Oregon Construction Contractors (CCB) Practice Test

What is the safest approach when using metal flashing in construction?

1. To mix different metals as needed

2. Only use aluminum flashing

3. Not to mix metals that come in contact

4. To use plastic instead of metal

The correct answer is: Not to mix metals that come in contact

The safest approach when using metal flashing in construction is to avoid mixing metals that come in contact. This practice is crucial because different metals can have varying reactions to environmental factors, leading to corrosion or galvanic reactions when they are in contact with each other. When two distinct metals are exposed to moisture, one metal can corrode faster than the other, which can compromise the integrity of the flashing and the overall structure. By not mixing metals, you ensure greater longevity and durability of the flashing, preventing costly repairs and maintenance down the line. Using compatible materials that have similar properties minimizes the risk of deterioration caused by electrochemical reactions. While options like using only aluminum flashing or opting for plastic might seem viable, they do not address the core issue of compatibility and durability effectively in all construction scenarios. Additionally, mixing different metals can lead to serious performance issues, making the choice to avoid such combinations the strong and safest recommendation for construction practices.