A crack needs context: location, movement, water entry, and the surrounding masonry. Widening cracks, leaning, or loose masonry call for keeping clear and prompt professional evaluation.
Updated September 10, 2026
Your home in Los Angeles.
About 58% of occupied homes in Los Angeles heat primarily with utility gas. Many chimneys in Los Angeles therefore vent a gas furnace, boiler, or water heater rather than a wood fire, and those flues still need inspection for liner condition, moisture, and blockage. About 0.1% of occupied homes in Los Angeles use wood as their primary heating fuel. Most fireplaces in Los Angeles see occasional use, and even occasional use calls for an inspection before the heating season. The nearest NOAA climate normals station (Culver City, about 1 mile from the Los Angeles city center) averages 1,368 heating degree days per year. That is a light heating season, so an occasional fire is more likely than day-to-day heating, but moisture still reaches masonry year-round, so note when water appears and have the source investigated before choosing a surface treatment.
What you can observe safely
- Photograph visible cracks safely from ground level.
- Keep any earlier photos for comparison.
What to avoid
- Do not climb onto the roof or enter the chimney.
- Do not alter gas components, venting, or safety controls.
- Do not use a test fire to diagnose the problem.
Possible causes to assess
- Masonry or mortar deterioration
- Movement requiring assessment
- Water-related damage
A symptom cannot establish the cause remotely. An assessment of the complete system helps determine the appropriate repair.
Chimney repair in Los AngelesA few common questions
Can this be diagnosed from a photo?
A photo can document a symptom and help prepare a visit. It cannot confirm concealed conditions or establish that a chimney or fuel-burning appliance is safe.