Flashing collects water and sends it outward, but at its ends water would otherwise flow sideways off the edge into the cavity or framing. End dams are folded, soldered or preformed upturns, usually about an inch or more high, at the ends of sill, head and lintel flashings. Missing end dams are among the most frequent findings in leak investigations.
Lintel flashing has no end dams, water's running off both ends and staining the brick below the window.
A cut-and-caulked end dam fails as the sealant ages; folded, soldered or preformed dams last as long as the flashing.
Also heard as
- end dams
- dam
Related terms
Through-wall flashing
Flashing that runs from the back of a masonry cavity out through the wall face to drain water outside.
Sill pan
A tray of flashing under a window or door with a raised back and ends, catching any water that gets past the unit.
Dog ear
A corner of flashing or membrane folded into shape without cutting, so the corner stays watertight.
Flashing
Thin sheet metal or membrane installed at joints and interruptions in a wall or roof to direct water back outside.