This will probably be the most controversial post I make on this blog. I’m actually going to make the case AGAINST building with shipping containers. Over the past several years I have corresponded with a fair number of people wanting to build a home or cabin out of shipping containers and, believe it or not, many times I try to talk them out of it. It’s not that I regret what I’ve done (I don’t), it’s just that I only see a limited number of reasons to build with shipping containers.

There are only two good reasons, in my mind, to build with shipping containers. The first is for security, which was my sole reason for embarking on this project. The second is to make an “architectural statement”. At one time I thought there was a third, such as a situation where you could get containers for free, but now that I’ve run the numbers that scenario doesn’t pan out. I’m sure you might find other unique situations, such as wanting to build a cat 5 hurricane-proof structure, but in most cases it doesn’t make economic or practical sense.

You may have noticed that I didn’t mention the environment. The vast majority of cabin builders are more concerned with practicality and cost than green construction. It’s not that they don’t care about the environment, it’s just that they don’t want to spend more than they have to for the latest, sometimes dubious, green building technology. I also don’t see re-purposing containers as a great environmental panacea in most circumstances. Shipping containers are best used for what they were originally designed for – the shipping and storage of goods. By the time a container is no longer able to do that effectively, I’m not sure I’d want to build with it anyway. If you feel the need to reduce your environmental impact, build small and insulate well.

I know I’m going to get comments like “I can build a container cabin for $20/sq foot” or “your cabin is overbuilt and too expensive”. Both of these comments are true if you don’t mind living in a shack more appropriate for a third world refugee camp. I’ve seen shipping container “cabins” with no insulation, the wrong insulation, raw plywood flooring, no wallboard or paneling, no roof, no foundation, and no utilities. If all you want is a metal box lying on the ground then yes, shipping container construction can be both easy and cheap. To be fair, those in warmer climates can get away with much more than I can in the northern US, so let’s just consider this discussion applicable to temperate climates only.

Pros

1. Security. In my opinion, this is the greatest strength (no pun intended) of shipping container construction. I can’t think of an easier way to incorporate passive security in an above ground structure. The only other reasonable option would be a concrete building with a similar style metal door.

I’m under no illusion that I’ve built some kind of Fort Knox. There are several relatively easy ways to break into my cabin; it’s just that it will take a far greater level of effort to do so than compared to a conventional structure. My old cabin could be broken into in approximately 10 seconds with nothing more than the boot on some miscreant’s foot. This one would take about 10-20 minutes with a cutting torch or the right power tools. If someone is going to go to that level of effort, they’re going to be disappointed by what they don’t find inside.

2. Architecture. I’m only going to touch on this briefly. I have seen some absolutely unique and beautiful shipping container cabins, although some of the most unique among them would be difficult to live in. I have nothing against creating a structure for the sake of art, but that is beyond the scope of this usually practical blog. For those who build for the sake of art, cost and practicality is seldom a concern.

Cons

1. Cost. One of the more common misconceptions prospective builders have is that building with shipping containers will be less expensive. I’m here to tell you it’s not, especially if you want something that lives like a real house or cabin. I’ll compare the construction costs of three similar cabins; my container cabin, my container cabin if it had been built with used containers and a pier foundation, and a cabin built using conventional materials.

My 480 sq ft (external dimensions) shipping container cabin, fully furnished, cost nearly $36,000 ($75/sq ft) to build. The only construction extravagances in this build, at least to me, were the new (one trip) shipping containers and a purposefully overbuilt foundation. The costs also included several thousand dollars spent on contractors, but I would have had to spend that with a conventionally built cabin also – I’m trying the best I can to compare apples to apples between the three builds.

Next is the scenario of building the same cabin with used shipping containers and a pier foundation. There’s really not much difference between the price of new (one trip) and quality used containers. I can purchase a new 20′ container right now for $2,650. The lowest priced used containers that I’d be comfortable building with are running about $1,500. I might also save a few hundred dollars on shipping since I could probably get them locally, but overall I’m only saving about $3,900 with the used containers.

If your soil is appropriate for concrete piers, you can definitely save some money compared to my foundation. In my location, I have had such ongoing trouble with concrete and wooden piers heaving that I would never trust them for a permanent structure. Another advantage to piers is that they can be a do-it-yourself proposition, if you are skilled enough, which could save you even more. The final cost of my cabin with used containers and piers would be about $29,000 ($60/sq ft).

I’ll also include the scenario of using free shipping containers with this build. Even if you were fortunate enough to find three shipping containers for free, all of the other associated costs such as shipping, crane rental, welding, and reinforcement, would still be required. Due to this, the free shipping container scenario would still cost about $24,500 ($51/sq ft).

Now we get to the interesting comparison with conventional construction. Please keep in mind that some of my numbers might look strange, but I was trying to keep the cost categories as similar as possible to the container cabins. For example, a conventional construction shell would typically include the roof, but I had those costs separated out with my container builds.

The big savings for this cabin were in the shell (walls) and insulation. Building a shell with 2×4’s, OSB, and siding is so easy and inexpensive, at least in my part of the world, it’s hard for anything else to compete. You also have to consider that a shipping container shell still needs to be framed inside for attaching wallboard or paneling. This essentially turns the shipping container into very expensive siding if you don’t need its security.

For insulation I priced it with fiberglass batts for the walls (R13) and ceiling (R25), and extruded polystyrene foam panels for the slab. I wish there was another, more cost effective option for insulating shipping containers besides spray foam, but there really isn’t. The total cost for a conventional material version of my cabin would only be about $20,500 ($42/sq ft). The bottom line is that I spent an extra $15K just to build with shipping containers. I’m very fortunate to have an understanding wife.

2. Difficult construction. Having built cabins with both conventional materials and shipping containers, I can tell you that building with conventional materials is far easier. Normally straightforward tasks like electrical, plumbing, painting, and trim work can take several times longer when working with containers. This is potentially a hidden cost that’s not shown in the cost figures above – keep this in mind if you plan on hiring out a lot of the finish work.

3. Local approval. A common question I’m asked is “how did you get it approved?”. The answer is that I didn’t have to. I’m fortunate to be in a somewhat remote, forested/agricultural area with a fair number of questionable hunting cabins and farm outbuildings. I did get a building permit, for all of five dollars, but the township seems to care more about taxes than construction. Most builders won’t be so lucky, and it’s usually quite difficult to get approval for a non-conventional building such as this.

4. Treated plywood floors. While this wasn’t a deal breaker for me, there are those who will shy away from using containers because of this. Since I was only building a weekend cabin, I encapsulated my plywood floors with epoxy and I feel comfortable with that decision. On the other hand, if I was going to build a permanent residence I would probably replace the treated plywood with untreated. This would probably be more for resale value than anything else. Replacing the plywood floors in my cabin would have cost about $900 in plywood alone.

5. Design limitations. Designing an efficient and liveable cabin in multiples of 8, 20, and 40 foot lengths is a huge limitation. Need an extra two feet on one end to fit your dream kitchen? It’s not going to happen without taking something away from an existing space. The flexibility of frame construction to scale to virtually any size is a substantial benefit compared to container construction.

Summary

I’m not telling anyone they shouldn’t build with shipping containers, just that they should truly assess their reasons for doing it before they proceed. A shipping container cabin can be comfortable, secure, and aesthetically pleasing, but it will cost you considerably more than a conventionally built cabin. It’s not that different than wanting to build a log cabin – my true dream cabin, by the way. Log cabins also cost more per square foot than conventional construction, but somehow they seem like a better aesthetic deal to me.

In summary, I don’t regret my decision to build with containers. The peace of mind when I lock up my cabin is priceless – well, at least $15K worth.

Please feel free to disagree with me. I do enjoy a robust, yet cordial, debate.