Simplified Alternatives to Traditional Exterior Wall Bracing

Although codes have long required that exterior wall bracing be able to resist racking from wind forces, recent years have seen these requirements grow in complexity. Even some engineers struggle with them. Never fear, now there’s an alternative, easier way to satisfy the code’s intent for exterior wall bracing.

The problem is that the wall bracing chapter in the 2012 International Residential Code (IRC Section R602.12) is 28 pages long and details approaches that range from let-in braces to gypsum board to structural panels. Although it does include a “simplified” bracing method for entry-level homes with simple geometry, anything taller, more complicated, or with lots of windows and doors – in other words, most custom homes – will probably need to be engineered.

The alternative mentioned above, which fits into a 7-page pdf document, was developed by APA, the Engineered Wood Association . Tests have shown it to provide adequate exterior wall bracing racking resistance on even the most complex exterior walls.

What this method does is provide the builder with greater design flexibility. For instance the IRC requires that wood bracing panels be at least 48 in. wide to count toward the overall exterior wall bracing requirement; with the APA method, on the other hand, panels as narrow as 16 in. wide can be counted, which means that exterior walls can have more windows and still meet the code.

The APA method requires the use of plywood or OSB bracing panels, which are stronger than other materials, and specifies that those panels be installed continuously from one end of the wall to the other. Panels must be at least 7/16 in. thick and must be fastened with an enhanced nailing schedule (which is spelled out in the document). Following these prescriptions will provide adequate bracing even on walls with lots of openings, as long as the bracing panels extend above and/or below those openings to maintain the continuous line.

There are limitations – for example, when building exterior wall bracing, exterior walls must be no higher than 10ft. tall, foundations must be concrete, and floor cantilevers can’t exceed 24 inches – but the vast majority of one and two-story homes should conform.

Although this alternative isn’t an official part of the IRC, it has been adopted by a few states and is pending in others. But APA technical representative Tom Kositsky says that most building officials understand that it meets the code’s intent. “The vast majority of building officials around the country recognize this approach,” he says. “So far we haven’t run into one who doesn’t get it.”