There was a time, not too long ago, when used shipping containers, known to some as intermodal containers, ISO containers, or Sea-Tainers, were free. Those days are gone, and now you can expect to spend at least $2,000 on a used container, and closer to $4,000 for a 40-footer. If you’re in the container business there are better deals to be had, and that’s something I’m working on, because aside from housing, I have a lot of uses for these things. I currently own only one, a 20-footer I took in trade for some home remodeling. I could probably make good use of at least fifty more of them. That’s really not an exaggeration.

Container houses are trendy. They can be quite upscale. There are TV shows about them, countless articles online, and successful companies all over the world that build them. Container homes are generally a type of modular home, though the majority of work is more often done at the build site. From a practical standpoint, there are three, main advantages to building with shipping containers: cost, build time, and structural strength. In truth, I can frame a house as quickly as I can build one out of containers, probably faster, but with the cost of lumber going through the roof lately, I can’t frame 320 square feet for anything remotely close to $4,000. And the container isn’t just a shell — depending on your design, you might need no external siding or roofing. It’s entirely possible, however, to more than make up for any money you’ve saved by shelling out for specialty products to finish out your home.

•Portability: Containers are portable as part of their essential purpose; they’re the only product discussed in this article that is specifically intended to be transported by truck, train, and ship. They are under the dimensional limits for transport on North American roadways, and probably nearly all the world’s roadways, though I haven’t checked every country’s laws. It has to be noted, however that to be transported on a container ship, the unit has to be certified, and the certification is voided if the container is modified. Put a door or a window in it, and you’ll either have to spend more to ship it as cargo, or you’ll have to get it re-certified, which won’t be possible if any of the modifications protrude outside the container’s standard dimensions, and likely even if they don’t, since container walls are meant to be load-bearing. Going down the highway on a truck or sitting on a rail car is far less taxing than the rigors of transoceanic travel, so a modified container that can be easily, and legally, transported overland may not be so easily moved by sea. In addition, most container houses are similar to the modular homes discussed above in that once they are set up on-site, they’re no longer very portable. This is obviously less true of a smaller home made from a single container. Portability score: 3

•Ease of setup: Whether the setup process is easy or complex depends entirely on the needs of the homeowner. A single container can be set on blocks or a concrete slab quite easily. One person can level the container, with the main challenge being that its construction is so rigid that lifting one corner raises the entire end, unlike wooden structures that can be easily leveled on corner at a time. For more complex builds, the setup can involve a telescoping forklift or a crane, and lots of clamping, drilling, and welding. Many homes utilize a hybrid design, where a roof spans the distance between two or more containers, creating a large, open area. Once the structure is complete, the rest of the build can take longer and require more special skills than finishing a stick-built house. I’m at a bit of a loss for how to score this, but I have to look at setup in conjunction with transport, in that even if I want a basic, single-unit home, if I want to send it by container ship, I have to wait to install the doors, windows, and any other protrusions. That means doing a lot of on-site work unless I just buy the house from a builder and let someone else do it. And that’s not out of the question. Setup score: 2

•Quality of materials: Shipping containers, prior to any modification, are built like, well… like you would have to build anything that’s going to be stacked onto a ship and expected to survive storms at sea. The rest of the materials can be whatever you want them to be. There are some excellent container building systems out there, and some good DIY options, but where issues arise is in the use of lead-based paint throughout, and plywood flooring that’s heavily treated with pesticides. I’ll talk more about this in the sustainability section. Materials score: 2

•Use of space: You have a lot of options here; for the simplest designs, you’re limited to the eight-foot wide interior of a single container, and that can present some challenges. Making significant modifications, such as cutting out large sections of the wall, can eliminate some of the structural advantages to building with containers. They can be stacked, so multi-story buildings are possible, and they can even be cantilevered, which is pretty cool, but to get high ceilings you have to have a hybrid design. And regardless of your design, without significant cutting and welding, you’re dealing with 8.5-foot increments for width and, in most cases, 20 and 40-foot length increments. As I’ve worked up building designs, I’ve frequently run into issues where I needed just a few extra feet and had to either add an entire container or sacrifice space somewhere else. Because of their modular nature and fixed dimensions, I find the design possibilities at once both endless and limiting. It’s actually a pretty good analogy for a discussion of the nature of infinity, which is not within the scope of this article. Space score: 3

•Suitability to the climate: It’s a metal box. Metal boxes get super hot, or cold, and condensation is a major issue. My container had mold on its ceiling when I got it, after sitting empty for a year or two. Thus, measures have to be taken to mitigate those issues, and that means either lots of ventilation or very good climate control, with interior wall coverings that resist moisture. Such products do exist, including insulated forms that fit the contours of the container wall. Climate score: 3

•Pest resistance: This is where container houses really shine. Shipping containers are meant to be rodent proof and resist insects. They do have plywood floors, but my container also has sheet metal below the floor substructure, which would make it very difficult for rodents to get in. The insecticide in the plywood floor presents some problems for the home’s inhabitants, but it’s a bigger problem for bugs. The container’s pest resistance is the main reason I got mine — I was tired of rats messing up my stuff. Pest score: 5

•Style: Your container house is going to be a bit, dare I say it, boxy; there really is no way around that. You can, however, use all manner of wall coverings, both inside and out, to give it just about any look you want, and it’s not like most houses don’t have square corners anyway. If you’re creative, you can make something great, to match nearly any taste, although there are certainly some motifs that would prove more challenging than others. ‘Log cabin’ comes to mind. Style score: 3

•Sustainability: Here’s where I get a little controversial. Container homes are often heralded as the pinnacle of sustainable housing, which I don’t believe is entirely deserved. On the one hand, most people are buying used containers, which means the home is made from up-cycled materials, though not entirely. Up-cycling is good. On the other hand, the container has lead paint and toxic chemicals in it, and in addition to the health concerns these things raise, they can take an environmental toll, just from their presence on your property. Some builders have opted to strip the paint and remove the plywood, but that requires more paint and more flooring, so that only the steel is being reused, and all that stuff you’ve ripped out has to be disposed of somewhere. Other builders order custom containers that don’t have lead paint or pesticides, but those aren’t up-cycled. The steel itself might be recycled, but what you’re buying at that point isn’t really a container, it’s a modular building material. And since the container has to be built out, whatever materials you use to do that may or may not be considered sustainable. It seems more and more petrochemical products are going into housing these days, and container houses are no exception. Finally, you’d better plan on using some good insulation, or you’re going to use a hell of a lot of energy for heating or cooling. Oh— and they’re pretty much all made in China, which might be an issue for you, whether your concern is the environment or human rights. It’s certainly the reason I wouldn’t order a purpose-built one. I like containers a lot, but I’m not giving them the points for sustainability that a lot of other people think they deserve. Sustainability score: 2

•Price: You can definitely go cheap. You could, in theory, live in a container without modifying it at all. It would suck, but you could do it. You could also build a million-dollar container house, which would suck in a completely different way. They’re a hell of a lot cheaper to move than mobile homes, though, and that has to count for something. Plus, if you plan on doing your build-out on-site, you can ship your materials inside the same container you use for your build, and that’s just smart and efficient. I’m splitting the difference on this one, too. Price score: 3

The problem with unweighted scoring criteria — container homes scored lower than manufactured or modular homes, even though they’re better for my purposes than either of them.

Total score: 26

Biggest pro: Pest resistance

Biggest con: Toxic chemicals

Must unique feature: They’re dual purpose, starting life as one thing and ending as a totally different thing.