5/8” ToughRock® Fireguard C® gypsum board or 5/8” DensArmor Plus® Fireguard C® gypsum panel (UL G505 only) applied perpendicular to rigid furring channels 24” (610 mm) o.c. with 1” (25 mm) Type S drywall screws 12” (305 mm) o.c. Drywall end joints located midway between continuous channels and attached to additional pieces of channel 62” (1575 mm) long with screws 12” (305 mm) o.c. Furring channels attached with 18-gauge (43 mils) wire ties to open web steel joists 24” (610 mm) o.c. supporting 3/8” (10 mm) rib steel lath and 2” (51 mm) concrete slab. (Two hours restrained and unrestrained.)
