How to Protect Your Timber Decking

Questioning how we can make our homes look better and stay that way for longer is something many have asked, particularly those who have experience in home maintenance like re-coating of timber decks.

Technology is constantly improving in this area making paths for new developments and advances in coatings and there are a great range of products available. Coatings and paint systems are not only there to visually enhance our homes but importantly also provide the layer of protection from environmental factors.

It’s true that certain timber species, under favourable conditions can last hundreds of years. Some external structures constructed from durable hardwoods which have the sapwood preservative-treated are often left to weather naturally. An example of this is pier timbers. The larger end section sizes of these timbers in comparison to domestic decking, and that they are often rough-sawn contribute to less impact from weathering and allow a longer service life.

When timber cladding and decking is left without a protective coating to inhibit water penetration from rain the surface will eventually grey off in appearance. What’s actually happening is the natural colouring in the wood is being leached from the surface cells of the wood. It is also exposed to ultraviolet sunlight and this with other chemical and mechanical processes is what describes weathering.

The repetitive drying out and re-wetting of the timber can cause small shallow splits and cracks called ‘checking’. Eventually this also causes the grain to be raised and a once smoothly machined surface can become rough. Pier timbers again are a good example of how the inherent wood colour has turned a silvery grey colour and the surfaces have checked.

External timber that receive a protective coating from the weather will mostly maintain its natural colouring. Most importantly a coating will help to stabilize the timber from dimensional changes. A deck that has been pre-oiled all round, had cut edges resealed and has a finishing coat applied is in a better position to remain stable in comparison to an unprotected deck.

The exclusion or the keeping out of moisture in timber is a key factor for board stability, minimising the natural expansion and contraction from environmental conditions that can often affect decking and claddings.

Timber species that have higher shrinkage rates are more susceptible to checks, cracks and cupping.

Weathered timber is attractive though gradually, depending on the durability of the species, checks and cracks will deepen and if fungi are present decay or rot will start. Favourable conditions of temperature and dampness will accelerate the fungal attack. Rotting timber is never a good thing and rectification can become expensive.

Unfortunately coating external timber is not a once off solution and ongoing seasonal coatings are often required. Maintenance is vital for the long service of timber used externally. The need to do this can vary greatly depending on the level of exposure to weather, wear and tear through traffic and the type of coating used.

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