THE DEFINITIVE GUIDE TO ROOF CLEANING

See pics two and a few. I am now getting ready to refinish the deck once more this summertime. See Photograph 4 of existing issue. The blotchy search has rather dissipated because of weathering from snow/rain (I live in northern Illinois). What did I do Mistaken very last yr? What does one advise I do this 12 months? Do I utilize the RAD stripper,