Loose material, open joints and flaking brick faces are different defects. Repair scope should identify what is unsound and why it deteriorated.
Published by Chimney Sweep Pages · September 24, 2026 · Editorial method
First decision
Keep people away from falling material. Visible leaning or movement requires prompt professional assessment.
Possible explanations—not a diagnosis
Moisture entering masonry and repeated weather exposure
Incompatible mortar or earlier surface patches
Movement or deterioration of the chimney structure
Several conditions can occur together. Only an appropriate on-site assessment can distinguish them in your home.
What the investigation should clarify
A masonry specialist may map damaged units, examine joints and consider crown and flashing conditions. Repointing replaces failed mortar; it is not a remedy for a structurally unstable chimney. Structural concerns may need an engineer rather than a cleaning company.
Do not pull loose bricks or mortar to assess the extent. Keep the appliance out of use if the chimney or vent integrity is uncertain.
One question worth asking
Why is repointing, partial rebuilding or another approach appropriate, and what evidence supports that boundary?
Ask for the findings, access limitations and proposed next steps in writing. Keep diagnosis separate from a repair estimate so you can seek another opinion with the same evidence.