Pejorative for a room of low quality (esp. prison cell)
Solution 1:
A shithole, as defined by Oxford Dictionaries Online, is slang for a terrible place to live in.
An extremely dirty, shabby, or otherwise unpleasant place
Solution 2:
An unpleasant and dreary place can be called a dump.
Dump
noun
An unpleasant or dreary place
Why are you living in a dump like this?
Oxford Dictionaries Online, linked here, has other examples.