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Polish concrete, burnish concrete

How to Polish Concrete

Published April 26, 2021

Polished concrete is becoming more popular in a wide variety of applications. It is often seen in retail and institutional environments for a clean, hygienic look and the ease of maintenance under high-traffic conditions. By choosing to leave the concrete exposed as a finish also eliminates the material and energy consumption associated with adding a floorcovering.

The process of mechanically polishing concrete is like scratching the surface until the scratch patterns become too fine to see. To effectively polish concrete, it must be hard enough since the harder the concrete, the better it will take a polish. This is why before polishing we recommend sealing concrete with Lithi-Tek 4500. Densifiers like Lithi-Tek 4500 react with calcium hydroxide trapped in the concrete to form additional calcium silicate hydrate, filling the pores and increasing surface hardness. Lithi-Tek 4500 will react with the ingredients in concrete to densify while allowing deep penetration to chemically harden and fortify the substrate. After the chemical reaction occurs, the substrate will be more abrasion resistant and help protect the surface from wear, moisture and efflorescence while remaining breathable. Concrete, left untouched, presents a problem to polishing: The surface is usually not hard enough to polish especially since the surface is usually the softest layer. By applying a chemical densifier to concrete before polishing like Lithi-Tek 4500 this problem is solved.

A basic polished concrete process is:

  1. Prep the floor

    • Remove coatings, glue, paint, contaminants

    • Repair cracks/spalls

    • Check flatness and hardness

  2. Initial grinding (cutting stage)

    • Use metal-bond diamonds (typically 30/40 grit → 80 grit)

    • This opens the concrete and removes imperfections

    • Heavier cuts expose more aggregate

  3. Densify

    • Apply a concrete densifier like the Lithi-Tek 4500

    • Hardens the concrete surface and improves polishability

  4. Continue refining

    • Transition to finer grits:

      • 100/200 resin

      • 400 resin

      • 800 resin

      • 1500–3000 for high gloss

    • Each step removes scratches from previous grits

  5. Optional stain/dye

    • Add color after early grinding stages if desired

  6. Burnish / protect

    • Apply guard or stain protection if specified

    • Burnish for additional sheen and easier maintenance

Typical finish levels:

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