Cracked chimney crown leaking into the chase
Why it happens here
Crowns crack from freeze-thaw movement and from being built too flat to shed water. In Smithburg, snow sits on a flat crown for weeks, and the water finds the crack. Once it is in, it runs down the outside of the flue and shows up as a ceiling stain.
Our approach
We chip out the failed crown mix, rebuild the crown with a proper slope and overhang, and seal it. We water-test before we leave so you know it is fixed, not just patched.