Q. When fastening Zip System sheathing to wall and roof framing with our pneumatic nailers, we’ve found that it’s difficult to keep nail heads from penetrating the applied protective barrier on the face of the panels. Won’t these holes compromise the moisture barrier’s integrity and lead to problems later on? Should they be covered with tape? And what happens if the Zip tape fails?
A. Chris Rogers, technology manager at Huber Engineered Woods, the manufacturer of Zip System wall and roof sheathing, responds: With a sheet-type water-resistive barrier (like housewrap), any small hole can become an entry point for water, which can then spread to the area between the sheathing and the housewrap. This water has a direct path to the wall cavity through the gaps between the sheathing panels.
The Zip System panel has a phenol-impregnated kraft-paper overlay laminated to it; for water to get behind this moisture barrier, it would have to migrate around the nail head and flow down the shaft of the nail all the way through the panel.
Our testing has shown that minor penetrations in the moisture barrier caused by overdriven fasteners won’t compromise the system’s ability to resist moisture, nor will they void the manufacturer’s warranty. And unless the fastener creates a hole all the way through the panel, it isn’t necessary to apply tape to overdriven fasteners.
Keep in mind, though, that overdriven fasteners can reduce the panel’s shear strength, a problem with any wood diaphragm or shear wall constructed with structural OSB or plywood.
