Cleaning and preparing your exterior timber for coating

For best results clean all timber prior to application of coatings with Quantum’s timber conditioners and cleaners. This will prevent early adhesion failure and drying issues due to contamination caused by tannins and extractives. All external timbers under 12 months old require preparation with SAP STRIP. Old, weathered, grey timbers and dirty timber require cleaning with DEX PREP.

So what products do you need to use?

SAP STRIP: Wood Conditioner

If the timber is under 12 months old or is high in tannins or a dense timber, apply a solution of SAP STRIP Wood Conditioner. This will release the tannins and extractives that can cause contamination of the coating, preventing poor adhesion and compromised coating performance.

DEX PREP: Timber Brightener

To clean and brighten old, weathered, dirty or grey timber, apply a solution of Dex Prep prior to coating the timber.

Apply DEX PREP (one part DEX PREP to five parts water) with a stiff brush. Leave for 10-15 minutes to allow the timber to neutralise and rid the surface of any darkening which may occur in the cleaning process.

For severe staining a stronger solution may be needed. Use undiluted DEX PREP or a mixture of one litre DEX PREP to one litre of water.

Q-STRIP: Biodegradable Paint Remover

Is a paint remover for all old and previously coated timber surfaces. Q-STRIP is safe to use around plants and will lift a coating in 45 minutes.

Leave Q-STRIP for a minimum of 45 minutes to soften and dissolve film. Remove by scraping, scrubbing or power washing. When the film is removed wash with water and allow the deck to dry.

Test your timber:

When using transparent coatings, wet the timber first. If it appears black, more cleaning with DEX PREP is necessary to eliminate all grey areas. If this is not done, the surface under the coating will appear black and be visible though the finishes coating.

Important Note: Ensure all cleaning solutions are removed from the surface before applying the decking finish.


  • All timbers require cleaning prior to coating.
  • SAP STRIP will rid the surface of tannins and extractives
  • DEX PREP will prepare older timber for coating
  • Q-STRIP is a paint remover

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On May 12, 2017, posted in: News by