The cleanliness of wood surfaces should be taken care of regularly, as mould spores thrive on a dirty surface and if the wood surface is not cleaned thoroughly before treatment, dirt and mold can, in the worst case, remain "forever" on the wood surface. Good cleaning allows the protective treatment to have the best possible effect, as the water opens up the causes of the wood, allowing the new oil to penetrate better inside the wood.
Before treatment, wash the terrace with WOODCARE.GUIDE Maintenance Clean to avoid binding dirt, dust, or other impurities to the wood surface. Remove any loose material from the surfaces with a root brush, sponge, or patio cleaner, rinse thoroughly with water and allow the surface to dry. Previous wood treatment agents can also be removed with RK Terrace Wash, which also removes oils and old pigments. An old terrace with dozens of wood oil treatments may require repeating the cleaning several times.
Using a pressure washer to clean the terrace can damage the wood due to its excessive pressure. However, pressure washers are available with an optional terrace washer that makes cleaning easier and faster but does not damage the wood. If the causes of the wood have emerged, sanding may also be necessary to achieve a smooth surface.
Moldy, mossy, or algae surfaces are washed with WOODCARE.GUIDE Mold Wash and any grease are removed, for example, with RK White Spirit. Read more about cleaning moldy surfaces.
If a film has been formed on the surface of the wood by previous treatment or several layers of oil, the wood should be cleaned with RK Terrace Wash, which removes the non-breathable film that is harmful to the wood. The film is formed if excess and unabsorbed oil is not removed from the surface, or if the surface has been treated several times with wood oil.
You can test whether there is a film on the surface by trying if the oil is absorbed into the wood. If the oil is not absorbed, there is a film on the surface. After removing the film, the wood oil can be absorbed again and it protects the wood from decay, but at the same time keeps the wood breathable, allowing the soil moisture to evaporate from inside the wood. Please note that after cleaning with RK Terrace Wash, the surface must always be re-treated.