This is my second time using this product. I extended the time for a redo by a year because of an overly wet summer last year. The two uncovered decks didn't have time to sufficiently dry out! By this spring, water was no longer beading on the surface of the wood but there was no damage to the wood itself. One of the decks is in full sun for most of the day and the second is mostly shaded. DEFY works successfully on both. Algae grew on the small shaded deck but only on the surface. Not into the grain of the wood like I had experienced previously with other products. I chose the driftwood gray and am very pleased with the color. Even after three years it faded very little. It is very important to follow the directions and do a second coat on a still wet first coat...this makes a significant difference in the final color.