what is a weep vent

A weep vent, also known as a weep hole or a weep-brick, is a small opening that allows water to drain from within an assembly. Weep vents are typically found in masonry veneer or cavity walls, just above the flashing, and are used to drain water back out through the weep holes. The weep holes allow wind to create an air stream through the cavity, which removes evaporated water from the cavity to the outside. Weep vents are critical to prevent water intrusion in buildings and homes, and they allow the building to "breathe" by allowing water to exit. Weep vents are also used in metal windows and glazed curtain walls to permit interstitial condensation to escape, and in automotive water pumps to protect the bearings by letting out water that leaks past the seal.