Wash Your House Quickly and Painlessly
Most houses will need to be washed down prior to painting. Wipe a white cloth across the side of your house and you will witness years or even decades worth of accumulated gray soot and dust. Even in the most desperate of painting projects, it is still recommended to wash down the house.
Washing down your house by hand is the most effective and the most work-intensive way to get your house clean. But what is the least you can get by with?
If you own a pressure washer, spray down the house two times. First, clean it with a soapy solution. Second, rinse it with clean water.
If you have no pressure washer, your second-best option is to thoroughly hose it down.
In any case, your main goals should be to knock off the big, visible junk (spiderwebs, wasp’s nests, leaves) and to wash away that thin soot and dust.
Source: The Spruce