Home›Knowledge›Gypsum Board — 5/8" Type X (Fire-Rated)
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Gypsum Board — 5/8" Type X (Fire-Rated)

Updated Mar 25, 2026
Fire-rated gypsum wallboard providing 1-hour fire resistance when applied to each side of a wood or steel stud wall. Required by IBC for fire-resistance-rated assemblies. 4x8 and 4x12 sheets standard.

Type X gypsum board contains special core additives (glass fibers and other materials) that increase fire resistance. 5/8-inch Type X on each side of wood or steel studs provides a 1-hour fire-resistance-rated wall assembly. Key properties: Weight approximately 2.2 psf. STC rating of 35-55 depending on assembly. Provides abuse resistance for commercial corridors. Meets ASTM C1396. UL designs: U305 (1-hr wood stud), U411 (1-hr steel stud), U419 (2-hr steel stud with double layer). Regular 1/2-inch gypsum is NOT fire-rated. Type C provides enhanced fire performance. Moisture-resistant (green board) and mold-resistant (purple board) versions available but have different fire ratings. Always verify UL design number for specific assembly rating.

TAGS
gypsumdrywallfire-ratedtype-xcsi-09wall-assembly
DETAILS
csi division
09 - Finishes
environmental
{"recyclability":"partial","sustainability_grade":"B"}
material class
gypsum_board
cost benchmarks
[{"date":"2025-Q4","unit":"SF","region":"us_national","cost_low":0.42,"cost_mid":0.55,"cost_high":0.75}]
physical properties
{"stc_range":"35-55","weight_psf":2.2,"thickness_inches":0.625,"fire_rating_hours":1}
applicable standards
["ASTM C1396","UL Design U305","UL Design U411"]
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