Tough conditions call for tough materials. Any time wood is exposed to the weather, it can take a beating — and so can the nails used to fasten it. Even if you frame a deck with pressuretreated wood, rusting nails can weaken your structure over time. Rusty nails also cause appearance and performance problems for wood siding. Builders typically use galvanized nails for framing decks, for applying wood siding, and for installing exterior trim. But not everyone knows that "galvanized" can have more than one meaning when you're talking about nails. All galvanized nails are made of steel and coated with zinc. The zinc coating is what protects the nail from rust. But how much zinc is on
