Base Layer: 5/8” (15.9 mm) ToughRock® Fireguard X® or 5/8” (15.9 mm) DensArmor Plus® Fireguard® gypsum panels applied vertically to a double row of 1-5/8” (41 mm) (18 mils) steel studs 24” (610 mm) o.c. and not less than 1” (25 mm) apart with 1” (25 mm) Type S drywall screws 8” (203 mm) o.c. at edges and 12” (305 mm) o.c. at intermediate studs. 5/8” (15.9 mm) gypsum board pieces 12” (305 mm) long x not less than 4-1/2” (114 mm) wide located at 1/3 points used as cross braces fastened to stud pairs with three 1” (25 mm) Type S drywall screws at each end of brace. Optionally 25-gauge (18 mils) stud or runner pieces, not less than 4-1/2” (114 mm) long, may be used as cross braces and attached with two No. 8 x 1/2” (13 mm) self-drilling steel screws at each end. Where total cavity depth exceeds 9-1/2” (241 mm), cross braces shall be fabricated with 25-gauge (18 mils) stud or runner pieces. Face Layer: 5/8” (15.9 mm) ToughRock® Fireguard X™ or 5/8” (15.9 mm) DensArmor Plus Fireguard gypsum panels applied vertically to each side with 1-5/8” (41 mm) Type S drywall screws 8” (203 mm) o.c. at joints and floor and ceiling runners and 12” (305 mm) o.c. at intermediate studs. Sound Tested with 3-1/2” (89 mm) fiberglass insulation stapled in stud space
