Chimney leak repair in San Antonio
A stain on the ceiling next to the chimney, water in the firebox, or a musty smell after rain all point the same way. Chimneys leak in a handful of predictable places, and the fix depends on which one.
Where chimneys leak
- Flashing. The metal that seals the joint between chimney and roof. Lifted step flashing, a missing counter-flashing or dried-out sealant is the most common cause of a stain beside the chimney.
- The crown. Cracks in the slab on top let water straight into the brick and down the outside of the flue.
- No cap. An open flue takes rain straight down into the smoke chamber and firebox, where it rusts the damper.
- Brick and mortar. Masonry is porous. Old brick with receding mortar joints soaks up a lot of water in a long rain.
- Chase cover. On a factory-built fireplace, the flat metal top of the framed chase. Cheap galvanized covers rust and sag, then pond water, and the water runs down inside the chase.
What leak repairs cost
| Job | Published range | Source |
|---|---|---|
| Crown repair | $750 to $1,000 | Fixr, Jan 2025 |
| Flashing repair | $200 to $300 | Fixr, Jan 2025 |
| Sealing or waterproofing | $150 to $500 | Fixr, Jan 2025 |
National published ranges, not a San Antonio average and not a quote.
Roofer or chimney company?
Flashing sits between the two trades. A roofer can re-flash a chimney, and a chimney company can too. If the problem is up top or in the brick, it is chimney work. Ask whoever comes to find the actual entry point, with a photo, before anything is sealed; sealant smeared over the wrong joint just hides the next stain.
About waterproofing
A breathable masonry water repellent can help old brick shed water. It should let water vapor out, and it is no substitute for fixing a cracked crown or failed flashing first. Fixr puts chimney sealing at $150 to $500.
Questions San Antonio homeowners ask
Why is my chimney leaking when it rains?
Usually flashing, a cracked crown, a missing cap or a rusted chase cover. Heavy, wind-driven rain finds the weak spot first. Note where the stain appears and send a photo.
Can I seal a leaking chimney myself?
You can caulk an obvious gap as a stopgap, but staying off the roof is safer, and sealing the wrong spot traps water. Have the entry point found first.
Will homeowners insurance pay for a chimney leak?
Insurers often cover the water damage from a sudden leak but not the repair of worn flashing or mortar. Check your policy and document the damage with photos.