FAQ answered by roofing contractors Seneca Creek Home Improvement:What nails are suitable for use with roof shingles?
Galvanized steel nails are the best nails for securing roof shingles. The nails feature a clear protective coating to prevent rusting. Other types of metal nails with a similar protective coating also work well. Though some contractors use staple guns, they should only use staples as a temporary solution and use nails, too.