Outdoor decks and patios are beautiful extensions of your home, perfect for entertaining and relaxing.

But constant exposure to moisture, humidity, and organic debris can lead to mildew growth.

Left unchecked, mildew can damage wood, concrete, and stone surfaces, making them slippery, unsightly, and unsafe.

In this guide, you’ll learn how to remove mildew from outdoor decks and patios, why it’s important, and what steps you can take to prevent mildew from coming back.

Why Mildew on Decks and Patios Must Be Removed Immediately

Mildew is a fungus that thrives in damp, shaded areas. It affects not just the appearance of your outdoor spaces but also their safety.

Mildew on wood decks and mildew on concrete patios can create slippery surfaces that pose a fall risk, especially after rain.

Over time, mildew can degrade the material, whether it’s wood, composite, or stone.

It can also contribute to respiratory issues and allergies for sensitive individuals.

Prompt mildew removal protects your home’s value, enhances curb appeal, and ensures your outdoor living areas remain safe and welcoming.

Step-by-Step: How to Remove Mildew from Outdoor Decks and Patios

Step 1: Gather Mildew Cleaning Supplies

To start removing mildew, collect the following items:

Stiff-bristled brush or broom
Garden hose or low-pressure power washer
Gloves and safety goggles
Commercial mildew remover for decks or patios
Optional: White vinegar, baking soda, or a bleach solution for mildew (1 cup bleach per gallon of water)

Make sure everything is ready before starting to avoid delays.

Step 2: Clear Furniture and Accessories

Remove outdoor furniture, planters, rugs, and other items from your deck or patio.

This allows full access to the entire surface and protects items from getting damaged or contaminated with mildew.

Wash or store cushions and fabrics separately to prevent mildew transfer.

Step 3: Sweep Loose Debris

Use a stiff broom to sweep away leaves, dirt, and other debris.

Organic matter, like leaves and soil, can feed mildew, so clearing it away is essential.

Pay close attention to corners, cracks, and crevices where moisture may collect.

Step 4: Apply a Mildew Cleaning Solution

Spray a deck mildew cleaner or a DIY solution (like white vinegar or diluted bleach) directly onto affected areas.

Always follow the label directions for commercial cleaners, and spot-test on wood surfaces before applying widely.

Natural mildew removal methods like vinegar work well for light mildew, while bleach solutions are effective for stubborn or widespread growth.

Step 5: Let the Cleaner Sit

Allow the cleaning solution to dwell on the surface for 10–15 minutes.

This gives the product time to break down mildew and lift it from the surface.

If the cleaner begins to dry, lightly mist the area to keep it damp for the full duration.

Step 6: Scrub the Surface

Use your brush to scrub the mildew-affected areas thoroughly.

For wood deck mildew, a soft-bristled brush is ideal to avoid damaging the surface.

For concrete patio mildew, a wire brush may be necessary for deeper penetration. Focus on grooves, joints, and textured surfaces where mildew tends to hide.

Step 7: Rinse Thoroughly

Rinse the entire area with a garden hose or pressure washer on a low setting.

Be thorough, residue from cleaners or mildew can attract more dirt and damage the surrounding vegetation.

Avoid using high-pressure settings on wood as it may cause surface damage.

Step 8: Let the Area Dry Completely

Before returning furniture or walking on the area, allow it to dry fully.

Sunlight and airflow help eliminate any remaining moisture and prevent mildew regrowth.

Use fans or blowers for shaded areas that retain moisture longer.

Tips to Prevent Mildew on Outdoor Decks and Patios

Removing mildew is just the first step. These mildew prevention tips can help keep your deck or patio clean and mildew-free year-round:

Improve drainage: Ensure water flows away from your patio or deck. Fix poor grading or install drainage solutions to prevent puddles.
Increase sunlight exposure: Trim overhanging trees and shrubs to allow more direct sunlight, which naturally kills mildew spores.
Clean regularly: Sweep your deck or patio weekly, and rinse off dirt and debris, especially during wet seasons.
Use mildew-resistant sealers: Apply a mildew-resistant deck stain or sealer annually to protect wood from moisture infiltration.
Avoid overwatering: Keep plant containers elevated and avoid excessive watering near decks or patios.
Ventilate properly: Allow airflow beneath and around the deck to speed up drying after rain.
Spot treat early: Remove mildew at the first sign to prevent it from spreading or becoming harder to clean.

When to Call a Professional for Mildew Removal

If you’re dealing with widespread mildew, persistent stains, or hard-to-reach areas, it might be time to call a professional.

Deck cleaning services use powerful tools and expert techniques to remove mildew safely from any outdoor surface.

Whether it’s professional patio cleaning or an annual deck deep clean, expert help can save time and extend the life of your outdoor features.

Final Thoughts: Keep Mildew Off Your Deck and Patio for Good

Now that you know exactly how to remove mildew from outdoor decks and patios, you can take action to restore your space.

A consistent cleaning routine and the right preventive steps will go a long way in keeping mildew at bay.

If mildew removal feels overwhelming or if you’re short on time, NW Maids is ready to help.

Our trained cleaning professionals can handle everything from routine maintenance to deep mildew removal, leaving your outdoor areas fresh, safe, and ready for enjoyment.

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