Impregnating WPC decking boards – explained step by step

WPC decking boards require regular impregnation in order to retain their positive properties. To make sure that nothing goes wrong, here is a small guide.

Impregnating WPC decking boards
WPC decking boards must be impregnated regularly

The decking boards made of WPC (Wood-Plastic-Compoud) are relatively undemanding and easy to maintain, which is due to the high proportion of plastic. They do not have to be constantly oiled or painted with wood preservatives.

However, so that they do not lose their positive material properties such as moisture resistance and stability so quickly, you cannot avoid regular impregnation. This also serves above all to protect against dirt and signs of ageing.

We would like to explain step by step how you impregnate the wood-plastic composite.


You need:

  • Bucket with lukewarm water
  • WPC cleaning agent
  • wiping cloth
  • WPC impregnating agent
  • Paint roller or brush
  • Paint tray or flat tray
  • funnel
  • kitchen paper

Prepare decking boards

To ensure maximum effectiveness of the impregnating agent, the boards must be thoroughly cleaned before application. Pour lukewarm water into a bucket and add some WPC cleaning agent for heavily soiled planks (available here for less than 20 dollars) according to the manufacturer’s dosage recommendation.

Spread the water or the washing solution generously on the boards with a wipe. Then remove the dirt with a scrubbing brush or brush. The loosened dirt can be easily removed with the cloth. After cleaning, wait until the terrace is completely dry.

Impregnate WPC planks

Now put the impregnation (My recommendation: Greenwood Protection Impregnation colorless) in a paint tray or a flat dish. You can use a wide paintbrush or a paint roller for the application. The brush is the better choice if the surface of your planks is textured and has distinct depressions. When applying the product, follow the basic rule: “No dry spots, no standing liquid”.

Observe how quickly the WPC absorbs the impregnation. If no moisture is visible after five to seven minutes, the boards are still absorbent and you can apply a second thin layer.

“Tip: When impregnating the planks, work backwards so that you do not step into or kneel on the wet surface.

Allow impregnating agent to take effect

The boards should be completely dry 20 to 25 minutes after the last application. If residues of the impregnating agent remain, the substrate is already completely saturated. Remove these residues easily with some kitchen paper. If any impregnating agent remains in the paint pan or tray, pour it back into the sales container using a funnel.

Very important: keep an eye on the weather

The entire process of cleaning and impregnating WPC planks should take place in the dry. Even on the following day it should not rain if possible. Therefore, keep an eye on the weather forecast to choose the perfect day for the important maintenance of your WPC terrace. We wish you good luck!

Don Burke

I am Don Burke, one of the authors at My Garden Guide.  I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.

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