A specialized assembly of sheet metal installed where a chimney penetrates a roof deck. It typically consists of step flashing woven into the roofing material and counterflashing cut into the masonry mortar joints, directing water down and away from the vulnerable penetration.
Heard on the job
The roofer missed a spot on the chimney flashing and now water is running down the brick inside the attic.
Related terms
Counterflashing
Flashing set into the wall above a base flashing, overlapping it downward to shed water off its top edge.
Flashing
Thin sheet metal or membrane installed at joints and interruptions in a wall or roof to direct water back outside.
Raggle
A groove cut into a masonry or concrete wall to receive the top edge of a metal flashing.