Hot-Dipped Process
Select galvanized nails that have been hot-dipped in molten zinc if you prefer galvanized steel over stainless steel. Hot-dipped galvanized nails are resistant to corrosion; however, the zinc coating in galvanized nails often reacts negatively with the natural protective oils in cedar. Galvanized nails eventually rust and deteriorate when exposed to rain and severe weather conditions, but the zinc coating delays the process. According to the Western Red Cedar Lumber Association (WRCLA), stainless-steel nails are the best choice, especially if your cedar planks are finished with a transparent stain.
Galvanized Nails That Don't Split
Choose galvanized nails that don't split cedar planks. Split-proof nails have thin shanks and blunt tips that penetrate cedar firmly without splintering the wood. If you live in an area that is susceptible to severe weather conditions, opt for split-proof galvanized nails that have spiral or ringed threads for stronger holding power. Use galvanized nails with textured heads to avoid glossy or shiny nail marks in your cedar surface.
Installation
Drive galvanized nails into cedar planks or shingles carefully to avoid splitting, splintering and cracking. Apply light pressure when hammering galvanized nails and avoid high-powered nail guns. Heavy nailing can distort the surface of the wood and cause unwanted warping. WRCLA recommends predrilling nail holes at mitered corners, near edges and near ends to avoid splitting the wood.
Avoid Copper Flashing
Never use galvanized nails with copper flashing. Copper flashing is a roofing material, made from copper, that adds protection between roofing tiles and ceiling rafters. Copper flashing is especially useful along the perimeter of a roof where slopes come together and where eaves meet gutters. "Old House Journal" reports that galvanized nails and copper have a battery-like reaction that corrodes both metals quickly. Corrosion causes bleeding and discoloration in cedar woodworking.