Why Your Vinyl Siding Can Get Moldy (And How to Treat It)

Vinyl siding is one of the most durable and affordable siding options out there, making it the most desired cladding material in North America. It’s beautiful, low-maintenance and eco-friendly, and what more could you want from a siding?

Although vinyl siding boasts many amazing features, it doesn’t mean that it’s immune to issues, and one of those issues is mold. Mold and mildew can accumulate on vinyl siding, which can be a downside to the cladding material, but luckily there are easy ways to treat it!

Why Does Vinyl Siding Get Moldy?

Yes, vinyl siding is low-maintenance, but mold can still grow on it for a number of different reasons. If you’re thinking about investing in vinyl siding, or are curious because you have vinyl siding on your home now, it’s helpful to learn what leads to mold and mildew.

Dirt Build Up

When dirt accumulates on the surface of your siding, it can lead to the build-up of mold and mildew. Dirt on your siding not only makes your home look unclean, but can result in mildew since fungus feeds on dirt and dust. You also have to be careful of any trees located in close proximity to your siding. Sugary sap can end up on your siding, which acts as food for fungus. Mildew and mold feed on sugar, dust, dirt and other things attached to your siding, so it’s important you keep your siding clean.


Water can also cause mold and mildew to develop on your vinyl siding. If moisture gets stuck behind or in your siding, you may end up finding mold and mildew on your exterior. This can be attributed to anything from rainwater, to washing your siding with a power washer, to a broken gutter dripping on your siding. If there’s excessive moisture that causes your siding to stay wet, mold is likely to start growing.

Not Enough Sunlight

A lack of sunlight is another reason for the growth of mold and mildew. Mold flourishes in dark places, so if an area of your house doesn’t get much light, it’s more prone to mold and mildew. If there’s a porch roof or tree that’s preventing part of your house from ever getting light, you may want to consider removing it.

How to Treat Mold on Your Siding

To remove the mold on your siding, all you have to do is wash it with a homemade oxygen bleach solution. Mix powdered oxygen bleach with warm water and apply it to your siding. This will work best when your siding is dry and in the shade rather than sun. Allow the solution to sit and fizz on the siding for 10 minutes, then scrub with a brush and rinse with a garden hose.

Another option is using a pressure washer, but you have to be careful if you choose to do so. If you use it improperly, it can cause serious damage to your siding, leaving you worse off than you were in the first place. The water from a pressure washer can be driven into cracks, causing water damage to your home. Make sure to read the instructions and use caution if you decide to go this route.

Vinyl siding can get moldy, but as long as you maintain it and treat it when you see it, your home will be clean and mold free!