What is the maximum hole that can be drilled in 2x4 studs in load bearing walls for wiring or plumbing?
The diameter of drilled holes in studs should not exceed 40 percent of the stud depth, and the minimum edge distance to the boundary of the hole shall not be less than 5/8-inch. When studs are doubled, drilled holes should not exceed 60 percent of the stud depth. Holes of maximum diameter should not occur in more than two consecutive studs. Adjacent holes, or holes and notches should not occur in the same cross section. As an example, a 2x4 can have a maximum hole of 1 3/8-inch or 2 inches if studs are doubled.