Metal on Roofs

When you work on a roof, be careful not to mix metals, especially on metal roofs. Putting different metals together over time can cause massive corrosion. This is why you will never see a lead flashing on a metal roof, the lead and galvanized metal react with each other and corrode. In truth two metals often generate a small electrical current, This is the principle behind what’s called a thermocouple, a device that is used to measure temperature, usually in high temperature applications.