The address interests me. That is nine blocks from where I grew up (4xx 17th Avenue) and is definitely a totally residential area - must have been a garage (called basements in SF even though above grade) next time I am in the City (which may be years, if ever) I'll try to remember to have a look. Google is no help, house numbers not visible, but they are the typical for SF 25' wide/zero clearance lots. Other parts of the country call similar construction "row houses" in a perjorative sense, but if you want one of these, you'ld better bring LOTS of money, often well over $1 million.