Stained Stucco

Shawn G.

New member
We did a "prep for paint" house washing this past weekend, and I need to ask a question.

There was a black stain around the top 2-3 feet just under the roofline of the house. I thought it might be mildew, but we hit it with strong bleach and detergent mixture and nothing happened. We did wash a ton of dirt off the house, but the black stain is still there. We tried brushing straight chemical and even tried brushing a small hidden section with full strength concrete cleaner. Nothing happened.

The stucco is approximately 60 years old. We were told that the soffit was installed about 5 years ago, and the stains were there before the soffit was installed.

When we cleaned the soffit, more black dirt came out through the perforations.

Anyone know what the black stain is? Could it just be 60 year old dirt that will never come off?

Thanks in advance.

Ron Musgraves

Exterior Restoration Specialist
Staff member

I would love to help yah, I think you have the answer its 60 year old dirt. That’s stained in the paint the stucco and everything else. I know you can sometimes rinse & rinse & rinse those soffits and dirt still keeps piling out.

Hey if it’s a paint prep job wont they be painting that surface? Maybe if I had a picture I could help.

Shawn G.

New member
Sorry, not able to do pictures yet. Maybe in the budget for next year.

I just wanted some assurance that there was nothing more i could do to get this off. Never seen such a hard stain. Now i feel better.

Yes it is prep for paint. I will be recommending that the customer prime the stained areas prior to paint so that the stains don't show through the new paint job.

I took a couple of samples of the stained stucco and the stain actually "soaked" into the stucco, below the paint. I'll hang on to these samples just in case......

Thanks for the input.


Sounds crazy but it might be the sand from the shingles that did that staining. Don't ask me how that is what a painter once told me. Your guess is as good as mine. Ask a roofer if this could happen.

Sounds like what happens on gutters. The tar from the shingles gets on their and man its murder. The only thing I have found that works on this is a product called Gutter Zap I bought some and like it very much.