What are roofing nails made of?
Short answer. Most roofing nails are carbon steel with a zinc coating, either hot-dip galvanized for a thick coat or electro-galvanized for a thinner one. Stainless steel, copper and aluminum roofing nails also exist, and the right choice depends on the roofing material and any metal flashing the nail passes through.
The common options
- Hot-dip galvanized steel. The nail is dipped in molten zinc, leaving a thick, slightly rough coating. It is the most corrosion resistant galvanized type and a common pick for shingles and wood shakes.
- Electro-galvanized steel. Zinc is plated on electrically, giving a thin, smooth coat. Many coil nails for asphalt shingles are made this way, and roofing nails for shingles must meet the ASTM F1667 standard the building code references.
- Stainless steel. Expensive but the longest lasting. Used on coastal homes, cedar, slate and some metal roof details.
- Copper. Used with copper flashing and on slate, where the nail has to match the flashing metal.
- Aluminum. Used with aluminum flashing and trim. It is soft, so it is not a general shingle nail.
Why the metal has to match
When two different metals touch with moisture present, the less noble one corrodes faster. That is galvanic corrosion, and it is why a plain steel nail through copper flashing shows up years later as rust streaks and loose metal. Bright, uncoated steel nails do not belong on a roof at all; they rust within a few seasons in Georgia humidity.
What this means for a Georgia home
Inland Georgia has no salt air, so standard galvanized nails are the norm for asphalt shingles. Humidity and condensation in a poorly vented attic still attack the nail tips that poke through the deck, and rusty nail tips or drip marks on the attic floor are a sign the attic needs better airflow. See roof ventilation basics and roof anatomy explained.