how to fix concrete dusting
Tips & Tricks

How to Stop Concrete Dusting

If you often sweep or clean the concrete of your garage floor only to have it feeling dusty and gritty the next day or after a few hours, then you might have a problem with concrete dusting. However, you don’t need to fret if you’re experiencing any of this because you can reduce or completely stop concrete dusting depending on the severity of the problem and the applied solutions.

What Is Concrete Dusting?

Dusting or chalking is the formation of loose powder due to the slow disintegration of a weak top layer of concrete. The characteristics of such surfaces include:

  • They powder under any traffic, including foot and vehicle traffic.
  • They can easily be scratched by a nail or even by sweeping.

What Causes Dusting to a Concrete Surface?

A concrete floor dusts under traffic if the wearing surface is weak. The weakness might be caused by:

  • Poor mixing at the concrete plant
  • Excess silt or clay in the concrete mix
  • The old age of the concrete
  • Badly cured concrete
  • Inadequate ventilation in enclosed spaces
  • Placement over a non-absorptive subgrade or polyethylene vapor retarder.

The most common reason for concrete dusting is excess bleed water at the surface.  When there’s too much water in the concrete mix, it will rise to the surface during the finishing process. The bleed water can carry cement and finer particles to the surface, forming a weak layer of concrete at the uppermost top of the slab.

The surface laitance is a porous layer of softer concrete that breaks down slowly and creates a white powdery surface. Sometimes the surface might be so smooth that a nail or a sharp screwdriver can easily scratch it.

Additionally, concrete dusting is also typical when water is added to the surface during the finishing process. DIY concrete finishers or less experienced people can add water to the surface during a last-ditch effort to create a smooth, troweled surface.

Will Concrete Dusting Ever Stop on Its Own?

Pressure washing and sweeping of the concrete never seem to get it completely clean because the surface is in a constant state of disintegration.

Concrete dusting isn’t likely to ever stop on its own. If you leave it untreated, the fine concrete dust might become very annoying as it finds its way onto the surface of laundry machines, vehicles, workbenches, and anything else in the garage. Concrete dust can also be found in your house when you move it around on the bottom of your shoes.

How to Manage Dusty Concrete Floors

You can manage dirty concrete floors using the following tips:

Use PVA Glue

You can use polyvinyl acetate (PVA) as a concrete sealer to protect your concrete floor from disintegrating. You can apply PVA sealer with a paintbrush after cleaning your concrete floor thoroughly.  When the PVA glue dries, it will leave a clean floor that isn’t dusty. However, you should be aware that the floor might crack quickly after using PVA glue.

Use a Vacuum and Avoid Sweeping

You can opt to use a vacuum instead of sweeping your concrete floor. When you use a broom to clean your dusty concrete floor, you’re essentially redistributing and moving the dust instead of removing it. A vacuum with an excellent internal filter will catch fine dust and enable you to perform efficient cleaning.

How to Get Rid of Concrete Dust

There are several solutions for stopping or fixing dusty concrete. However, the effectiveness of the solutions will depend on the severity of the concrete dust. Here are some of the solutions:

Apply a Quality Densifier

If you’re dealing with light concrete dusting, you should consider applying a quality densifier. Densifiers are non-film forming and will not change the look of concrete. Instead, they work by penetrating the upper layers of the concrete surface to create a chemical reaction with the minerals. When the reaction occurs, a hard substance known as calcium silicate hydrate (CHS) is formed to fill the capillaries and open pores at the concrete surface.

The resulting reaction increases concrete’s surface strength by 20% to 40%, depending on the initial condition of the concrete. Densifiers are usually most effective on a better concrete surface and less effective on a worse surface. Therefore, they would be less effective if concrete dusting was pretty bad. That is why densifiers only reduce or stop light concrete dusting.

If you opt for a densifier as a method of sealing powdery concrete, then you should consider lithium-based ones because they’re the most effective and easiest to apply. Additionally, they are relatively inexpensive because all you’ll have to do is clean the concrete before application.

Acrylic Concrete Sealer

You can opt for an acrylic concrete sealer if you deal with moderate concrete dusting. These sealers are film-forming and create a protective coating on the surface. The thin coating layer acts as a barrier over the concrete; therefore, sealing in and stopping the concrete dusting.

A Floor Coating Will Help

If a densifier or an acrylic concrete sealer cannot solve the dusting problem, you should consider a concrete floor coating. A coating will leave a visible surface on concrete and penetrate the pores to bond and coat the concrete with a protective layer.

The floor coating stops concrete dusting by preventing abrasion to the surface. Popular coatings include epoxy, urethane, or acrylic. Epoxy coatings are pretty popular; however, a urethane coating might be best for areas with high traffic or heavy abrasion.

Can You Seal Dusty Concrete Without Reinstalling It?

Suppose your concrete’s surface is soft enough to gouge easily with a nail or screwdriver, or your concrete dusting is more severe. In that case, you might have to opt for shot blasting, aggressive grinding, or scarification of the concrete surface.

This aggressive mechanical process effectively removes the soft upper layers of concrete to expose the more rigid surface underneath. But, unfortunately, it also leaves the concrete with a very rough finish.

At this point, you are left with a couple of options, the first being to coat over the rougher finish with a thick, multi-layer commercial epoxy coating system.  The second option is to smooth out the concrete’s surface with less aggressive grinding stones, and then you can properly seal the concrete.

How to Fix and Seal Powdery Concrete

You can try the following solutions if you want to fix and seal powdery concrete:

Use Water-Based Acrylic Sealers

Water-based acrylic sealers are economical, low-odor surface binding sealers that seal the surface and suppress concrete powdery and crumbling dust in a single, easy application.

Clear solvent Acrylic Sealer

Most professionals always opt for clear solvent acrylic sealers for concrete protection. A single coat penetrates the concrete substrate, where the resin sets and stabilizes the absorbent surface. A second coat builds a durable and protective non-yellowing finish that eliminates dust and hardens the surface.

Epoxy Sealers and Coatings

Water-based epoxy coatings offer excellent protection to concrete surfaces. Compared to traditional floor paints, they provide complete encapsulation of dust particles, incomparable durability, and depth of color.

Check this too: How To Clean Oil Off Concrete Garage Floor

Concrete dusting is pretty annoying because of the damage it might cause in your home. If you want to avoid and stop concrete dusting, ensure proper floor installation and use correct protective coatings. The tips above will also help you deal with concrete dusting.

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