Retrofit studs and existing studs shall be connected using minimum 2 × 4 nailers as indicated in Figure 1706.3(d), provided the following conditions are met. Nailers may be comprised of multiple members lengthwise.
1. Both the primary stud and the retrofit stud shall be butted to nailers and both shall be fastened to the nailer with 3-inch fasteners. Fasteners connecting each stud to the nailer shall be spaced 6-inches (152 mm) on center.
2. Fasteners into nailers through the face of either member shall be offset vertically by a minimum of 23/4 inches (70 mm).
3. Fasteners into nailers shall be a minimum of 23/4 inches (70 mm) but not more than 6 inches (152 mm) from the end of the shorter of the primary stud or retrofit stud to which they are fastened.
4. Fasteners shall be placed minimum 1/2 inch (13 mm) from the edges of studs.