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Oxidation Removal on Vinyl Siding

Homeowner's Guide


If you have a vinyl-sided home, odds are high that your siding is oxidized. In this article, we will explain what oxidation is, why streaks can be left on your siding after a pressure wash, and how we go about fixing this problem.

What is oxidation?

Oxidation is a white, chalky substance that develops on the surface of vinyl siding. You can test if your siding is oxidized by rubbing your finger on the siding and checking to see if there is any chalky residue left over on your finger. If that is the case, do not be concerned. Oxidation is a normal process of aging and your siding is not damaged, seriously degraded, or in need of replacement. 


What causes vinyl siding to oxidize?

UV rays and exposure to the outside will cause anything to deteriorate. Wood rots, metal rusts, and concrete cracks. As vinyl ages, UV rays cause the vinyl, which is made of PVC, to irradiate and slightly change in chemical makeup. Irradiated PVC will react with oxygen in the air to develop a layer of chalk that is electrostatically charged to the siding. If your siding is only 5 years old the oxidation layer can be relatively thin when compared to siding in a similar situation that is 20+ years old. 


We find that oxidation is by far the worst on the south side of homes as it gets the most sun here in the northern hemisphere. If you happen to live in the southern hemisphere, it would be the north side of your home that is affected the worst. We also have noticed over time that lighter-colored vinyl siding such as blue and light gray are the most obvious when oxidation has been partially removed. 


If you happen to have a vinyl-sided home, you may notice that your siding behind a bush or under your deck may be a different color than the vinyl siding exposed to the sun. Any area around your home that is protected or even partially protected from the sun's UV rays will be oxidized significantly less than other areas and this will only get more noticeable with time as those areas will not have a white, chalky layer on top of them.


Why are there streaks on my home after a pressure wash?

Unfortunately, some of our customers get unlucky when we wash their home and some streaks will be visible. This situation is by far the most common issue with pressure washing, with 2-5% of customers affected. This can occur due to our employees being slightly closer in some areas than others, certain angles removing oxidation more than others or a variety of other subtle variables that can result in partial oxidation removal on your siding. The employee working on your project did nothing wrong despite the end result. This is nothing to be concerned about as your home is not damaged but it is very unsightly. If you happen to be one of these customers, please finish this article and give us a call if you need further assistance. 


How do I fix the streaks on my house?

Fortunately, these streaks fix themselves quickly. Depending on your exact circumstances, largely the age and color of your siding, the unevenness should resolve itself in 4 to 8 weeks. If your siding is newer, the sun is unimpeded by clouds, and the oxidation was only partially removed, we have seen oxidation resolve itself within hours. Usually, it will take much longer, especially in homes that are older.


Once the days begin to get shorter fewer UV rays will hit your siding and help to redevelop that oxidative layer. So if it is approaching winter and the oxidation streaks are still visible, you may have to wait as long as the next summer for the siding to even out completely. This is an unfortunate circumstance but your siding will return to normal.


Why not remove all the oxidation? Wouldn’t that fix the problem altogether? 

The reason we wait for the UV rays to do the work is that oxidation comes back quickly in almost every single circumstance. There are companies that specialize in oxidation removal but we recommend that you save your money and let the vinyl siding return to its normal state. Oxidation removal is an expensive service that serves no real purpose other than to fix uneven or streaky siding in the short term. EcoWash does not perform oxidation removal and our contracts explicitly state that we are not liable if you would like this service performed. 



  • Oxidation is a layer of chalk on vinyl siding that is the result of natural aging.

  • Pressure washing can occasionally remove streaks of the oxidized layer.

  • Removal of oxidation does not damage the vinyl and is completely reversible.

  • Streaks on your home are not a sign of employee error as many variables could be to blame.

  • As UV rays react with the vinyl over time, the streaks will go away. 

  • In 3 months, nearly every issue of oxidation removal has been resolved.

  • Oxidation streaks resolve more quickly in the summer than in the winter.

  • There is no need to pay for an expensive oxidation removal service if you have been affected.

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