How to Remove Stains From Any Patio Surface

Your patio should be a relaxing oasis, a place for summer barbecues, morning coffee, and evenings with friends. But over time, stubborn stains from grill grease, rusty patio furniture, and creeping mildew can turn your beautiful outdoor space into an eyesore. Don't worry, you don't have to live with it or immediately call in the professionals.

The great news is that with a little know-how and the right cleaning methods, you can tackle most patio stains yourself. The secret isn't just scrubbing harder; it's about scrubbing smarter. The key is to match your cleaning technique to both the type of stain and the material of your patio. Using the wrong cleaner can be ineffective at best and permanently damage your patio at worst.

In this guide, we'll walk you through everything you need to know, just like we were on the phone with you. We'll help you identify your patio surface, diagnose the type of stain, and give you step-by-step instructions to get your patio looking brand new again.

Step 1: Play Detective - Identify Your Patio and Your Stain

Before you grab a brush, take a moment to assess the situation. This is the most important step, as it determines your entire plan of attack.

What is Your Patio Made Of?

Different materials require different care. Here’s how to tell the three most common types apart:

• Concrete: This is the most common and durable patio material. It typically looks gray and has a uniform, slightly gritty texture. It might be a single poured slab or made of individual concrete pavers.
• Natural Stone: This category includes materials like flagstone, slate, limestone, and granite. Natural stone patios have a more organic look with variations in color, shape, and texture. The surface can be smooth or rough-hewn. These materials are beautiful but can be more porous and sensitive to harsh chemicals.
• Outdoor Tile: Often made from ceramic, porcelain, or quarry tile, these patios are characterized by uniformly shaped pieces separated by grout lines. Tiles can be glazed (shiny, sealed surface) or unglazed (matte, more porous finish).

What Kind of Stain Are You Dealing With?

Next, get a good look at the stain itself. The color and texture will give you clues about its origin:

• Oil or Grease Stains: These are usually dark, circular spots left behind by barbecue drips, tiki torch fuel, or automotive leaks. They often look wet or shiny even when dry.
• Rust Stains: These are reddish-brown and often appear in the shape of whatever metal object was sitting there—the legs of a chair, the base of a planter, or an old forgotten tool.
• Mildew or Algae Stains: These are typically black or green patches that thrive in damp, shady areas of your patio. They might look fuzzy or slimy.
• General Dirt and Grime: This isn't a specific spot but rather a dull, dirty film that covers the surface, making your patio look old and tired.

Once you’ve identified both your patio material and the type of stain, you're ready to get cleaning! Find your patio type below and follow the instructions for your specific stain.

How to Clean a Stained Concrete Patio

Concrete is tough, which gives you more options for cleaning. However, it's also porous, meaning stains can soak in deep if left for too long.

Removing Oil and Grease Stains from Concrete

1. Absorb the Excess: If the stain is fresh, start by covering it with a quarter-inch layer of clay cat litter. Let it sit for at least 15-20 minutes (or up to a few hours for older stains) to draw the oil out of the concrete.
2. Sweep and Dispose: Sweep up the cat litter and dispose of it in a sealed trash bag.
3. Scrub with a Degreaser: Apply a commercial concrete cleaner or a strong degreasing agent directly to the stain.
4. Get Scrubbing: Use a stiff-bristled nylon brush to scrub the area vigorously for several minutes. Work the cleaner into the pores of the concrete.
5. Rinse Thoroughly: Rinse the area with a hose. Try to direct the runoff away from any nearby plants or lawns. Let it air-dry completely to see the final result.

Removing Rust Stains from Concrete

1. Dampen the Area: Lightly wet the rust stain with some water.
2. Apply a Rust Remover: Use a commercial rust remover specifically designed for concrete. These products are often acidic, so be sure to wear gloves and eye protection. Apply a thin layer to cover the stain.
3. Let It Work: Allow the product to sit for about 10-15 minutes, but don't let it dry out. You can mist it with a little water if needed.
4. Scrub and Rinse: Scrub the stain with a nylon brush. You should see the rust color start to fade and lift. Rinse the area thoroughly with your hose.

Removing Mildew from Concrete

1. Mix Your Solution: In a bucket, mix one cup of powdered oxygen bleach with a gallon of warm water. Oxygen bleach is a safer alternative to chlorine bleach and won't harm your plants as easily.
2. Soak the Stain: Pour the solution over the mildew-stained area and let it soak for at least 10 minutes.
3. Scrub Away: Use a stiff scrub brush to scrub the mildew away. The combination of the cleaner and the scrubbing action should lift it easily.
4. Rinse Clean: Give the patio a good rinse with your hose on a low-pressure setting.

How to Clean a Stained Natural Stone Patio

Natural stone is more delicate than concrete, so it requires a gentler touch. Never use acidic cleaners (like vinegar or lemon juice) or wire brushes on stone, as they can cause etching and permanent scratches.

Removing Oil and Grease Stains from Stone

For stone, we’ll use a poultice, which is a thick paste that pulls the stain out as it dries.

1. Make the Poultice: Mix baking soda with a small amount of water until it forms a thick paste, similar in consistency to peanut butter.
2. Apply the Paste: Spread a half-inch thick layer of the paste over the entire oil stain.
3. Cover and Wait: Cover the area with plastic wrap and tape down the edges. This keeps the paste moist so it can work longer. Let it sit for at least an hour, preferably in a shady spot.
4. Scrape and Rinse: Once the paste has had time to work, remove the plastic wrap and use a plastic scraper or old credit card to scrape off the dried paste. Rinse the area with a hose on low pressure.

Removing Rust Stains from Stone

1. Choose the Right Product: Find a pH-neutral, stone-safe rust remover. Read the label carefully to ensure it's safe for your type of stone (e.g., limestone, slate).
2. Apply and Wait: Following the product directions, apply a thin layer to the dampened rust stain and let it sit for 15 minutes. Keep it moist.
3. Gently Scrub: Use a soft-bristled brush to gently agitate the area. Avoid aggressive scrubbing that could scratch the stone.
4. Rinse Thoroughly: Rinse the area completely with clean water.

Removing Mildew from Stone

The process is similar to cleaning concrete, but with an extra precaution.

1. Protect Your Plants: Before you start, thoroughly water any plants or grass bordering the patio. This prevents them from absorbing the cleaning solution runoff.
2. Use Oxygen Bleach: Mix a solution of one cup oxygen bleach per gallon of warm water.
3. Apply and Scrub: Pour it on the mildew and let it sit for 10 minutes. Use a soft-bristled brush to scrub the mildew away gently.
4. Rinse Well: Rinse the patio and the surrounding plants one more time with clean water.

How to Clean a Stained Outdoor Tile Patio

When cleaning tile, your focus should be on both the tile surface and the grout lines, where stains love to settle.

Removing Oil and Grease Stains from Tile

1. Create a Paste: Sprinkle baking soda generously over the oil stain. Add a little warm water to create a paste.
2. Scrub Gently: Use a soft-bristled brush to scrub the paste into the tile and especially into the grout lines.
3. Rinse and Mop: Rinse the area with clean water and mop up any excess to prevent dirty water from settling back into the grout.

Removing Rust Stains from Tile

1. Use a Gel Cleaner: Look for a gel-based rust remover that is safe for tile and grout. The gel consistency helps it cling to the surface without running everywhere.
2. Apply and Wait: Dampen the stain, apply the gel, and let it sit for about 10 minutes.
3. Scrub and Rinse: Gently scrub with a small brush (an old toothbrush is great for grout lines). Rinse with clean water and mop the area dry.

Removing Mildew from Tile

1. Spray It Down: Use a commercial mold and mildew cleaner that is safe for tile. Generously spray the affected areas.
2. Let It Penetrate: Let the cleaner sit for 5-10 minutes to kill the mildew.
3. Scrub and Rinse: Scrub the tile and grout lines with a brush, then rinse the entire area with clean water. For sealed tile, it's a good idea to dry it with a towel to prevent water spots.

When a Stain Won't Budge: Calling a Professional

You’ve tried everything, but that stubborn stain is still there. Don't be discouraged! Some deep-set stains require professional-grade equipment. Professional services typically use pressure washers and specialized chemical treatments that are more powerful than what’s available to consumers.

According to Forbes, hiring a professional for pressure washing can cost between $0.25 and $1.00 per square foot, depending on the size of your patio and the severity of the staining. It can be a worthwhile investment to get your outdoor space looking perfect again.

A Clean Patio is a Happy Patio

Cleaning stains off your patio is a satisfying DIY project that can dramatically improve the look and feel of your home's outdoor space. By correctly identifying your patio material and the type of stain, you can choose the perfect method to restore its original beauty.

For more personalized home maintenance guides, project reminders, and a direct line to vetted professionals when you need them, download the Casa app today. We take the guesswork out of homeownership, empowering you to handle any project with confidence. Get your outdoor oasis back in shape and keep it that way with a little help from Casa.