International Building Code Section 2513

International Building Code 2513.1

General. Exposed natural or integrally colored aggregate
is permitted to be partially embedded in a natural or colored
bedding coat of cement plaster or gypsum plaster, subject
to the provisions of this section.

International Building Code 2513.2

Aggregate. The aggregate shall be applied manually or
mechanically and shall consist of marble chips, pebbles or similar
durable, moderately hard (three or more on the Mohs hardness
scale), nonreactive materials.
2006 INTERNATIONAL BUILDING CODE. 505
GYPSUM BOARD AND PLASTER

International Building Code 2513.3

Bedding coat proportions. The bedding coat for interior
or exterior surfaces shall be composed of one-part portland
cement, one-part Type S lime and a maximum of three parts of
graded white or natural sand by volume. The bedding coat for
interior surfaces shall be composed of 100 pounds (45.4 kg) of
neat gypsum plaster and a maximum of 200 pounds (90.8 kg)
of graded white sand.Afactory-prepared bedding coat for interior
or exterior use is permitted. The bedding coat for exterior
surfaces shall have a minimum compressive strength of 1,000
pounds per square inch (psi) (6895 kPa).

International Building Code 2513.4

Application. The bedding coat is permitted to be
applied directly over the first (scratch) coat of plaster, provided
the ultimate overall thickness is a minimum of 7/8 inch (22 mm),
including lath. Over concrete or masonry surfaces, the overall
thickness shall be a minimum of 1/2 inch (12.7 mm).

International Building Code 2513.5

Bases. Exposed aggregate plaster is permitted to be
applied over concrete, masonry, cement plaster base coats or
gypsum plaster base coats installed in accordance with Section
2511 or 2512.

International Building Code 2513.6

Preparation of masonry and concrete. Masonry and
concrete surfaces shall be prepared in accordance with the provisions
of Section 2510.7.

International Building Code 2513.7

Curing of base coats. Cement plaster base coats shall
be cured in accordance withASTMC926. Cement plaster bedding
coats shall retain sufficient moisture for hydration (hardening)
for 24 hours minimum or, where necessary, shall be kept
damp for 24 hours by light water spraying.
506 2006 INTERNATIONAL BUILDING CODE.
GYPSUM BOARD AND PLASTER