Circumscribed crack on brick chimney

[Marc]

This is a prefab fireplace with a metal flue inside a brick chimney. 1994 construction.

The crack completely circumscribes the chimney with a steady width all the way around. The mortar adheres overhead in most places but adheres to the bottom in a few places.

Never seen this before.

We had hurricane Laura with winds over 100 mph two weeks ago, but nothing else in this subdivision seems to have taken any damage.

Any idea what's going on? I've until 9 AM tomorrow to submit this report.

Thanks in advanced.

Edited September 10, 2020 by Marc

[John Kogel]

I have seen similar where a masonry flue liner would seem to be supporting the upper section while the lower section settled. In one case where I knew the owner, we filled the gap with fresh mortar and made sure the liner was intact and tight. Nothing bad happened that time, but the crack was more of a fine line.

For yours, it looks like a repair job for an experienced professional mason.

That would be caused by settlement of the chimney pad, or expansion of the steel liner possibly, not storm related, IMO.

[Marc]

30 minutes ago, John Kogel said:

I have seen similar where a masonry flue liner would seem to be supporting the upper section while the lower section settled. In one case where I knew the owner, we filled the gap with fresh mortar and made sure the liner was intact and tight. Nothing bad happened that time, but the crack was more of a fine line.

For yours, it looks like a repair job for an experienced professional mason.

That would be caused by settlement of the chimney pad, or expansion of the steel liner possibly, not storm related, IMO.

I guess it's possible that a flue liner is present and that a prefab fireplace has been inserted into a masonry firebox.

[Jim Katen]

5 hours ago, John Kogel said:

I have seen similar where a masonry flue liner would seem to be supporting the upper section while the lower section settled. In one case where I knew the owner, we filled the gap with fresh mortar and made sure the liner was intact and tight. Nothing bad happened that time, but the crack was more of a fine line.

For yours, it looks like a repair job for an experienced professional mason.

That would be caused by settlement of the chimney pad, or expansion of the steel liner possibly, not storm related, IMO.

I once owned a house where that happened. The terra cotta liners were supporting the upper section of the chimney. I never patched it, just left it like that. For all I know it's still like that. 

[Marc]

36 minutes ago, Jim Katen said:

I once owned a house where that happened. The terra cotta liners were supporting the upper section of the chimney. I never patched it, just left it like that. For all I know it's still like that. 

I'm somewhat inclined to recommend patching to help keep rainwater out.

[Bill Kibbel]

The chimney was circumwhat?  You need a mason that's also a mohel.

[Marc]

22 minutes ago, Bill Kibbel said:

The chimney was circumwhat?  You need a mason that's also a mohel.

I made a slight error.  How's this: The gap circumscribed the chimney. I'll give you that it's an unusual use of the word but it seems appropriate...IMHO

[Jim Katen]

Maybe the mohel was already there and the chimney hasn't had time to heal yet. 

[Marc]

2 hours ago, Jim Katen said:

Maybe the mohel was already there and the chimney hasn't had time to heal yet. 

I'll put that in my report.