The high pressure stream will definitely reach that high using the zero degree spray tip. However, you will only be able to spray detergent at low pressure which will only reach about 10-15'. We do carry a couple accessories that can be used to increase your spraying distance and allow you to spray detergent at high pressure. Using one of these attachments will definitely take care of what you need to do.
I posted links to the products I am referring to below:
Ladder Saver
GP High Pressure Soap Shooter/Rinse Nozzle