How often should roof flashing be replaced?

How often roof flashing should be replaced depends on material, exposure, and whether it was installed correctly, but generally flashing should last as long as the roof covering if made from quality materials, yet often needs replacement sooner. Galvanized steel flashing typically lasts 15 to 20 years before rusting, especially in coastal or humid climates. Aluminum flashing can last 20 to 30 years but can corrode when in contact with dissimilar metals. Copper flashing is the most durable, lasting 50 to 100 years and often outlasting multiple shingle roofs. Lead flashing also lasts many decades. In practice, flashing should be inspected every time the roof is inspected, at least every 2 to 3 years, and whenever shingles are replaced. When you replace your shingle roof, which is typically every 20 to 30 years for architectural shingles, you should always replace all flashing including step flashing around chimneys, walls, and valleys, as reusing old flashing is a common source of leaks. Flashing may need earlier replacement if you notice rust, cracks, gaps, or leaks around chimneys, vents, skylights, or walls. If flashing was improperly installed, such as using caulk instead of step flashing, it should be replaced immediately with proper metal flashing. Quality installation with compatible materials and sealants extends flashing life significantly.