Yea I got a "ring" from a x jet 5'er on a deck one time,,,not good, will not set another one on a deck,,I 25.00 "up sale" washing the deck "too" because I"m going to do it anyway to prevent this and keep things even,,,and always get it. (pays for gas) also I learned F13 in a house wash will turn solid light brown stain florescent green,,,OOps! thank God that one was a buddy and he had a gallon left to paint over the green splotches. Won't "hot mix" around a deck I'm not redoing either anymore. Lessons we live learn,,,others call PANIC!