A specialized piece of sheet metal flashing installed where a sloped roof meets a vertical penetration, like a chimney or a dormer wall. It sits on top of the roofing material and bends up the vertical surface, directing water safely down the slope and preventing it from seeping into the joint.
Heard on the job
The roofer forgot the apron flashing on the low side of the chimney, and now water is pouring into the attic.
Do not mix it up with
- Step flashing: Apron flashing covers the horizontal base of a penetration, while step flashing weaves into the shingles along the sloped sides.