The Importance of a Weep Screed

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.  

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.

Rainscreen-compatible weep screedMTI'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

See Weep Screed Products 

Want To Learn More?

Get detailed drawings on our weep screeds used in:

Download our article about effective weeps & weep screeds

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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.”