FREP Hangers: A Rust-Free Alternative with Built-In Moisture Management
September 4, 2025
In the ongoing effort to improve durability and performance in timber framing, FREP (Fibre Reinforced Engineered Polymer) hangers offer a compelling alternative to traditional metal connectors—especially in environments where corrosion is a concern.
Why FREP Hangers Will Never Rust
Unlike metal connectors, FREP hangers are non-metallic, meaning they are completely immune to rust and corrosion. This makes them ideal for use in:
- Coastal and marine environments (C4–CX zones as per AS 4312)
- Structures with preservative-treated timber
- Areas with high humidity or chemical exposure
Where metal hangers require protective coatings (ZMAX, HDG, stainless steel), FREP hangers eliminate the need for corrosion protection altogether, simplifying compliance with the NCC and AS 4312.
Ventilation Ridges: Built-In Moisture Control
FREP hangers feature ventilation ridges on the seat of the hanger—an innovation designed to promote joist breathability. These ridges:
- Allow air circulation beneath the joist
- Reduce moisture buildup at the connection point
- Help prevent timber decay and mould growth
This design is especially beneficial in enclosed subfloor spaces or humid climates, where trapped moisture can compromise both timber and metal connectors over time.
Quick Comparison: FREP vs. Metal Hangers (LUS)
| Feature | LUS Metal Hanger | FREP Hanger |
|---|---|---|
| Material | Galvanized Steel | Fibre Reinforced Polymer |
| Nail Size | 4 × 3.75mm | 8 × 3.2mm |
| 90mm hanger Capacity | 3.8kN | 3.2kN |
| Corrosion Risk | High in C3–CX zones | None |
| Moisture Management | None | Ventilation ridges |
Engineering Capacity Perspective
For a typical deck floor load of 2kPa, a 90×45 F27 hardwood joist spanning 2m has a reaction force of approximately 1.6kN—well within the FREP hanger’s 3.2kN capacity. Even a 190×45 F27 joist spanning 4m only reaches about 3.2kN, matching the FREP hanger’s rated strength.
This means FREP hangers are structurally suitable for most residential applications, while offering superior durability in corrosive or moisture-prone environments.
Conclusion
FREP hangers represent a next-generation solution for timber framing. With zero corrosion risk, built-in ventilation, and adequate structural capacity, they offer engineers and builders a reliable, long-lasting alternative to traditional metal connectors—especially in challenging environmental conditions.
Note:
- Image 1 shows a typical galvanised hanger that has rusted away a few years after being installed under a saltwater pool deck.
- Image 3 shows the ventilation ridges.
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