Not really a problem

i powerwashed my parents house the other day. it was real bad, never been cleaned before. one side was streaked green and on the back had a dark green/ almost black streak coming down the siding.

House is vinyl siding and painted trim. i used sh at 2.5 to 2.5 water with 16 oz simple cherry. everything seemed to go pretty well. the algae on the siding faded out after about 5 minutes. i used the pressure washer to follow it up (3.7 gpm 3500psi unit). the area that was 2nd floor and higher, i used the 0 deg nozzle to rinse. the lower areas i used the 15 deg tip. i wasnt really working close up to say i was using “pressure”. however there was some artillery fungus over the mulch in the front yard and on those spots i got up closer (very close to be honest) with 15 deg.

now the results…
higher areas, 2nd floor and up, look great. lower areas have a “powdery film” on it. its not just on the vinyl siding either. its on the paint too. when i run my fingers across it, it transfers to my fingers. the areas where i was closer trying to remove the artillery fungus (also the areas that i let my son try) have streaking.

anyone now whats causing the powdery film? how do i correct the streaking that my son caused?
looking for causes and solutions.


Power stuff is most likely oxidation. Sun beating on it. Dont know how to really remove it. ( don’t think there is a way). Look on some websites & check for chems that may help. It being an issue has never been a problem for me. Hope that’s helps a little.

As for streaking re wash the area or whole side. That may help. Apply chems from the bottom going up as you probably know

Ok. Thanks