Late this spring, after cleaning and brightening, I sealed my cedar deck using the Armstrong Clark product. I am getting what I believe to be mildew (not sure) and would like to know what I can/should use to remove it without damaging the finish on the deck. I am posting a picture of the "before" and "after". Any advice will be GREATLY appreciated!! Thanks...
That is both mildew and dirt. The good news it is lying on top of the wood and not in or under the stain. Have you tried some soapy water? We have also used a product called Wet and Forget for things like this.
Have similar issue with my new redwood deck that was installed last July. Now it has mildew looking dirty dark spots. Tried cleaning with Scotts Outdoor Cleaner and it didn't work. Tried to scrub one section multiple times to test with a deck cleaning brush and it did not work either. Appears the grime or mold has penetrated the stain into the wood. Stain I used was Sherwin Williams Deckscapes. Natural color. I live in Inland NW,Spokane Wa. Not much snow this past winter but a lot of moisture.
TC
If it is in the coating you will need to strip and brighten for the prep. Try the TWP 100 Series.