While vinyl and aluminium decking has become more popular in recent years, timber is still the material of choice for most decking projects, and the elegance and old-world charm of a timber deck is still pretty much impossible to match with decks made of more modern materials. However, while timber does not suffer from the traction problems associated with aluminium decks, and do not perish in intense sunlight like many vinyl decks, there is one problem to which they are uniquely vulnerable -- mould.
Preventing mould is far easier (and cheaper) than removing it once it spreads across your deck, so nipping your fungal problems in the bud by choosing an inherently mould-resistant timber deck is always a prudent move. To help guide you in your quest for fungus-proof timber decking, keep the following guidelines in mind as you shop around:
Choose a naturally mould-resistant timber
With the right treatments and precautions, a deck made of pine, spruce or other inexpensive softwoods can be tremendously mould-resistant, your best bet is to choose a hardwood deck. As a general rule, hardwoods are denser than softwoods, reducing the amount of moisture they absorb and making them inherently resistant to fungal growth and damage. Many hardwoods also contain natural oils that inhibit the spread of mould even if you don't chemically treat them.
Tropical hardwoods such as teak, ipe and mahogany are known far and wide for their excellent mould resistance, but you don't have to opt for exotic tropical hardwoods to get a mould-proof timber deck. Many native Australian hardwoods have excellent resistance to fungal growth, and are considerably cheaper and more environmentally friendly than tropical hardwoods. Jarrah, spotted gum and blackbutt are three excellent native choices.
Choose pressure-treated timber
All timber decks should be treated periodically with mould-resistant surface treatments, such as waxes, oils and stains, but choosing a timber deck that has already be subjected to these treatments will get you ahead of the game. If you wish to maximise your deck's resistance to mould as much as possible, consider pressure-treated decks.
The timbers of these decks are sealed in vacuum chambers with an array of potent anti-fungal chemicals, which are forced deep into the pores of the wood as the air is drawn out of the chamber. This powerful anti-fungal treatment ensures that the protective chemicals penetrate to the very heart of each timber, giving you a timber deck that will resist mould for decades to come, even without regular maintenance.
Consider sealed decks
Another effective way to avoid mould problems in your deck's future is to choose one that has been treated with all-weather sealants. These sealants are made from extremely durable resins and epoxies and form a watertight 'skin' over the surface of your deck's timbers to prevent any moisture from penetrating the wood and encouraging fungal growth. These treatments will need to be re-applied every few years to remain effective, but even a large deck can be resealed in the space of a few hours using nothing more complex than an ordinary paintbrush.