Basically the choice is between real wood -softwood and hardwood. There are also synthetic and polymer constructed boards which are used in the USA more than here in the UK at present. So will will simply discuss the pros and cons of softwood and hardwood. What timber to use for decking - hardwood or softwood?
There are other types of decking board available - composite deck boards and also Vinyl (UPVC) boards and systems. We will discuss those at a later stage. Most of these non wood decking materials are best installed by professional deck installers.
Softwood is not necessarily soft - nor hardwood hard! Both types of wood are suitable for decking, and a properly treated and maintained softwood deck can last up to 40 years.
All timber used in an exterior situation, end up the same colour if it is not treated or stained in some way - grey! A softwood deck - if stained, can look similar to hardwood. A large timber supplier recently had a picture of a softwood deck on their website - built by Top Deck Decking Ltd, and stolen from their website - claiming that it was hardwood! We pointed out their error!
When new, most hardwoods will either have a golden brown or red/brown appearance. Treated softwood will typically be light green/brown, and after just a few weeks exposure to light, will turn what is best described as 'honey-brown'.
The vast majority of decks in the UK are constructed from commercially treated (tanalised) softwoods. Typically, the guarantee against rot - providing that all cuts are properly treated - will be 15 years. You can expect a properly constructed deck to last many years longer than that.
A typical stack of good quality softwood decking. The colour soon changes to honey brown
The image on the left is not typical of quality hardwood decking, but
serves as a warning. In this instance, the installers were the same
company that provided and installed the swimming pool. Obviously not
experienced in deck work - either choice of materials or craftsmanship.
They used masonry nails to fix the decking!! Whilst hardwood decking 'could' be nailed, the choice of nail would centre around a ridged or ring shanked nail to ensure extra grip and negate the risk of popping! A Smooth masonry nail does NOT fit this specification.
A 6 month old hardwood surround to a swimming pool! Note the splits starting - for a bare feet area!