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Concrete block vs shipping container bunker

95K views 97 replies 64 participants last post by  Inkognito 
#1 ·
Why is everyone so amazed by the shipping container bunker? I just do not understand it. A concrete block bunker is much better in my opinion for various reasons that I will outline.

A shipping container is an awkward size, a rectangle. If you only plan on having a 1 shipping container bunker, your size is seriously impacted once you add stairs going down into the bunker. If you are smart, you would probably add a ladder with a large hatch at the top to load and unload the bunker.

A 2 shipping container bunker does not benefit much from the added container, as it is still a narrow rectangle connected to another narrow rectangle by a door. Basically, an extra $1,500 - $2,000 for a bedroom.

The cost to benefit ratio just isn't there for me with a shipping container. After re-enforcements done and the time spent, I would be better off to build a concrete block bunker.

A 20 foot long x 8 foot high (just a perimeter wall for example) would use 12 blocks for the height and 15 blocks for the length. At $1.50 a block that is $270 for that sized wall. Do a square like that, just a little over a grand.

Add the price for filling the slots with concrete and pouring a foundation, you will come out a little more expensive than a shipping container bunker. If you are lazy or not mechanically inclined, not doing the work yourself will cost you a boatload more than a shipping container bunker.

With a concrete block bunker, you can build it exactly how you like. 1 big room, 2 small rooms, a room in the middle, you name it. A good idea would be to have the stairs to the bunker come down outside of the perimeter, take a turn, and follow a 6 foot hallway to the entrance door. Have the hallway sunken 4 feet below the rest of the structure, and the structure wrapped around the hallway on 3 sides. One could add gunports to hallway, allow you to shoot into the hallway from ABOVE and easily eliminate intruders.

It just sickens me watching doomsday bunkers and seeing someone spend $75,000 on a crappy re-enforced shipping container. Does anybody here have a concrete block bunker / shelter that they would like to share or discuss?
 
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#3 ·
No matter how well you coat the metal shipping container, with it being in continuous contact with the damp soil it will begin to rust and eventually will fail.

The roof and sides of the container are not designed to be load bearing. They can be stacked because the four corners are load bearing pillars. Given enough soil on the top of the container and/or the added weight of a vehicle driving over it, the container may collapse. Add in the weakening of the metal over time by corrosion and the collapse becomes even more likely.

But I am not a structural engineer nor did I stay in a holiday inn express last night.
 
#4 ·
Well, I have direct experience with 20 and 40 TEU containers. Most of the ones I see for sale have been disqualified from the shipping industry for one reason or another. The number one reason is because of corrosion. They spend thier entire service life on a ship or on a pier. By the time they get to the secondary market they are pretty beat, and they only sell for a few thousand dollars. They do not even cost 75K new!
I will say though, they are quick to install, easy to move to the location, and easy to outfit, all you need is a stud welder and you are in business.
They are damn small though, and will continue to rust.
 
#5 ·
Concrete blocks is what I had in mind, a lot cheaper in my opinion than those steel container bunkers. Now, I will admit I have no experience at this whatsoever, but it's what I have thought about for years.

Now, I did make a doghouse one time back when I was a kid with blocks. More throw together than anything. If I remember right it was like 3 blocks high and about 5 blocks longs in the back with just a piece of plywood for the roof. No sand, concrete or anything in the holes. My dog sure seemed to appreciate it though.

I have had plans made up for a 25' x 30' x 7' high, but I want 3 blocks thick surounding. I'm still deciding if I want sand to fill them up or pour concrete inside but I hope that would make for better cooling efficiency and harder to shoot through if someone was shooting at me and fire proof. The only thing i'm having problems is with the roof. Like I said I have no experience so not really sure how to use blocks for the roof.

I think if my figures are somwhere in the running I think that will cost around 5000 give or take.
 
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#8 ·
Buried bunker?

No.

Heavy duty storage container that you can drop somewhere and leave it alone?

Sure.

I would coat it with something first, and I would make sure the doors are in good shape and the rest of it doesn't leak.

Personally, I would rather spend a little more money and get multiple mil-surplus comms shelters. Stronger, insulated and mean for human habitation.
 
#12 ·
Eight inch reinforced concrete roof. Check out a storm drainage bow culvert. Those things are usually six to eight feet wide per barrel and up to eight feet high. I have seen them with up to three barrells wide. They can handle a semi with no problem. Just make sure you seal them before you backfill.
 
#14 ·
I would definitely go with concrete instead of shipping container. A quality bunker is very expensive.
If you are talking about a 20'X20' bunker, you probably would need load bearing walls in the middle. There would need to be a very good foundation under each wall.
You would probably need 12" block with vertical and horizonal rebar.
If planning on putting dirt on the roof, the top will require a lot of steel in it.
You might want to price pre-stressed double T's. You set it on the walls and weld it in place.
People think building a bunker is built like a basement, it takes much more strengh with the cement roof and dirt covering.
I could see a 20'X20' bunker costing $50,000 easy.
 
#39 ·
People think building a bunker is built like a basement, it takes much more strengh with the cement roof and dirt covering.
I'm a bit skeptical. I've seen a couple houses built with a basement beneath the garage - 2 and 3-car garages in fact.

You have regular-thickness reinforced walls, precast concrete hollow-core slabs for a deck with a poured slab on top of it. It don't move.

I realize that dirt will be a much heavier dead load than a couple of cars, but it seems like a problem that could be easily overcome with proper engineering/design.
 
#15 ·
Have a great supply of 12" used cement blocks and may use them instead of my old school bus. Can sell the bus for scrap for about $1500. That will go a long way towards materials for the block structure.
ETA: a 4" roof properly supported will be ample to handle most any load.
 
#21 ·
In my experience a shipping container can make a very effective buried "bunker". Given the physical properties they do not match the structural integrity or ease of a custom floorplan of most modern concrete structures, but are not an option one should so easily overlook. Though I am not an expert authority on structural engineering some sense, research, and the experience of building four underground "container" structures has given me some insight.
The shipping container approach offers a convenience factor very difficult to match, which is a key factor in most peoples decision to undertake such a project. The ability to simply "drop in" a complete room is an attractive idea.
On the topic of rust/corrosion, very few containers are unserviceable. Most only require a quick buff of rust spots as initial prep, Though I recommend a complete removal of all surface material, I.e. paint, rust, corrosion. (Those friends [4], I built shelters for and I could completely strip a single container in a single day with wire wheel equipped angle grinders. [Outside surface only]). After which we would coat in primer/sealer, then paint with corrosion resistant marine enamel. The entire process of which took about a week with overnight cure time between coats. This has reliably been shown to prevent "rust-through" in our setups. The oldest of which was completed in June of 2005. By "rust-through" I mean any spots where the metal rusted all the way through as to leave a hole. Most shipping containers are designed to handle the extremely corrosive salt-air and water/rain of open sea, and are decomissioned far before thier serviceable lifespan. So though they may look rough, they still have a good many years of life if properly reconditioned.
The ability to support vehicles, is a common concern, (though it seems this isn't often an issue as they are most commonly placed in a location where they will not likely be driven over) And in our experience an internal frame of 4x4 studs, and 4x6 beams, placed perpendicular to the long walls, spanning the same area as the doors if looked in on from the end, (looks like old mineshaft supports...) every four feet (five total in a 20' container ) seems to be enough to support most common passenger vehicles. Though I would like to highly recommend placing sealed and painted (to reduce significant rot) 3/4 inch plywood on the top of the container exterior before covering as we did, With a frame of 2x4 joists on 16 inch centers. 3/4inch pressure treated plywood can support several hundred pounds of pressure in the spaces between the joists and pressure is greatly reduced and spread out after being covered with soil so less would likely be necessary (called displacement), but this is the system we used so it is the only method I feel comfortable describing.
Another common concern is available floor space. The average 20' container seems to be about 8 feet wide, and of course 20' long. Which gives roughly, 160 sq.ft. of useable space. Remember... this is an emergency shelter/storeroom, comfort is a secondary, at best, concern. After the ability to keep your person/s and/or stored items safe of course. If this is not enough simply double up. This can be accomplished by stacking units, placing them side-by-side, end-to-end, in an "L" pattern, or in different locations with some form of adjoinment (such as concrete culvert ).
Also containers make a great "core" for block bunkers, adding a steel barrier in addition to concrete and And soil to protect against any number of possible hazards. Achievable by pouring your foundation, placing your container, and building block walls directly against the perimeter walls of the container, adding your ceiling as you would any standard buried block room. Or by using the internal supports described above you would be able to support a poured concrete ceiling, directly onto the top of the container.
This has simply been an account of my experience with the shipping container bunker building process and in no way should be used as a definite guide. The most important thing to consider is your individual needs. Including but not limited to size needed, level of protection desired, budget, time constraints, and permanence desired. Remember, a shipping container is much easier to dig up and transport if needed, such as if you decide to move. This is not an anti-concrete rant of course, but an attempt to keep containers from being dismissed so easily. Hope this offers a little insight to your options.
 
#22 ·
In my experience a shipping container can make a very effective buried "bunker". Given the physical properties they do not match the structural integrity or ease of a custom floorplan of most modern concrete structures, but are not an option one should so easily overlook. Though I am not an expert authority on structural engineering some sense, research, and the experience of building four underground "container" structures has given me some insight.
The shipping container approach offers a convenience factor very difficult to match, which is a key factor in most peoples decision to undertake such a project. The ability to simply "drop in" a complete room is an attractive idea.
On the topic of rust/corrosion, very few containers are unserviceable. Most only require a quick buff of rust spots as initial prep, Though I recommend a complete removal of all surface material, I.e. paint, rust, corrosion. (Those friends [4], I built shelters for and I could completely strip a single container in a single day with wire wheel equipped angle grinders. [Outside surface only]). After which we would coat in primer/sealer, then paint with corrosion resistant marine enamel. The entire process of which took about a week with overnight cure time between coats. This has reliably been shown to prevent "rust-through" in our setups. The oldest of which was completed in June of 2005. By "rust-through" I mean any spots where the metal rusted all the way through as to leave a hole. Most shipping containers are designed to handle the extremely corrosive salt-air and water/rain of open sea, and are decomissioned far before thier serviceable lifespan. So though they may look rough, they still have a good many years of life if properly reconditioned.
The ability to support vehicles, is a common concern, (though it seems this isn't often an issue as they are most commonly placed in a location where they will not likely be driven over) And in our experience an internal frame of 4x4 studs, and 4x6 beams, placed perpendicular to the long walls, spanning the same area as the doors if looked in on from the end, (looks like old mineshaft supports...) every four feet (five total in a 20' container ) seems to be enough to support most common passenger vehicles. Though I would like to highly recommend placing sealed and painted (to reduce significant rot) 3/4 inch plywood on the top of the container exterior before covering as we did, With a frame of 2x4 joists on 16 inch centers. 3/4inch pressure treated plywood can support several hundred pounds of pressure in the spaces between the joists and pressure is greatly reduced and spread out after being covered with soil so less would likely be necessary (called displacement), but this is the system we used so it is the only method I feel comfortable describing.
Another common concern is available floor space. The average 20' container seems to be about 8 feet wide, and of course 20' long. Which gives roughly, 160 sq.ft. of useable space. Remember... this is an emergency shelter/storeroom, comfort is a secondary, at best, concern. After the ability to keep your person/s and/or stored items safe of course. If this is not enough simply double up. This can be accomplished by stacking units, placing them side-by-side, end-to-end, in an "L" pattern, or in different locations with some form of adjoinment (such as concrete culvert ).
Also containers make a great "core" for block bunkers, adding a steel barrier in addition to concrete and And soil to protect against any number of possible hazards. Achievable by pouring your foundation, placing your container, and building block walls directly against the perimeter walls of the container, adding your ceiling as you would any standard buried block room. Or by using the internal supports described above you would be able to support a poured concrete ceiling, directly onto the top of the container.
This has simply been an account of my experience with the shipping container bunker building process and in no way should be used as a definite guide. The most important thing to consider is your individual needs. Including but not limited to size needed, level of protection desired, budget, time constraints, and permanence desired. Remember, a shipping container is much easier to dig up and transport if needed, such as if you decide to move. This is not an anti-concrete rant of course, but an attempt to keep containers from being dismissed so easily. Hope this offers a little insight to your options.
And that's where you should've stopped. :eek:
 
#25 ·
Was it reinforced in any way? A cylinder on its side is one of the weakest geometrical shapes. Or was it the big square type? Curious as to where its located, ground freeze/thaw can play havoc on concrete structures. A link would be appreciated, im also curious as to the price, wall thickness, length, LOL lots of things really. I've often thought of using multiple containers with concrete culvert "hallways". Or possibly a section placed at a verticle angle to use as a stairwell. Though since moving to FL recently I've noticed I've only got about 6 feet of depth before striking water so another buried project is off the books at the moment. :(
 
#26 ·
Seems to me that gabions surrounding the container would help tremendously with soil pressure from the sides. And the floor actually will support vehicles (they ship cars in them too). The wood portion of the floor is treated with pesticides. Why not treat the roof and sides, take out the wood flooring, turn it upside down, build the gabions in the hole, put in any additional supports for your comfort, bury it upside down and attach plywood or whatever for a ceiling/roof, build planter boxes out of the old pesticide treated floor and fill them with dirt and put ontop of the steel rafters that were previously under the container. Or pour concrete over the rafters and have a driveway, or whatever. The strength is in the floor AND on the corner. You could even bury one container and mount a 2nd container on top of the first to use as a shed or fill the 2nd container with dirt. MANY options prevail with how to use them. For myself though, I am trying to figure out how to form and build my own concrete culvert as I feel they would be more permanent because of the eventual rusting issue.
 
#30 ·
TRM thanks for the info, was always curious about their design, given how thin some of them appear, they don't look as though they'd have much room for any internal reinforcing structure which kinda baffled me.

Almightyoz, remembering as far back as elementery school... triangles are of the strongest basic geometric shape and horizontal cylinders of the weakest. That is the information I've always been provided. But all the engineers, teachers, contractors, and architects I've spoke to may have been sharing a multi-decade mass delusion. Their ability to remain straight as if suspended doesn't really play a part here. Unless one was to hang it from its center or ends alone... but that would just be silly. As for my age, I was born in 87, badic math and the ability to count the candles on my cake every year makes me 25. The first having been completed at 18. How did you even get 21 anyway? Besides, there are MIT grads barely out of their 20s. So your point is mute.

Survivalguy72 though they were an amazing g engineering feat for their time, most were not meant to handle large amounts of weight outside that of their structural design and that of its transferred material. Lol I doubt anyone was driving across them in a loaded down suburban.
 
#33 ·
TRM thanks for the info, was always curious about their design, given how thin some of them appear, they don't look as though they'd have much room for any internal reinforcing structure which kinda baffled me.
Usually the pipe structure reinforcement is welded steel mesh; some smaller concrete pipes may be unreinforced (up to 30 inches dia, max). On the large water projects out here in the desert, we used a bell and spigot design with steel rings welded together.

You had to place your CLSM (controlled low strength material, think 3 sack slurry) as very specific locations; otherwise, you would float the pipe. It would break at the rings.

Typical wall thickness ranged from 6 inches to 14 inches depending on the type and pressure of the pipe. They're stout, and massively expensive.

We handled those pipes with cranes; I've seen them float a 144 ID RCP across Lake Mead. Wish I could find the pictures, you can't believe it until you see it.

Typical cover on a pipe of that size was 15 feet +; the authority wanted it way below everything else. Traffic wasn't a problem, but very heavy equipment (think massive crawler cranes, like the Manitowoc 18000) may require special protections.
 
#31 ·
As for the submarine nonsense, they have several internal support structures, ribs, and bulkheads, spanning the width of the entire vessel in multiple places. Where as concrete culverts do not... so that doesn't really apply here either. Also in regards to the arch, the "average Joe" wont typically have the money or technical knowledge to create a a complex shape of that sort. Though adding that shape in an attempt to discredit me was rather pointless anyway. Because though it may resemble, part, of a cylinder, it is not a cylinder, but its own individual shape. Which i made no initial comment on. So again... your comment was pointless. Speaking of trolls...
 
#35 ·
I am planning a concrete "cellar" to put in under the backyard garage building I am hoping to construct this summer.

I would only go with a shipping container as an external, above ground storage means.
 
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#36 ·
The absolute best load bearing shape in the world is and has always been an arch. From ancient rome on through to today. Ideally I would LOVE to have a nice brick arched structure underground a lot like a lot of subway tunnels/terminals.



I believe an old school bus or six would be a better option than a shipping container, as they are designed to completely roll over and not collapse.

What I want to do is bury a series of 12 foot reinforced concrete storm drains, they are an incredible option in my opinion. Not as "homey" as a square unit but durable. You could even go as far as filling it before you completely bury it and have only a manhole access, sewer style. It would feel like living on a submarine, but humans are adaptable.

 
#38 ·
The absolute best load bearing shape in the world is and has always been an arch. From ancient rome on through to today. Ideally I would LOVE to have a nice brick arched structure underground a lot like a lot of subway tunnels/terminals.

That's a catalan arch, which I'm probably going to use on my bunker if/when I get to build one. You use three layers of tile (you can make them yourself with a tile-press machine, you don't even have to bother with firing them), and the roof structure is almost as strong as concrete and rebar, at a fraction of the price, and something you can build yourself.

I did some research on earth bermed structures and bullet penetration test results (most of the buildings in certain areas in Afghanistan and Iraq are built with earth, there's some VERY interesting literature out there), and for me the gold standard would be

a) outer layer of a 24-36 inch rammed earth wall
b) middle layer of sand bags, tamped, compressed, and tied with barbed wire a la earthbag housing, with a place on the roof where I can easily pipe a LOT of water
c)inner layer of hand made earth bricks, placed lengthwise.

All of that can go on a fairly deep and wide rubble trench foundation.

At that point, there isn't anything short of direct mortar fire that's getting through that wall, and even then... it'd really depend on the mortar. Multiple strikes with a .50 caliber at a perfect range and perfect angle won't penetrate (as many as 50 in the same location). The first layer of rammed earth pulls off the jackets. The sand deforms the slugs. You can't get an arrow through it. You can't get jack through the wall. All of the building materials are literally dirt cheap (I can get sand in my area for $24 a ton, same with decent clay for making bricks with), the technology is simple, and it's thick enough to give you an incredible thermal effect. On hot, dry days you can dampen the sand between the layers and get whole-building air conditioning. There's enough mass there to give you a nice thermal flywheel effect. There's almost NO maintenence.

If you go the cheap route to make this building, you'll need less than a thousand dollars in tools. You can spend more and a gas powered tamper might be well worth your while to get, but you CAN do it with a few hand tools.

There's a lot of nifty reasons to do something like this. The downside is that it's a truly, bogglingly, amazing gianantic amount of work. Like, holy cow, a lot of work.

My plan is to get some 19 year old rainbow hippy kids and feed them over the winters while they build it for me. :D

I've also looked at earth bags and tire bales, but in Texas I'd have to kiss some government butt to get permission to do tire bale construction. On the other hand, a 5 foot thick layer of compressed tires is ALSO not going to let any bullets get through, no way no how, and if done right you can get paid to put up a tire bale wall.
 
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