NASCLA Accredited Commercial General ContractorWoodMedium
A builder is constructing a deck for a commercial restaurant that will be exposed to significant weather elements and is designated as a high-traffic area. The deck framing will be installed over a concrete slab. Which type of wood fastener is generally NOT recommended for this application due to potential corrosion issues and reduced long-term durability?
- AStainless steel fasteners
- BHot-dip galvanized fasteners
- CFasteners conforming to ASTM A153
- DElectro-galvanized fasteners
Show answer & explanationAnswer & explanation
Correct answer: D. Electro-galvanized fasteners
Electro-galvanized fasteners have a thin zinc coating that offers minimal corrosion resistance, especially in outdoor, high-moisture, or treated wood applications. Hot-dip galvanized and stainless steel fasteners provide much superior corrosion protection suitable for exterior structural use. ASTM A153 refers to the standard for hot-dip galvanized coatings, which is acceptable.
Why the other options are wrong
- A. Stainless steel fasteners offer superior corrosion resistance and are ideal for harsh outdoor environments, treated wood, or marine applications.
- B. Hot-dip galvanized fasteners provide excellent corrosion resistance suitable for outdoor and treated wood applications.
- C. ASTM A153 is the specification for hot-dip galvanized coatings, which provides good corrosion resistance and is suitable for this application.
Wood Fastener Corrosion
The degradation of metal fasteners when exposed to moisture, chemicals (e.g., from treated wood), or dissimilar metals, leading to loss of strength and structural integrity.
- Electro-galvanized has poor resistance.
- Hot-dip galvanized offers good resistance.
- Stainless steel provides superior resistance.
- Treated wood chemicals accelerate corrosion.
Memory trick: For outdoor wood, choose coatings that are thick and strong, or else your fasteners won't last long.