Job: 03-30364 Title: Rp-Architecture Reference & Speciﬁcation
#175 DTP: 216 Page: 46
Gypsum board goes by many names: gypsum wallboard (GWB), drywall, plasterboard, and
Sheetrock (a trademarked brand name). Gypsum board is a less expensive alternative to
plaster, because it requires less labor, time, and skill to install, but it still provides excellent
re-resistance and sound control.
Gypsum, a naturally occurring mineral, is formulated chemically when combined with water,
starch, and other elements into a slurry and placed between paper faces to become gypsum
board. When gypsum board is exposed to re, the water is released as steam, providing a re
barrier until the water is completely eliminated (calcination). When the gypsum is completely
calcined, its residue still acts as an insulating barrier to ames, preventing the structural
members behind it from igniting.
Panel sizes may
vary depending on
the type of board,
they fall in the
4’ (1 220) wide by
8’ (2 439) to
16’ (4 877) high.
Widths of 2’ (610)
and 2’-6” (762)
and heights of
6’ (1 829) may also
be available for
boards and core
SI Preferred Sizes
Standard panel size
is 1 200 x 2 400 mm.
600 mm, 800 mm,
and 900 mm.
Backing board: Used as a base layer when
multiple layers are needed, improving re
resistance and sound control.
Coreboard: Thicker boards, 1” (25.4) and
2” (50.8), used to enclose vent shafts,
emergency egress stairs, elevator shafts,
and other vertical chases.
Foil-backed: Can work as a vapor barrier
in exterior wall assemblies and as a thermal
Preﬁnished: Covered in a variety of nishes
such as paint, paper, or plastic lm for
installation without further nishing.
Regular: Used for most applications.
Type X: Short glass bers in the core hold
the calcined gypsum residue in place for
increased re resistance protection ratings.
Water-resistant (green board): Water-
resistant board with a water-repellent paper
facing (colored light green to distinguish it
from other walls) and a moisture-resistant
core (also available in type X); used as base
for tiles and other nonabsorbent materials in
46 THE ARCHICTECTURE REFERENCE + SPECIFICATION BOOK
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