Nail Depth Matters

New research published in the Forest Products Journal suggests that overdriving nails reduces building durability. When nails are slammed into OSB to a depth of 3.2 mm or more, they make panels stiffer, but higher stresses on the joints cause them to lose some of their peak load capacity. “As nail overdriven depth increases, the bearing capacity of the panel is reached sooner along the loading sequence,” the researchers note. “The panel therefore fails before the nail.” The team points to the (mis) use of pneumatic nailguns—which are often poorly adjusted. They found that 80% of nails in the San Francisco area had been overdriven, with one-third of them at least 3.2 mm too deep. The fix, fortunately, is simple—adjust all nailguns to do the job right.