Polished concrete flooring is gaining popularity thanks to its durability, elegance, and ease of maintenance. But not all polished concrete is the same. Contractors can tailor the grind, aggregate exposure, and sheen level to create strikingly different polished concrete floors.

In this article, we’ll look at the factors that determine the type of polished concrete finish and help you choose the ideal style for your facility.

Factor 1: Grinding Levels 

Grinding levels shape the concrete surface. The concrete polishing process progresses through several grinding steps using specialized equipment with abrasive pads:

• Hand-held grinders are used for tight spots and edge work.
• Walk-behind concrete grinders polish large areas.

The pads range from coarse grits to fine grits. Key grinding levels include:

• Level 1 (Flat Grind): Base grinding with minimal reflection.
• Level 2 (Honed): Low-sheen matte finish with slight overhead reflection.
• Level 3 (Polished): Increased sheen and side/overhead light reflectivity.
• Level 4 (Highly Polished): Very-fine grits or burnishing creates high gloss.

Densifier chemicals applied during polishing harden and protect the concrete surface.

Factor 2: Gloss Level 

One of the biggest determinants of the look and feel of polished concrete is the final gloss level, referring to how much light the concrete surface reflects. A gloss meter is used to accurately assess the gloss level achieved by concrete polishing. This device measures the amount of reflected light from the concrete surface.

Gloss values typically range from 0 to 100 gloss units (GU). The concrete polishing industry measures gloss at a 60° angle - the international standard for evaluating gloss.

Gloss Level Categories

• 0-10 GU: Flat, no gloss. Light is scattered, not reflected.
• 10-25 GU: Eggshell finish. Minimal gloss, light scattering.
• 25-40 GU: Satin finish. Some light reflection, low sheen.
• 40-70 GU: Semi-gloss. Medium light reflectivity, noticeable sheen.
• 70-85+ GU: High gloss. High wet look reflectivity like a mirror.

The higher the gloss unit reading, the more light is reflected for a brighter, glassier appearance. Gloss meters help specify and validate the desired gloss level during the polishing process. They ensure the work achieves the intended aesthetic goals.

The Concrete Polishing Council identifies four common gloss levels:

Matte or Satin Finishes

A lower gloss level of 20-50 on the gloss meter produces a matte or satin concrete finish. These floors have minimal light reflection and a flatter appearance. The concrete will look lightly textured but not overly shiny.

Semi-Polished Finishes

Semi-polished concrete achieves a gloss level of about 50-60. At this sheen level, the floor clearly reflects lighting and surroundings. The concrete has a noticeably vitreous appearance.

High-Gloss Finishes

Highly polished concrete reaches a gloss level over 60 on the meter. The floor will deeply reflect images like a mirror. This wet look highlights the floor’s smoothness.

Burnished Finishes

Burnishing uses a mechanical polisher after the polishing stages. This adds an extra layer of sheen, typically reaching a gloss level over 80. Burnished concrete has a glass-like finish.

Factor 3: Aggregate Exposure

The aggregate in the concrete mix also influences the look by adding dimension. Polishing progressively exposes more of the aggregate for a textured appearance. The Concrete Polishing Council defines four common classes:

Class A - Cream Exposure

Cream polished concrete leaves the aggregates mostly covered for a smooth finish.

Class B - Fine Exposure

This exposes some fine sand aggregates for a salt-and-pepper speckled effect.

Class C - Medium Exposure

Medium aggregate exposure reveals pea gravel-sized aggregates for light texture.

Class D - Large Exposure

Large aggregate exposure uncovers bigger aggregates up to 1⁄4 inch for a highly textured look. Large exposure can increase slip resistance.

Combining gloss level and aggregate exposure types lets you create polished concrete floors aligned with your aesthetic vision and functional needs.

Tailor the Finish to Your Facility

Choosing the right concrete finish involves balancing visual appeal, performance, and maintenance. Here are a few guidelines:

• Matte finishes hide dirt and imperfections well in high-traffic areas.
• Satin finishes add shine while minimizing slick surfaces in commercial settings.
• Semi-polish works well for industrial sites that want some reflectivity.
• High-gloss creates a "wow" factor for retail interiors and showrooms.
• Burnished finishes take high gloss a step further for a modern decor look.
• Light aggregate exposure adds traction and visual interest. Heavy exposure makes cleaning easier.

With the various options, you can specify a polished concrete floor that aligns with your business while showcasing the concrete’s natural beauty. Polished concrete is highly customizable to meet functional and aesthetic needs. Reach out to discuss which finish could be the perfect fit!