What is the minimum length of drywall screw for attaching 1/2-inch gypsum board to wood studs?

What is the minimum length of drywall screw for attaching 1/2-inch gypsum board to wood studs?

• A. 1 1/4 inches
• B. 1 1/8 inches
• C. 2 inches
• D. 3/4 inch

Answer: (B)

The length must cover the drywall thickness plus enough of the screw to bite into the stud for a secure hold. For 1/2-inch gypsum board, you want about 5/8 inch of the screw to penetrate into the wood stud. So the minimum total length is 1/2 inch (the board) plus 5/8 inch (into the stud) equals 1-1/8 inches. That’s why the shortest screw that provides proper bite is 1-1/8 inches. Using a shorter screw wouldn’t reach into the stud enough and could pull out, while longer screws are common but not required for the minimum.