Entire home spotted floating across San Francisco Bay

It’s a houseboat that has been built up like an on-land home.

Fairly common in Australia and New Zealand to relocate complete houses. I’ve seen them done here in NZ fully furnished.

Most houses here are wooden construction with corrugated steel roofs which keeps the weight down.

It's pretty rare (excluding mobile homes and pre-fab homes, of course). I grew up in the US and have lived in Australia for over a decade now, and I have seen exactly one house moved in each country.

However, I have seen a large number of historical log cabins fully dismantled and rebuilt elsewhere in the US — generally to rescue them from destruction or to transport them to open-air museums. (My grandparents were involved in that trade and personally dismantled and rebuilt 27 log cabins.)

It's a regular home built to float on water. Often 2-story, roof terrace / balcony, the works. In the NL there are many examples. Designed to be anchored in quiet waters & sit there.

In contrast with houseboats, which are often re-purposed old cargo ships. Which were originally designed to move often (and thus, deal with choppy waters & so on).

In practice both types rarely move. But it happens occasionally. Over the course of last summer I've seen ~half a dozen crossing various lakes here. They're even for rent here (as a halfway between boat & vacation home).

On land: it's been done... 'once or twice'.