What kind of fire rating does plaster provide?
Portland cement-based plaster, commonly called stucco, has long been and continues to be a popular choice for finishes on buildings. It allows for a wide expression of aesthetics, is a cost effective finish, is durable in all types of climates (especially wet ones), and offers fire resistance. Fire resistance is typically classified by a fire rating, but what kind of fire rating does plaster provide? Things that influence the fire rating of a plaster system include the type of material used for the support member, the size of the support member, the presence/absence and type of exterior sheathing, the aggregate in the plaster mix, the presence/absence of insulation, presence/absence of interior wall finishing materials (gypsum wallboard, etc.) and the thickness of the section. The type of member—wall, partition, ceiling, or other, and member classification (load bearing-LB or non-load bearing-NLB)—also influences the rating. In 1991, the Foundation of the Wall and Ceiling Industry publ
