In many parts of the United States, it’s becoming common for builders to install rigid-foam sheathing on the exterior of framed walls. However, this raises a potential problem: Because rigid foam isn’t structural, how are the walls braced to prevent racking? There are at least five ways to brace a foam-sheathed wall, the first of which most builders and inspectors are familiar with.
Using continuous plywood or oriented-strand-board (OSB) sheathing under the foam allows you to use the prescriptive section of the code—a simpler route than an engineered solution—even in high-wind areas. Where rough-cut 1-in. boards are available from local sawmills, diagonal board sheathing is also worth considering. It is a strong, vaporpermeable, code-approved method of bracing walls. If you aren’t building in a high-wind area, however, continuous sheathing is likely to cost more than other bracing solutions. Here are four alternatives.