I have asked this question before but it was never answered.

You might try Trisodium Phosphate (TSP). Be sure to follow safety precautions.

Hi Linda! I checked online and it seems like this is a common issue in areas with warm climates. This website outlines how to tackle the mold problem and does step by step instructions. Also a handle list of supplies which did not include bleach! (Yay!). http://www.doityourself.com/stry/removing-mold-and-stains-from-brick-and-stucco  ; Good luck!

Lowes has a product that you can use. I can't recall the name but it does work. I had mold in my basement near the sump pump just from dampness. I sprayed, waited, and washed it off. It disappeared. I will look and see if I can find the bottle. I hope it moved with me when I switched houses...twice in a year. Ugh!

I'd use a powerwasher

Try using a mixture of white vinegar and dish soap. It will take some elbow grease.

Wet & Forget is the best. You use a sprayer to spray it on and without rinsing the mold gradually disappears. All my neighbors used it so I did too. Used it on roof, mailbox and back of house that doesn't get a lot of sun. Can buy at some big box stores and Amazon.

You might want to try this from a DIY site. http://www.doityourself.com/stry/removing-mold-and-stains-from-brick-and-stucco Hope this works for you!

Depends upon whether or not the mold has stained the paint. When I lived in a Florida stucco, I found that a bucket of warm water with dish soap and bleach worked best. It takes a little elbow grease and a stiff brush. However, I did have some spots where the mildew stained the paint and there was no solution but to repaint. Good Luck!

If you have a power washer, you can out whatever solution you decide on in the tank and run it trough with the power wash

it also depends on why the mold is there. If water is seeping into the stucco or behind the stucco around unsealed window trim, or cracks that could be allowing moisture to sit in and behind the stucco, etc, then cleaning the surface would only be temporary. Make certain there is not damage first. If the mold is not coming from damage, then any of the aforementioned mold cleaner should take care of it. But, the mold can cause staining and or color changes in your paint.

Did you get your answer yet?

The mold has “roots” into the stucco, of which you know it is porous, being essentially a 3-stage concrete surface.

I’d not only use a mold killer, but also scrub it into the stucco, keeping in mind that those precious plants next to the house need to be transplanted or they will die.