Bests & Worsts Reviews from Amazon

As other reviewers have stated, this does work but it takes some time. I applied it to a shingle roof that was almost black with mold/fungus that was a result of being under a tree and partially shaded. I only bought 1 gallon which makes 6 sprayable gallons when mixed with water. I applied it in June and had my doubts since there was no immediate gratification, however over the next few months it was startling how it changed. See picture taken in October. (taken from a quadcopter in case you are curious) Since I bought only 1 gallon I didn't have enough to do the whole (roughly 1800 sq ft) roof and wasn't going to buy more until I was sure it would work. You can see where I sprayed. It does need to be exposed to rain to be cleaned off over time as the product directions state otherwise you'll need to brush/spray it off after a few days. The product description is a bit misleading with regards to the hazards. If you peel back the label or go to the manufacturer web site you'll see the specific hazards. It is a corrosive, so don't spray it when the wind will blow it back in your eyes or on your skin. Don't let pets on it unless it is dry. I have used Jomax with bleach and it did not clean my roof like this product has.