50x30mm WPC Joist Composite Decking Support Beam for Outdoor Deck Subframe
50x30mm WPC Joist - Composite Deck Substructure Beam
This WPC (wood-plastic composite) joist measures 50mm x 30mm in cross-section. It is produced as a substructure beam for decking systems, laid over the ground or a sub-frame to carry deck boards and keep them clear of standing water. The composite joist combines the stiffness of timber with the weather resistance of recycled plastic, so it holds its shape and line through sun, rain and temperature swings.
Key Specifications
| Product Type | WPC Joist / Deck Substructure Beam |
| Section | 50mm x 30mm |
| Available Sections | 50x20mm, 50x25mm, 50x30mm |
| Material | Natural wood fiber blended with recycled HDPE and process additives |
| Surface Finish | Smooth |
| Density | 1.25-1.35 g/cm3 |
| Water Absorption | ≤ 1.0% (24h immersion test) |
| UV Resistance | UV-stabilized formulation; 2000h QUV accelerated aging tested |
| Service Life | 20-25 years under normal outdoor use |
| Model | HS-WJ-5030 |
Why a 50x30mm Composite Joist
- Stable section: extruded to a consistent 50x30mm profile so deck boards sit on an even, level line.
- Weather resistance: unlike timber battens, the joist does not rot, warp, twist or splinter in wet or freezing ground conditions.
- Rot and termite proof: no chemical treatment needed, so no leachate risk in planted or waterside areas.
- Fast layout: straight, uniform beams cut layout time and keep board spacing accurate.
Performance Highlights
- Low water absorption keeps the joist dimensionally stable over repeated wet-dry cycles
- UV-stabilized so the profile resists surface degradation under long sun exposure
- Consistent screw-holding for hidden clips or stainless-steel fasteners
- Termite and rot resistant, with no toxic wood preservatives required
Material & Environmental Responsibility
Joists are made from natural wood fiber and recycled HDPE, reducing the use of virgin plastic and preserving timber resources. The composite contains no toxic wood preservatives, and production off-cuts are reground and recycled in-house.
Installation & Maintenance
Laid over compacted ground, pedestals or a timber sub-frame, and fixed with standard clips and stainless-steel fasteners; recommended deck board span and joist spacing are supplied with each order. Clean with a broom and occasionally wash with mild soap and water; no refinishing is needed.
Quality Assurance & Testing
Each production batch is tested for water absorption, UV stability and dimensional tolerance before shipment. Joists are produced to CE and RoHS requirements, and third-party inspection is welcome before shipment.
Manufacturing & Export Experience
Manufactured by HS, a WPC profile producer based in Chengdu, Sichuan, China, with more than 18 years of composite extrusion and embossing experience. Our export team supports OEM/ODM branding, project take-offs and combined container loading for overseas buyers.
Applications
Ideal as the substructure for composite decking on patios, terraces, balconies, boardwalks, roof decks and garden decks.
Customization & Ordering
- OEM/ODM packaging and custom branding available for volume orders
- Free installation guidance and accessories list provided with each order
- Project quantities and combined container loading supported
Contact our export team for a quotation, free samples or a technical data sheet for your project.
Get in Touch
Have questions about our products or want to discuss a custom order? Our team is ready to help you.