Section 1707 Lateral Braces
At each end of a retrofit stud, a lateral brace shall be installed as indicated in Figure 1707.1(1) or Figure 1707.1(3) for trusses and Figure 1707.1(2) or Figure 1707.1(4) for conventionally framed gable end walls. Lateral braces shall be allowed to be omitted in accordance with Section 1706.6 or 1707.4.1. Alternative methods for providing lateral bracing are allowable in accordance with Section 1707.4. Lateral braces shall be minimum 2 × 4 lumber except as required by Section 1706.6 or 1707.4.1.
Lateral braces shall be placed approximately perpendicular to the attic-framing members and extend so they are attached to a minimum of three attic-framing members. The attic-framing member farthest from the gable end wall shall be a minimum of 6 feet (1829 mm) from the exterior sheathing or siding on the gable end wall. Lateral braces shall be installed with their wide faces across attic-framing members. Where the method of Section 1708.1.1 is used, lateral braces shall butt against the sheathing or siding of the wall. Where the method of Section 1708.1.2 is used, lateral braces shall butt against the retrofit studs.
Where ceiling joists or truss bottom chords are deeper than 6 inches (152 mm), an anchor block shall be installed in each space between ceiling members along the length of the lateral brace except for the space next to the gable end wall.
Anchor blocks shall be fastened to lateral braces with a single row of 8d common nail, 10d common nails or #9 screws with minimum penetration into lateral braces equal to the thickness of the anchor block or 1 inch (25.4 mm) whichever is greater. The minimum number of fastener shall be the maximum that can be placed in a single row with minimum 23/4-inches (70 mm) distance between fasteners and 23/4-inches (70 mm) distance to ends of anchor blocks except that the number of fasteners need not exceed three per anchor block made of nominal 2-inch thick lumber. For nominal 2-inch thick lumber anchor blocks, the number of fasteners need not exceed three fasteners per anchor block.
Where existing conditions prevent installation of lateral braces in accordance with Section 1707.2, lateral braces shall be permitted to be omitted 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.
Where existing conditions prevent the installation of lateral braces of required length in accordance with Section 1707.1, a splice member shall be permitted to be installed to bridge interruptions. Splice members shall be at minimum the same size lumber as the lateral braces they bridge. Although Figure 1707.4.2 illustrates the general methods that can be used where attic-framing members are spaced 24-inches (610 mm) o.c., the methods apply to other on center spacings. Splice members may extend beyond those shown and are allowed to be fastened to the main lateral brace segments farther than shown. Splice members shall be fastened at each end using the number of fasteners equal to the total number that would be required to be placed in total in that part of lateral braces more distant from the gable end wall. For a lateral brace that requires three fasteners at each roof framing members and installation across three roof framing members, the number of fasteners in the splice need not be more than nine fasteners if the interruption is between the gable end wall and the first attic-framing member; six fasteners if between the first and second framing members, and three fasteners if between subsequent interruptions. Fasteners shall be spaced 1/2 inch (13 mm) from the edges of lateral braces, 1 inch from each other, 1/2 inch (13 mm) from the edge of attic members, and minimum 23/4 inches (25.4 mm) from the ends of lateral braces and from the ends of splice members.
Where conditions exist that prevent installation of lateral braces in accordance with Section 1707.4.1 or 1707.4.2, lateral braces shall be permitted to be shortened, except where the brace is adjacent to an omitted lateral brace of Section 1707.4.1, provided all of the following conditions are met.