The Absolute Best Decking Oil for Merbau

The outdoor deck is the quintessential gathering place for Aussies—a place for friends and family to honour birthdays, Christmas, Easter, and any other celebration worth having. Australian hardwood decks are commonly made of Merbau—a smooth hardwood grown in the Southeast Pacific Rim, including Northern Queensland. It’s termite-resistant, durable, and has a beautiful red finish[2], making it a favourite for decking.

If you have a merbau deck that needs to be oiled, here’s some of the best decking oil for merbau wood.

Merbau decking oil

Merbau contains many natural oils (including tannin) which protects the wood from splits and cracks. Oil treatments help to enhance this natural protection, block harsh UV rays, and replenish the oils already found in the wood. 

While many wood treatment products claim to be the best on the market, many of them simply sit on top of the wood. When you apply a high-quality oil treatment, however, the oils seep into the grain, providing deeper protection and helping the deck to retain its lustre for longer.

The best decking oil for merbau depends on your specific needs, but there are two categories proven to work: water-based oil treatments and non-water-based[1]. There are advantages to both, but all treatments will need to be reapplied every 9 to 18 months.

Water-based oil treatments

Water-based oil treatments add a more natural tint to the timber, rather than darkening it[3]. While water-based treatments soak into the wood fibres, they also cover the surface with an acrylic medium, blocking the pores of the wood. This protects the deck from weather damage, and the harsh edges of shifting furniture. 

Water-based treatments require more prep time, as the entire deck needs to be washed free of dirt and leaves, and left to dry before application[4]. Failing to properly clean the deck can lead to a patchy and peeling deck. 

Water-based oil treatments are opaque, which hides the natural grain of the wood. These treatments are more expensive than their counterparts, coming in anywhere from $136 to $360 for a 10L can. Water-based oil treatments are best for those in tropical climates, as they are water repellant, and offer more protection against mould and fungus growth. 

Brands like Intergrain and Sikkens offer high quality water-based oil treatments. Intergrain’s UltraDeck Timber Oil offers a guarantee that your deck will never flake, blister, or peel if applied properly. The UltraDeck is specifically formulated for high traffic areas, and can be applied in hot or cold weather. Sikkens’ Cetol BLX-Pro is non-toxic and environmentally friendly while still adding deep protection, making it a great choice for young families. 

Oil-based treatments

Non-water-based oil treatments penetrate more deeply into the wood’s core fibres for maximum protection, but don’t leave a surface coating. They darken the natural colour of the wood, and take longer to dry between coatings. This makes it easier to get an even colour over the entire deck. 

Though darker, the natural grain is still visible with a non-water-based oil treatment. These treatments are a little cheaper, and start from anywhere between $109 to $300 for a 10L can. Non-water-based oil treatments are recommended for those in harsher climates, or with open decks that are constantly exposed to the elements. 

Formula development has allowed oil-based treatments to evolve, and become more resistant to moulds and fungus growth. Sikkens’ Cetol HLSE is a breathable, water-repellent oil-based treatment, with a micro-porous structure to avoid mould, blistering, or peeling. This makes it a great option for those in humid climates who prefer an oil-based formula. Nature’s Timber Oil, from Intergrain, is an oil-based treatment that is 95% naturally derived and sustainable materials, and is just as long-lasting as chemical-based formulas. Both Sikkens and Intergrain have formulas that only require three coats for a polished final look. 

Choosing the best merbau decking oil for you

Deciding on which treatment will work for your deck depends on the way you use it—is it covered, or open and exposed to the elements? How often do you use it? Has your deck been treated before, or is it newly installed? New timber needs to be weathered—most experts recommend waiting 6-8 weeks after your deck has been installed, so the natural tannin can leach through the wood completely[5]. This prevents staining caused by runoff after the oil treatment is finished. 

Many wood and deck installation companies have timber experts available to give you an opinion on what type of treatment will be best for your merbau deck. To get the most out of your deck, properly applying an oil treatment is essential. As a high-traffic area, laying the right protection on your merbau deck will mean less hassle and more enjoyment! 

References

1. 2019, Merbau Decking Oil – How and When to Oil Your Merbau Deck, Australian Treated Pine.
2. 2020, The Top Reasons Why Merbau (Kwila) is Used for Outdoor Construction, Narangba Timbers.
3. 2020, Choosing the Best Timber Decking Oil: Independent Review, Austim.
4. Rob Schneider, 2019, Oil or water-based Decking Treatment?, HiPages. 
5. 2017, Five Things To Do Before Oiling A New Deck, Brisbane’s Finest Floors.

Enjoy this blog? You might like to read our Oiling A Deck guide, which tells you everything you need to know about oiling your deck effectively.