This specification covers gypsum boards which include the following: gypsum wallboard for use on walls, ceilings, or partitions and that affords a surface suitable to receive decoration; predecorated gypsum board for use as the finished surfacing for walls, ceilings, or partitions; gypsum backing board, coreboard, and shaftliner board for use as a base in multilayer systems or as a gypsum stud or core in semisolid or solid gypsum board partitions, or in shaft wall assemblies; water-resistant gypsum backing board to be used as a base for the application of ceramic or plastic tile on walls or ceilings; exterior gypsum soffit board for exterior soffits and carport ceilings that are completely protected from contact with liquid water; gypsum sheathing board for use as sheathing on buildings; gypsum base for veneer plaster; gypsum lath for use as a base for gypsum plaster application; and gypsum ceiling board for interior ceilings and walls. Gypsum board shall consist of a noncombustible core, essentially gypsum, surfaced with paper bonded to the core. The specimens shall comply with the following required physical properties: core, end, and edge hardness; straightness of the edges and ends; length; tapered edge depth; flexural strength; humidified deflection; nail pull resistance; permeance; water resistance; and surface water absorption.