Are Flagstone Walkways Slippery?

Flagstone is a popular material used for patios, walkways, and other hardscaping features in outdoor spaces. Its natural beauty and rustic aesthetic make it a timeless choice. However, one concern that arises with flagstone is the question of slipperiness, especially when wet. So are flagstone walkways actually slippery?

What Makes Flagstone Potentially Slippery?

There are a few factors that can contribute to making flagstone slippery:

Exposure to Moisture

One of the biggest reasons flagstone can become slippery is when it is wet1. Areas like pool decks that are constantly exposed to moisture are prone to developing slippery flagstone surfaces. The water acts as a lubricant between the stone and shoes, causing a loss of traction2.

Buildup of Organic Growth

Over time, flagstone can develop a buildup of moss, mold, algae, or lichen3. This organic growth thrives in damp, shaded areas and forms a slimy film on top of the stone. Walking on this slippery organic layer, especially when wet, can be dangerous.

Type of Stone

Not all flagstones have the same texture and porosity4. Smoother, denser stones like bluestone and travertine tend to be more slippery than textured, porous sandstone. The rough surface of sandstone provides better grip.

Surface Treatments

Some flagstone walkways are given a polished finish or coated with a sealant5. While this helps protect the stone, it can also make the surface dangerously slick when wet. Unsealed, textured flagstone provides the most traction.

Factors That Contribute to Increased Slipperiness

There are a few additional factors that can exacerbate the slipperiness of flagstone walkways:

Constant Moisture

Flagstone surfaces that are consistently exposed to moisture are at highest risk of becoming slippery6. Areas around pools, hot tubs, or fountains tend to stay damp and develop slimy organic growth.

High-Traffic Areas

Heavily trafficked flagstone walkways become polished over time7, causing the texture and pores of the stone to wear down. This creates a smoother, more slippery tread.

Shaded Locations

Flagstone walkways in heavily shaded areas are prone to moss, mold, and algae growth8 that can make the surface extremely slick. Insufficient sunlight inhibits drying.

Improper Installation

Flagstone installed without proper base preparation and drainage can settle unevenly or become prone to standing water9. This leads to slippery conditions when wet.

Freeze-Thaw Cycles

In colder climates, repeated freezing and thawing of flagstone can create small pits, cracks, and even powdery surfaces10 that become slippery when wet. Sealing may help protect against this.


Grease, oil, leaves, sand, and other debris that collect on the surface of flagstone can create slippery conditions, especially if not promptly cleaned11.

How Slippery Are Different Types of Flagstone?

The inherent texture and porosity of the stone itself plays a major role in determining slip resistance. Here is how some common types of flagstone compare:


Sandstone provides the best natural grip of all flagstones. Its extremely rough, porous surface texture offers exceptional traction, even when damp


Slate flagstone is moderately slip-resistant. Its fine grain structure offers better grip than polished stones but can still become slippery when wet


Bluestone flagstone is prone to slickness. Its dense composition and relatively smooth finish causes it to become very slippery when wet, especially with organic buildup


Limestone can be quite slippery, though traction improves with more textured finishes. Its low porosity allows water to easily saturate the surface


Travertine is notoriously slippery, especially when honed or polished. Small pits in its surface can gather moisture and organic growth. A rough finish provides slightly better grip


Granite flagstone offers moderate traction. A polished finish is quite slippery when wet, while thermal or sandblasted textures improve grip

Best Practices to Reduce Slipperiness

If you already have a flagstone walkway or are planning a new installation, there are several best practices you can follow to enhance safety:

Choose Textured, Porous Stone

Select flagstone materials with rougher finishes and more porous compositions, like thermaled granite or textured sandstone. The surface traction of these materials withstands moisture better.

Allow Proper Drainage

Ensure flagstone is installed with a gravel base and adequate slopes for drainage. This prevents standing water that can lead to slippery organic growth.

Limit Shade and Overhangs

Prune back trees and shrubs to allow ample sunlight to reach the flagstones. This inhibits moss and algae growth.

Clean and Power Wash Regularly

Routinely sweep debris from the stones and power wash annually to prevent buildup of slippery organic films. Be sure to fully dry after cleaning.

Apply Anti-Slip Treatments

Consider applying sealer and grit combinations or commercial anti-slip treatments formulated for natural stone. This can help improve traction.

Add Handrails and Ramps

Install handrails and create gradual slopes rather than steps for improved stability, accessibility, and safety.

With prudent material selection, proper installation, routine maintenance, and anti-slip treatments, the risk of slippery flagstone walkways can be significantly reduced. Always take extra precautions in wet conditions by wearing slip-resistant footwear and watching your step. Prioritizing safety will allow you to enjoy your beautiful flagstone walkway without worry of falls.

FAQs About Flagstone Walkway Slipperiness

Is all flagstone slippery when wet?

No, not all flagstone is equally slippery when wet. The amount of natural texture and porosity of the stone has a major impact. More porous, textured stones like sandstone provide better grip than smooth, dense stones like travertine.

What kind of flagstone is least slippery?

Sandstone is widely regarded as the least slippery type of flagstone, even when damp. The rough-hewn texture and porous composition of sandstone provide exceptional traction for walking.

Should I seal my flagstone walkway?

Sealing flagstone can help protect it and inhibit organic growth, but may also increase slipperiness. Look for specialty sealers designed for natural stone that contain anti-slip grit or additives to provide traction.

How can I make my slippery flagstone walkway safer?

Options to reduce slipperiness include power washing, applying anti-slip treatments, improving drainage, adding texture with grit, installing handrails, creating gentler slopes, and using caution when wet.

What kind of shoes are best for walking on flagstone?

Choose footwear with slip-resistant soles and avoid smooth leather soles. Rugged lug soles provide the best grip. Waterproof boots with deep tread also enhance traction on damp flagstone.

Can you etch flagstone to make it less slippery?

Yes, you can lightly etch or acid wash flagstone to reveal more of the stone's natural texture and improve traction. However, this will permanently alter the appearance. Test a small area first.

Will repairing flagstone pits and cracks reduce slipperiness?

Yes, filling in pits, cracks, and eroded spots can help level the surface and improve traction, especially if properly sealed afterwards. Ensure repairs allow adequate drainage.

Should I replace my slick flagstone walkway?

If improving an existing slippery flagstone surface proves too difficult, replacement may be the best option. Consider replenishing joints, installing a textured stone, adding an anti-slip underlayment, or using an alternative material.


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