IBC Design 721.1(3) 26-1.1

1-Hour Fire Rated Wood I-joist (minimum I-joist depth 9-1/4" with a… — Two layers of 1/2" Type X gypsum wallboard…

IBC Table 721.1(3), Item 26-1.1: Wood I-joist (minimum I-joist depth 9-1/4" with a minimum flange thickness of 1-1/2" and a minimum flange cross-sectional area of 2.25 square inches; minimum web thickness of 3/8") @ 24" o.c.. Ceiling: Two layers of 1/2" Type X gypsum wallboard applied with the long dimension perpendicular to the I-joists with end joints staggered. The base layer is fastened with 1-5/8" Type S dry wall screws spaced 12" o.c. and the face layer is fastened with 2" Type S drywall screws spaced 12" o.c. in the field and 8" o.c. on the edges. Face layer end joints shall not occur on the same I-joist as base layer end joints and edge joints shall be offset 24" from base layer joints. Face layer to also be attached to base layer with 1-1/2" Type G drywall screws spaced 8" o.c. placed 6" from face layer end joints. Face layer wallboard joints to be taped and covered with joint compound. Minimum slab thickness — 1-hr: Varies". Minimum ceiling thickness — 1-hr: 1". Prescriptive assembly from the adopted building code — see table footnotes for conditions.