Tips for choosing the correct decking finish option

ARTICLE Abodo Wood

Choosing an appropriate decking finish can be challenging. Often homeowners are disappointed with results, or have problems with cracking, blistering and failure of coatings within a relatively short space of time.

In general, exterior deck coatings can be grouped into three types.

Penetrating Wood Oil

Penetrating wood oils are mineral oil or plant oil based, and contains a form of pigment. The oil penetrates into the wood while the pigment sits on or just below the surface of the wood, providing UV protection, and colour to the wood. Penetrating wood oils provide natural wood finish – basically as natural as you will achieve from a wood coating. The primary benefit of penetrating wood oil is that it penetrates into the wood, stabilising it, yet not creating a surface film to crack or flake like film-forming coatings. Regular re-application or penetrating oils will be required– approximately every 6 – 24 months. Penetrating wood oils are recommended for decking, weatherboards and exterior cladding. Avoid mineral oil based exterior wood oils; untreated or mildly treated mineral oils have been identified as a type 1 carcinogen.

Our suggestion: Elements Protector Oil – a plant based formulation for eco homes.

Wood Stain

A wood stain consists of a colorant suspended or dissolved in an agent or solvent. The suspension agent can be water, alcohol, petroleum distillate. Wood stains generally do not penetrate wood and will slowly disappear as the colour starts to fade and finish itself breaks down. Wood stain finishes usually have more pigment than a penetrating wood oil – you won’t be able to see the wood grain as well, but for the same reason the colour in wood stains typically to last longer than penetrating wood oils.

Wood stains are better suited to cladding and weatherboard applications, where a heavy pigment colour is desired.

It is better to avoid heavily pigmented wood coatings in a decking application – wear marks can occur around commonly used areas, where the pigment is worn off the surface of the decking. Re-application for wood stains will be required every 2-4 years.

Our suggestion: Resene Woodsman – a water based formula with Environmental Choice certification

Film Forming

Film forming coatings create a pigmented film on the surface of the wood using acrylic resins or other proprietary technology. The film provides moisture and UV protection to the wood, and typically provides excellent short to medium term protection. However a film coating must be maintained, which means an annual check. Failure to maintain a film forming coating can result in wearing, flaking and cracking, which makes remedial work time consuming and expensive. On the plus side, the lifespan of a film forming coating is longer than for penetrating stains and oils, film forming coatings can last up to 5 years.

In areas of wear or failure an additional coat is required as soon as possible to avoid further flaking of the coating. Generally do not recommend film forming coatings for decking, weatherboards or cladding. In some cases film forming coatings may suit semi-protected applications like entrance doors and window joinery.

Our suggestion: Intergrain – a durable film forming coating with some penetrating characteristics

Summary

In summary, the benefit of penetrating oils or stains is that, while they require more maintenance than other coatings, the maintenance process is simpler. Just clean the timber and apply the coating to dry wood- no sanding or stripping back is required. Film forming coatings typically last longer than alternative coatings, but if left unmaintained they may require stripping back and more rework.

Abodo - Wood products and wood care supplies

Abodo's goal is to create a range of healthy, renewable and durable wood products for the future. The Abodo range spans decking, cladding, weatherboards and exterior timbers. Want to learn more about Abodo? Visit the Abodo website.

You might be interested in reading: Decking options for your outdoor living.

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*All information is believed to be true at time of publishing and is subject to change.