How do you wash stain off house stucco? (1 Viewer)

[DustinLC]

Some heavy rain we got recently washed some green growth on the roof to the side of the house. The house has stucco on the outside. Do I just get detergent and start scrubbing?

 

[Drew Bethel]

From ThisOldHouse.com

"When we clean stucco, or other kinds of sidings for that matter, we use a concentrated cleaner designed for exterior use only, such as Jomax, and activate it with household bleach. After spraying any nearby plants with water to protect them from the chemicals, I mix the cleaner with bleach (following the directions on the cleaner bottle) and squirt the solution on the walls using a simple pump sprayer. After the stuff has been on for a few minutes, I gently rinse it off with a pressure washer, starting at the top of the wall and working down. Don't blast away with an aggressive nozzle or you could end up damaging the stucco surface."

 

[MikeH1]

Muriatic or hydrochloric acid. Mixed with water to a 1/10th ratio.