Why is My Deck Not Absorbing New Oil?

Written by

CUTEK®

12 March 2025

•

3 min read

When looking to coat your timber deck with a penetrating oil, preparation is key to ensuring the process is efficient, easy, and effective long term. A common problem applicator’s run into is that the timber does not seem able to absorb the oil and will not dry, which begs the question, why is my deck not absorbing new oil?

Common reasons for penetrating oil not absorbing:

Too much moisture in the timber
Temperature
A barrier preventing the absorption of the oil

Too much moisture

If your deck is newly built or is unlikely to have any kind of coating on the timber, consider the possible water content of the timber.

If the timber is too wet, the oil is unlikely to absorb as efficiently or effectively. Ensure your timber is thoroughly dry before applying a coat of oil. If you have experienced recent rainfall, allow several days for the timber to thoroughly dry out before coating. Consider testing a small area prior to coating the entire deck to ensure the timber is dry enough. If it absorbs well and does not discolour, proceed with the application. In the event that the deck colour looks darker or different than expected, stop and wait a few days for the moisture content to dissipate and reapply.

Temperature

Cold temperatures will raise the viscosity and make the oil thicker, which slows down the penetration process. To assist this, place your can of oil in a warm, sunny spot or in a bucket of hot water. This will lower the viscosity of the oil and assist in the penetration time.

Cold climates and shaded and undercover areas that do not receive direct sunlight will require a longer drying period to allow full absorption of the oil.

A barrier preventing the absorption of the oil

For new timber, the barrier could be mill glaze, sometimes known as machine glaze. This occurs only with new timber and takes place during the timber machining process.

For pre-existing decks, your deck is likely to already have a coating on it. If this is not removed, the deck will struggle to absorb the oil and it will remain on the surface of the timber rather than penetrating.

To remove an existing coating

Existing coatings, like a stain, varnish, or glue on the timber, encases the wood and prevents other elements or oil from being absorbed into it.

To remove this coating, follow these steps:

Apply CUTEK® Wood Stripper to the deck; this will remove all remaining traces of the old coating. If you do not have CUTEK® Wood Stripper on hand, you can sand the deck back to bare wood, ensuring you have removed all traces of the previous coating.
Use CUTEK® Restore to restore and brighten your timber after using CUTEK® Wood Stripper or sanding.
Wait for your deck to thoroughly dry before applying CUTEK® Extreme CD50 with a CUTEK® Colourtone, if desired.

Please note, we always recommend testing all CUTEK® products on a small area prior to applying to your entire deck.

The CUTEK® difference

CUTEK® oil penetrates the timber to protect it from the inside out. Where other coatings envelope the wood, CUTEK® Extreme CD50 deeply diffuses into the timber, protecting your deck long term. Contact us for more advice on how to seal wood utilising CUTEK®’s wood finishing range.