It’s Time to Switch to Cap Fasteners
Gone are the days of hammer tackers for installing housewrap and roof underlayment.
Synopsis: Once upon a time, a hammer tacker was the best tool for attaching housewrap and roof underlayment to house sheathing. Now, according to builder Mike Guertin, it’s time to switch to cap fasteners. These tools are not only more effective but also are what you need to comply with manufacturer instructions and building codes. Caps are 1-in-dia. or larger plastic or metal disks fastened with nails or staples. The cap increases the fastener’s surface area, meaning less chance for tearing even under windy conditions or foot traffic. Pneumatic cap staplers are available in two styles: tools that attach lighter weight 20- and 21-ga. staples; and tools that attach 18-ga. staples, which have more holding power. Pneumatic cap nailers also are available. Additionally, National Nail makes a hammer tacker that has a manual cap-feed trigger.
Hammer tackers, the tools used to fasten the membrane you’re counting on to back up your siding or roofing, are obsolete. They don’t meet most house wrap and underlayment manufacturers’ instructions and, by extension, don’t comply with building codes. If this is news to you, you aren’t alone.
When I talk with building pros about the now-fading era of hammer tackers, they often respond with skepticism. They claim they’ve used hammer tackers for X number of years without a problem, or they point out that everyone else uses them. Unfortunately, most installers are not aware that cap fasteners — 1-in.-dia. or larger plastic or metal disks fastened with nails or staples — are a more effective alternative.
In fact, of the 52 synthetic-roof underlayment and house wrap installation instructions I recently researched, 43 called for a minimum 1-in.-dia. cap-type fastener. And starting with the 2012 IRC, cap nails are required for fastening roof underlayment in high-wind areas. Have I…