Thread: Cracks in chimney

Home built 30 years ago, masonry chimney in center of structure and has 6 flues (4 fireplaces, heating unit and one not used). Roof and chimney hit by tree during sandy. Blue stone cap damaged as was mortar/wash cap. No other damage to exterior. In the attic there are at least (4) cracks along mortar joints. Is this a concern?
Side noted: All flues have failed due to holes/gaps at mortar joints, however there are not cracks in flue sections. What should be done with the cracks? Should an engineer review structure?

Rich Roshak

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Those exterior cracks look like nothing to be concerned about. They can be re-pointed.

All the flues have failed? How was that determined? I assume they are clay liners and a licensed chimney sweep did a level II NFPA inspection? If that's the case then new liners might have to be installed, although chimneys in the middle of homes draft pretty well and I don't see any signs of efflorescence on that CMU. I don't think an engineer's opinion is in order. This looks like a job for a licensed chimney sweep or an HVAC Pro.

These should answer your question.

Richard
There appears to be a pipe running up the flue?
There doesn't appear to be a liner(s) and mortar gaps from what I can see would warrant further assessment/repair.

Listed chimney liners are only approved for installation into an otherwise intact chimney with a minimum of 4" solid masonry units. If you have CMU block greater than 4" wide, you know it has hollow cells and can thump them to tell if not push-filled with grout/ mortar. Therefore, this chimney would have to be torn down and rebuilt and not just relined. Note that with cracks, the air around the liner gets heated and can push out through cracks causing an offset ignition somewhere up the wall.

The first job of a liner, whether terra cotta tiles or metal is to provide a pathway for exhausting flue gases and heat while containing them. If the walls of the chimney have been breached then it can no longer perform its intended function.

The issue of what caused this failure is secondary here. It has failed and must be replaced. Addressing the cause would be a matter of an insurance claim if it was from a covered peril. It would be of importance if rebuilding the chimney and the footing was defective. A listed factory chimney would be an option, albeit expensive with 5 appliances to vent.

That appears to be a chimney sweeping rod with duct tape on it to me.

I think the camera is attached to that rod.

Are those flue liner tiles we are looking at? I see you found defects. That is enough to condemn the chimney, IMO. They may be able to have a new liner installed.