Walk into any building supply store in Ontario and both of these get called "composite decking". They are not the same material. One is a wood-flour-and-polyethylene blend; the other is a solid polymer with no wood in it at all. That single difference drives almost everything else — how it burns, whether it can grow mould, what it weighs, and how long it lasts. Here is the honest comparison.
| ASA/PVC (DeckiWood) | PE wood-plastic composite (WPC) | |
|---|---|---|
| What it is made of | Solid ASA/PVC polymer with a co-extruded ASA cap. No wood flour. | Roughly 50–60% wood flour bonded with high-density polyethylene (HDPE), usually with a PE cap. |
| Flame spread (ASTM E84) | PVC decking typically tests around 25 — Class A, the best rating available. | HDPE composites typically test 110–155 — Class C. Pure HDPE alone rates about 98. |
| Mould and mildew | No organic content, so surface mould has nothing to feed on. | The wood flour is a food source. Capping helps, but cut ends and shaded, damp areas stay vulnerable. |
| Water | The polymer does not absorb water — including at cut ends. | Wood fibre absorbs. A cap resists it; every cut you make on site opens an uncapped edge. |
| Weight | Lighter. Less load on the substructure, and one person can carry a board. | Heavier — wood flour is dense. More structure, slower installation. |
| Colour retention | The ASA cap is the same polymer family used on exterior automotive trim. Very little fade over decades of UV. | PE caps fade and chalk sooner, particularly in strong direct sun. |
| End of life | A single polymer, so it can be recycled. | Wood bonded to plastic is a mixed material — it generally goes to landfill. |
| Typical service life | Commonly quoted at 50 years or more for PVC decking. | Commonly quoted at 25–30 years. |
| Up-front cost | Higher per square foot. | Lower per square foot. The gap narrows or reverses once you count a mid-life replacement. |
No, though shops often use "composite" as a catch-all for both. Composite decking (WPC) is a blend of wood flour and polyethylene — usually around half wood by weight. PVC decking has no wood in it at all; it is a solid polymer board. When a supplier quotes you "composite", ask which of the two they mean, because the performance differences are not small.
Mould needs something organic to eat. PVC has no wood flour, so nothing on the board itself will feed it. Wood-plastic composite does contain wood, which is why manufacturers cap it — and why the cut ends, where the cap is gone, are where problems usually start on a shaded, damp deck. To be precise: pollen, leaf litter and dirt can sit on any deck surface and grow mould in that debris. The difference is that on PVC you wash the debris off and it is over; on WPC the board can become part of the problem.
PVC, by a wide margin, and this is one of the few places with hard test numbers. Under ASTM E84, PVC decking typically returns a flame spread index around 25 — Class A. HDPE-based composite typically returns 110–155, which is Class C. For reference, southern yellow pine rates about 70 and pure HDPE about 98. The chlorine in PVC makes it inherently difficult to sustain combustion; polyethylene is essentially a solid fuel. If you are building near a fire pit, a BBQ, or in an area with wildfire exposure requirements, this is the number to look at.
All exterior materials weather. What matters is the cap layer. DeckiWood uses an ASA cap — the same polymer family used for exterior automotive trim and siding precisely because it holds colour under UV. PE caps, used on most wood-plastic composite, fade and chalk noticeably sooner. Expect a subtle mellowing over the first season on any board; what you should not accept is visible chalking or patchy colour after a few years.
It can be, if the surface is smooth — this is a fair criticism of older, glossy PVC boards, and worth being straight about. Slip resistance comes from surface texture, not from the base polymer. DeckiWood boards use an embossed anti-slip wood-grain surface for this reason. If you are comparing products, ignore the material label and put your hand on the actual board: a deeply textured PVC deck will out-grip a smooth composite one.
Colour matters far more than material. A dark board of either type will be uncomfortable barefoot on a July afternoon in southern Ontario; a light board of either type will be manageable. PVC has a small advantage in that it is less dense and can be produced in lighter tones. If bare feet are a priority — around a pool, for instance — choose a lighter colour first and worry about the polymer second.
Freeze-thaw damage is a water problem. Water gets into the material, freezes, expands and breaks it apart from the inside. PVC does not absorb water, so there is nothing in the board to freeze. Wood-plastic composite can take on moisture through cut ends and damaged cap, and that trapped water is what causes swelling and surface flaking after a few Ontario winters. This is the single biggest reason we build in PVC for this market.
Yes — a solid polymer moves more with temperature than a board that is half wood flour, and it would be dishonest to claim otherwise. It is handled entirely at installation: leave the specified end and side gaps, fasten according to the instructions, and let the board move. Every long-run decking material has a gapping spec; PVC's is simply less forgiving of being ignored. Our installation guide gives the exact figures, and it is the one thing we ask contractors not to eyeball.
PVC costs more per square foot up front. Whether it is worth it depends on your horizon. Both materials are sold as maintenance-free, so the running cost is similar — the difference shows up at replacement. If PVC lasts 50 years where a composite deck is replaced at 25, you buy the deck once instead of twice, and you avoid a second round of demolition and labour. For a deck you intend to keep, or for a rental or commercial property where a mid-life rebuild is disruptive, the arithmetic usually favours PVC. For a property you plan to sell in five years, it may not.
Yes — it is a single polymer, so it can be reprocessed at end of life. Wood-plastic composite is a bonded mixture of two materials that cannot practically be separated again, which is why it typically ends up in landfill. Worth noting for balance: many composite brands use recycled plastic as an input, which is a genuine point in their favour at the front end. PVC's advantage is at the back end.
Anywhere the deck is wet most of the time, the case for PVC is strongest: no water absorption, no organic content to rot or grow mould, and no swelling at the cut ends where boards meet posts and hardware. Add a textured surface for grip and a lighter colour to keep it cool underfoot. DeckiWood is built for exactly these conditions — gardens, boardwalks, docks and courtyards.
Three things. The cap is ASA rather than plain PVC or acrylic, for UV and colour stability. The core is foam-structured, which cuts weight without giving up stiffness — easier to handle on site and less load on the substructure. And the surface is embossed for grip rather than left smooth. Boards are 138 × 25 mm and available in Carbonized Wood, Golden Teak, Green Sandalwood, Teak and Walnut.
DeckiWood® decking · Request a quote
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