Workers in this group install laths and apply plasters to walls and ceilings of buildings. Their functions include: applying one or more coats of plaster to interior walls and ceilings of buildings to produce finished surface; moulding and installing ornamental plaster panels and trimming and casting ornamental plaster cornices; applying protective and decorative covering of cement, plaster and similar materials to outside building surfaces; making and installing decorative plaster fixtures of fibrous plaster; performing related tasks.