WPC decking joists is indispensable accessories for installing WPC deck. Generally, there are many materials for joists. They include wood, WPC and aluminum alloy. How should we choose from those?
Types for WPC Joist
The joist material is as following: WPC keels, aluminum alloy keels, and wooden keels. each with its own characteristics.
WPC Joist
Material Composition: Wood fiber + Recycled plastic
Advantages:
• Waterproof, anti-corrosion, and insect-resistant
• Low deformation rate and thermal expansion
• Maintenance-free and long-lasting
• Eco-friendly and recyclable
Disadvantages:
• Slightly higher cost than wooden joists
• Lower load-bearing capacity compared to aluminum joists
Applications:
Commonly used for outdoor balconies, garden terraces, and landscape walkways in residential or light commercial areas.
2. Aluminum Joist
Material Composition: High-strength aluminum alloy
Advantages:
• Excellent load-bearing strength
• Completely waterproof and rustproof
• Lightweight yet highly stable
Disadvantages:
• Relatively high cost
• Requires more precise installation
Applications:
Ideal for high-end commercial decking, poolside platforms, and coastal or high-humidity environments.
3. Wooden Joist
Material Composition: Treated wood or hardwood
Advantages:
• Low cost
• Easy to cut and install
Disadvantages:
• Prone to rot, deformation, and moisture damage
• Requires regular maintenance and painting
Applications:
Suitable for indoor or temporary decking structures; not recommended for long-term outdoor use.
WPC decking are outdoors, wooden joists can rot or warp, while WPC or aluminum joists resist water, corrosion, and stay stable. so we use wpc and aluminum joists to install WPC Decking.
Soild WPC Joist VS Hollow WPC Joist
| Type | Structure | Advantages | Disadvantages | Applications |
|---|---|---|---|---|
| Solid Joist | Solid structure | High strength, strong load-bearing, stable | Heavier, slightly higher cost | Public platforms, commercial areas, high-traffic zones |
| Hollow Joist | Hollow lightweight structure | Lightweight, easier to transport and install, cost-effective | Lower load-bearing | Residential balconies, garden terraces, landscape walkways |
Suggestion：For heavy loads or high-traffic areas, use solid WPC joists; for residential or decorative use, hollow joists are enough.
Installation Tips
- Keep joist spacing at 300–400mm for even support.
- Ensure a level, well-drained base to prevent water buildup.
- Use stainless steel fasteners or clips to avoid corrosion and loosening.
- Each square meter of WPC flooring typically requires about 3 meters of WPC joist.
- Solid keel is 40*25mm, hollow keel is 40*30mm, their length is customized and is usually 3m
Why Choose WPC Joists?
Durable – Resistant to water, termites, and UV; won’t rot, crack, or warp like wood.
Strong – High-density material supports heavy furniture and foot traffic when spaced 300–400mm.
Easy to Install – Works with concrete or steel frames, solid or hollow boards; use standard stainless steel clips.
Eco-Friendly – Made from recycled wood and plastic, reducing timber use.
Cost-Effective – Slightly higher upfront cost but minimal maintenance and long lifespan.
If you would like to purchase or get a free B2B quotation for WPC joist, welcome to fill in our request a quote chart. We will give you response in 1 working days.
