Galvanized Steel Mesh for Stucco: Purpose, Types, and Installation
This article was prepared by the team at Stucco Champions, experts in residential and commercial stucco systems across Southern California.
Before any cement is applied, the foundation of a long-lasting stucco system begins with galvanized steel mesh. Also called metal lath, this material provides the necessary structure and bonding surface for the layers that follow.
What Is Galvanized Steel Mesh?
Galvanized steel mesh is a zinc-coated metal lath that resists corrosion. It’s installed over a building’s sheathing and forms the base for the first layer of stucco: the scratch coat.
Why Galvanized Mesh Is Essential
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Reinforces the stucco system
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Provides grip for the scratch coat to key into
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Distributes stress and reduces the risk of cracking
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Prevents detachment from the substrate
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Resists corrosion through its zinc galvanization
Without galvanized lath, stucco adhesion weakens, leading to surface failures over time.
Common Mesh Types Used in Stucco
| Type | Description |
|---|---|
| Expanded Metal Lath | Formed into a diamond pattern; excellent for keying |
| Welded Wire Lath | Grid-style; often used for large commercial projects |
| Self-Furred Lath | Features built-in spacers to create space over building paper or sheathing |
Stucco Champions Tip: We install self-furred, code-compliant lath to ensure proper drainage and optimal bond. This aligns with ASTM C1063, the industry standard for stucco installation.
How It’s Installed
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Apply two layers of weather-resistant building paper
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Fasten the galvanized mesh to framing or sheathing using approved fasteners
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Overlap seams by at least 1 inch
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Ensure mesh is flat and tight to prevent sagging or improper bonding
Correct mesh installation is one of the most overlooked — yet most critical — parts of a stucco job.
Where It Fits in the Stucco Process
Galvanized steel mesh is used at the very beginning of a three-coat stucco system:
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Step 1: Scratch Coat – Bonds directly to the mesh
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Step 2: Brown Coat – Smooths and levels the surface
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Step 3: Finish Coat – Adds final color and texture
This makes mesh installation a key step in ensuring the entire system performs long-term.
FAQs About Stucco Mesh
Can I skip the metal lath if I’m applying stucco over concrete?
Yes — when bonding directly to solid masonry or concrete, adhesive agents may be used instead of mesh. But for wood or sheathed framing, lath is required.
How long does galvanized steel mesh last?
With proper installation, the galvanized coating prevents corrosion for decades — often 50 years or more.
Is all mesh the same?
No — self-furred, expanded, and welded options serve different project types. Residential jobs often use self-furred expanded lath.
Summary
Galvanized steel mesh is the first critical step in building a strong, long-lasting stucco exterior. It supports adhesion, resists corrosion, and ensures your scratch coat locks in properly. At Stucco Champions, we follow strict installation standards to deliver a finish that’s both beautiful and durable.
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