Some of the benefits of using 15 degree coil nails galvanized for outdoor decking applications include:

Improved withdrawal resistance

The 15 degree angle of the nail shank helps lock the nail more firmly into the deck framing members. This provides better resistance against the upward and lateral forces that can cause nails to loosen over time.

Reduced splitting

Driving the nail at a 15 degree angle creates a longer and narrower entry point into the decking boards, reducing the chances of splitting the wood. Straight nails can cause excessive splitting, especially in hardwood decking materials.

Better drainage

The angled hole created by 15 degree nails allows for better drainage of water, reducing the risk of moisture becoming trapped and degrading fasteners or wood. This helps preserve the lifespan of the deck.

More seating

The longer path of the angled nail shank allows it to seat more deeply into deck framing members, providing increased tension and shear resistance. This improves the structural integrity of the deck.

Compatibility with concealed fastener systems

Some decking boards have slots or grooves to hide fixings and fasteners. 15 degree nails are compatible with these concealed fastener systems, allowing a clean finish without exposed nails.

So galvanized 15 degree nails provide a combination of benefits for outdoor decking applications, including improved grip, reduced splitting, better drainage, deeper seating, and compatibility with hidden fastener systems. These features work together to help extend the life and durability of your deck. However, standard coil nails remain a good option for simpler deck designs as well.