This might be a question for my building inspector.
I'm opening up the floor plan in my house and now that I've got all the walls open around the chimney I see that the clearances are only about 1.25" at best and zero at worst for the main supporting wall. I believe code calls for 2" around the chimney. Does this need to be corrected or is this considered grandfathered in? I don't know how I could move the wall further away from the chimney anyway. How about if I leave the structure around the chimney as is?
Ask your inspector. Its been my experience that when you open up something that exposes a problem, then that problem must be brought up to code. If the problem is not uncovered, then no. I run into this with plumbing and framing all the time here in VA