One Container, Two, or a 40 Instead

Almost every first conversation we have starts with a floor area. It is the wrong place to start. The number of containers you use changes the structure, the transport, the foundation and the resale far more than it changes how the house feels to live in.

The three shells

A 20 ft high-cube gives about 160 sq ft of internal floor and arrives as a single load on a standard trailer. A 40 ft high-cube gives about 320 sq ft and needs a longer trailer and a longer crane reach, but costs less than two 20s and has half the joints. Two containers side by side gives 640 sq ft and a decision to make about the wall between them.

All three are 8 ft wide externally. After insulation and lining you are living in about 7 ft 2 in. That constraint does not change no matter how many boxes you buy, which is the thing most people have not internalised when they arrive.

The 8 ft problem, and the only two answers

A 7 ft 2 in internal width is fine for a corridor, a bathroom, a galley kitchen or a bed with a walkway. It is not fine for a living room you want to put a sofa and a chair in facing each other. There are exactly two solutions.

Delete the shared wall. Weld two containers together, remove the long wall between them and replace it with a moment frame. You get a 16 ft clear span, which is a normal room. This is what our Meridian 80 does, and it is the single most expensive structural decision in our catalogue, because that wall was doing real work. It is also the one that most changes how the house feels.

Push out. Add a framed extension, a notched deck or a glazed link between two separated boxes. Cheaper than a moment frame, and it gives you a room with a different character rather than a wider version of the same one. Our Longwater 60 uses a glazed link between two 30 ft units, which splits living from sleeping and doubles as the rainwater catchment.

Transport is a real constraint, not a detail

A 40 ft unit is one crane lift and one trailer, but that trailer needs a turning radius and the crane needs somewhere to stand within reach. On tight urban infill and on steep rural tracks, two 20 ft units are often the only thing that will physically arrive.

We survey access before we price the build for exactly this reason. It is not unusual for the survey to change the model, and it is much better that it happens before the drawings than after.

If you might ever move it

A single 20 ft unit on screw piles can be craned off, put on a tilt-bed and taken somewhere else. That is a genuine property of the building and it is why our Basecamp 20 uses bolted foundations and no concrete anywhere. Leased land, family land and sites with an uncertain future are all good reasons to stay at one container and keep everything demountable.

The moment you weld two containers together and pour a slab, you have built a house. That is usually the right decision. It should be a decision, not something you discover.

A rough guide

• One person, or two who are out a lot, on a tight budget or a temporary site: a single 20 ft. Datum 20 or Basecamp 20.
• Two people living in it full-time, wanting a real kitchen and a separable sleeping end: a single 40 ft. Shelf 40, or Ridgeline 40 off-grid.
• A family, or anybody who wants a room wider than 8 ft: two or three containers with a moment frame or a courtyard. Meridian 80, Courtyard 100, Cantilever 120.

Every one of those has been built more than once, and every one started as a standard shell that moved. If none of them is quite right, that is expected. The configurator is the fastest way to find out what your version looks like.