What the...?

[John Orr]

I guess I've seen it all now.

I washed a house yesterday - white vinyl. I've cleaned hundreds just like it, except...this one turned color!

I downstreamed my usual housewash mix, which has bleach in it, and when I went back to rinse, ALL the siding had an orange stain. I've never seen anything like it. I tried rinsing, nothing - pressure, nothing. (I was getting pretty nervous, as I didn't want the homeowner to see her house before I figured it out.) I tried various cleaners, with almost no effect.

Finally, I thought, why not acid? So I sprayed a little oxalic acid and...it disappeared! I wound-up downstreaming oxalic acid over the entire house! (Rinsed like crazy, and didn't let it dry.)

So my question is: How did this happen? It must have been rust, but from where? The staining was from the ground to the 2nd story peak, evenly spread from side to side.

Any thoughts?

 

[Bigboy]

reckon you could have covered a hardwater stain which will have a yellow tint or is there a gravel road nearby,it will also leave a yellow tint and acid is the only thing I know of that will remove both...scarely huh

 

[John Orr]

Hardwater stain? Possible...but over every square inch...to the roof? No gravel roads either. It looked pretty good when I started. For a while, I thought I would be making my first insurance claim!

 

[timhays]

this has happened to me before,downstreaming bleach housewash mixture carried some sediment from my coil onto the house,couldnt get it off,luckily for me its on my own house,what the dilution on the oxalic?

i think i will try that.
i know that acetone will remove anything from vinyl