Accoya or composite (WPC): which to choose for your deck?

What exactly is WPC?

Wood-plastic composite boards (WPC) are made by extruding a blend of wood fibres or flour and plastic polymers, sometimes wrapped in a protective shell. The result is regular and easy to mass-produce — but it is no longer wood: it is a plastic material with a wood pattern, whose performance depends almost entirely on the manufacturer’s recipe. From one brand to the next, everything changes: density, behaviour in the sun, warranties.

Barefoot at noon: you feel the gap immediately

This is THE criterion the catalogues forget — and the first regret of composite deck owners at our latitude. The thermographic tests published by the manufacturer Accsys (run in Japan, at 32 °C ambient air) show an Accoya board markedly more bearable than a composite board in the same sun. The reason is physical: a light wood with low conductivity (measured at 0.1022 W/m·K) stores and releases far less heat than a dense, often dark plastic blend. Under the Caribbean sun, that is the difference between a deck you sprint across and a deck you live on.

Around the pool: the slip question

The plastic content of WPCs tends to make them slippery, especially wet. Accoya has been tested by its manufacturer for slip resistance in demanding uses — pool surrounds, outdoor showers, stairs, shop entrances — with better results than the composites compared. A deck’s slip resistance also depends on the board profile, its finish and the installation details — which is why we select a suitable profile around pools. For a pool surround or a pontoon, where people walk barefoot and wet, it is a safety criterion before being a comfort one.

Over time: flatness, splinters, looks

Accoya’s dimensional stability (almost no swelling or shrinkage) keeps boards flat and gaps even, without splinters, despite years of weather. With WPC, you have to live with thermal expansion — strict installation rules, working gaps — and with scratches or stains that are hard to repair: you cannot sand plastic. Aesthetically, finally, Accoya’s grain is that of real wood, unique on every board: in through-tinted Color Grey, the tone holds over time — where a printed pattern simply wears out.

Environment and end of life

Accoya comes from fast-growing FSC®-certified softwood, transformed with no added biocide, certified Cradle to Cradle Gold — and Platinum for material health. At end of life, it is wood: it recycles. Most wood-plastic composites, an intimate blend of two materials, are not recycled: they end up incinerated or landfilled. For a purchase meant to be sustainable, end of life is part of the calculation.

And the warranties?

Accoya boards are covered by a written warranty from the manufacturer Accsys: up to 50 years above ground and 25 years in ground contact, subject to installation and use conditions. Composite warranties exist too, but they are commercial, highly variable by brand and range, and often hedged with extensive exclusions. Always read the small print — reading it is part of our job.

The match in brief