Timber preparation for decking oil or timber finishes

Timber Preparation Guide: Before You Oil Your Deck

Achieving a professional, long-lasting finish on your deck isn’t just about the oil you choose—it’s about the preparation. Whether you are using Aussie Clear, Aussie Clear Light, or our rich Walnut Timber Finish, correct preparation ensures the oil penetrates deep into the wood fibres rather than sitting on the surface.

1. Preparing New Timber (The 6-Week Rule)

If your timber is new, Preschem recommends allowing it to weather for 4–6 weeks before applying any finish.
Why wait? New timber contains natural resins and waxes that can block oil absorption. Weathering opens the grain, ensuring your first application of Aussie Clear penetrates deeply and lasts significantly longer.
  • Pro Tip: If the timber is clean after weathering, a simple scrub with fresh water the day before oiling is usually enough to prepare the surface.

2. Restoring UV Weathered Timber

For regular maintenance, you must remove the grey “patina” caused by UV exposure. This ensures the timber surface returns to new, and the application of oil will look sensational.

The Water Test: Is your deck UV weathered?

Splash water on the boards. If the natural colour returns, the timber is ready to oil. If the timber turns dark grey or black, the sun’s UV rays have weathered it grey, even if it’s just a little. This requires Grey Deck Cleaner to strip away the weathering and restore the surface for a fresh coat of Aussie Clear.

3. Dealing with Stains and Mould

  • Sapstain & Mould: Use Grey Deck Cleaner to strip away organic staining and prepare the surface for oiling. 
  • Stubborn Stains: Persistent marks like red wine may require a light sand (no more than 1mm) before cleaning. 
  • Concrete Stains: Because it is oxalic acid-based, Grey Deck Cleaner also effectively removes oil stains from masonry and concrete surrounds. 

4. Using a Pressure Cleaner

Using a pressure cleaner can make preparation a breeze, but avoid standard high-pressure nozzles as they can erode and “fur up” the timber. Always use a wider car cleaning nozzle or a dedicated deck cleaning attachment for a safe, even finish.

Ready to Achieve the Perfect Finish?

Once your deck is clean and dry, choose your premium Australian Made protection: