Recycled Composite Decking’s Carbon Edge
Plastic bags become porch boards—and the carbon math is turning heads. While wood still smells like the forest, new composite planks score lower on embodied CO₂ than pressure-treated pine and slash landfill waste at industrial scale. Here’s how the three market leaders measure up.
From Sawdust to Soda Bags: Anatomy of a Modern Board
Trex, TimberTech, and Fiberon use the same two feedstocks in different ratios: reclaimed wood flour and polyethylene film. The film comes from grocery bags, pallet wrap, even online-shopping mailers that would otherwise head to landfill. The wood side is mostly mill leftovers—no fresh logging needed.
- Trex advertises 95 % recycled content across its decking portfolio (ICC-ES SAVE, 2025).
- TimberTech’s Advanced PVC line runs ≈60 % recycled polymer with no wood, while its “Composite” SKU blends ≈80 % recycled mix (TimberTech Full-Circle Report, 2025).
- Fiberon specifies 94 % recycled mix in its Wildwood cladding boards (SCS Global, 2024).
Embodied Carbon Head-to-Head
TimberTech is the only brand with cradle-to-grave LCA results in the public domain today. Converting its figures for a 1 000 ft² deck to square-meter terms gives a useful benchmark:
| Material | GWP A–C (kg CO₂e / m²) |
|---|---|
| TimberTech Advanced PVC | ≈14 |
| TimberTech Composite | ≈15 |
| Pressure-treated pine | ≈17 |
| Brazilian Ipe | ≈116 |
(TimberTech Full-Circle Report, 2025)
The delta seems small on paper, yet a 50 m² deck upgrade from pine to PVC avoids ≈150 kg CO₂e—about nine days of electricity for an average US home (EIA, 2025). Fiberon and Trex have not released verified GWP numbers, so any “carbon-negative” marketing claims remain just that.
Plastic Waste Diverted: The Big Trash Tally
Volume matters when you pitch to carbon-conscious specifiers. Recent disclosures tell a clear story:
- TimberTech: target to recycle 1 billion lb of scrap annually by 2026, equal to every suitcase on every flight out of JFK for a year (TimberTech site, 2024).
- Trex: processed 377 million lb of plastic film in 2024—plus 674 million lb of waste wood (Trex Sustainability page, 2025).
- Fiberon: recycles ≈100 million lb of plastic a year and claims to save 1 million trees from harvest (Fiberon press release, 2025).
The headline? One composite board can lock away up to 2 000 plastic bags for three decades of service.
Transparency Scorecard: Who Shows Their Math?
- TimberTech: Third-party EPDs published on SmartEPD. Provides module-split impact tables and declares biogenic carbon separately.
- Fiberon: Cradle-to-gate EPD for Wildwood cladding verified by SCS Global in 2023. Decking EPD promised but not yet live.
- Trex: No EPD. Holds an ICC-ES SAVE verification for recycled content but skips full LCA disclosure.
Architects hunting LEED v5 points will notice the gap. Manufacturers without an EPD risk knockout punches at bid time when specs call for product-level carbon data.
What This Means for Manufacturers Plotting Their Own Boards
- Collect granular feedstock data early. Recycled polymer streams vary by melt index and contamination. Sorting it up front prevents headaches during the LCA boundary review.
- Pick the same PCR as your rival. Bidders compare apples to apples. If the market leader uses the “Outdoor Decking” PCR from SmartEPD, copy it unless you have a strategic reason not to.
- Design for disassembly. End-of-life credits can shave several kg CO₂e per m² if the board is fully recyclable. Mechanical fasteners beat glue every time.
- Tell the waste story. Specifiers love a circular-economy stat. Keep your bale-count ledger handy; it might close the sale faster than a carbon number alone.
- Speed still rules. A nine-month EPD cycle leaves you watching projects sail by. Streamlined data collection tools now cut that window to six or even four months, freeing up R&D to tackle performance tweaks instead of spreadsheet duty.
Carbon Is the New Slip-Resistance
Composite decking began as a low-maintenance play. In 2025 the pitch has flipped: less carbon, less garbage, same barefoot comfort. Brands that open their LCA books will bank the spec wins, and those that hide behind glossy brochures risk splinters. Getting your numbers ready is not optional anymore, it’s table stakes. Don’t let enviromental paperwork be the board that breaks the project.
Frequently Asked Questions
How much embodied carbon can switching from pine to composite decking really save?
TimberTech’s verified LCA shows roughly 3 kg CO₂e saved per square metre when moving from pressure-treated pine to its composite line (TimberTech, 2025). Over a 50 m² deck that equals about 150 kg CO₂e, or the emissions from nine days of electricity use in an average US home.
Do Trex, TimberTech, and Fiberon all publish EPDs for decking?
No. TimberTech has full EPDs on SmartEPD, Fiberon offers an EPD for its Wildwood cladding but not yet for decking, and Trex currently provides only recycled-content verification rather than an EPD.
Which brand diverts the most plastic waste today?
TimberTech has the most ambitious stated goal: recycling 1 billion lb of waste annually by 2026 (TimberTech, 2024). Trex currently processes ≈377 million lb per year and Fiberon about 100 million lb.
Does composite decking always beat wood on carbon?
Not automatically. Verified data show premium composites can outrank pressure-treated pine and tropical hardwoods on cradle-to-grave GWP, but the margin depends on recycled content, energy mix, and board lifespan. Without an EPD you can’t prove the claim.
What PCR should a new decking manufacturer use for an EPD?
Most US brands follow the Outdoor Decking and Railing PCR under EN 15804 published by SmartEPD. Using the same rulebook keeps your numbers directly comparable to existing market data.
About the Author
With a passion for sustainability and a love for complex data, Toby helps manufacturers efficiently collect data from across their organization and get their EPDs done right. He’s especially interested in how AI can support human expertise, helping R&D and factory teams work faster, smarter, and with less friction.
