Unsightly mold growing on vinyl siding is one of the many frustrating problems homeowners will face from time to time. And while this situation is completely natural,  and can easily be fixed, completing the task might be a little overwhelming as it requires a substantial amount of effort and time.

This is particularly true for someone who does not know how to remove mold from siding. Learning how to remove dirt buildup on siding is not that difficult, however – even if you are a new homeowner or an amateur all-around cleaner. 

But first, what makes mold grow on vinyl sidings?

What Causes Mildew to Grow on Vinyl Sidings?

Vinyl siding has several properties that make it mold-prone, but there are also several external factors that might cause mildew to develop on your home’s siding. One of these factors is excessive moisture.

A wet surface or a high moist accumulation provides the perfect conditions for mildew to develop. This is why mold and dry rot are often seen in the bathroom wall, kitchen, and other damp areas. And a house exterior—vinyl sidings, in this case—can also make an excellent breeding ground for mildew.

But why and how?

Simple. Some areas of your house exterior accumulate excessive moisture from humid air and, at the same time, a lack of sunlight which would prevent the buildup. These conditions gives fungi spores an excellent place to grow and spread. It is why (if you noticed) mildew most often grows in shady areas where the siding does not get much sunlight. 

But apart from those two, dirt buildup adds to the problem as well. Molds and fungus feed on dirt. And the larger the buildup is, the faster the growth and spread are.

Is It Possible to Stop the Mildew from Growing Back?

While it is best to opt for a siding that is not prone to molds, there are various ways to prevent your vinyl siding from becoming a breeding ground. The first, and most effective, solution is to keep your siding dry. 

Here are the common sources of moisture you will need to avoid. 

A damaged or clogged gutter can trigger mildew to grow on your sidings as a clogged gutter can cause gutter leakage which will make your siding constantly wet, especially during rainy days. You may even need to clean mold off of your gutters. Thus, if you notice some water leaking from the gutter, make sure to address it immediately. 

One way to thwart off moisture on any kind of surface is sunlight. A house with tall and bushy trees—as well as shrubs—can block the light and heat your siding needs to protect itself against mildew. The same goes for vines and moss climbing on your house sidings.

If you have a dryer, you probably have already noticed the mildew buildup on your sidings where the dryer is placed. The reason is that the ventilation produces steam, and this steam prompts molds to grow and spread. To combat this, make sure to place your dryer in an open area so the moisture will not get stuck. 

Now that you know how to prevent molds from growing, let us talk about the different ways to remove mildew buildup. 

Do It Yourself 

If you do not have the budget to hire a professional cleaner and you have the time to do the job anyway, DIY is an excellent option. You can thus clean your siding in the following ways:

The most recommended—and widely used—way to clean vinyl siding is to by pressure washing. The concentrated stream of water easily removes mildew and dirt buildup in just a few washes. For even better results, the process works best if the water is mixed with a mildew-killing solution. However, do take note that pressure washing is best done by professionals. The pressure in water can damage your siding, especially if you do not know how to do it properly. Too much pressure can also leave water marks on the siding.

There are several vinyl siding cleaners commercially available. However, if you want an environmentally friendly cleaner, you can make a solution out of vinegar, water, and elbow grease. 


As they say, the best way to fix a problem is by preventing it in the first place. Here are a few tips to prevent mildew and dirt buildup. 

  • Occasionally clean your siding. Remove dirt buildup, mold, and grime on a regular basis. If you are going to DIY, make sure that you have a piece of siding-friendly equipment to prevent damage. Otherwise, it is best to hire professional cleaners.
  • Do regular checkups. Regularly inspect your siding as well. Not only to check for mold and dirt buildup, but also to find other vinyl siding damages such as holes and crack due to either insect infestation or woodpeckers. 
  • Repaint or reseal vinyl siding. Another way to maintain your siding and keep it free from damages is to repaint or reseal it occasionally. This is also a particularly effective way to prevent moisture buildup.  Repaint your sidings every couple of years; every five or three years, if needed.

Hire a Professional Cleaner

If you are busy or you simply are not confident in your ability to do the job, it is best to hire a professional cleaner. Professional cleaners are trained to clean all types of surfaces, including house exteriors. Hiring someone can be a much better approach, since these people know how to thoroughly clean sidings.

There are a number of cleaning services across the US that provide pressure washing for all types of surfaces, including house siding. 

Taking Care of Vinyl Siding

Mold growth is common on vinyl siding, especially if the siding does not get enough sunlight or is prone to moisture. Despite this, there are ways to prevent and remove the mold to keep your siding in good shape. In fact, learning how to do the job efficiently is not that difficult, whether you are a new homeowner or an amateur house cleaner. 

Editorial Contributors
avatar for Matt Greenfield

Matt Greenfield

Matt Greenfield is an experienced writer specializing in home improvement topics. He has a passion for educating and empowering homeowners to make informed decisions about their properties. Matt's writing focuses on a range of topics, including windows, flooring, HVAC, and construction materials. With a background in construction and home renovation, Matt is well-versed in the latest trends and techniques in the industry. His articles offer practical advice and expert insights that help readers tackle their home improvement projects with confidence. Whether you're a DIY enthusiast or a seasoned professional, Matt's writing is sure to provide valuable guidance and inspiration.

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