Vinyl Siding: 3 Spotty, Streaky Problems & What To Do About Them

22 October 2015
 Categories: Construction & Contractors, Articles


In a perfect world, the vinyl siding on your home would always be free of spots. However, since the world is not perfect, vinyl siding can have green, brown, and/or white spots. It's important to understand where the spots come from. That way, you can effectively remove them and prevent them from returning again, hopefully. Here are 3 common discolorations on siding, why they happen, what you can do to remove them, and how you can prevent the problems from recurring.


Problem: Green spots on the vinyl siding of houses are mold and/or mildew. These are organisms that use enzymes to digest and decompose organic matter. And while vinyl siding is not organic in nature, mold and mildew feed from the sugars, pollen, and other organic particles that can accumulate on the siding from nearby trees and vegetation. Mold and mildew need moisture to survive, which is why you're more likely to see this problem after a rainy period or in higher humidity. 

Solution: To clean mold and/or mildew from your siding, you'll need to use a product that has mildewcide in it to kill them, since they are living things. These products can be found in home improvement stores, and they attach to your garden hose for easy application.  

Prevention: Keeping your vinyl siding free of organic matter that mold and mildew feed off of can help prevent growth of the organisms. Hose down or power wash (low pressure) the vinyl siding occasionally, paying close attention to areas with trees and vegetation nearby. 


Problem: If you have brown spots or streaks show up after winter, it's a sign that you have a problem with ice dam formations along your roof line. The brown spots and streaks are actually water that has seeped through your roof structure and into the walls. It then weeps through the siding as it drips down the walls. 

Solution: Place a few drops of bleach in hot, soapy water and use it to scrub the vinyl siding to remove the brown spots and streaks. Or hire a siding contractor to professionally clean the siding.

Prevention: To prevent the problem in the future, you'll need to eliminate ice dam formations on your roof. This usually occurs when heat in the attic melts the snow on the roof, which causes the melted snow to get underneath the roofing shingles where it will refreeze and form an ice dam. Sometimes, ice dams form due to improper attic ventilation. Hire a roofing contractor, such as those at Lifetime Exteriors, to determine the root cause of your brown streak problem. 


Problem: If you have white areas, run your hand over them and you will find a coating of white powder on your hand. White spots on your vinyl is from a combination of the oxidation of water (acid rain) and the UV inhibitors in the vinyl material breaking down. When the UV inhibitors break down, it causes the vinyl siding to be rough, which makes it easier for the material to absorb water. Also, the longer that moisture remains on the siding, the more prone it is to grow mold. 

Solution: Remove the white areas by scrubbing them with a vinegar-water mixture. Alternatively, you can power wash the siding, but only do so on a low setting to prevent damage while cleaning. However, it's important to avoid doing this in direct sunlight, because the UV rays can cause the cleaning solution to dry too rapidly, which can cause staining. 

Prevention: Hire a siding contractor to apply a UV sealant to protect the vinyl siding from the harsh sunlight that causes the material to deteriorate. Then regularly clean the siding by spraying it down with a garden hose to remove residue from acid rain.