Written by Stucco Champions — Southern California’s Authority on Exterior Plastering.
What Is Stucco Weep Screed & How Is It Used?
In the hierarchy of stucco components, the Weep Screed is arguably the most important. It is the first piece of metal installed on a home, yet it is often misunderstood by homeowners and even some general contractors.
This simple L-shaped flashing serves two critical functions: it sets the depth of the stucco (7/8") and, more importantly, it allows trapped moisture to escape the wall cavity. Without it, water would pool at the bottom of the wall, rotting the mudsill and framing studs. This guide explains the mechanics of this vital component.
1. The Mechanics: How It Drains
Stucco is not waterproof; it is a reservoir. Rainwater absorbs into the cement and eventually hits the waterproof building paper behind it. Gravity pulls this water down the wall.
The weep screed is installed at the foundation line (the bottom of the wood framing). It has small holes punched into the bottom leg.
The Exit Path: Water runs down the paper, hits the slanted leg of the screed, and exits through the holes, dripping harmlessly onto the concrete foundation or ground below.
2. The Code Requirement: Clearances
According to ASTM C1063 and the California Building Code, the weep screed must be placed at specific heights to prevent moisture wicking.
- 4 Inches Above Earth: If the ground is soil/mulch, the screed must be 4" high.
- 2 Inches Above Paving: If the ground is concrete/pavers, the screed must be 2" high.
Why? If the screed is buried in dirt, the holes get clogged, and moisture from the ground wicks up into the stucco (capillary action), leading to rot.
3. Types of Screed: #7 vs. "J" Metal
Not all screeds are the same. The profile matters.
The #7 Foundation Screed (Standard)
This is the V-shaped profile most common in modern construction.
Pros: The V-shape acts as a drip edge, forcing water away from the foundation. It is rigid and holds a straight line well.
Best For: New construction and full re-stucco projects.
The "J" Weep (Retrofit)
This looks like a square "J" channel with holes in the bottom.
Pros: Lower profile, less visible.
Cons: Harder to lap paper over correctly. Often used in retrofits where the old screed is cut out.
4. Common Failure: Buried Screeds
The most common failure we see in Southern California is homeowners burying their weep screed with new landscaping or concrete patios.
The Consequence: When you pour a new patio against the stucco, you block the drainage holes. Water backs up into the wall, causing the paint to bubble and the studs to rot.
The Fix: You must install a channel drain or cut back the concrete to restore the 2-inch gap.
We often see well-meaning homeowners caulking the gap between the weep screed and the foundation to "seal it." Do not do this. You are sealing the water in. The holes must remain open to breathe.
Conclusion: Respect the Drain
The weep screed is the unsung hero of your home's envelope. It works silently to keep your framing dry. By maintaining proper ground clearance and keeping the holes free of paint and debris, you ensure your stucco wall lasts for decades.
Last week, we shared How To Cut Through Stucco. If you are retrofitting a screed, you will need to cut the old wall first.