The Concrete Space

The Testing Terms of Concrete Polishing

Posted by Tony Corsini on 7/31/20 11:00 AM

THE TESTING TERMS OF CONCRETE POLISHINGOver the last two decades, the demand for polished concrete has grown drastically. Twenty years ago, when Hoover & Wells started polishing concrete floors, customer expectation was set by specifying a desired gloss level. Although gloss testing is important, there are other tests that have been developed in recent years that will better define the overall expected outcome of the polished concrete surface. Distinctness of Image, Haze, and Roughness Average can be used in addition to the Gloss test to ensure the owner gets the quality floor he or she is paying for. The testing needs to be performed before the application of a sealer/guard because these products tend to give inflated readings. So, let's go over some of these terms and what they mean!

Distinctness of Image (DOI)Distinctness of Image (DOI):

Distinctness of Image measures the sharpness of a reflected image in a coating surface. Similar coatings may have identical gloss values but visually the quality may be very different. A visually poor coating may have a highly textured dimpled appearance known as "orange peel". When a reflected object is viewed in such a coating the image becomes fuzzy and distorted.

A surface that has a perfect undistorted image returns a value of 100. As the value decreases the image becomes more distorted.

Photo courtesy of Kojak316 - Distinctness of Image DOI reference image through CC BY-SA 4.0

Glossy concrete polishing


High quality gloss surfaces have a clear, deep, brilliant finish. Haze causes a drop in reflected contrast and causes halos to appear around light sources, these unwanted effects dramatically reduce visual quality.

Roughness Average (RA):

RA is simply an average of how rough a surface is. It is measured by finding deviations from the through line of where a perfectly level surface would be.


A simple measurement proportional to the amount of light reflected from a surface determining how shiny a surface appears.

Hoover Wells uses the Elcometer 408 to test its floors. Learn more about the gloss meter we use here. Call the professionals at Hoover Wells for more information about testing polished concrete floor systems!


CURIOUS ABOUT ALL THE Standards and Guidelines we follow?

Let's go through the standards and guidelines of various concrete systems and the surface preparation, application, safety precautions, and clean-up of each system offered!


Topics: Concrete Polishing, Floor Systems, Surface Preparation, The Hoover Wells Advantage, Concrete Terms


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