International Building Code 2502.1
Definitions. The following words and terms shall, for
the purposes of this chapter and as used elsewhere in this code,
have the meanings shown herein.
CEMENT PLASTER. A mixture of portland or blended
cement, portland cement or blended cement and hydrated lime,
masonry cement or plastic cement and aggregate and other
approved materials as specified in this code.
EXTERIOR SURFACES. Weather-exposed surfaces.
GYPSUM BOARD. Gypsum wallboard, gypsum sheathing,
gypsum base for gypsum veneer plaster, exterior gypsum soffit
board, predecorated gypsum board or water-resistant gypsum
backing board complying with the standards listed in Tables
2506.2, 2507.2 and Chapter 35.
GYPSUM PLASTER. A mixture of calcined gypsum or calcined
gypsum and lime and aggregate and other approved
materials as specified in this code.
GYPSUM VENEER PLASTER. Gypsum plaster applied to
an approved base in one or more coats normally not exceeding
1/4 inch (6.4 mm) in total thickness.
INTERIOR SURFACES. Surfaces other than
WEATHER-EXPOSED SURFACES. Surfaces of walls,
ceilings, floors, roofs, soffits and similar surfaces exposed to
the weather except the following:
1. Ceilings and roof soffits enclosed by walls, fascia, bulkheads
or beams that extend a minimum of 12 inches (305
mm) below such ceiling or roof soffits.
2. Walls or portions of walls beneath an unenclosed roof
area, where located a horizontal distance from an open
exterior opening equal to at least twice the height of the
3. Ceiling and roof soffits located a minimum horizontal
distance of 10 feet (3048 mm) from the outer edges of the
ceiling or roof soffits.
WIRE BACKING. Horizontal strands of tautened wire
attached to surfaces of vertical supports which, when covered
with the building paper, provide a backing for cement plaster.