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.”