For the purpose of the Washington state public works law, chapter 39.12 RCW, plasterers apply gypsum, portland cement, stucco, imitation stone, and kindred materials and products to interior walls, ceilings, and partitions and to exterior walls of buildings, and finish those materials and products.

The work includes, but is not limited to:

• The spreading of plaster over laths, masonry, or any other base, using trowel and smoothing the plaster with darby and float for uniform thickness.

• The application of all the various manufacturer's brand names of "thin coat" or "plaster veneer."

• The application of all bonding agents and mastical.

• Roughing of undercoat with wire or metal scraper to provide bond for succeeding coats of plaster.

• The application of all malleable plastic materials and apoxy materials.

• The setting in place of plasterboard, insulationboard, "styro-foam and bead-board," ground, locks, patent dots, cork plates, brownstone and acoustical tile, fiberglass reinforcement and finished products.

• The plastering of joints, nail holes, and bruises on wallboard.

• The grouting and filling of door bucks, runners and similar installations.

• The application of scratchcoat, browncoat, and finishcoat of plaster to wood, metal, or board laths successively to all ceilings and walls when finished with terrazzo or tile, and the application of any plastic material to same.

• The fireproofing of all building assemblies with plaster materials, sprayed fiberglass or similar materials, whether applied to gypsum, metal lath or directly.

• All waterproofing work, such as the cutting and placing of nylon mesh and the plastering and finish of all exterior wall insulation and plaster finish systems.

• The application of crushed stone, marble or ceramic chips and broken glass where embedded in plaster, cement, plastic, or similar materials.

• The placing of acoustic blocks with any plastic material, regardless of thickness.

• The placing, by any method, of plaster or composition caps and ornaments.

• Creating decorative textures in finish coat by marking surface of coat with brush and trowel or by spattering it with small stones ("stucco") where plastering equipment and/or materials are used.

• The operation and control of all types of plastering machines, including power trowels and floats.

• All clean-up work.