Chimney cracks, gaps, movement indoors

Evaluate & repair cracks, gaps, movement in masonry chimneys seen indoors:

This article describes structural movement of chimneys that can be observed or predicted indoors in buildings. Our page to photo shows a leaning brick chimney in the attic of an older home. The lean may be excessive in this flue - making further detailed inspection of the chimney for gaps, cracks, leaks, fire or gas hazards important.

Chimney Movement detected indoors

Chimney Movement detected indoors in masonry chimneys can cause damage to the flue liner or openings that might admit sparks (fire risk) or gases (carbon monoxide hazards) into the building structure or even into occupied spaces.

The photograph here shows a leaning, corbelled brick chimney in a pre-1900 home.

When inspecting an old chimney which was corbelled over at an angle to come out at the center of the building roof's ridge (done for aesthetic reasons) inspect the chimney carefully at the attic floor where the chimney changes from angled (corbelled) to vertical.

This floor-level inspection, that is, inspection at the point from which a leaning masonry chimney begins to deviate from its original vertical structure, is a critical space to look for hidden and possibly dangerous damage, especially if the chimney is small, possibly constructed of a single brick wythe in thickness.

If the corbelled chimney flue has sagged along with the roof, the chimney may be cracked and open at this point even though other cracks were not seen.

In the attic inspect the chimney thoroughly at all accessible surfaces, floor to roof.

Our photo at left shows severe movement and openings in this brick chimney in an attic close to the roof surface. The vertical mortar joints between the bricks show openings of about 3/4" in width - you can see that the mortar has fallen over on an angle in these openings.

This chimney is a fire hazard, a carbon monoxide hazard, and a collapse hazard. Further inspection would be needed to determine if the damage was only in this area and due to water and frost (no chimney cap or crown) or if the chimney was moving and settling - leading to a need for reconstruction.

This damage pattern is more likely to be found on single-wythe thick brick chimneys than on chimneys built with multiple wythes of bricks forming the chimney wall.

...

Continue reading at CHIMNEY MOVEMENT, ONGOING vs STATIC or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• MASONRY CHIMNEY GUIDE - home
• CHIMNEY INSPECTION DIAGNOSIS REPAIR - home
• CHIMNEY COLLAPSE RISKS, REPAIRS
• CHIMNEY CRACK DIAGNOSIS
  • BRICK CHIMNEY CRACKS & COLLAPSE
  • CRACKED CHIMNEYS, MASONRY BLOCK
• CHIMNEY DAMAGE by LEAKS & FROST
• CHIMNEY INSPECTION CHECKLIST
• CHIMNEY INSPECTION, FLUE INTERIOR
• CHIMNEY LEANING, SEPARATION, MOVEMENT
  • CHIMNEY INSPECTION from GROUND
  • CHIMNEY MOVEMENT CAUSES
  • CHIMNEY MOVEMENT CLUES, INDOORS
  • CHIMNEY MOVEMENT, ONGOING vs STATIC
  • CHIMNEY FOOTING DEFECTIVE / MISSING
  • FOUNDATION SUPPORT for CHIMNEYS
• CHIMNEY REPAIR METHODS

Suggested citation for this web page

CHIMNEY MOVEMENT CLUES, INDOORS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to CHIMNEYS & FLUES

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Questions & answers or comments about diagnosing & repairing cracked, leaning, separating or moving chimneys - clues visible from inside the building.

	HOME	ABOUT	ASK a QUESTION	CONTACT	CONTENT USE POLICY	DESCRIPTION	POLICIES	PRINT	PRIVACY
	© 2026 - 1985 Publisher InspectApedia.com - Daniel Friedman