A professional strength concentrate for washing roofs and deck. This one gallon container mixes to make 10 gallons and will clean 2000 square feet. It will not harm or discolor shingles. It restores the natural color to wood. No Scrubbing or brushing is needed. Contains no bleach, solvents, acids or phosphates and will not harm grass or shrubs. You can even use it with a pressure washer.