Noticed when I looked up that some mortar was loose on the top of my chimney.
House is 25 yrs old.
Climbed up to have a look.
The mortar around the clay pipes is soft and worn. Also the mortar that joins the 2 cement caps was loose.
Water was getting through and freeze/thaw cycle damaged many of the bricks below.
Talking to my engineer bro, seems this is a common problem that only gets worse and results in an irreversibly, badly damaged chimney that would need to be replaced.
He told me to chip out all the loose mortar, clean with wire brush and re-cement after wetting old cement first. Sloping the new cement so water runs off. Also remove the loose brick faces and repair with cement where possible.
Thought you all should know.
Fortunately weather is still good enough to do the job.