How To Repair A Leaking Chimney
How Chimney’s Are Sealed
Chimney leaks are almost always related to the lead flashing’s that lay on top of the shingles, and direct water away from the chimney. Lead flashing is installed on the lower edge first, and sealed into the mortar of the chimney. Then lead step flashing is used to go up the side, over lapping each piece directly below it, and woven into each row of shingles. A cap is placed on top that covers and overlaps the step flashing.
Lead flashing used for chimney sealing will usually last the life of the roof and should always be replace when your home is being re roofed.
Why Chimneys Leak
- High winds blow up a piece of flashing
- Flashing is broken (usually do to flying object)
Chimney Repairs
If you discover a broken piece of flashing, it should be ground out of the mortar, and a new piece should be attached. It is possible to use tars and sealants to seal a leaking chimney for a few years. If the lead seal around your chimney wears out before you need to replace the rest of your roofing system. You can usually buy some time with sealants.
Properly installed flashing do not require tar and sealants. If you live in the upper north east, you should first wrap your chimney in ice and water shield as a counter flashing. Counter flashing’s are sometimes used encase water should penetrate your primary flashing.
In extreme wind driven rain situations even the best sealed chimney may leak some. (100 year storm scenario).




