The Importance of a Weep Screed

What Makes A Good Weep Screed?

According to, “A weep screed is a type of building material used along the base of an exterior stucco wall.  The screed serves as a vent so that the moisture can escape the stucco wall finish just above the foundation.”  It terminates the bottom of a cementitious-based thin veneer rainscreen & should allow liquid moisture that drains down the back side of a thin veneer rainscreen to freely exit the thin veneer.

It is critical that the drainage/weep holes be

  • numerous - less than 1 inch apart
  • located directly below the rainscreen drainage plane
  • large to ventilate the rainscreen air gap

This provides an immediate exit point for liquid moisture that drains down the rainscreen drainage plane/drainage mat that cannot be blocked by the stucco or mortar.

LR Weep Screed Product Image

Fact: Most Weep Screeds Don't "Weep"

Most weep screeds feature small, infrequent holes - not for weeping - for attachment. The drainage mechanism on these products is shrinkage of the cementitious materials away from the weep screed.

Dependence on a “shrinkage crack” to handle the amount of moisture that can be potentially drained to the bottom of the wall is inviting moisture-related building envelope failure! Plus, there is no potential for ventilation, which is shown to have a significant impact on keeping walls dry.

MTI's Weep Screed is Designed to Drain

MTI manufactures one of the few rainscreen-compatible weep screeds that actually weeps.

  • Designed to accommodate the full depth of the rainscreen drainage plane (drainage mat) system
  • Large 1" holes with frequent placement for maximum weeping & ventilation
  • Can be used with MTI’s Weep Screed Deflector to protect against termites and move water away from the foundation
  • Works with multiple veneer choices like stucco, thin stone, ACMV, and thin brick
Rainscreen Compatible Weep Screed Annotated

Want to Learn More?

Get detailed drawings on our weep screeds used in:

Code References
Section 2512.1.2, Weep Screeds, of the 2012 International Building Code states, “A minimum 0.019-inch (0.5 mm) (No. 26 galvanized sheet gage), corrosion-resistant weep screed or plastic seep screed, with a minimum vertical attachment flange of 3.5 inches (89 mm) shall be provided at or below the foundation plate line on exterior stud walls in accordance with ASTM C 926.  The weep screed shall be placed a minimum of 4 inches (102 mm) above the earth or 2 inches (51 mm) above paved areas and shall be of a type that will allow trapped water to drain to the exterior of the building.  The weather-resistant barrier shall lap the attachment flange.  The exterior lath shall cover and terminate on the attachment flange of the weep screed.”