Well Paula from Austin, The Answer is this. As far as I can see you are talking about Power washing your home. You would need a chemical washer <a power washer that has a hose to add chemicals> you want to use a outdoor bleach, but there is house cleaner at Lowes that might work better. You want to dilute 20 parts water 1 part cleaner. This job is best handled by a professional but a homeowner can do it.

Thank you, I hope this answers this question.