Practical Engineering: Building Strong Garage Door Walls, continued
Follow the Recommendations
Before using this technique on a job, take time to study the APA's literature, available free online at www.apawood.org/bracing. This document suggests that the Narrow Wall Bracing Method should be:
• used next to garage doors only
• applied only to the first story of residences up to two stories
• used only on structures that are entirely sheathed
• used only in Seismic Design Categories A through C
And as you might expect, you should always confirm that the codes and inspectors who govern your area have no problems with the APA system.
As a builder, I feel the trickiest aspect of the APA method is the fussy placement of the anchor bolts. Most of the foundation subs I've worked with would likely have difficulty grasping the importance of accurately placing the bolts: If they're 3/4 inch off, you may not be able to install the plate washers. My strategy is to highlight the bolt placement details on the copy of the plans I give the sub, and to remind him that the amount of his final payment is directly tied to accurate anchor bolt placement. Retrofitting a botched bolt placement would be time consuming and expensive.
The restriction on sheathing penetrations is also problematic from a supervisor's standpoint: I've got to make sure everybody on the site knows not to mess with the narrow-wall sheathing. My approach? Spray paint "NO HOLES" on the sheathing and the housewrap as they're installed. It's a good idea to explain the same thing to the homeowners, so they don't later decide to put a pet door in the wall. I also document this restriction.
Contributing editorCarl Hagstromis a builder in Montrose, Pa., and presents structural clinics at JLC Live.