[luckylion]

Ah, thanks for the explainer! Makes sense that manufactured housing is its own special category then. We do have those, but it's super rare (likely because they'd still need to comply with lots of local regulation, and it becomes more complicated, not less).

[alistairSH]

No problem, it's pretty different that what's typically done in Europe (and I have no idea how standardized that is - though there are definitely lots of home/building shows in the UK where they by prefab from central Europe, etc).

We basically have the following... - RV (camper van and larger bus-based) - true mobile homes, follow a distinct set of federal rules. Generally not allowed permanently anywhere (most parks have a limit on number of weeks/months you can stay), though there are exceptions. Don't have permanent plumbing or electric supply (plug in with extension cord, black water tank that needs dumped periodically).

- "Mobile homes" (old name)/manufactured housing - "one piece" homes designed to roll to location, be dropped in place, and generally not moved again. Once on site, permanently plumbed and electrified. Older homes tend to be rotten nasty cheap things. Newer ones can be quite nice, but they still carry a bad reputation. Follow their own federal rules. In theory can be moved again, but rarely happens.

- Prefab (sometime also called modular) - factory built homes, but usually not delivered complete. Instead usually delivered as components (sometimes whole rooms, sometimes just walls and roof). Generally must adhere to local building regs. Built on a normal foundation. Truly permanent once installed.

- Normal construction on site. Local rules.

And because prefab has to follow local rules, which can vary substantially by region (CA with earthquakes/fires vs east coast without much in the way of natural disasters), the cost savings often isn't there.