All exterior lath must be corrosion-resistant materials.

All exterior lath must be corrosion-resistant materials.

• A. Corrosion-resistant materials
• B. Magnetic materials
• C. Non-metallic materials
• D. Wood

Answer: (A)

Exterior lath is continually exposed to moisture and weather, so it must resist corrosion to prevent rust, loss of strength, and failure of the plaster bond over time. The requirement is about the material’s ability to withstand corrosive attack, not about other properties; using corrosion-resistant materials keeps the exterior plaster system durable and long-lasting. Magnetic properties aren’t related to weather resistance, and wood is not suitable for exterior lath because it can decay and deteriorate when wet. Non-metallic materials could be corrosion-resistant in some cases, but the question emphasizes the need for corrosion resistance as the defining requirement, rather than classifying by material type alone.

Exterior lath is continually exposed to moisture and weather, so it must resist corrosion to prevent rust, loss of strength, and failure of the plaster bond over time. The requirement is about the material’s ability to withstand corrosive attack, not about other properties; using corrosion-resistant materials keeps the exterior plaster system durable and long-lasting.

Magnetic properties aren’t related to weather resistance, and wood is not suitable for exterior lath because it can decay and deteriorate when wet. Non-metallic materials could be corrosion-resistant in some cases, but the question emphasizes the need for corrosion resistance as the defining requirement, rather than classifying by material type alone.