The answer to 'how long does flashing last' is that flashing typically lasts between 20-50 years, depending on the material used and the environmental conditions. Flashing is the thin metal or plastic material installed around chimneys, dormers, and other roof penetrations to prevent water leaks. High-quality metal flashing like copper or aluminum can last up to 50 years, while lower-cost plastic flashing may only last 20-30 years before needing replacement.
Proper installation and regular inspection of flashing is key to maximizing its lifespan. Flashing should be checked periodically for cracks, holes, or separation from the roof or wall, and repaired or replaced as needed to maintain a watertight seal. Homeowners should also be aware that flashing may need to be replaced if the roof is re-shingled or if major renovations are done to the home.