Laths for Plastering in USA: Comprehensive Guide to Types, Uses, and Benefits

When it comes to plastering projects in the USA, laths play a pivotal role in ensuring a durable, smooth, and high-quality finish. Whether for residential or commercial construction, choosing the right lath for plastering is essential to achieve optimal results that stand the test of time. In this extensive guide, we delve into everything you need to know about laths for plastering in the USA, covering types, materials, installation techniques, and industry standards to help professionals and DIY enthusiasts make informed decisions.

What Are Laths and Why Are They Essential for Plastering?

Laths are narrow strips or sheets of material, traditionally wood or metal, fixed onto a wall or ceiling surface to serve as a base or framework for plaster application. They provide the necessary support and adhesion for plaster, enabling it to grip firmly and remain intact without cracking or falling off.

In the modern USA construction industry, laths ensure:

• Structural integrity of plaster layers
• Improved moisture resistance
• Enhanced fire resistance when using metal laths
• Better surface uniformity for plaster finishes

Understanding the function of laths is crucial in selecting the right type based on your specific project needs, environmental conditions, and compliance with American building codes.

Types of Laths Used for Plastering in the USA

1. Wood Laths

Historically predominant, wood laths are thin, narrow strips of wood spaced evenly across a frame. Made primarily from pine or cedar, wood laths provide a natural, breathable base for traditional plastering methods.

• Advantages:
  • Easy to cut and install
  • Natural material with good breathability
  • Cost-effective for small or restoration projects
• Disadvantages:
  • Susceptible to moisture damage and rot
  • Prone to warping and splitting over time
  • Less fire-resistant compared to metal options

Wood laths remain popular in restoration or renovation projects where maintaining historical accuracy is essential.

2. Metal Laths

In the USA, metal laths have largely replaced wood laths in new construction due to their superior durability, fire resistance, and consistent quality. They are typically made from galvanized steel or stainless steel and come in various configurations:

• Expanded Metal Lath: A sheet of steel that is slit and stretched to create a mesh-like pattern, providing excellent plaster keying.
• Self-furring Lath: Features dimples or ribs that keep the lath away from the substrate, allowing plaster to encapsulate it fully.
• Wire Lath: Woven wire mesh, less common but still used in specialty applications.
• Advantages:
  • High durability and longevity
  • Excellent fire resistance, critical for USA building codes
  • Resists rust when properly galvanized
  • Provides a strong mechanical bond with plaster
• Disadvantages:
  • Heavier and more expensive than wood laths
  • Requires specialized fasteners and installation skills

3. Gypsum and Synthetic Laths

More recently, gypsum lath and synthetic lath products have gained traction in the USA market, especially in interior drywall and plaster veneer systems.

• Gypsum Lath: Acts as a base for plaster with inherent fire resistance and mold resistance.
• Fiberglass Mesh Lath: Used mainly as reinforcement for thin-coat plaster or stucco, offering crack resistance and flexibility.

These materials complement modern plastering techniques and enhance performance, especially in areas prone to moisture or structural movement.

Choosing the Right Lath for Your USA Plastering Project

Selecting the appropriate lath depends on various project-specific factors:

Environmental Conditions

• Exterior vs. Interior: Metal laths are preferred outdoors for their weather resistance, while wood laths might suffice indoors if moisture is controlled.
• Moisture Exposure: Galvanized or stainless steel laths prevent corrosion in humid or wet environments.

Project Type

• New Construction: Metal laths are standard for durability and compliance with building codes.
• Restoration: Wood laths are often mandated to preserve architectural integrity.
• Renovation: Gypsum or synthetic laths may be used for plaster veneer systems.

Building Codes and Standards

In the USA, lath installations must comply with ASTM standards such as ASTM C1063 for metal lath and plaster, and local building codes that dictate fire resistance and structural requirements. Ensuring adherence to these standards is non-negotiable for legal and safety reasons.

Installation Best Practices for Laths in Plastering

Proper installation of laths is critical for the longevity and performance of plaster finishes:

Fastening

• Use corrosion-resistant nails or staples for wood laths.
• For metal laths, employ self-drilling screws or specialized fasteners that comply with manufacturer recommendations.
• Maintain proper spacing to allow plaster to key through and around the lath.

Substrate Preparation

• Ensure surfaces are clean, dry, and structurally sound.
• Attach laths to studs or framing members firmly without sagging.
• For metal laths, use self-furring types when attaching directly to solid surfaces to create an adequate plaster cavity.

Plaster Application

• Apply a scratch coat that keys into the lath surface.
• Follow with one or more brown coats for leveling.
• Finish with a smooth top coat for aesthetics.

Adhering to these steps ensures that the plaster adheres optimally to the lath, minimizing risks of cracks or detachment.

Benefits of Using Quality Laths for Plastering

Investing in high-quality laths for plastering in the USA delivers numerous advantages:

• Enhanced durability and resistance to environmental stresses
• Improved fire safety—a critical factor in modern building safety standards
• Superior adhesion and plaster retention, reducing maintenance costs
• Consistent surface finish with fewer imperfections
• Compliance with building codes, preventing costly rework or penalties

Where to Buy Laths for Plastering in the USA

Reliable sourcing is vital for project success. Leading USA suppliers and manufacturers offer a range of laths tailored for different plastering needs, including:

• National building material distributors
• Specialty plaster supply companies
• Online retailers with fast shipping and technical support

Ensure you choose products with proper certifications and warranties to guarantee quality.

Conclusion

In the evolving landscape of plastering in the USA, selecting the right laths is foundational to delivering high-performance, aesthetically pleasing, and code-compliant finishes. Whether opting for traditional wood laths in historic renovations or galvanized metal laths for modern constructions, understanding the nuances of each type, proper installation techniques, and sourcing quality materials will ensure your plastering project stands the test of time.

We recommend consulting with industry professionals and local building authorities to align your lath choice with specific project requirements and regulatory standards. With the right approach, laths transform mere plaster into a resilient, elegant, and enduring surface.

Thank you for reading this comprehensive guide on laths for plastering in the USA.