What Causes Mold on Siding and How to Avoid It

Siding protects the structural integrity of your home and safeguards it from the weather 24/7. One of the most common problems with home siding is unhealthy mold growth. Wood is particularly susceptible to mold buildup and rot, and vinyl can easily become moldy as well.

Mold can harm your health and damage your home, so it’s vital that you spot it and deal with it if it shows up on your siding. It’s even better to prevent mold growth! Here’s how:

How to Spot Mold on Your Siding

Pesky fungi build-up like mold grows without being seen at first. In fact, you may smell it when you are outdoors before you see it.

What Mold Growth Looks Like

When your siding begins to get moldy, you will see nasty looking patches on your exterior. It appears fuzzy, slimy, and can vary in color from dark green to bright red or black. If left untreated, mold can cause structural damage to your home. It’s unhealthy and can spark allergic reactions as well as provoke respiratory problems like asthma.

What Conditions Trigger Siding Mold Growth?

Anyplace excessive moisture and a lack of sunlight exist together, unhealthy mold can grow and thrive. There are some basic things that contribute to mold growth on your siding, and the good news is—they are avoidable!

1. Excessive moisture around your home exterior

Mold on your siding thrives when the ground adjacent to your home is constantly wet. Poor drainage, a faulty gutter system, and leaky faucets can all contribute to water pooling around your foundation—which mold loves.

2. Too much shade around your home

Shade created by the trees in your yard keeps the sun from accessing your siding, hindering its ability to dry off after it rains or snows. In humid, damp climates—like Dayton’s—mold can thrive as a result.

• Your soffits aren’t exposed to direct sunlight and can attract mold growth.
• Dense bushes bordering your home create just what mold needs to thrive—dark, wet spaces.
• Ivy and other vines on your siding allow water to penetrate it and foster mold growth.

Note: Pay special attention to the north side of your home exterior because that is usually where the most mold or mildew builds up. The reason for this is because the north side gets the least amount of direct sun, making it an ideal place for mold to grow. When moisture doesn’t have the opportunity to evaporate, it just sits on your siding, giving mold the perfect conditions to thrive in.

The Best Ways to Prevent Mold Growth on Siding

Rather than dealing with trying to eliminate unhealthy mold, take these simple steps to avoid it in the first place.

1. Keep your home exterior well maintained to bolster it against mold growth

• Clear gutters and downspouts of debris at least twice a year.
• Fix leaking faucets and hoses to minimize moisture in your yard.
• Plant trees and shrubs away from your home so the sunlight can reach your siding and the air can circulate well around it.
• Place sprinklers away from your home so you water your lawn, not your siding. Keep siding out of the splash zone from all water sources.
• Recognize that your dryer vent emits steam, which encourages mold growth. Your dryer should vent into an area that isn’t enclosed, so the moisture has a place to go. Keep vegetation away from your vent.

2. Keep your siding in tip-top shape

• Do an inspection of your siding a few times a year so you spot any damage early on and can address it before it causes more costly problems.
• Keep wood siding well sealed by repainting it regularly. Address any areas where you see chipped or cracked paint.
• Remove dirt and debris from siding twice a year with a good cleaning.  

3. Fortify your exterior with moisture-resistant James Hardie replacement siding

One way to permanently rid your siding of pesky mold is to reside your home with Hardie siding. Made of cement, sand and cellulose, this durable siding resists moisture intrusion and mold growth.

What to Do If Your Siding Is Moldy

If you spot mold on your siding, understand that the quicker you deal with it, the less mold you will have to remove. If mold appears, handle the issue by using a natural anti-fungal soap or a treatment recommended by the manufacturer. Test anything you use on your siding in a small area to verify it will work effectively and won’t cause any damage.

Create your own cleaning solution by mixing three parts vinegar with seven parts water. Scrub the moldy area with a cleaning solution and let it soak for five minutes before rinsing it thoroughly. If one round of cleaning doesn’t remove all the mold, clean it again until the mold is completely gone.

Realize that moldy wood siding may need to be replaced.

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Avoid the Hassles of Mold Growth with Hardie Siding Installation

The makeup of your siding material has a major role in whether it will attract mold growth or not. As a James Hardie Elite Preferred contractor, American Way Exteriors specializes in Hardie siding installation. It’s the strongest siding available, stands up to Ohio’s harshest weather, and resists mold growth.  

Learn more about long-lasting, beautiful James Hardie siding replacement.