However, the first thing I need to do is replace the existing plastic j-box with a metal one rated for ceiling fans. Seems simple enough, except for one thing: how am I supposed to get the original box out of the ceiling?!
Since I don't have access to the box from an attic, I can't tell from below how the box is mounted. I assume it's nailed into the joists, but this is an old, old home, and nothing about it is standard. Is there any trick to removing the old box? I guess I could cut a larger hole in the drywall and patch it up when finished, but I would prefer not to do that if a less-messy option is available. I'm also not opposed to taking a sawzall around the outer perimeter of the box (being careful not to cut the wire), but I would prefer not to do that as well.