Are Polished Concrete Floors Slippery?
There are many misconceptions about polished concrete flooring. It is not slippery and is a very high traction flooring option.
Polished concrete does stand up well in both wet & dry conditions, making it a perfect choice for office buildings, residences, retail stores, warehouses, and industrial environments – to name just a few.
The Problem with Slippery Floors: Falls, Injuries and Deaths
Polished Concrete has a High Coefficient of Friction – Meaning Falls Like the One Shown Above are Less Likely with Polished Concrete than With Most Other Flooring options
The National Floor Safety Institute (NFSI) is a non profit organization that is dedicated to preventing slips, trips, and falls. It is their mission to establish flooring standards (including concrete flooring) to improve the overall safety of floors. They also provide testing, certification and education in the goal of accident prevention.
According to the NFSI (quoting the CPSC), there are close to 2 million injuries that result in a fall each year that can be attributed to floors and flooring materials. Many of those injuries are from customers visiting commercial businesses. Others may be employees of businesses. Also quoting the NFSI, 85% of worker’s comp claims are as a result of employees falling down after losing their balance on slippery floors.
The NFSI has established standards for a variety of conditions related to walkways, including NFSI B101.1-2020. This standard allows for contractors to perform an accurate measurement of the wet static coefficient of friction of walkways. This standard applies to all walkways and floors including both unpolished and polished concrete floors.
There are two types of coefficient of friction measurements relevant for measuring how slippery a concrete floor are static and dynamic. Their definitions and thresholds are provided below.
What is the Static Coefficient of Friction?
The static coefficient of friction is a measure of the force required to move an object across a surface. The higher the coefficient, the more force is required. For hard flooring, historically OSHA requires a static coefficient of friction of at least .5, and NFSI certification has historically required a value of at least .6.
What is the Dynamic Coefficient of Friction?
The dynamic coefficient of friction is a measure of the force required to keep an object moving across a surface once it is already in motion. For hard flooring, the dynamic coefficient of friction needs to be at least .42 to be compliant with ANSI/NFSI guidelines.
Note that walkways or floors that include elevation changes – like ramps – should have a higher coefficient than those prescribed above.
Determining How Slippery a Polished Concrete Floor Is
There are numerous tools used to measure how slippery a floor is. Some of these tools and their uses are outlined below.
Pendulum
A pendulum slip resistance tester works by measuring the force necessary to cause a standard rubber slider to slip on a polished concrete floor. The tester is placed on the floor, and a weighted arm is allowed to swing freely. As the arm swings, the rubber slider comes into contact with the floor and experiences frictional forces.
A slippery floor will allow the rubber slider to proceed virtually unimpeded – which indicates a slippery floor – and the reading will be very close to zero. A floor with a higher coefficient of friction will cause the slider to register a higher coefficient of friction.
Tribometer
A tribometer is a tool that is used to measure slip resistance. There are different kinds of tribometers in use. As an example, one way a tribometer is used involves measuring the force required to move a “sled” over a floor surface. The sled is affixed with a standardized rubber material. The test is done by applying a standard force to the sled and dragging the sled across the floor. From this process, the tribometer is able to effectively measure the static coefficient of friction for a hard surface like polished concrete.
Variable Angle Ramp
A variable angle ramp is sometimes used for measuring slip the coefficient of friction in Europe. Part of the floor is removed and attached to the device. A tester who is fully protected, will attempt to walk on top of the flooring at different angles until they slip. Measurements are recorded and the coefficient of friction is calculated.
Polished Concrete Slipperiness Under Different Conditions
Polished concrete is especially popular in commercial buildings because it looks great and requires very little upkeep. While the overall level of the slipperiness of polished concrete can vary based on conditions, it is overall a very stable surface that isn’t slippery.
Polished concrete is not very slippery when dry
The beautiful, reflective nature of polished concrete can give many the false impression that a polished concrete floor is wet – when in fact it is bone dry.
When dry, polished concrete is at its best. When properly polished, concrete provides extremely high traction that is compliant with the ANSI/NFSI B101.1 standard. Whether you’re in a commercial building or in a residential home, polished concrete provides great footing for all those who walk on it. It is less slippery than many other hard flooring, including wood floors.
Polished concrete is not very slippery when wet
All flooring is subject to the occasional spills or accidents which allow liquids to settle on the floor, create a wet area, and present a potential hazard. These spills tend to make the polished surface slippery.
That said, even a wet polished concrete surface still provides pretty good traction and will tend to provide enough grip for people who inadvertently walk into a pool of liquid that has settled on the floor.
When Concrete Gets Slippery: Dirt, Grime, Chemicals
Polished concrete requires little ongoing maintenance when compared to just about all other flooring options. That said, the facilities manager or building owner will want to take care to establish a regular maintenance schedule with a floor scrubber to keep dirt, grime, and dust from settling on the polished concrete floor. Fine particulates can present a slip hazard and can make the grip of concrete surface less effective if it is coated with a layer of fine-grained debris.
And spills – even water should be cleaned up promptly. While concrete doesn’t lose much grip with water, other fluids (like grease or oil) can present a major hazard and should be cleaned up immediately to prevent the possibility of injury.
How Do You Make Polished Concrete Less Slippery?
If you’re noticing that your existing concrete floor is becoming a slip and fall hazard, there are two main methods to try: regular cleaning, using a different sealer, and using floor coverings
1. Clean regularly
As previously covered, make sure you’re running a floor scrubber regularly to keep your concrete floors clear of potentially hazardous debris. Regularly mopping up accidental spills will also help your floor keep its traction.
Be Sure to Properly Clean and Maintain Your Concrete Floors
2. Use a Sealer with Grit Additives
As part of the concrete polishing process, a sealer is applied to the surface of the concrete. Think of the sealer as a floor coating applied to the concrete slab.
This sealer prevents dirt, stains, chemicals, liquids and other debris from penetrating into the sealed concrete flooring – which could cause the concrete to degrade, pit, and crack over time.
To increase the slip resistance of your polished concrete, you could remove the sealer from the existing concrete and instead seal floors with an anti slip grit additive sealer. The grit embedded within the sealer can provide you with a polished concrete finish with the additional traction that you’re looking for.
3. Floor Coverings
Consider laying down rubber mats or coverings that won’t slip on top of the polished floor to provide extra grip and traction to those who use the concrete floor. These would go best in high-traffic areas or areas that are prone to spills.
Ideal locations for appropriate floor coverings may include entrances (where the elements like snow and rain can be tracked inside) or near work environments that are notoriously wet (like drink stations in a restaurant).
Frequently Asked Questions
Does Sealing Concrete Make it Slippery?
Usually no.
A concrete sealer is used to protect the underlying polished concrete from being penetrated by liquid and other contaminants. While concrete sealer provides a highly reflective look, most aren’t very slippery and even provide traction when wet.
If using an inferior sealer or if you need additional grip for your polished concrete floors, you can incorporate a grit additive into your sealer to provide more grip.
Is Stamped Concrete Slippery?
Commonly used outdoors, stamped concrete is a decorative concrete that has approximately the same coefficient of friction as regular concrete. While the texture and pattern of the concrete can add additional grip, the best way to reduce the possibility of slipping is to apply a grit additive to the sealer that you’re using to seal your stamped concrete. This can provide a traction boost.