When it comes to outdoor timber structures like decks there is a building material available called Wood Plastic Composite (WPC) that is now favoured amongst many builders and homeowners for its durability.
WPC is also known by a lot of other names such as eco-wood, plastic wood, composite wood, and natural fibre plastic wood. It is comprised of wood fibres, plastics and fillers to produce what looks like a timber board. The benefits are that it is not timber - so it is nowhere near as susceptible to rot, insects, discolouration, and weathering. Therefore it is now a popular alternative to timber for cladding, screening and decking - but is not typically suitable for structural joists or load bearing support.
The benefits of Wood Plastic Composite are clear. It does not require regular sanding, weather-proofing, oiling, painting or coating. It also will not warp if installed properly, and typically does not splinter (making it a great deck material for children). It is also highly resistant to termites and can be superior to timber in bush fire areas (check with the supplier). It also is a great pool surround product given its moisture resistance characterisitcs.
However, the downside can be colour fading, scratching, and the inability to rejuvenate with oil or stain, like you can with timber.
Therefore look for a high quality WPC that is guaranteed to retain its colour and has UV tolerant features. Get a sample and do a scratch test on it - especially if it is for a deck. Some cheaper WPC materials can display an ugly white scratch that is difficult to mask.
We conclude that most quality WPCs are superior to timber for outdoor application - but what is the cost comported to using timber?
A 137mm wide quality composite board can be purchased for about $16.40 a linear metre, whereas comparable width blackbutt decking timber is about $10.80 per linear metre at large hardware outlets. However, you also have to factor in the extra time and materials you will need to finish the timber surface. Whilst then the price is fairly comparable, the difference is that the timber will continue to cost time and money to keep it maintained, whereas the composite wood will not.
Each brand is different, but look for WPC that has been manufactured using recycled plastics and even recycled timbers, and environmentally friendly production methods. That way your new decking has not actually utilised any forest!
Thanks to Modwood Australia and Ultrashield for the images.