California Lathing and Plastering Contractor (C-35 License) Practice Exam

When evaluating gypsum lath, the term listed means the product has been tested and approved for use in plaster systems by the appropriate standards or code bodies. Lead-backed describes a gypsum lath that includes a lead backing as part of its listed specification. This makes it the correct way to identify the listed type you’re being asked about. Lead backing serves as part of the listed product, giving it a specific purpose and certification in plaster systems.

The other terms describe different features or products: perforated refers to holes in the lath to help key the plaster, and Type X is a fire-rated gypsum board used in walls, not a plaster lath listing. Saying all of the above would imply that every item is a listed gypsum lath type, which isn’t what the listing refers to in this context.