I've been trying to find the leak in my chimney for over a year. Part of the
problem appears to have occurred when the siding contractor allowed water to
be delivered to the J channel on a 45 degree angle along a fascia board; the
water was soaking the sheathing behind the chimney. I THINK that's corrected
but I really don't know. Is there a camera available to rent that can
connect to my portable computer at the fireplace and examine the flue for
points of entry? What about sealing the bricks with a clear chemical. I used
so expensive stuff about two years ago and it seemed to help somewhat. It's
very hard to determine since the source is unknown and each rainfall brings
new variables so one never knows if what one did the last time really
contributed to the "fix" or if the rain simply wasn't sufficient to get the
fireplace wet. My fire bricks in the lower two rows are becoming saturated
from water behind them; the mortar is eroding. House is about 35 years old.