Advice wanted for top of brick chimney

My chimney has been in for 20+ years. It’s a yellow brick chimney with terracotta liners, a stainless cap, and the top has a layer or mirror across the bricks up to the terracotta liners.

Over the years, the mortar started to wear away and had some cracks in it. I’ve kept it patched with mortar. It’s now wearing very thin and I need to do something with it. Shall I skim it with another coat of mortar, or is there a better idea? I see a neighbor has used what looks like a white elastomer roof coating. His house sits low and it kinda looks like heck, white elastomer above a brown brick, but you probably wouldn’t see it on my chimney being highest on a hill.

Any recommendations?

 

Your chimney is brick with a liner.
The liner comes out of the top and there is a cement cap that covers the brick and seals the liner.
Is it the cap that is deteriorated ?

A picture would be helpful...... How to insert pictures.

 

I just cleaned my chimney today, I should have taken a picture while I was up there.

My top isn’t much different than others in the neighborhood. Without a picture, I’ll try and describe it.

The liner sticks up above the brick about 2”. The brick layer put mortar up against the liner, sloping it downward. The mortar was probably about 1” thick, down to almost nothing as it covers the top of the brick. There is no cement cap on the top.

My concern of just putting new mirror on the old, is whether it would adhere well.

 

That mortar on the top is the cap.
It should be replaced.... not patched.
Cement is much stronger than mortar and lasts a lot longer.

Most caps are too small and don't overhang the brick and allow water to run underneath and into the brick.
Bonding the cap material directly to the flue is also a reason for cracking as the flue expands and contracts breaking the masonry crown.

 

This isn’t my chimney, but it’s almost identical. My mortar isn’t that thick.

 

A proper cap overhangs the brick.
The cap in that picture is cracked.
The thickness is good but probably no reinforcement in it.

 

I had cracked mortar on top of one of my chimneys that allowed a leak. I had stainless-steel chimney caps made that covers the entire chimney top. They look good and I'll never have the problem again.