Except as allowed by Section 1706.5, a retrofit stud shall be installed at each primary stud longer than 3 feet (914 mm) where lateral braces can be installed using the methods of Section 1707. The size of retrofit studs shall be as required by Table 1704.1 for the appropriate retrofit configuration. Where straps are installed using the L-bent strap method of Section 1708.1.1, retrofit studs shall extend from the top of the lower lateral brace up to the bottom of the upper lateral brace, except that a maximum gap of 1/8 inch (3 mm), is allowed at the bottom and 1/2 inch (13 mm) at the top. Where straps are installed using the U-bent method of Section 1708.1.2, retrofit studs shall extend beyond the ends of lateral braces such that lateral braces can fully butt against the retrofit studs.
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.
- 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.
- Fasteners into nailers through the face of either member shall be offset vertically by a minimum of 23/4 inches (70 mm).
- 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.
- Fasteners shall be placed minimum 1/2 inch (13 mm) from the edges of studs.
- Nail plates shall be spaced such that vertical spacing between plates shall be a maximum of 20 inches (508 mm).
- There shall be at least three fasteners through each nail plate into both the primary and retrofit studs.
- Fasteners used to secure nail plates to studs shall be a minimum 11/2 inches (38 mm) long and fasteners shall be a minimum of 23/4 inches (70 mm) and a maximum of 6 inches (152 mm) from the ends of retrofit studs.
- Fasteners placed in nail plates shall be spaced a minimum of 23/4 inches (70 mm) along the length of lumber and 23/4 inches (70 mm) from ends of lumber.
- Fasteners shall be placed a minimum of a 1/2 inch (13 mm) from the edges of the studs and a maximum of 11/2 inches (38 mm) from the abutting vertical edges of primary and retrofit studs.
NAIL PLATE FASTENING
The broad face of retrofit studs may be reduced in width by methods of cutting, boring, or notching at any number of locations along their length provided that all of the following conditions are met.
- The wide face of retrofit studs shall be sized such that the remaining minimum width of the member at each location of reduced width shall not be less than that required by Table 1704.1.
- The distance between segments of reduced width shall be a minimum of 8 inches (203 mm) and shall be allowable at the ends of retrofit studs.
- The average spacing of fasteners connecting retrofit studs to existing studs shall be maximum 6 inches (152 mm) on center.
- The minimum vertical distance between fasteners on studs shall be a minimum of 23/4 inches. (70 mm).
- Retrofit studs reduced in width shall not be spliced within 12 inches (304.8 mm) of the location of reduced width. Splice members shall not be notched.
Where existing conditions prevent installation of a full length retrofit stud in accordance with Section 1706.1 or 1707.4, the retrofit stud and its associated two lateral braces shall be permitted to be wholly or partially omitted from that location by installation of a ladder assembly for Retrofit Configurations A and B as defined in Table 1704.1 provided all of the following conditions are met. This method is not allowed for Retrofit Configurations C or D.
- No more than two ladder assemblies are permitted on a single gable end.
- There shall be at least two retrofit studs and lateral brace assemblies on each side of the location where a retrofit stud is omitted.
- Where both of the retrofit studs on each side of an omitted retrofit stud would be required by Table 1704.1 to be 2 × 4, they shall both be 2 × 6. Where either retrofit stud on the side of an omitted stud would be required by Table 1704.1 to be 2 × 6, they both shall be 2 × 8. Where either retrofit stud on the side of an omitted stud would be required by Table 1704.1 to be 2 × 8, they both shall be 2 × 10.
- Lateral braces adjacent to the omitted lateral brace shall be minimum 2 × 6 lumber extended over four roof framing members and be fastened to each of the four attic-framing members crossed, using minimum four (4) 3-inch long fasteners. Fasteners shall be installed in accordance with Section 1706.4.
- Ladder rungs shall be of minimum 2 × 4 lumber installed horizontally with their wide face oriented horizontally and installed to span between the retrofit studs on either side of the omitted retrofit stud. The edge of the ladder rung shall bear against the primary stud at the location of the omitted retrofit stud. Ladder rungs shall be vertically spaced a maximum of 16-inches (406 mm) on center.
- Where ladder rungs cross and bear against the primary stud at the location of the omitted retrofit stud, they shall be attached to the primary stud using a stud-to-plate connector with a minimum capacity of 175 pounds (79 kg) in the direction perpendicular to the gable end wall. Ladder rungs shall be attached to the retrofit studs on both sides of the location where the retrofit stud is omitted using two 3-inch long fasteners driven through the retrofit stud and into the end of the ladder rung.
- Notching of the ladder rungs shall not be permitted unless the net depth of the ladder rung is a minimum of 31/2 inches (89 mm) in the area of the notch.
Retrofit studs shall be permitted to be spliced provided all of the following conditions are met.
- Retrofit studs shall be butted to one another at the splice joint and a minimum 4 foot (1219 mm) length of splice member shall be centered at the butt joint.
- Lumber splice members shall be nominal 2-inch lumber with the wide face width equal to or wider than the face width of the spliced retrofit studs.
- Splice members shall be attached to each of the retrofit stud members on each side of the splice with minimum 7 rows of 3 fasteners for a total of 21 fasteners. Rows of fasteners shall be minimum 23/4 inches (70 mm) from the end of the splice member, minimum 23/4 inches (70 mm) from the splice joint and ends of members, and spaced evenly along the 18-inch (457 mm) splice overlap between these two limits.