I'm in the process of trying to air seal my basement. During the process I pulled out some fiberglass insulation that was shoved on each side of my masonry chimney in the ceiling where it enters the first floor on it's way to the attic. I noticed that the wood framing around my chimney is very close on three sides, well under the supposed 2 inch minimum for framing that I've heard about (attached are pictures looking up on each side).
I would like to know if this is something I should worry about before I air seal it (with high-temperature caulk and sheet metal) OR what else do I need to find out to make sure I'm in no danger of the wood catching fire?
To provide more information about my setup, I have a oil burning furnace for forced heat air that vents into a diagonal 4 foot metal flue. That metal flue enters my masonry chimney about 5 feet above the basement floor. The house was built in 1954 and the current furnace was installed in 2001. My suspicion is that I'm probably fine since it's been that way likely since the house was built, but I don't want a home inspector flagging it if/when I sell the house.