Lath

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Lath

What is Lath?

Thin strips of wood, metal, or other material used as a base for plaster application, providing mechanical attachment and support for wet plaster finishes in construction applications.

Description

Lath is thin strips of wood, metal, or other material used as a base for plaster application, providing mechanical attachment and support for wet plaster finishes in construction applications. This substrate system creates a framework that allows wet plaster to key into gaps and irregularities, forming a strong mechanical bond as it dries and cures. Lath has been used for centuries in plastering applications and remains an important component in traditional and specialty plaster systems for both interior and exterior applications.

The primary purposes include providing mechanical attachment for plaster systems, creating a substrate for wet plaster application, enabling proper keying and bonding of plaster materials, supporting the weight of wet plaster during application and curing, allowing for thermal expansion and contraction of plaster, providing reinforcement against cracking and movement, and creating a base for decorative and functional plaster finishes.

Types and materials involve wood lath, metal lath, gypsum lath, and specialty lath products for different plaster applications.

FAQs

  • What is lath?

    Lath is thin strips of wood, metal, or other material used as a substrate for plaster application, providing mechanical attachment and support for wet plaster finishes.

  • What types of lath are available?

    Common types include wood lath (traditional thin strips), metal lath (expanded metal, wire mesh), gypsum lath, and specialty synthetic products.

  • How does lath work with plaster?

    Lath provides gaps and openings that allow wet plaster to flow through and key mechanically, creating a strong bond as the plaster cures.

  • Is lath still used in modern construction?

    While largely replaced by drywall in residential work, lath is still used for specialty plaster applications, restoration work, and high-end finishes.

  • What spacing is required for wood lath?

    Wood lath strips are typically spaced with 3/8″ to 1/2″ gaps between strips to allow proper plaster keying and attachment.

  • How is metal lath different from wood lath?

    Metal lath provides superior attachment, doesn’t shrink or swell, resists fire and insects, and works better for exterior stucco applications.

  • Can lath be used for exterior applications?

    Yes, metal lath is commonly used as a base for exterior stucco systems, while wood lath is typically limited to interior applications.

Fun Fact

Fun Fact: The word “lath” comes from the Old English “laett,” meaning a thin strip of wood! Traditional lath was often made by splitting logs with a tool called a “lath hammer” or “lathing hatchet.” Some historic buildings have lath made from chestnut wood that’s over 200 years old and still in excellent condition. Interestingly, the spacing of lath strips was so critical that experienced plasterers could tell the quality of a job just by looking at the lath installation!

CSI Code

09 29 00

NAHB Code

910