Guide to Preparing a Concrete Surface


Guide to Preparing a Concrete Surface

Updated: December 22, 2023

While we often discuss using finishing processes on metal, they also play a critical role in concrete surface preparation. A concrete surface in need of repair or coating should go through the preparation process to ensure successful results. Below, you’ll discover the fundamentals of concrete surface prep and your options for completing the process.

When Should I Prep My Concrete Surface?

Before repairing or finishing your concrete surface, you should prepare it by getting rid of unsound concrete and roughening it. The preparation process achieves both of these goals. Unsound concrete can appear as:

  • Visible cracks or microcracks in the concrete
  • Blisters formed by trapped air bubbles under the concrete surface
  • Scaling created by frozen water expanding the concrete
  • Spalling (peeling or flaking concrete)
  • Delamination (separation of the surface’s paste layer)

You can check if the concrete has unsound material by tapping it with a hammer and looking for any resulting indents or damage. In sound concrete, the hammer will bounce.

Why Should I Prep My Concrete Surface?

The concrete preparation process determines the success of surface repairs and coating bonds. To make concrete repairs that last, you’ll need the repair material to bond to the surface securely. An inadequately prepared concrete surface can cause the concrete and the repair material or coating to debond.

In the case of unsound concrete, the unsound layer will detach itself over time, resulting in further damage. When you perform repairs on a properly prepared surface, the repair or finishing and concrete will bond as one unit.

How Do I Prep My Concrete Surface Using Surface Roughening?

Wondering how to sandblast concrete? This is just one of several methods to prep a concrete surface. The right course of action depends on the concrete’s roughness. The steps involved in preparing concrete for repairs or finishing include:

  • Using mechanical methods, like sandblasting, to remove unsound concrete from the surface
  • Cleaning any surface contaminants present on the concrete
  • Roughening the concrete surface to prepare it for a coating or overlayment

Do I Need to Etch My Concrete During Prep?

During concrete surface preparation, you can use a variety of methods to roughen the surface, including etching and abrasive blasting. Learn more about some of the most common techniques used in this preparation step below:

  • Acid etching: Performs light abrasion for sealants, films and coatings.
  • Abrasive blasting: Creates a smooth to rough surface profile for finishings and repair overlays.
  • Water jetting: Can dislodge coarse aggregates for thick coatings and repair overlays.

Should I Use a Special Polish on My Concrete?

When choosing a coating for your prepped concrete surface, consider getting a coating created specifically for concrete. These finishes feature sealing properties for concrete and often hold up better on the concrete’s rough surface. Some general coatings and resins also work well for concrete, so we recommend consulting your supplier to see what they suggest.

Contact Finishing Systems for Advice From the Experts

You can count on Finishing Systems for the abrasives and equipment you need to perform abrasive blasting on your concrete. For more information about our products or to get a free quote, we encourage you to contact our team online.

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