Polished Concrete

Polishing Basics

Simply put, polishing concrete is using heavy-duty polishing machines equipped with progressively finer grits of diamond-impregnated segments or disks (comparable to sandpaper) to gradually hone down surfaces to the desired degree of shine and smoothness.

The process begins with the use of coarse diamond segments bonded in a metallic matrix. These segments are coarse enough to remove minor pits, blemishes, stains, or light coatings from the floor in preparation for final smoothing. Depending on the condition of the concrete, this initial rough grinding is generally a three to four step process.

The next steps involve fine grinding of the concrete surface using diamond abrasives embedded in a plastic or resin matrix. Crews use ever-finer grits of polishing disks until the floor has the desired sheen. For an extremely high-gloss finish, a final grit of 1500 or finer may be used. Experienced polishing crews know when to switch to the next-finer grit by observing the floor surface and the amount of material being removed.

Standards for Polished Concrete

There are not published standards for polished concrete, but it is generally agreed that the concrete must be polished through the sequence of disks ending with 400-3000 grit diamonds to be considered polished concrete. At this level the concrete will exhibit a glossy sheen and high reflectivity without the use of a topical coating.

Benefits of Polished Concrete

During the polishing process an internal impregnating densifier is applied. This densifier sinks into the concrete and is invisible to the naked eye. It not only protects the concrete from the inside out, it also hardens and strengthens the concrete. This eliminates the need for a topical coating, which significantly reduces maintenance.

Options with Polished Concrete

If the decision is made to polish concrete in advance of the concrete being poured, there is a stunning array of available options:

  • Colored aggregate can be applied to the concrete mix or “seeded” into the top layer of the mix. The polishing process will reveal these aggregate.

  • Integrally colored concrete can be used.

  • Glass can be “seeded” into the mix. The polishing process will reveal the glass pieces.

  • Nails, bolts, computer chips, or any other objects can be seeded into the mix and then polished smooth.

  • Polished Concrete can be stained with a wide variety of concrete dyes to give it color, designs and pattern work while keeping the highly reflective surface

  • Of course, any of these options can be combined together or into a pattern.

Can All Concrete Be Polished?

Almost any structurally sound concrete floor, whether new or old, can be polished. But there are some exceptions.

For new floors, no special mix design is required to achieve good results. However, the floor should be in place at least 7 days before the main grind and 28 days before high polishing begins to ensure adequate curing. Some retail and warehouse facilities that plan to polish their floors after placement may specify the installation of as smooth a floor as possible to minimize the polishing steps required.

Existing floors typically require some surface preparation prior to polishing to remove dirt, grease, coatings, or blemishes. However, floors that are wavy, need extensive patching, or are extremely porous may not be good candidates for polishing. An experienced contractor can usually determine a floor’s suitability.

Applications for Polished Concrete

Because polishing is a multi-step process, customers can choose the level of sheen—from satin to high-gloss—that meets their maintenance and aesthetic requirements. This versatility makes polished concrete an ideal flooring material for a variety of applications. American Concrete's primary customers include:

  • Schools

  • Universities

  • Municipal buildings

  • Retail stores

  • Hospitals

  • Hotels and restaurants

  • Office buildings

  • Auto showrooms

  • Sports Complexes

Ease of maintenance is the key reason many public and private facilities are opting for polished concrete. Not only are polished floors easy to clean, they hold up extremely well to heavy foot traffic. They also eliminate the need for messy waxes or coatings as well as the associated labor, time, and expense to apply them. The highly reflective surface is hard to scratch and classified as a non slip floor.

The high light reflectivity of polished concrete is another important benefit, especially for automobile dealerships, office buildings, hotels, restaurants, and other public facilities that want to project a bright, clean, professional image. Some customers simply want a look that’s unique. Polishing can give concrete a higher degree of shine similar to polished marble or granite—than can be achieved with a high-gloss coating. This makes polished concrete a particularly good alternative for businesses that can’t afford marble or granite floors but want the same brilliant, mirror-like finish. It’s also possible to produce a terrazzo look by grinding through the top few millimeters of the concrete surface to expose the aggregate.