Which of the following is a consequence of using dissimilar metals in roofing?

Using dissimilar metals in roofing can lead to a negative galvanic reaction, which occurs when two different metals come into contact in the presence of an electrolyte, such as moisture. This reaction can cause accelerated corrosion of one of the metals. In the context of roofing, this means that if dissimilar metals are used without proper precautions, such as insulation between them, one metal may corrode faster than it normally would. This can ultimately compromise the structural integrity and lifespan of the roofing system, leading to leaks, weakened materials, and increased maintenance costs.

The process is driven by the electrochemical series, where metals are ranked according to their tendency to oxidize. When a more active metal is in contact with a less active metal, the more active metal will corrode preferentially. This is particularly important for roof systems, where environmental factors can exacerbate corrosion effects, potentially leading to significant damage over time if not properly managed.

Recognizing the consequences of using dissimilar metals is crucial for making informed material choices in roofing projects, ensuring long-term durability and performance.