Ya know, a lot has happened in the last few years. Major thing
is that houses have gotten tighter, so there is not as much air
coming around doors and windows to supply the air that would
go up the chimney.
So if you don't already have it, I suggest pipes to supply adequate
combustion air into the firebox. Consider whether the inner size
of the chimney portions is really needed. Masonry holds up, it's up
to you to decide what, if anything, is needed to be done differently.
Remember that the standard fireplace is seen by utility companies
as a negative heat source.

On Apr 15, 6:42*pm, "RogerT" wrote:
I own a property that has a brick chimney that extends maybe 10 feet or so
above where it comes through the roof at the back of the house. *The