Yes, always plural. And therefore 'are'. But you would always always have something before it: My lodgings are very comfortable. His lodgings are very cheap - I can't think of an example where you would use it 'bare'. Both that and digs are very British words, I think. I'm not sure if Americans would use them - we rarely do.

"Lodgings" is very rarely used in the U.S.. "Lodging" is more common, but still rare, and if used, would more likely be used as a verb. "Where is he lodging?" "Housing" would be the more common term as a generic for different places to live. "Housing is expensive in NYC." "Housings" is not a word.

Being American, I am inclined to agree with Gary's answer. However, I think it is an American/British English difference. http://www15.uta.fi/FAST/US1/REF/engtran.html