Metal Roofs offer the best protection against ice, snow and ice dams. Sheet metal restoration fabrication on roofs are known to last between 50 and 100 years. Many roofing companies offer a lifetime warranty when installing metal shingles. Roofs typically show damages many years before needing a complete replacement. Signs of repair include damaged or missing shingles, cracks, blisters and leaks that are caused by a variety of reasons.