For more than thirty years silicones are used as water repellents for masonry. Their excellent properties make them also attractive for non-mineral substrates like wood. Although it was always thought that silicones are not able to perform on wood, a new type of aqueous silicone materials proofed the opposite: Excellent water repellency and astonishing durability were achieved. This paper describes the nature of these products, the background of their performance and the test results on wood.