Lath in USA: Comprehensive Guide to Materials, Applications, and Industry Trends

Lath has been a cornerstone in American construction for centuries, evolving from traditional wooden slats to innovative modern materials. Whether applied in stucco systems, plastering, or stone veneer installations, lath in the USA plays a crucial role in creating strong, durable, and aesthetically pleasing structures. In this guide, we dive deep into the types of lath used in the United States, their applications, specifications, and the latest industry trends shaping their use across commercial and residential projects.

What Is Lath?

Lath refers to a thin material—traditionally wood or metal—used as a backing or framework to support plaster, stucco, or other wall finishes. It serves as a key reinforcement component, anchoring wet finishes and enabling them to adhere effectively to surfaces.

Types of Lath Commonly Used in the USA

Wood Lath

Wood lath was once the standard material used in early American construction. Thin, narrow strips of wood were nailed horizontally across wall studs to support wet plaster.

• Dimensions: Typically 1 inch wide and 4 feet long
• Spacing: Around 3/8-inch between each strip to allow keying of plaster
• Application: Historic restorations, heritage homes

Metal Lath

Today, metal lath is the most widely used variant in the USA due to its strength, fire resistance, and compatibility with various construction systems.

Expanded Metal Lath

• Material: Galvanized or stainless steel
• Forms: Diamond mesh sheets
• Features: High tensile strength, superior bonding
• Applications: Stucco walls, stone veneer, tile substrates

Self-Furring Lath

• Design: Dimpled to allow automatic furring from the surface
• Benefit: Maintains proper spacing from the substrate
• Usage: Exterior insulation finishing systems (EIFS), curved or irregular surfaces

Paper-Backed Lath

• Composition: Metal lath integrated with asphalt-impregnated paper
• Purpose: Combines moisture control with structural support
• Standard: Meets ASTM C847 requirements

Fiberglass Lath

Increasingly popular in modern construction, fiberglass lath offers corrosion resistance and is lighter than metal.

• Advantages: Non-conductive, non-rusting, compatible with all climates
• Usage: Coastal constructions, high-humidity zones

Key Applications of Lath in American Construction

Stucco Systems

Lath forms the foundation of three-coat and one-coat stucco systems.

• Three-Coat Stucco: Scratch coat, brown coat, finish coat applied over lath and building paper
• One-Coat Stucco: Integrates base and brown coat, saving labor while retaining durability

Interior Plastering

In interior settings, lath supports gypsum or lime-based plasters.

• Benefits: Acoustic insulation, fire resistance, traditional aesthetics
• Installation: Typically attached to framing with galvanized nails or staples

Stone Veneer and Tile Backing

Heavy cladding materials like stone veneer and large-format tiles require reinforced backing. Metal or fiberglass lath systems allow proper anchoring and long-term stability.

Specifications and Standards for Lath in the USA

The manufacturing and application of lath in the United States must comply with stringent building codes and standards:

• ASTM C847: Standard for metal lath
• ASTM C933: Specification for expanded metal lath
• ASTM C1032: For welded wire lath
• ASTM C1063: Installation guidelines for lath and stucco

Proper compliance ensures fire resistance, load capacity, and moisture protection—crucial elements in both residential and commercial applications.

Moisture Control and Weather Barriers

Lath often functions in tandem with weather-resistive barriers (WRBs) to prevent moisture ingress. In multi-family or high-rise constructions, double-layer WRBs are often required under lath systems.

• Best Practices: Overlap WRBs by a minimum of 6 inches horizontally and 2 inches vertically
• Moisture Flashing: Required around windows, doors, and wall penetrations

Modern Advancements in Lath Systems

Prefabricated Lath Panels

The introduction of pre-assembled lath panels has increased labor efficiency and installation consistency. These panels are especially useful for large-scale projects like schools, hospitals, and commercial buildings.

Synthetic Lath Systems

Innovative systems use polymer-based materials to enhance flexibility and reduce weight. These are particularly suitable for seismic zones and projects requiring reduced structural loads.

Sustainability and Environmental Considerations

Green building initiatives in the USA have influenced the development of eco-friendly lath materials:

• Recyclable Metal Lath: Made from post-industrial steel
• Low-VOC Adhesives and Coatings: Improve indoor air quality
• LEED Compliance: Some lath systems contribute points to Leadership in Energy and Environmental Design (LEED) certifications

Challenges and Installation Best Practices

Installing lath requires precision and an understanding of how load, weather exposure, and substrate conditions affect the overall assembly.

• Fastening: Use corrosion-resistant fasteners (stainless steel or hot-dip galvanized)
• Overlap: Lath sheets must overlap by at least 1 inch at seams
• Furring: Always ensure proper furring distance to prevent bridging and moisture retention

Regional Use of Lath Across the USA

Western States (California, Arizona, Nevada)

High use of stucco over metal lath, driven by arid climates and architectural trends. Local codes often specify two layers of WRB under lath.

Southern States (Texas, Florida)

In humid and hurricane-prone zones, fiberglass lath and corrosion-resistant metal lath dominate. Mold resistance and structural stability are key.

Northeast and Midwest

Historic renovations rely heavily on wood lath and traditional plastering techniques, while new construction often prefers metal lath for energy-efficient wall systems.

Lath Market Trends in the USA

Increased Demand for EIFS-Compatible Lath

Energy efficiency mandates have spurred growth in lath systems compatible with EIFS. These assemblies allow continuous insulation and vapor permeability.

Digital Layout and Robotic Installation

High-tech job sites now use BIM (Building Information Modeling) and robotic lath applicators to streamline large projects, reducing human error and speeding up timelines.

Conclusion

Lath remains a fundamental element in the structural and aesthetic integrity of American buildings. With advancements in materials, evolving codes, and growing demand for energy-efficient solutions, the future of lath in the USA looks promising and progressive. Whether you’re a contractor, architect, or property owner, understanding the nuances of lath systems is essential for building projects that last for generations.

This article is crafted to provide an in-depth overview of lath in the USA, covering its types, uses, standards, and emerging trends to serve professionals seeking reliable construction insights.