PolyAl vs WPC: which lasts longer outdoors?
Short answer
For outdoor furniture, decking, fencing and urban infrastructure, PolyAl outperforms WPC on moisture resistance, chemical resistance and end-of-life recyclability. WPC retains a slight edge on look-and-feel (wood texture) and stiffness, but absorbs moisture and degrades faster in wet or chemical environments.
WPC mixes wood flour or fibre with a polymer binder (often PE or PP). It looks closer to natural wood, but the wood fraction absorbs water, swells, and shortens lifespan in humid or aggressive environments. PolyAl is a 100% polymer-aluminium pellet — no organic fibre to rot — so it shines exactly where WPC struggles.
Side-by-side comparison
| Property | PolyAl | WPC |
|---|---|---|
| Origin | 100% recycled, EU origin | Mixed (wood + virgin or recycled polymer) |
| Moisture absorption | Negligible | Significant (wood fraction) |
| Resistance to rot & fungi | Total | Limited |
| Chemical resistance | UNE 56875:2021 intensive use | Medium |
| UV stability | Excellent | Good (color may fade) |
| Density | 950 – 1050 kg/m³ | 1100 – 1400 kg/m³ |
| Stiffness / flexural modulus | 220 – 520 MPa | 2000 – 4000 MPa |
| Look-and-feel | Industrial polymer | Wood-like texture |
| End-of-life recyclability | Yes (single polymer stream) | Limited (composite) |
| Splinters / maintenance | None | Possible |
Choose PolyAl when…
- Outdoor furniture, planters, decking and fencing exposed to rain.
- Logistics crates and bins washed with chemicals.
- Applications where end-of-life recyclability matters.
- Long-life infrastructure (15+ years) with zero maintenance.
Stick with WPC when…
- You need a wood-like aesthetic for visible architectural cladding.
- Your part requires very high stiffness (flexural modulus > 1000 MPa).
- Indoor applications with controlled humidity.
FAQ — PolyAl vs WPC
Why does PolyAl last longer outdoors than WPC?
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WPC contains wood flour or fibre that absorbs water, swells, and feeds fungi. PolyAl is 100% polymer + aluminium with no organic fraction, so it doesn't rot, swell or splinter — even after years of rain, snow and UV.
Is WPC stiffer than PolyAl?
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Yes. WPC's wood fibres act as a natural reinforcement, giving flexural modulus of 2000–4000 MPa vs PolyAl's 220–520 MPa. For load-bearing decking joists, WPC or steel reinforcement is preferred.
Can I recycle WPC at end of life?
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Only with difficulty. The wood-polymer mix is hard to separate and most WPC ends up in landfill or energy recovery. PolyAl, being a single polymer stream with mineral aluminium, can be reground and reprocessed in standard PE recycling lines.
Which is cheaper, PolyAl or WPC?
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Pellet pricing is comparable, but total cost of ownership favours PolyAl in wet or chemical-exposed applications because of lower maintenance and longer service life.
Can PolyAl mimic a wood look?
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PolyAl has an industrial polymer aesthetic. For surfaces where wood look is critical, WPC remains a better choice — but for structural and outdoor parts where durability matters more than aesthetics, PolyAl wins.
Run the numbers on your application
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