No — but it decides what the deck looks like in two years.

Left untreated, every timber deck weathers to silver-grey. Some people want that. If you want to keep the colour the timber had on day one, an oil is what holds it, and it needs to go on early and be maintained.

Oiling also slows the surface checking and splitting that comes from repeated wetting and drying.

Sooner than most people think. A new deck should be coated once the timber is clean, dry and ready — not left bare for a season.

The trap is oiling timber that is still too wet, or that has surface residue on it. Oil applied over a damp or dirty board will not penetrate properly and will not last. Clean it, let it dry, then coat.

Follow the drying time on the product you are using rather than a rule of thumb, and avoid coating in direct hot sun or when rain is due.

An oil penetrates into the timber and protects from within. It wears back gradually and evenly, so recoating is a clean and straightforward job.

A stain carries more pigment and does more to change the colour of the board. Heavily pigmented and film-forming products give a stronger colour but can wear in patches rather than fading uniformly.

For exterior decking, a penetrating oil is generally the easier product to live with because maintenance is a clean and recoat rather than a strip back.

It holds the colour as long as the coating is maintained. Greying is UV breaking down the timber surface, and the pigment in the oil is what screens it.

Once the coating wears back, greying starts again. So the honest answer is that an oil does not stop greying permanently — it postpones it for as long as you keep recoating.

How long between coats depends on sun exposure, traffic and the colour. A fully exposed west-facing deck needs attention far more often than a covered alfresco.

The WOCA Exterior Wood Oil range covers thirteen colours: Natural, Larch, Bangkirai, Merbau, Teak, Hazelnut, Walnut, Anthracite, Grey, Stone Grey, Thunder Grey, White and Black.

They fall into three groups:

• Timber tones — Natural, Larch, Bangkirai, Merbau, Teak, Hazelnut and Walnut. These keep the deck reading as timber.
• Greys — Grey, Stone Grey, Thunder Grey and Anthracite. A controlled, even grey rather than the patchy silver of untreated timber.
• White and Black — for a deliberate, contemporary finish.

Buy a tester. We stock the WOCA Exterior Wood Oil Tester in 25ml, available across the full colour range.

This is the single best thing you can do before committing. Oil colour looks completely different on Merbau than it does on pine or on a Rosewood batten, and nothing on a screen will tell you that. Brush a tester onto an offcut of your actual decking, let it dry, and look at it outside in daylight.

A few dollars on testers is cheap next to recoating a whole deck in a colour you do not like.

A timber tone keeps the deck warm and traditional, and it is the usual choice where the timber is a feature — Merbau, hardwood, anything with grain worth showing.

A grey gives you the weathered look deliberately and evenly, rather than letting the deck go there on its own in patches. It suits contemporary and coastal houses, and it hides dust and wear better than a dark timber tone.

Worth knowing: greys and darker colours generally show fewer marks between coats, while Natural shows the most change as it wears.

Yes, and it is the step that decides whether the coating lasts.

New timber carries mill residue and handling marks. Older timber carries dirt, grey weathered fibre and sometimes mould. Oil applied over any of that sits on the surface instead of penetrating, and it fails early.

We stock WOCA Exterior Wood Cleaner 2.5L for this. Clean, rinse, let it dry properly, then coat.

WOCA Exterior Wood Primer 2.5L is applied to prepared bare timber before the oil, to even out how the surface takes the coating.

It is most worth using where a deck would otherwise absorb unevenly — mixed boards, patchy timber, or where you want the most consistent final colour. Follow the product instructions for whether your project needs it.

WOCA Exterior Wood Shield 2.5L is a protective product for exterior timber, used alongside the oil range.

Check the product instructions for where it fits in your particular job — the right sequence depends on the timber and the finish you are after. If you are unsure, tell us what you are coating and we will talk it through.

The oil comes in 2.5L and 20L. Coverage depends heavily on the timber — a dense, tight-grained Merbau board takes far less than an open, thirsty softwood, and bare timber takes more on the first coat than on the second.

Work from the coverage rate on the product for your timber and the number of coats you are applying, and allow extra for the first coat on bare boards. Send us your deck area and the timber and we will work it out with you.

The 20L is worth looking at once you are past a small deck — and it saves running out mid-deck, which is how you end up with a visible join.

• Coat full boards end to end. Stopping mid-board leaves a lap mark you cannot remove later.
• Avoid direct hot sun. The coating flashes off before it penetrates. Early morning or late afternoon is better.
• Watch the weather. Rain on a coating that has not cured will ruin it.
• Stir thoroughly and keep stirring. Pigment settles, and an unstirred tin gives you a colour shift partway through the deck.
• Use the same batch across one deck where you can.

Always follow the application instructions on the product itself.

Tannin. Merbau is a tannin-rich hardwood, and in the first weeks of weathering rain leaches it out of the boards and carries it onto whatever is below — usually pale concrete or render.

It is normal, it is temporary, and sealing the timber reduces it considerably. Coating the deck early is the best way to limit it.

If it has already stained, a suitable tannin remover will usually lift it off concrete.

Yes, and hardly anyone does.

An unsealed underside and unsealed cut ends take up and release moisture at a different rate to the sealed top face. That imbalance is what causes cupping, movement and splitting later. Sealing every face lets the board move evenly.

It matters most on step treads and wide boards, where the consequences show up fastest.

No. Composite decking is designed to be low maintenance and does not need the oiling or recoating cycle that natural timber requires.

Upkeep on composite is washing and sweeping to clear dirt and debris, including out of the board gaps. The oils and stains here are for natural timber — hardwood decking, battens, screening, posts, handrails and step treads.

It depends far more on exposure than on time. A fully exposed deck in Queensland sun needs attention considerably more often than a covered or shaded one, and high-traffic areas wear first.

The practical test is to look at the deck rather than the calendar: when the colour starts flattening off and water stops beading, it is due.

A penetrating oil recoats easily — clean it and put another coat on. It does not need stripping back, which is what makes it the easier product to maintain long term.

WOCA Exterior Wood Oil Refreshing Soap 2.5L is a maintenance product for oiled timber, available in Natural and White.

It is used as part of regular cleaning on an already-oiled surface, to freshen it between full recoats. Match it to the tone of your existing finish and follow the product instructions.

Yes. Tell us the timber species, whether the deck is new or being recoated, the area in square metres, how much sun it gets, and the look you are after — timber tone, grey, or white and black.

We will point you to the colour, work out the quantity, and tell you which prep products the job actually needs. Start with a tester if you are undecided.

Browse the full Decking Wood QLD range of timber oils and stains, decking, structural timber and hardware.