If you’re the facility manager for a warehouse, hardware store, or similarly housed business, you may have noticed a fine dust that settles on your products or equipment over time. Even after vacuuming or mopping, this ever-present dust returns, perhaps even making your facility appear dingy or dirty. Worse, it may compromise the quality of your products and reduce the efficiency of your equipment.
If your building has concrete flooring, you may have correctly narrowed down the source of the dust to the floor itself.
But what makes some concrete floors dustier than others and—more importantly—how do you stop your floor from creating such a dusty mess?
What Causes Concrete Floor Dust?
To understand why some floors shed dust constantly, we need to look at the composition of the concrete itself. Concrete is a hardened composite that contains hard aggregate, such as pieces of crushed rock or sand, that are bound together with cement (the “glue” that holds everything together).
Most modern concrete uses Portland cement, a powder made of fine particles of gypsum, clay, and quicklime (calcium oxide). When the cement is combined with water, the quicklime undergoes a chemical reaction that turns it into calcium hydroxide. As it solidifies, the lime locks the aggregate into place.
However, a few things can go wrong during curing that lead to an especially dusty concrete floor.
Improper Mixing
if the water-to-quicklime ratios are not right during the initial curing stage, some of the lime won’t bond properly. Too-dry cement includes powdery “free lime,” which can be released as dust.
In other cases, too much moisture can cause the finest particles of the cement to rise to the surface layer before the slab solidifies. These fine particles on the surface will be prone to breaking off as a fine powder.
Poor Curing Environment
The environmental conditions during the initial drying (curing) stage of your concrete floor can also affect how dusty it is. Cold temperatures, windy conditions, or too much condensation can lead to a powdery or “soft” concrete surface.
Water Issues
Floors that initially cure well can also begin to shed if they have too much moisture exposure. Water seeping into the natural pores of concrete can weaken and dissolve some of its chemical bonds. (Occasionally water vapor can also rise from the soil below your concrete slab and cause a host of other challenges.)
Unfortunately, dustiness is not a temporary phase. A concrete floor that is prone to dusting will continue to shed into the future.
Is Concrete Dust Toxic?
Concrete dust in small quantities (such on the surfaces of a warehouse) is not particularly dangerous. It’s unlikely to cause illness, though it could be aggravating to people with asthma or other lung sensitivities.
It is true that prolonged exposure to the fine particles of quartz and silica in concrete can lead to chronic bronchitis, lung cancer, or a lung condition called silicosis. But these conditions are typically seen only in people who work in extremely dusty environments—for example, workers who spend more than a decade in a factory handling dry cement.
So concrete dust does not pose immediate health risks for the typical individual. It can, however, compromise food or beverage products, and create extra work by requiring you to clean products before shipping them.
How Do I Clean Concrete Dust from Your Floors?
Daily sweeping, regular mopping with a damp (not wet) mop, or vacuuming can help improve air quality and reduce the concrete dust that settles on surfaces. For larger facilities, rentable concrete floor scrubbers (which are typically used to clean spills and stains) can also remove some of the dust.
Unfortunately, for particularly “soft,” powdery floors, scrubbing and sweeping may actually have the opposite effect by loosening more dust into the air.
Most cleaning solutions are only temporary measures. A powdery concrete floor will continue to release dust indefinitely.
How to Stop a Concrete Floor from Shedding Dust
To prevent your concrete floor from releasing dust in the future, you have two general options:
- Improve the strength and integrity of the concrete itself.
- Seal the surface to prevent dust from escaping.
Methods to strengthen the concrete itself include concrete polishing, use of a densifier, or application of a penetrating sealer. These options can improve the integrity of the concrete on both a physical and chemical level. Sometimes these methods are combined (for example, adding a densifier during the concrete polishing process).
By contrast, surface coatings, such as epoxies or polyurethane, lock the floor beneath a durable layer. These methods typically focus on the integrity and strength of the coating itself and aren’t usually combined with polishing or sealers.
Concrete Floor Polishing
Polishing a concrete floor increases its visual appeal—giving it a low gloss or even a high shine. But the benefits go beyond aesthetics, as the process also strengthens the physical properties of the floor itself.
Concrete polishing is a multi-step process that uses a grinding machine to smooth the surface of the floor—often in 10 separate stages. The intensity of the grinding process actually compresses the floor, filling in many of the concrete’s open pores and increasing its density. The condensing process even reaches down to a molecular level, locking particles in and preventing the release of loose particles in the future.
As you can imagine, a dry polishing process can create a lot of dust during the various grinding stages. Most of this dust is removed with a commercial vacuum, but if it’s important to keep dust down during the process itself (such as in a food and beverage facility), there is also a “wet polish” method that uses water to keep the dust out of the air.
Learn more about concrete polishing.
Densifiers
A concrete floor densifier may be applied on its own or as part of the polishing process. A densifier is a liquid chemical solution that soaks into the floor and reacts with the calcium hydroxide (free lime) on a molecular level. It binds with the calcium ions to form a kind of gel that fills in the open pores, making the floor more compact and locking the molecules into place.
Decreasing the porousness of the floor also makes it less permeable to liquid. Since water seeping into the floor can contribute to the chemical breakdown of the concrete, a denser floor is more resistant to dust caused by water damage.
Learn more about concrete densifiers.
Penetrating Sealers
Like a densifier, a penetrating concrete sealer will soak into a concrete floor to fill in the pores and capillaries. It not only reduces dust shedding but also allows the floor to repel oil or dirt.
There are several sealer formulas on the market, each with its own advantages. Most use either a base of silane and siloxane (to repel water) or a fluorochemical base (to repel water as well as oils). A penetrating sealer typically doesn’t change the appearance of the floor.
Concrete Floor Coatings
The other option for reducing concrete dust is to “lock” the concrete under a surface coating. A coating over the top layer of the concrete creates a physical barrier that keeps water, oil, and contaminants from soaking into the floor below and stops the top layer of concrete from shedding into the air above.
Topical coatings do change the appearance of the floor, often adding an attractive gloss as well as the option of customizable colors and patterns. The most common concrete floor coatings include:
- Epoxy (highly durable and customizable; best for indoor use)
- Polyurethane (durable and long-lasting; versatile for both indoor and outdoor use)
- Acrylic (quickest and least expensive, though considerably less durable; best for low-traffic areas)
- Moisture barriers or other coatings designed to solve industry-specific challenges
Read more about the pros and cons of each type of coating.
To make sure the coating bonds properly with the floor, the surface will have to be prepared, usually by making it more abrasive. If your concrete surface is especially soft and dusty, you may need to consult a flooring specialist before attempting to install a coating.
Need a Professional Opinion?
If you’ve found yourself in a perpetual battle with concrete dusting in your facility, these solutions should offer some relief as well as protection for your concrete floor. However, before settling on a method, we recommend having an expert evaluate the specifics of your facility’s floor, to ensure the solution you choose will be successful.
If you’re in the southeastern US, a flooring specialist from CPC Floor Coatings would be glad to give you an assessment and help you find the best solution for your space.