Project education
Chimney Leaks: Finding Where Water Gets In
A chimney passes right through the roof, and the joint around it has to shed water from every side. When it does not, a stain often appears on a ceiling or wall near the fireplace.
The pieces around a chimney
- Step flashing: metal pieces woven in with the shingles along the sides
- Counter flashing: metal set into the brick that laps over the step flashing
- A cricket: a small peaked section behind wider chimneys that turns water aside
The brick and the crown
Not every chimney leak is a flashing problem. Cracked mortar, porous brick or a cracked crown at the top can let water soak down through the chimney itself.
Clues from inside
A stain that appears only during wind-driven rain from one direction may point to one side of the chimney. A stain that shows up in any heavy rain can suggest the crown or brick.
What a repair involves
A repair should address the actual entry point. Sealant smeared over the joint may stop a leak for a while, but it rarely lasts as long as properly installed flashing.
Next step
Describe your stain and when it appears, and send photos of the chimney from the ground.