Washing dark blue vinyl - tips

I’m sure there are plenty of guys her who can offer tips on cleaning dark colored siding. The advice I offer is from my experience with dark colored siding.

Specifically regarding dark blue vinyl siding, my nemesis. The siding wears or oxidizes different than other dark colored siding. It takes sometimes days to dry in the shade and while drying the color can look uneven. While drying it can look like there is soap residue, stains or uneven in color.

I always take pictures of the effected areas of blue siding when I do the estimate. Customers don’t pay attention to their siding till after you clean it. Then they see “fading”, “staining” or “residue” in their terms after you clean when it was always there. Pictures have saved me a few times.

Note in the estimate or over the phone that the siding is discolored. Which is normal for blue vinyl, at least in my area. I highly recommend written estimates because customers can’t argue something in writing.

Always pre-wet the blue vinyl or any dark colored vinyl and don’t let your mix dry on it. I know guys say they don’t pre-wet but in the summer heat and with the dark siding I highly recommend it. Just as you would never throw soap on a black car without wetting it first why would you do it on hot dark colored siding. Its a precaution.

I do the same with green and dark green siding but I have always seen blue as the color to wear the quickest.


Literally did a house today (dark blue vinyl) and forgot how annoying they are. I take 55 million “before” pictures anytime I’m doing any shade of darker blue vinyl and, like you said, have a disclaimer section in there addressing the problems you outlined. With that said, dark blue is the only color that has ever given me problems (uneven drying, oxidation, etc.).

I always internally blamed it on living near the ocean and the salt air messing with it…that being said, I’m totally talking out of my ass; the salt air has nothing to do with it. Like you said, get everything in writing in your estimate/quote. Glad I’m not the only one who dislikes dark blue vinyl

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BillC - Thanks for this post. I had question for you, do you ever see this with newer siding (~6yrs old since install), or only on older siding showing the uneven drying/soap residue/stains? I guess I assume its only on older siding because you can already see affected areas and take pics of those areas pre wash. Thanks again for the post.

I’ve seen it on newer siding. I can’t say under six years but definitely under ten. I had one green house where it was under two years. That house had tge siding replaced by the manufacturer because the original green siding oxidized so fast. It’s not from soap or staining. I think it’s the same thing that happens to white siding but it’s just not visible on white siding.
I don’t know if you can see the botchy spots

This one you can see the uneven color under the siding ledge. It’s not dirt. This one is under 10 years old.

This is same house, different wall. All these pics are before I cleaned thank God. These were cya pics that I made the home owner aware of. I no longer deal with it becuase I have enough work.

Thats crazy. Haven’t come across any that look that way yet, but thanks for the heads up on what to look for. In your experience, having washed houses of darker shades, if you ever did get the splotchy/soap residue look, would it eventually clear up once dry?

Those real bad ones were dry. It does seem like they do take a couple days to dry and look better.

They changed the siding on the first story and left the old oxidized siding on the second story. I hate blue siding.

Can you tell what side the sun hits all day?