Pier foundations are chosen quite often by DIY home builders as they are the simplest, cheapest, and quickest foundation to lay down. It doesn’t require any special equipment, and it doesn’t require very much experience to DIY.
It will save a lot of time and money by choosing pier foundations as you don’t need to excavate a ton of dirt to achieve the required depth. You would only need to excavate the ground for the piers. Generally, all that is required is a 24”x24”x24” holes.
Compare this to a concrete slab where you will need to dig for footings, you would need to excavate more than 20 (or 40) feet by 10 feet, or more, and will need equipment to excavate the area.
It is important to note that this is considered a shallow foundation. If you are placing your home on a really soft soil then this may not be your best type of foundation to use. For most situations though, this is what we recommend as it is cost effective, easy to install and provides good support for your home.
Slab Foundation: A Solid Permanent Foundation Choice
A slab foundation is the most time-consuming foundations of the four. This foundation choice is great for warmer climates that don’t have to worry about freezing and for areas with soft soil. It is the preferred method when encountering soft ground and the need to equally distribute the weight of the home.
This concrete foundation, or concrete slab, can be either built to the exact dimensions of the container, or if cladding is going to be added to the container then you would want to build it slightly larger than the footprint of the container so that the cladding can also rest on the slab.
Depending on the type of soil, local water tables, and the frost level in your area the foundation may be dug as shallow as 18-inches all the way to 10-feet.
A couple of reasons to choose a this foundation option, in addition to soil type, is it provides a solid base with no pockets or dead space underneath the container level.
This can help prevent a lot of problems, such as bugs, cold/hot pockets, and spreads the load of the container over a larger area than a pier foundation.
Due to the additional concrete that is used in this foundation, and with the amount of soil that needs to be excavated slab foundations are vastly more expensive over using pier foundations.
Something to note with going with a slab foundation is that once the concrete is set there is no way to access utility lines like there is with going with a pier foundation. If a water pipe leaks or breaks, then a section of concrete will have to be cut out to access the pipe.
A slab foundation is possible as a DIY but will require an excavator if you need to dig very deep, which can also be DIY. Most equipment rental places will have some kind of an excavator for rent. However, it is always best to either consult with an architect engineer or have a contractor do it for you.
Strip Foundation: A Footing Foundation For Container Homes
A strip foundation (also known as a trench foundation, or footing) is a combination of pier and slab foundations. Typically, when building a slab foundation, a strip, otherwise known as a footing, is laid down before the slab for stability and strength.
A strip foundation is a strip of concrete which is laid to support the container. Usually the concrete strip is 1-2 feet wide and can be anywhere from 2-4 feet deep.
A strip foundation can be built in a couple of different ways; as a perimeter of the container or it can be built at the top and bottom of the container.
Typically people will turn to a strip foundation if their ground is a little softer than normal, however, they don’t want to pay for an expensive concrete slab foundation.
It is sort of the best of both worlds. This is a great option if on a budget and want to keep costs down instead of doing a slab foundation but have less firm ground to lay your foundation on.
In areas where the ground stays damp for much of the year because of heavy or constant rain, a rubble strip foundation using loose stones below the concrete strip can be used. This will work as a filtration system by allowing the water to run through the stones and drain away.
As with the other foundations that we’ve discussed strip foundations also have weaknesses. Strip foundations have a weak resistance to wind and earthquakes. Due to their shallow form strip foundations are best used for a small or medium-sized build.
Pile Foundation: Right Type Of Foundation For Placing Your Container With Solid Weight Distribution
Pile foundations are utilized when the type of soil in your local area is too weak to support a concrete base. It also happens to be the most expensive foundation that we’ve discussed in this article.
Piles are a cylindrical solid steel tubes that are hammered into the ground until the piles reach a more stable load bearing ground. Pile foundations are not recommended as a DIY build as they require expensive specialized equipment.
A contractor would be needed to install the foundation due to the specialist equipment, typically a pile driver.
After the piles are driven in place and secured, they are usually capped with a block of concrete. Once all the piles are secured you end up with a grid system of concrete caps which look very similar to concrete piers.
The Cost To Install A Foundation
We understand the 4 types of foundations and which ones are more expensive than others but what can you expect to actually pay to install a foundation for your container dwelling?
Unfortunately, the answer will vary depending on the size, type and whether you complete the work yourself or hire it out to a contractor. With that said, here are a few expense estimates to at least give you an idea of what to expect.
Concrete Pier Foundation – As your most affordable option, this will typically cost you about $550 for a 40’ shipping container.
Concrete Slab Foundation – The price for this will vary greatly depending on the depth you need to dig, however, on average the cost is about $6000 per 40’ converted storage containers.
Strip Foundation – On average, the cost for a strip foundation is around $5000 for a 40’ shipping container.
Pile Foundation – This is a tough one to estimate as you will need to hire a contractor and the depth of your steel pile and subsequent concrete filling could vary greatly. Just know that this is a very expensive option and it is best to consult a local contractor to learn more about the costs associated with this work.
Are Container Homes Hard to Build?
Prefabricated shipping container homes are quick to construct and very easy to set up. Once the container home is delivered to your land, you will likely need a crane or something similar to place the container on your foundation.
If it is a single container, then this is pretty much all you need to do. If you have a multiple container setup then you will likely need to join the containers together, which is a simple process that most contractors can easily handle.
Having A Foundation Is A Good Idea!
Even though container’s comes with a sturdy base, it should still be placed on a foundation to preserve its structural integrity and prevent any possible future damage. The choice of foundations depend on the factors listed above, do your research and you’re going to give your container home the right foundation it needs!