A: Two of the most common ones are copper and lead. These two especially should be kept away from our metal products. Even by having one in close proximity of the other will cause problems. For example, water splashing into a copper gutter will cause corrosion on the metal roof since the back splash hits the metal roof.
Some more examples are:
- Copper lightning rods (Instead use aluminum lightning rods).
- Copper coils are found inside air conditioning units (The water from the unit needs to be drained by pumping the water off the roof through PVC pipe.)
- Lead pipe flashings (Use EPDM dektites)
When dissimilar materials need to be used, be careful that they will not get wet and that a barrier sheet separates them.