Deck Preparation for Staining and Oiling

Sooner than you think, the warm weather of spring and summer will return. Everyone will be looking forward to entertaining on, or simply enjoying their timber deck. So that means it’s time to start planning the deck preparation as part of its maintenance. After all we all want our decks liking like it did when it was first installed all those years ago.

But before you start oiling you have to prepare the deck to get a great result. This means removing the dirt, grime and the UV weathering that has built up. The best means to do that is to use Preschem’s Grey Deck Cleaner. This is a mild oxalic acid based cleaner that restores your deck to the “as new” colour. This doesn’t take long and you’ll need an hour or so. And I’ll let you in on a little secret. When I did my deck at home last year, it had been 2 years since I last done it. So I’m going to take you through this process step by step, with photos along the way.

Equipment list

It’s important to get this organised before you start. If you are using a pressure cleaner, please select the car cleaning attachment and not the regular attachment. You can erode timber with high pressure water. The Deck Preparation brush uses stiff nylon bristles and can be attach to a roller pole. They are available in all good hardware and paint stores.

  • Preschem’s Grey Deck Cleaner (1 jar makes 10lt. Enough for around 40m2)
  • Garden hose with trigger nozzle or Pressure Cleaner (with car cleaning nozzle only)
  • 15-20 litre plastic bucket
  • Deck Preparation brush and roller handle
  • PPE: Rubber Gloves, safety glasses and old long sleeved clothes or overalls

Deck Preparation

This is not a hugely onerous task. It takes me about an hour to an hour and a quarter in total for a 27 m2 deck. Remove everything off your deck. Furniture, BBQ, pot plants and of course, your pets.

Dissolve 1 kg of Grey Deck Cleaner into 10 lt of hot water. I can get away with using half a jar (500 g) in 5 lt of water, so you can do that too. You can use cold water, but this could to up take 10 minutes of constant stirring to dissolve the crystals.

Use the hose or pressure cleaner to wash the deck of dust, grime and to get the deck wet. You will notice that the weathering will turn dark grey when wet. This is the result you will get if you don’t do the deck preparation and oil the deck. And it will take about 7-8 months to disappear!

Scrub the deck with the deck reparation brush and pole, working methodically across the deck. You will notice the timber colour and features being restored as you go.

When you have finished scrubbing the deck, use your hose or pressure cleaner to thoroughly wash your deck. I find that if you’re using a pressure cleaner, it helps to do this process twice. If you notice the odd patch where the timber is still dark, reapply the Grey Deck Cleaner and don’t forget to rinse the deck thoroughly after its second clean!

Now all you have to do is wait overnight to allow the deck to thoroughly dry and then reapply with Preschem’s Aussie Clear decking oil.

Procedure summary

  • In a bucket, add hot water then dissolve the Grey Deck Cleaner as directed on the label
  • Hose or pressure clean the deck to remove surface dirt and grime
  • With the Deck Preparation brush, scrub the deck with the Grey Deck Cleaner solution
  • Thoroughly rinse the deck with hose or pressure cleaner
  • Repeat on any areas that are still dark or patchy