I would like to shed light on the convenience, structural soundness, and affordability of ISO shipping containers [commonly calles CONEXes] as potential add-ons, storage, or primary structure for your retreat or year-round compound. As an individual of efficiency, I am writing this article with the intent of casting out some research I have done on these containers; what they are capable of in a capacity form, and their versatility as a livable space. I hope many find this informative in its purist sense.
Availability: Due to the nature of our global economy, especially in reference to the U.S. and its desire to import more than it exports to the Asia Pacific, domestic shipping yards are in excess supply of such containers. Because shipping containers are simply boxes, when empty they exercise little function and merely take up space. Shipping containers, especially when being shipped from China, are more expensive to return empty then if they were to be recycled on domestic soil or reused in other applications. But before scrapping them, many companies attempt to sell them in their intended form to the public. In a sense, these containers are like a pound puppy that needs to be saved…and should be. A quick search via the Internet will show you large numbers of containers in various conditions from here and there but because the shipping industry does not stop at sea ports, any major city even inland will have a healthy supply to choose from. For a ratty container (20’) expect to pay between $800 and $1,200. This would be in less than ideal condition but still a good option for say material storage on your retreat property. Typically this means that the cube may no longer be perfectly cube-like say a slight dent or impression on one or more corner or has more than just surface rust on its exterior. Always check the double doors and see how well they close, whether with ease or with some finesse adjust your offer accordingly. The next level of quality will come in at a price of around $1,400-$1,800, again for a typical 20’ standard container. This is the price range that should exemplify a structural soundness that will be suitable to live in with certain modifications. The seaworthy paint should still cover 95+% of the container and it should be structurally true. Remember what these containers where built for. They hauled 50,000 pounds of goods through open-ocean, many times during storms. They should be watertight. Ask all of these questions to the seller at the very minimum so that they know you know what you are looking for. Hard for one to prove water tightness but you can go based on the sellers reaction and your best judgment from this article and further research. Be a smart shopper now, this may become your last line of defense. Finally, you can buy a brand new shipping container from companies that specialize in building them. Here you’ll find different sizes with different options like the garage style door or pre-insulated units for refrigeration. Expect to pay around +-$5,000 for a new box.
Dimensions: Two or three major size potions will be found most commonly although other odd sizes due exist. These all have corrugated sidewalls.
20’ standard shipping containers
(Interior dimensions) 19’ 4” long, 7’8” wide, 7’10” tall.
Tare Weight 4.900 lbs
Total cargo capacity 45,000 pounds
40’ standard shipping container
(Interior dimensions) 39’5” long, 7’8” wide, 7’10” tall
Tare weight 8.100 pounds
Cargo capacity 59,000 pounds
40’ High cube standard shipping container
(Interior dimensions) 39’5” long, 7’8” wide 8’10” tall
Tare weight 8.700 pounds
Max cargo capacity 58,000 pounds
Some general info that applies to all standard containers.
*Seaworthy steel alloy with saltwater and air resistant exterior paint
*Class D rating for storage of explosives (with this rating a high tolerance to fire)
*Pest resistant (many have a wooden floor that has been treated for pest resistance. This should be removed and disposed of properly.)
* Water tight but not water proof.
*Stackable to 7 high at full load (yes one will hold upwards of 200,000 pounds stacked on top). Note that cutting into the corrugated sides will lessen the overall strength. Reinforcing whenever taking away steel is common sense I’d hope.
*Insulated units do exist although interior dimensions will likely be even tighter. R-value 15-20?
[JWR Adds: Containers made of low carbon Cor-Ten steel (aka "weathering" steel) usually bring a premium. They have the longest life. Be sure to inspect wood floors for any signs that toxic chemicals might have spilled from cargo. But keep in mind that the wood used in the floors of almost all CONEXes are deep-treated with some nasty insecticides and fungicides.]
Getting Started: My suggestion with using shipping containers as habitable structures starts with completely ruling out the use of the 40’ containers. This prevents one from absolutely paying a delivery fee and/or a crane rental to remove it from a semi trailer. That said I have put all of my focus into utilizing the 20’ containers (Finding a 20’ insulated container would be most ideal). Here’s why. First, if you own a full size truck, you can haul one of these things empty on your own, either with a trailer you have or from a friend. A twenty-foot flatbed, or car hauler with a winch is not too hard to come by. It will likely be loaded on your trailer at the yard if you buy directly from a shipping company so all you have to think about is sliding it off your trailer in place. My theory has always been to own the trailer I go to pick it up with and leave it on in my drive way until I build out the interior at my leisure. Then it’ll be ready to haul to sight. Depending on your neighborhood or city ordinances this may or may not be an option but I’ve always felt that if people have a 35 foot camper trailer parked on the street in front of their house why not a 20’ shipping container for a few months? Either way, look up this info before hand as well as your states DOT regulations. Second main reason I like the 20’ size is its weight. At just shy of 5,000 pounds add a 3,000-pound trailer, an ,8000 pound haul for most diesel pick-ups ain’t no thing. Lastly, due to the 20’ container weight and size, it is much easier to maneuver in mountain terrain by trailer as well as when off the trailer on site. If you start with an empty container on site, a clever hoist system, a winch, and a block and tackle set up opens up the door to many possibilities. I’ve read about a couple that actually hoisted a container on top of another in a piggy-back fashion with two tree trunks joined and reinforced in an a-frame configuration and a 12,000 pound winch and pulley. They hauled their’s by trailer to site with a Toyota T-100. (An early Tundra.) Be creative with this. Egyptians built the pyramids thousands of years ago! Enough said.
[JWR Adds: Because the secondary market demand for 20-foot CONEXes is stronger than that for 40-footers, they often sell for about the same price. Go figure.]
Now you need a friend to teach you how to weld. Get an oxy-acetylene torch set up. You’ll cut as much as you will weld when building with these. I’ve seen used setups in safe working condition with tanks for $300 bucks. If you’ve got a weighty wallet then grab a new or used generator/ welder for $1,500-4,000. Stick with the Lincoln or Miller brands. They are equally as good at the end of the day and it really comes down to the Ford or Chevy argument. Power options are gas, natural gas, or diesel and most of the units will run a continuous 7-10 kw. The gas-powered is the least expensive and the N.P. or Diesel are substantially more expensive but better in my opinion for an unstable world. The U.S. has plenty of N.P. and is responsible for much of the world’s diesel refinement, not to mention ones ability to potentially run bio-diesel or appropriated veggie oil. But in a grid-down pinch, a diesel will reign.
I’ve always felt that a retreat built in phases would be the most feasible simply because of the advantage to make time and monetary “payments” on it. After owning the land (which is certainly a big step), one can start with a small but functional 20’ container cabin they have built in the driveway and then hauled to site. Keeping it in your driveway assuming you live in a more urban environment keeps you from hauling material out to your site. Build out the plumbing and windows and other comforts. Again, if the company you purchase from has not already, be sure to remove the chemically treated wooden floor and dispose of properly. Thoroughly scrub out the interior of the container for safe measures. Round up with your weight estimates as not to overburden or risk accident while hauling the container i.e. hold off on the spray on concrete or stucco siding until at your site. For the time being, use a cistern on site for water or haul it in each time you visit until a well is dug or a spring is utilized on the property. Photovoltaic panels are good in combination with the aforementioned diesel powered welder/generator to get things off the ground. All depends on where you are. Inline hot water heaters are great for low use and tight spaces and can be run on propane. Build a shower toilet to conserve space. In other words your entire bathroom is water-tight and its foot print is essentially a big shower pan. Utilize RV and camper galley components that run on propane and could eventually be converted to run on methane that you could capture on site through livestock and human waste methane converters. Use a fold down bed or bunks to be space efficient.
Example Build-out: My ideal set-up would likely be two 20’ containers, one stacked atop the other. I’d pick a south-facing hillside and cut into it just as one would do if building a conventional home. Before placing the container in its little nest, I’d dig a root cellar into the cut in and fashion a hatch in the floor of the bottom of the container for access. Build a retaining wall around the cut in and possibly use a local clay or concrete to form a basin next to the root cellar to act as a cistern for water storage if a well is too pricey initially. For remote applications, I’d resist using a septic system and resort to an outbuilding away from the main house. [Some deleted, for health and safety concerns.]
After the cistern is sealed and the root cellar dug, place the first container into the dug out. Stack the second container on top to use as a living quarter. A hatch could be cut to the roof to make an observation post. On the south-facing downhill wall of the two containers, build a sloped glass room to act as a green house or a room to gain. Use old windows from someone replacing theirs or check all the Freecycle type sites and Craigslist for deals. This would create a little bubble that would extend the growing season as well as act as a passive solar heater for the house whereas building into the ground a bit would assist with cooling in hotter months via use of the ambient geothermal temperatures. Be sure there is good ventilation for airing out the cabin in the summer months. Use gray water from the shower and sink to feed your small garden. For insulation I would use a spray on insulation to fill in the negative spaces of the corrugated walls. Do this on both the inside and out covering the interior with sheetrock and the exterior with a stucco like material.
Warning: As a final and important note on building with shipping containers, never bury them without proper structural support. Shipping containers were designed to bear a vertical load [on the corners] and be stacked atop one another. They perform this task very well but they were not designed to take a load from the sides (laterally). Burying a container without proper support around its perimeter such as reinforced concrete, the construction of which should be handled by a licensed engineer, could result in collapse. Not something you want to deal with after society has collapsed. Please note I am neither an engineer nor a contractor and that most of my research has been conducted over the Internet. I am simply sharing some of my findings and offering suggestions. Most states require a general contractor for home construction and many states now require a certification for that so not anyone can build away.