Galvanized nail — more commonly referred to in construction as roofing nails — are nails that are dipped in melted zinc. This extra coating makes them resistant to rust and ensures that they have a very long lifespan. Before you head out to the hardware store to buy galvanized nails for a special project, take a look in your toolbox — you might have galvanized nails and not even know it. When trying to determine if a nail is galvanized, there are a few telltale signs that will help you make the decision.
Place the nail under a light source and look at its surface. Galvanized nails, unlike other metal nails, don't have a shine to them. They appear dull and do not reflect light like other metals do.
Look down the sides of the nails for any drip marks. One of the ways manufacturers galvanize nails is by dipping them into melted zinc. This occasionally results in some small drip marks located on the sides of the nail.
Run your fingers over the surface of the nail. Galvanized nails are not smooth to the touch like regular metal nails. Instead, they are quite rough to the touch.