Written by Stucco Champions — Southern California’s Authority on Exterior Plastering.

Stucco Vents: Choosing the Right Airflow for Your System

Vents are the lungs of your home. They allow crawlspaces to breathe and hot air to escape the attic. However, in a stucco wall, a vent isn't just a hole with a grate; it is a complex flashing assembly that must integrate with the waterproofing paper to prevent leaks.

Selecting the wrong vent depth—or installing a retro-fit vent when you need a new construction vent—can lead to water intrusion and failed inspections. This guide breaks down the specific hardware required for stucco walls.

1. The Depth Rule: 7/8" vs 1-3/8"

Before you buy a vent, you must know the thickness of your stucco system. Vents have a "plaster ground" (a lip) that the stucco finishes against.

• Traditional 3-Coat System: Requires a vent with a 7/8" ground.
• One-Coat (Foam) System: Requires a vent with a 1-3/8" ground (to cover the 1" foam + 3/8" cement).

Warning: If you use a 7/8" vent on a foam wall, the stucco will stick out past the vent, creating a recessed trap for water.

2. Foundation Vents: The Crawlspace Breather

These are installed at the bottom of the wall to ventilate the sub-area.

Standard "New Construction" Vents

These are galvanized metal boxes with a wide flange. They are nailed to the studs before the lath and paper are installed. The paper laps over the top flange, ensuring a watertight seal.

"Retrofit" Louvered Vents

These have a flat face frame (like a picture frame). They are designed to be glued or screwed onto the surface of existing stucco.
Use Case: Replacing a damaged vent screen without breaking out the stucco. We simply cut the old mesh out and mount the new louvered cover over the opening.

3. Fire Safety: The Ember-Resistant Mandate

In Southern California's Wildland-Urban Interface (WUI) zones, standard vents are illegal.

4. Dryer & Exhaust Vents

Penetrating a stucco wall for a dryer requires a specific hood.

• Stucco-Specific Hoods: These have a built-in plaster stop (J-channel) around the square perimeter. This gives the plasterer a clean edge to trowel against.
• Surface Mount Hoods: Common cheap aluminum vents. They are screwed onto the finished stucco and sealed with caulk. While functional, the caulk eventually fails. We always recommend integrated stucco hoods for longevity.

Conclusion: Details Matter

Vents are small, but if installed incorrectly, they are major leak points. Always choose a vent with the correct ground depth for your system, and ensure the building paper is lapped properly over the top flange (shingle style) to keep your wall dry.