I have the same problem, put on the deck last June and over the past month more than half of my deck has turnded black, seems to simply have been scorched by the sun. I tried to clean to no avail and called Timber Tech today to file a claim. Seems there are many posts by folks with this related problem, so I find it hard to believe that the manufacturer was not aware of this issue. Needless to say I am extremely angry and am anxious to see what Timber Tech's response is.