Coastal and Floodplain Construction Inspector's Practice Exam

Fasteners in contact with preservative-treated wood must be made of what material?

1. PVC plastic

2. Untreated steel

3. Hot dipped zinc-coated galvanized steel

4. Aluminum

The correct answer is: Hot dipped zinc-coated galvanized steel

When using fasteners in contact with preservative-treated wood, it is essential to select a material that will resist corrosion due to the chemicals used in the treatment process. Hot dipped zinc-coated galvanized steel is specifically designed to provide a robust protective layer that prevents rusting and degradation when exposed to these treated woods. The galvanization process involves coating steel with a layer of zinc, which acts as a sacrificial barrier. This means that the zinc will corrode instead of the underlying steel, thereby prolonging the structural integrity of the fastener. Other materials, such as untreated steel, would be highly susceptible to corrosion, significantly shortening their lifespan and potentially leading to structural failure. Aluminum, while it has some corrosion resistance, may still react negatively with certain preservatives found in treated wood, compromising its strength and durability over time. PVC plastic, while resistant to chemical reactions, is not typically suitable for structural fasteners due to its lower load-bearing capabilities compared to metals. Choosing hot dipped zinc-coated galvanized steel ensures both compatibility with preservative-treated woods and longevity in various environmental conditions.