How to Clean Mildew Off Vinyl Siding

As dirt particles collect on your home’s vinyl siding, mold or mildew can form and bring long-term damage.

Fortunately, with the right approach and materials, you can successfully clean mildew off vinyl siding and prevent its return.

But first, it’s important to understand the environment mildew thrives in.

What Causes Mildew Growth

Mildew excels in damp, shady areas with poor air circulation. These factors contribute to its growth:

• High humidity levels
• Lack of direct sunlight
• Poor drainage around the home’s foundation
• Overhanging trees or shrubs
• Sprinkler systems that frequently wet the siding

The above conditions create the ideal environment for mildew spores to settle and multiply on your vinyl siding.

How to Clean Mildew Off Vinyl Siding

We recommend abiding by proper safety precautions when tackling a mildew problem.

Safety Procedures

When working with cleaning solutions and mildew, you should:

• Use a face mask to avoid inhaling mildew spores or cleaning fumes.
• Wear old clothes that cover your skin.
• Wear protective gloves and eye goggles.

These safeguards will help protect you from potential hazards associated with mildew removal, which may include skin irritation and mold spore inhalation.

Recommended Cleaning Solutions

While many homeowners turn to chlorine bleach, it has significant drawbacks including:

• Quick evaporation that fails to get to the fungi’s roots, leading to regrowth
• Environmental pollution
• Corroding metal fasteners and flashing
• Discoloration or damaging of certain types of siding
• Harming nearby plants and grass
• Staining clothing

For these reasons, oxygen bleach, or hydrogen peroxide, is recommended as a highly effective and environmentally friendly method of removing mildew from siding. You could also choose to use Commercial mildew removers designed for siding, Trisodium phosphate (TSP) and water or white vinegar and water solution (1:1 ratio).

Step-by-Step Mildew Removal Process

With appropriate safety procedures and cleaning solutions in place, you can clean mildew off your vinyl siding!

1. Inspect and Prep the Area

Find the affected areas by identifying dark spots and discoloration. Before cleaning, remove loose debris from the siding and cover nearby plants and landscaping with drop cloths. In addition, close all windows and doors to prevent the cleaning solution from entering your home.

2. Apply the Cleaning Solution

Follow these steps to effectively break down the mildew on your siding.

• Mix the solution, following the manufacturer’s instructions if using a concentrate.
• Pour the solution into a sprayer or pressure washer reservoir.
• Starting from the bottom and working your way up, apply the solution generously to the affected areas.
• Allow the solution to sit on the surface for 10–15 minutes, but don’t let it dry completely.

3. Scrub and Rinse

After the solution sat for 10-15 minutes, use a soft-bristled brush or sponge to scrub the mildewed areas gently. Rinse the siding thoroughly with clean water, starting from the top and working your way down. If the cleaning solution builds up, it can attract additional mildew.

Homeowners also turn to pressure washers to remove mildew. While this can be effective, it’s critical that extreme caution be taken to avoid damage. If you take this approach, make sure the pressure washer doesn’t exceed a medium pressure setting. The spray pattern should be at 40 degrees and the nozzle should be kept at least 12 inches from the siding at all times. These settings will prevent you from damaging your siding.

And don’t forget, Besroi Roofing is here to help! With 60+ years in business, we know the ins and outs of residential and commercial roofing. Our expert team can ensure you’re always getting the most from your vinyl siding.