house wash question

[Fairway]

Does anyone know what causes some vinyl siding to become chalky?-when you run your hand across the surface a chalky film the same color as the siding will come off. Is this just oxidation- if so how could the same (type,age&color)siding next door, which also has not been cleaned,not have this problem? We've seen this often on painted siding, especially aluminum, but this is the first time weve seen it this bad on vinyl and would like to know the reason for it.


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[Tony Ward]

There are probably several different reasons the surface can turn chalky from oxidation but one of the most common is people using bleach to clean off mold and mildew and letting it dry without thoroughly rinsing it before it dries. Bleach is a heavy oxidizer. Many homeowners will get outside with a pump sprayer and bleach misture and just spray down the sides without really knowing that properly cleaning it it is a little more sophisticated than this. Unfortunately, many "professionals" (weekend warriors) do this too with their pressure washers. They see the mold and mildew dissappear and assume that's all it takes.

Tony

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[Glenn]

I have seen this before on new vinyl siding and I assumed it was a thin film or glaze from the manufacturing process that had simply began to deteriorate from UV rays. I also agree with Tony.
Glenn

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"Hmmm, If everyone has a photographic memory... mine must be out of film."