What Causes Galvanic Corrosion on Metal Roofs?

Metal roofing has been gaining popularity due to its beauty, versatility, durability and long lifespan. Like all materials, it must be installed properly to avoid costly problems. One of the most common issues a metal roof can experience is galvanic corrosion. 

metal roofing

What Is Galvanic Corrosion?

Galvanic corrosion refers to an electrochemical process where one metal corrodes once in contact with another metal through an electrolyte. Water is a weak electrolyte, meaning water would be the catalyst in the installation of metal roofs. It can occur whenever two different types of metal come in contact with each other. When not prevented, it can reduce the lifespan of your roof and affect your home’s curb appeal. 

Causes and Prevention

Lead and copper are the common causes of corrosion in metal roofing systems. Because they have a high probability of corrosion, you should not use lead roofing products, such as lead roof jacks for pipe penetrations. Moreover, graphite is highly corrosive to aluminum and aluminum alloys. You should your roof replacement or new roof construction contractor not to write on a metal panel with a graphite pencil to avoid corrosion issues.

Keep in mind that copper may also react negatively with galvanized metal panels utilized in different metal roofing systems. Don’t use treated lumber that contains copper. If treated lumber or a lighting system with cable is necessary, make sure that the cable has aluminum instead of copper. 

Another instance where galvanic corrosion can occur is when there is an air conditioner (AC) on your roof. The AC may contain copper in the coils, and, once it condensates, the water with copper will cause corrosion on the roof. 

An experienced roofer like The Roofing Company would know how to prevent galvanic corrosion on your metal roof. As one of the area’s best roofing contractors, you can count on us to take care of your home. Call us at (970) 887-0104, or fill out our contact form to get a quote. We serve clients in Aspen and nearby communities around Colorado.