What are these stains on siding?

I was curious if anyone knew what these stains / marks are on this masonite/hardboard style siding?

Maybe someone power washed the house and water got behind the siding and came out, with dirt, were the siding was gapped the most.

Oh, and welcome to our forum, Paul!..Enjoy! :grinning_face_with_smiling_eyes:

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Do the sellers or their neighbor drive a diesel truck?

Some of them line up pretty good with the soffit vents. What type of attic insulation?

What’s on the other side of that wall?

Alot of good questions for the question. Here’s a couple more: Is it a garage wall or living space? What side of the house is it? Where are you located? Is that rust on the bottom of the gutters? Sure looks like it.
I’m thinking it’s a combination of things but need more info really. Could be a moisture issue mixed with dirt coming out, could be diesel suit… Could just be thin paint that has broken down…

Only one way to know for certain…


paint touch up ???

Thanks everyone for responding. This is in Atlanta, GA and the wall is on the second level of a house that has not been maintained that well and the wall is located in the North East corner of the house and it’s exposure is primarily to the east. Directly behind the wall is the master bedroom. The attic is insulated with blown fiberglass and that is some rust on the bottom of the gutters.

I’m not that concerned about it but wanted to make sure that I wasn’t missing an obvious explanation. My best guess is algae/mold or faded paint.

What year was the home built?

I will take a guess, 1978.

It was built in 1995

Composite lap siding. Messy stuff. I see the moisture wicking and deterioration down at the lower sidewall. Anyway, I would suspect air movement. I have seen homes from that era with no vapor barrier in Atlanta.

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