I got an email today for someone wanting their house pressure washed. I went out and measured the home which came out to 339 linear feet, single story. The home is wood-sided that is painted blue. What kind of chemical if any should I use? I normally do not use the chemical injector on vinyl sided homes. The house only had the typical grime such as cobwebs and dirt. I know the normal rate is around $1 per linear foot, but I am solo and that to me is way too high. I am going to quote around $215 total. Basically just want to know if I should use any chemical. The PW site didn't answer my question. Thanks and free bumps appreciated.