Our chimney has deteriorated quite a bit over the years (we've been here
only 10 years - house was built 1915). It appears a few decades ago
somebody put a coat of mortar over the whole exterior and painted it
with a silver colored substance. That has since cracked and pieces have
chipped off over the years (I've found several chunks in the yard while
mowing). 3 years ago we had a new furnace put in that required a sleeve
and they installed a galvanized sheet metal cap over the chimney, which
comes down the sides about 4-6". It has never leaked since we've been
here.

My thinking is I need to have the chimney fixed up prior to the roof
being redone so no damage is done to the new roof. I was thinking maybe I
could get by with either having it rebuilt from roof level up or
preferably to just remove the chimney to below roof level (it is in the
middle of the house) so only the metal sleeve comes out of
the roof (for the furnace/water heater, no fireplace). I assume that
is all they do when a new gas furnace is installed when no chimney
exists. Is that practical?

Thanks,
Michael