Flagstone is a durable and elegant natural stone that enhances patios, walkways, and outdoor spaces with its rustic beauty. However, exposure to dirt, moisture, and outdoor elements can cause flagstone to accumulate stains, moss, and grime over time. To maintain its longevity and appearance, knowing how to clean flagstone properly is essential.
In this guide, we’ll walk you through professional-grade cleaning methods, best practices for stain removal, and expert maintenance tips for keeping your flagstone surfaces in top condition in 2025.
Why Proper Flagstone Cleaning Is Important
Maintaining flagstone surfaces isn’t just about aesthetics—it’s also about preserving the integrity of the stone. Without proper cleaning, flagstone can become slippery, stained, and even deteriorate over time.
The Benefits of Cleaning Flagstone Regularly
- Prevents Moss and Algae Growth – Flagstone’s porous surface can trap moisture, making it prone to moss and algae, which can cause slipperiness.
- Enhances Durability – Regular cleaning removes acidic substances, dirt, and debris that can erode the stone’s surface.
- Boosts Curb Appeal – Clean flagstone patios, walkways, and driveways enhance the beauty of outdoor spaces, making them more inviting.
By learning how to clean flagstone properly, homeowners can extend the life of their stone surfaces and keep them looking pristine year-round.
How to Clean Flagstone: Step-by-Step Guide
Cleaning flagstone requires the right techniques and materials to prevent damage while ensuring a deep, thorough clean.
Step 1: Gather the Right Cleaning Supplies
To clean flagstone like a pro, you’ll need:
- A garden hose or pressure washer (low setting)
- A soft-bristle brush or push broom
- Mild stone-safe detergent or pH-neutral cleaner
- A bucket of warm water
- White vinegar (for tough stains, diluted with water)
Step 2: Rinse the Surface
Start by rinsing the flagstone with a garden hose to remove loose dirt, dust, and debris. If using a pressure washer, set it to a low pressure to avoid damaging the stone.
Apply a Cleaning Solution
Mix a mild pH-neutral stone cleaner with water and apply it evenly across the surface using a mop or sponge. Avoid using harsh chemicals like bleach or ammonia, as they can erode the stone’s natural finish.
Step 4: Scrub the Flagstone
Using a soft-bristle brush or push broom, scrub the surface in circular motions to lift dirt and grime from the stone’s pores. For stubborn stains, let the cleaning solution sit for 10 minutes before scrubbing.
Step 5: Rinse and Dry
After scrubbing, thoroughly rinse the flagstone with clean water and let it air dry. To speed up the drying process, use a leaf blower or a dry mop.
Properly drying the surface prevents water spots and reduces the risk of algae growth.
Removing Stains from Flagstone
Over time, flagstone may develop stains from dirt, organic material, and spills. Addressing these stains early prevents permanent discoloration.
How to Remove Organic Stains (Moss, Algae, and Mold)
Organic stains occur due to excessive moisture and lack of sunlight. To remove them:
- Mix white vinegar and water (1:1 ratio) and apply it to the stained areas.
- Let the solution sit for 10–15 minutes, then scrub with a brush.
- Rinse thoroughly with clean water.
If moss or algae persist, consider applying a hydrogen peroxide-based cleaner designed for natural stone.
How to Remove Oil and Grease Stains
Oil spills from grills, outdoor furniture, or vehicles can penetrate flagstone. To lift these stains:
- Sprinkle baking soda or cornstarch over the stain and let it sit for 30 minutes.
- Scrub with a soft brush and rinse with warm soapy water.
For deeper stains, use a stone-safe degreaser to break down the oil without damaging the stone’s surface.
Sealing Flagstone to Protect Against Future Stains
Applying a stone sealer is one of the best ways to protect flagstone from stains, water absorption, and weather damage.
Why Sealing Flagstone Is Important
- Prevents water absorption, reducing the risk of cracks and erosion.
- Enhances color retention, keeping the stone vibrant.
- Minimizes staining, making spills easier to clean.
How to Apply a Flagstone Sealer
- Ensure the flagstone is completely clean and dry before applying sealer.
- Use a paint roller or sprayer to apply an even coat of stone sealer.
- Allow the sealer to dry for at least 24 hours before walking on the surface.
Reapply sealant every 1–2 years to maintain protection and longevity.
How to Clean a Flagstone Sidewalk
A flagstone sidewalk should always be installed on a concrete base for stability and durability. Cleaning a flagstone sidewalk requires some careful attention.
Best Practices for Cleaning Flagstone on a Sidewalk
- Use a mild stone cleaner instead of harsh acids that can weaken the mortar.
- Rinse with a low-pressure hose to prevent damaging the mortar joints.
- Seal the flagstone to extend longevity and prevent moisture damage.
Cleaning flagstone sidewalks regularly helps preserve their appearance and prevents shifting due to moisture infiltration.
Common Mistakes to Avoid When Cleaning Flagstone
Using Harsh Chemicals
Avoid using bleach, ammonia, or acidic cleaners, as these can weaken the stone’s integrity over time. Stick to pH-neutral stone cleaners for safe and effective cleaning.
Applying Too Much Pressure When Washing
High-pressure washing can erode the flagstone’s surface and loosen the mortar holding the stones in place. Always use a gentle pressure setting or a garden hose.
Neglecting to Reseal the Stone
Skipping the sealing process leaves flagstone vulnerable to water damage and staining. Resealing every 1–2 years is crucial for long-term durability.
FAQs
1. How often should I clean my flagstone patio?
It’s best to clean flagstone at least twice a year, or more frequently in high-traffic areas.
2. Can I use a pressure washer on flagstone?
Yes, but use a low-pressure setting to avoid damaging the stone.
3. What is the best cleaner for flagstone?
A pH-neutral stone cleaner or a vinegar-water mixture works well for regular cleaning.
4. Does flagstone need to be sealed?
Yes! Sealing flagstone helps protect against stains, moisture, and weathering.
5. Where can I buy high-quality flagstone?
Lompoc Stone offers premium flagstone for patios, sidewalks, and landscaping projects.
Conclusion
Knowing how to clean flagstone properly ensures that your patios, sidewalks, and walkways remain beautiful and durable for years to come. Regular maintenance, proper stain removal, and sealing are key to preserving your flagstone surfaces.At Lompoc Stone, we specialize in high-quality natural stone solutions, offering premium flagstone products that are built to last. Contact us today to explore our range of flagstone materials and expert care recommendations!
