Symptoms
- Water stain on ceiling or wall near the chimney
- Visible gap, rust, or lifted metal around the chimney base
- Leak worsens in wind-driven rain
Likely causes
- CommonCracked or dried-out sealant at the flashing jointCaulk and roof cement shrink and crack over time, opening a path for water.
- CommonRusted or corroded flashingMetal flashing thins and develops holes after many years of exposure.
- PossibleFlashing pulled loose from the chimney or shinglesSettling, wind, or improper installation can separate flashing from its seal.
- PossibleCracked chimney crown or mortar allowing water to run behind the flashingWater entering above the flashing bypasses it entirely.
What to do
- From the ground or attic, note exactly where the stain lines up relative to the chimney to narrow down the leak side.
- Check the attic near the chimney for daylight, wet wood, or staining on the framing.
- From a ladder, visually inspect the flashing for gaps, rust holes, or lifted edges without walking on the roof.
- As a temporary fix, apply roofing sealant to small visible cracks in accessible flashing or counterflashing.
- Check the chimney crown (the concrete cap) for cracks, which is a separate but related leak source.
- Schedule a roofer or chimney specialist to properly reflash the joint, since sealant alone is a short-term patch.
- Have the chimney crown resealed or repaired at the same time if it's cracked.
Tools and parts
- Ladder
- Flashlight
- Caulking gun
Roofing sealantSearch: “roof and flashing sealant”
When to call a pro
Call a roofer or chimney specialist to properly reflash and reseal the chimney.
Safety
Use caution
Do not climb onto the roof near the chimney yourself; inspect from a ladder or attic and let a professional handle the roof surface.