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How to Prepare Floors for Concrete Coatings

Proper concrete substrate preparation is the foundation for all resinous flooring installation. An understanding of the basics can help facility managers make sound flooring decisions and assist building specifiers with effective design. For flooring professionals, concrete preparation is the foundation of company business.

Goals of Concrete Floor Coating Preparation

The purpose of concrete slab preparation is to ensure that the substrate is in optimal condition to receive application of the high performance flooring system primer and subsequent coats. To break it down, the goals of concrete preparation are to:

  • To “open the pores” of the slab surface to enable bond
  • Remove any existing coatings or sealers
  • Correct any existing contamination and/or moisture vapor issues
  • Smooth protrusions, ridges, trowel chatter
  • Key drains, cut in around stationery equipment, etc.
  • Fill any voids in substrate, i.e. cracks, potholes, spalls, pinholes 

After proper concrete preparation, the result is a structurally sound concrete slab with no cracks, pock marks or unevenness, and an “open” surface that is uncontaminated by any material that could interfere with the bonding of new resinous flooring.

Carefully cutting into the floor to apply concrete coatings

Careful cutting-in by Epoxy, Inc. of FL

Thorough undertaking to ensure maximum application of floor coatings

Attention to detail around drains by Epoxy, Inc. of FL

Results of Improper Surface Preparation

Preparation of the concrete surface is perhaps the most important step in resinous flooring installation. Not taking the time to thoroughly prepare the concrete surface can result in:

  • Poor bond, resulting in flooring system delamination
  • An inability of the coating to cure properly
  • Flooring surface defects, such as fish eyes or craters

With a little diligence and attention to detail, the expensive consequences of improper surface prep can be easily avoided.

What Are Some Methods of Concrete Preparation?

Shot blasting, diamond grinding and scarification are some of the methods that can be used to prepare both new and existing concrete slabs. In addition to creating the right “open” surface profile, removal of surface contaminants is critical, since any concrete hardeners, chemicals, grease, oil, moisture, standing water, excessive alkalinity or acidity will prevent resinous primers from penetrating the concrete. Failing to eliminate surface contamination can result in an incomplete bond and flooring system failures.

Preparing floor for concrete coatings

Thorough mechanical prep by CIC of GA

Vacuum floor prior to adding concrete coatings

Vacuuming of dust prior to coating by CIC of GA

How Can I Tell If the Surface Has Been Properly Prepared?

A quick and easy method to tell if the surface has been properly prepared is known as “the water drop test.” Simply sprinkle water droplets onto the concrete slab and observe. If the droplets quickly “wet out” the surface, absorbing into the concrete like a sponge, then a primer will do the same. In other words, barring other issues, it is then safe to proceed with the prime coat.

If, however, sprinkled water droplets remain beaded on the surface and do not penetrate the concrete, then a primer will do the same. This is a strong indication that a primer will not anchor well to the slab in its current condition.  In other words, further preparation steps are needed before priming can proceed.

In the end, proper preparation of the concrete slab prior to resinous coating installation helps ensure that the flooring system will look, perform and endure for years to come.

Local Florock technical representatives are available to answer concrete preparation and other questions.   Simply contact us to learn more.

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