CEM-6. These specially engineered nails are recommended for face and blind nailing many types of fiber cement siding such as Certainteed WeatherBoards or HardiPlank. The STORMGUARD Double Hot-Dip Galvanized coating on these nails insures excellent long-term rust protection. These nails meet the blind and face nail specification for lap siding 8-1/4? or less. Wider width sidings require blind (roofing) nails.