Anyone in the prepping community has heard about burying a shipping container for use as an underground bunker.
Those of us who have read a little farther have realized that’s not such a great idea, as the container isn’t strong enough to support the weight of the backfill when burying it. While the corners of shipping containers are immensely strong, the sides and roof aren’t, especially when we’re talking about tons of dirt and rocks.
But that’s not to say that shipping containers are all bad. You can buy a 40′ shipping container for less than $2,000, which is a great price. That’s cheaper than you can buy a cabin kit of half the size, and you’d still have to build the cabin.
So why not buy the container anyway? Just don’t bury it. People make homes out of containers, so why can’t they also be used to make a cabin in the woods for use as a survival retreat? The inside can be finished out just like it would be for burying, without bothering to put it underground.
I’m not convinced that bunkers are a good idea for prepping anyway. The notion of bunkers started back in the Middle Ages, with the need for a secure area to hide from catapults and trebuchets’ effects. The idea regained popularity, along with a facelift, in the last century, because of bombardment by aircraft. Since dropping a bomb from an airplane is just a bigger version of shooting a cannon shell, the same bunker protects from both.
As we moved out of World War I and II, we entered the Cold War with its nuclear arms race. This caused people and institutions to find places that could be used for fallout shelters. I can still remember the drills we did in elementary school, going from our classroom to our fallout shelter in the basement.
But World War II and the Cold War are both things of the past. So I have to ask the question; what does anyone need a bunker for today? Most people talking about bunkers are planning on using them for protection against social unrest, from what I’ve seen. While I can understand and agree with that need, I’m not sure that bunkers are the way to get it. I’m not too fond of the idea of being trapped inside a bunker, unable to see what potential attackers are doing outside.
Of course, there are plenty of people who still think bunkers are a good idea. Suppose you’re one of them, more power to you. I’m not trying to dictate the survival philosophy you use; I’m just explaining my reasoning. There are always multiple ways of dealing with any survival situation.
There are several advantages that I can see using a container for a survival retreat:
- First, the basic structure is already built, shortening the construction of the retreat.
- As best as I can tell, it’s about the cheapest way of coming up with the basic structure, other than scavenging materials. So it will save money over many other options.
- Shipping containers are secure, being made of steel and having four lock bars on end.
- While the 14 ga. corrugated steel used for the sides isn’t thick enough to stop anything more than a .22LR. Most people don’t know that. So they may not shoot, thinking it would be a waste of time.
- The shipping container is water-resistant, solving the problem of how to keep the rain out.
- Being ready-made, you can have the container delivered to your site, then start staying in it right away, even while working on it.
- The container is heavy enough not to be easily damaged by driving a vehicle into it.
That is not to say that using a shipping container for a survival retreat is ideal; it isn’t. Being metal, the shipping container will tend to be hot, which will make it uncomfortable in hot climates, especially in the summertime. The doors are not conveniently located, and there are no windows or vents. But those are things to work around, not deal killers.
Making a Survival Shelter Out of a Shipping Container
While a plain shipping container can be used as a shelter, it’s rather doubtful that anyone would enjoy staying in that. It would be a good idea to make some modifications. Of course, how extensive those modifications are and how long it takes to make them will depend on how much money and time are available to invest in the shelter.
How Big a Container Should You Buy?
Shipping containers come in two basic sizes: 20-foot and 40-foot. Both sizes are eight feet wide and eight and a half feet tall unless you buy what is known as a “high cube” container, which will be 9.5 feet tall.
Considering the cost difference, it’s more cost-effective to buy a 40-foot container than two 20 foot ones. However, two or even three separate containers provide you with more flexibility in your shelter’s design. They can be placed opposite each other, giving you a patio space in the middle, which can be used as the main living area.
Don’t just place the container on the ground if you can avoid it. While there are dry places and the ground is hard enough that the container won’t sink in, that’s not something you want to count on. If the container were to sink into the ground, jacking it out would be difficult. If it sinks unevenly so that the doors’ bottoms are below ground level, it will make the shelter unusable until the doors were dugout.
The solution is to put in a footer. That doesn’t have to be all the way around, as the container sits on the corners. So dig down and pour a two-foot by nine-foot reinforced concrete footer at each end. Whoever delivers the container will set them down accurately, so they should get the ends on those footers.
Do You Need a Roof?
The container itself is water-resistant, so a roof shouldn’t be necessary. However, the containers we’re talking about here are used ones. Chances are there will be some damage, and there might be some rusting. That could lead to a leaky roof if ignored.
The easiest way to put a roof on a container is to make what’s known as a shed roof. That’s a roof that slants to one side, usually the backside, rather than one where there are two sloping sides. A roof of this sort is faster and easier to build and will require a little less material. For roof covering, the least expensive way to go is with roll roofing material. That’s not only cheaper but faster and easier to install.
While roofing over the container, consider building an awning extending out from the side of the container. That will provide a shaded, outdoor living area, making it so that it isn’t necessary to be inside the container all the time. As this is a survival retreat, you may want to do most of your cooking outdoors, under this awning, as well as a host of other survival tasks.
Typically, this would be framed out with wood, covered with sheathing, and then shingles. But if money is an issue, the awning can be framed out and covered by a heavy-duty tarp. PVC pipe works well for this, as the pipe can be curved, making a curved room that will help stretch the trap, ensuring that it won’t flap in the wind.
That brings up an important point about using tarps. The way to keep tarps from becoming ruined in the wind is to stretch them and tie them down to the point where they won’t be flapping in the wind. That might require adding additional grommets. But it’s the flapping that causes them to be destroyed.
In the case where two containers are being used, the awning can be stretched between them, making a nice outdoor living area while providing roofs over the doors to both containers. Either way, make sure that you set up rainwater capture from your roof.
Windows and Doors
One of the biggest questions to ask yourself is whether or not you want any windows and doors. On one hand, adding them in makes the shelter much more livable. But on the other, it’s all but impossible to add them in without reducing your shelter’s security. While the container’s built-in doors are pretty secure, it’s doubtful that anything you put in will be entirely safe.
Commercial steel doors, used on warehouses and other industrial buildings, are much more secure than anything you can buy for a home. They also come in a steel frame, which makes them considerably harder to breakthrough. Although substantially more expensive, if you’re concerned about security, that’s the way to go.
Don’t dismiss the idea of making your own steel door. If you have a welder and some experience using it, you can build one out of standard steel stock. They do this regularly in Mexico, making some solid, secure, and also attractive doors. Those same tubes and profiles are available here in the US, although they can be a bit hard to find.
Since your shelter may very well be left sitting unoccupied while you are away, I’d recommend making it extremely secure. That includes putting a bar over the door, with quality locks at both ends. The same bar can be moved to the inside, as added security for the door when you are there.
Windows are essential so that you can have light inside the shelter. But you’ll get more light from skylights or solar tubes than you will from standard windows. Ensure that they are covered by some bars so that nobody gets the idea of breaking in through the roof.
For that matter, any windows should have burglar bars installed over them to keep people from breaking into the shelter. It would also be a good idea to have steel shutters which can be put into place from the inside, in the case of a firefight.
Plumbing, the Big Challenge
The biggest problem for most people is putting plumbing into their shelter. Before starting, you’ll need to make some decisions about what exactly you want. Putting an outhouse is much easier than setting up indoor plumbing and requires less water. You don’t save yourself digging by putting in indoor plumbing either, as you’ll have to have some septic tank and leech field to go with it.
Properly built, preferably out of cinder block, the outhouse can also serve as a bathing room, allowing your family to take sponge baths from a bucket. While that may not be as satisfying as a nice hot shower, you’re probably going to have to conserve water.
Keeping your water usage outdoors will make things much easier, although not as pleasant as a modern camper. If you decide to put in indoor plumbing, I’d recommend taking some time to look at how it is done in those campers. The systems used in them are designed for minimal water usage, making them more or less ideal for a survival retreat.
Finishing Out the Shelter
Whatever you do, I’d highly recommend insulating the container’s walls and roof. This will help keep in the heat in the wintertime and keep out the heat in the summer. You could use either Styrofoam panel insulation or spray in. The Styrofoam will be cheaper, but it’s easier to ensure no areas are missed with the spray in.
Depending on the size of your container(s) and how many people will be staying in it, you should probably break it up into rooms. Privacy is going to be a big issue, especially for married couples. You’ll also want a separate storage room, perhaps at the end of the container.
One possibility is to lay out a 40′ container so that the door end is the storage room. Then cut the rest into three basic areas: two bedrooms and living space between them. One bedroom can be for mom and dad, while the other has bunks installed for the kids. The main entry door would be installed in the living area, heading out to the patio area.
Whatever you do, remember that this isn’t your only survival project. You should be able to build a reasonably nice shelter for under $5,000, especially if you keep your eyes open for sales and/or used material you can get for free. But it’s also easy to spend as much as $50,000 fixing up a container home if you’re not careful. Make yourself a plan and stick with it as much as possible so that your family’s survival shelter will meet your needs without becoming overly burdensome.
rod Clark | March 9, 2021
In Magnetawan, ON, Canada, someone built a multi-storey apartment bldg out of 40 ft shippingcontainers. Its a least 3-4 stories, im not sure as its 4 yr since i have been thru the south end of town.
Karen Clemons | March 9, 2021
My daughter’s half brother was instantly killed by a railroad container when the door came off as he was opening it.
Be very careful when choosing.
Dale | March 9, 2021
There is another possibility for using shipping containers that you failed to mention. What about placing two or three 40′ containers next to each other, side-by-side? The containers can be welded or bolted together and you can cut doors in the inner walls of the containers to join them together, thereby creating one, large, single structure. Place the containers so that their doors are facing in opposite directions to give you a “front” and a “back” door. Another suggestion is to use a composting toilet instead of building an outhouse. Composting toilets are self-contained and do not require a water supply or plumbing. You can wall off a corner of one of the containers and add a door in order to create a “bathroom” for the toilet. Be sure to cut a vent in the roof to get rid of the smell. Creating an indoor toilet in this way negates the necessity of going outside to relieve yourself, especially in the middle of the night or during a raging snowstorm. And the odorless waste from the toilet once it has composted and broken down, is an ideal fertilizer for your survival garden.
William Halford | September 20, 2021
Those are good ideas. The only problem I see with the roof vent to get rid of the smell is that without a fresh air vent to allow air in to replace the smelly air, it won’t work well. Considering how airtight shipping container are, a fresh air vent is a must.
Frank corl | March 9, 2021
“I’m not convinced that bunkers are a good idea for prepping anyway.”
I’ll have to disagree with you on that one Bill
If a roving band of looters comes upon your retreat, they will shoot you through the walls. You have no place to go locked in a box.
If you had a cabin for a retreat or even a regular home, you would get burned out and still not have any ballistic protection.
The safest place to be when and if they come calling is underground. Anyone could wait a week underground with the proper supplies.
Most wont wait for you to come out. Hunger will make them move on. There will probably be easier prey somewhere else.
Not to say they wont come back at some point, but you will fair much better underground
William Halford | September 20, 2021
Without an air supply inlet, which would also require an exhaust to allow air to enter a sealed container, that won’t work. Even with an air supply, they may be able to sabotage, poison, or pollute the air supply if they find it. And anyone inside would have to take extra steps to be able to get out to defend against an attack against the air supply, or a standoff lasting longer than supplies would last. Being able to see out to get an idea of how many and how well armed they are would be more difficult. Game cameras could be used, but getting game camera signals through the walls of the underground steel container would be more difficult, as an outside antenna would be required, and the intruders could find an antenna, and destroy it. The best way would be to have one or more tunnels to get out and away at a distance, but that’s even more work and materials required. Tunnels would easily flood in a place where groundwater is too close to the surface, such as near swamps, lakes, etc. And it would be hard to keep tunnels from collapsing in soils that don’t give support, such as the sandy areas of Florida.
Frank Corl | September 20, 2021
First off, No one in their right mind builds a bunker with 2 pipes sticking out of the ground. that’s a dead give-away.
You can run your intake 10 or 20 feet away from the bunker. Have it run 10 feet up the side of a tree and paint it to match the tree, or you can run a pipe just to the surface, surround it by large rocks that cant easily be moved so it conceals your pipe. Unless you helped build that shelter, you won’t know whats there.
There are many different options for running your intake and exhaust pipes.
That brings up another thought, you must have an intake and an exhaust pipe. When I was a kid I was goofing around in my pool, and I used the vacuum hose to try to breath underwater. I couldn’t figure out why I had to stop. Breathing in and out into the pipe doesn’t expel the CO2. You end up breathing in the air you just expelled. You need to breath in from the hose than exhale into the water
William Halford | December 17, 2021
I never said anything about having vent pipes that are visible. I only said that and air supply inlet and an exhaust is needed. The need to hide them is a given.
John Dressler | September 20, 2021
Weld some 4X8 3/8″ thick steel plate to the inside of the container and you could ward off any attack above ground.
anonymous | March 10, 2021
We own a small 10′ x 10′ x 8′ container on a rural property to store our maintenance equipment. Keeps the tools out of the elements and deter their theft if found. We installed a caliche base pad, then placed 8″ x 8″ railroad creosote coated timber for the unit to sit on. Keeps it off grade so rust does not occur from sitting water.
We built a ‘roof panel’ of laminated steel secured to 2 x 4 lumber, then secured these to old tires. This was then placed on top of the container roof. Air space to keep interior cooler and prevent water from building up and starting rust. You can also store materials in that cavity but be advised this space may attract pests if nearby foilage allows them to climb there. Two of these units with a ‘dog trot’ porch between them would be nice.
The unit was $600 about six years ago – we consider it well worth the cost. We also erected an aluminum carport (20′ x 20′) as a shelter from sun and rain, and installed an elevated wood platform for a pre-installed sleep platform. Bug net keeps out flying insect pests. It works great in the buggy south.
Alan Macdonald | December 17, 2021
Must look like hell to the Clampetts next door.
Dale | March 10, 2021
I disagree, Frank. Bill is right. Bunkers are a bad idea. You’re trapped underground with one way out, unless you’re going to dig a series of tunnels, leading off in every direction to provide escape. And, attackers don’t have to wait you out. You need air to breathe, right? All they have to do is locate your air vent(s) and plug it up. You’re either going to suffocate or come running out, and, then, they have you. If they don’t want to wait a few hours for you to run out of air, they can build a fire around your vent and smoke you out. A bunker is just a grave you dug for yourself. If you’re above ground, at least you have the possibility of escaping or fighting your way out. And, what’s stopping you from buying some sheets of plate steel to bolt or weld to the walls of the container to armor it? You’d be better off to have an above-ground shelter and put a trap door in the floor with an emergency escape tunnel than you would be to be trapped in an underground bunker. Just my opinion.
Frank Corl | September 20, 2021
That was going to be my reply Poor Lazlo. Thank you
You always need 2 exits.
A properly built bunker should be placed so that a second exit exists away from the bunker and comes out behind a set of trees or rocks for example.
It could be a culvert pipe that you may have to crawl through, but it will get you out in case of emergency.
I find it kind of odd that most people just assume you dig a hole in the ground and hide in it. Cmon guys.
Poor Lazlo | March 10, 2021
Dale, the best bunker is one that no one knows about. You are right You NEED Two entrances or it becomes a death trap. You need a second, hidden entrance so you can kill those who are trying to rob you from the second position. You need a way to deliver Intel to you as well so that you know they’re coming and can take steps.
I am not military but I like how they think, Two is one, one is none. Meaning have a spare, and a spare for the spare.
I would have game cameras that I can view from inside in real time with motion activation alerts.
As far as shipping containers go why not, if the value decision is shelter from elements over defensive stance. But why not add a double stack of sandbags loaded with rock and gravel placed four feet away from the container, allowing you to move from firing position to firing position.
Illini Warrior | March 12, 2021
thing to remember about these types of “alternative” housing – it’s no-go within the financial & banking world – if you put allll kinds of pocket financed $$$ and DIY labor into a big complex >>> you’ll need to find a buyer down the road with the cash to buy at your price $$$ – no mortgages or financing – an appraisal might just find the CONEX build to be a value deficit for the property value ….
C is the name I choose | December 17, 2021
I agree with Poor Lazlo, ” …the best bunker is one that no one knows about.” As far as burying a shipping container, I don’t see a problem, as long as you consider it just the core of your underground “build’. Weld steel support “I” beams (like the ones in you basement) along the edges from strong point corner to strong point corner. Then weld (or bolt) as many cross supports as necessary strengthen the roof. Do this along the sides too, if necessary. Coat the whole thing with additional water proofing to provide more rust protection, Pour a cement footing at the bottom of your hole and put the container in it. Culvert pipes can be added for your entrance and escape tunnels. Alternatively, you could do what the folks who built the Ark II Project in Canada did with all of those buses they buried… shore up the inside of the container temporarily with wood beams and then pour rebar-reinforced concrete over the whole thing. The reinforced shipping container acts as the inner wall of your concrete forms until the concrete sets. Then remove the beams, back-fill and your done. Vent pipes and your entrance and exit points can be concealed to look like natural objects by using rocks (real or artificial) or plants. Be careful using artificial plants since they won’t change with the seasons and could become a give away. Don’t forget to muffle your vents, since sound can give you away just as much as appearance. As an emergency back-up, have CO2 absorbers and oxygen supplies in your bunker. With proper management, a bunker, even with multiple people in it, could stay hermetically sealed for days or even weeks. Submarines do it all of the time. The ground below six feet, stabilizes at about 56 degrees Fahrenheit (think of the inside of a cave.) all year round. To siphon off excess heat in you bunker, you might consider putting in an underground radiator (heat-sink) system of pipes with a simple fan run heat exchanger to cool things down. Also, a pump and water well that is accessed from inside the bunker would add to you ability to stay inside and concealed. Any coming or goings outside would increase you chances of being detected by hostile observers. Outside sensors and monitors are vital to showing you what kind of traffic is passing above and when it would be safe to come out.
William G Jones | March 12, 2022
So, where are these 2000 dollar shipping containers? I found them to be well over 5000 for a wrecked one