Practical Engineering: Strength of Plywood Sheathing

Occasionally a builder will ask whether let-in bracing is as good as plywood sheathing for resisting lateral loads on buildings. The answer is simple: Let-in bracing does not come close to plywood. In structural design calculations, engineers usually ignore any contribution that let-in braces may make. Code-Minimum Bracing Building codes generally prescribe that exterior stud walls be braced, at each end, with let-in 1x4s, metal strap devices, diagonal wood sheathing, or plywood or OSB sheathing. Figure 1 shows two common ways of complying. Let-in bracing. Building codes require you to nail let-in bracing with two 8d nails (or 13/4-inch staples) at every stud and each plate. Yet despite all these nails, the design lateral load capacity is limited by the