Concrete polishing: Grinding steps from prep to polish
By Painters USA Team
— Last updated January 20, 2023
It’s amazing what a little grinding, honing, and burnishing can do for an industrial concrete floor.
And when our clients see the outcomes of their polished concrete, they are amazed to see how a formerly dull floor is transformed to a finish that can resemble a mirror or a still, reflective lake.
If you’re considering polished concrete and are unfamiliar with the process, or if you’d like to have a better understanding of the technical details, read on!
Grinding levels in concrete polishing process
Concrete polishing is done in a number of steps that can range from a few to several, depending on the existing condition of the floor and desired outcomes.
Grinding is done by specialized equipment, including handheld and walk-behind versions. Painters USA crews often use them in tandem, for a more efficient, time-saving process:
- Hand-held grinders are used for spot sanding to smooth out minor irregularities or for angle and edge work in tight spaces.
- Walk-behind concrete grinders have drums with interchangeable abrasive tools or pads that rotate and press against the surface to grind and polish large areas.
Pads impregnated with industrial diamonds or synthetic abrasives are commonly used for concrete polishing. The process cycles through a number of different levels or steps, changing the grit from coarse to fine with each step.
The primary grinding levels in the concrete polishing process include:
- Level 1, Flat / Ground: Base grinding that results in little to no reflection.
- Level 2, Satin / Honed: Low-luster matte finish with slight overhead reflection.
- Level 3, Polished: Sheen with good side and overhead light reflectivity.
- Level 4, Highly Polished: Using very fine grit pads or burnishing with specialty pads results in various levels of shine.
High-shine floors may appear to be wet from some vantage points, and a person looking straight down at the surface could see a mirror-like reflection.
Concrete densifiers are a chemical solution that seals the pores and increases the surface density of concrete.
Densifiers are nearly a necessity in the concrete polishing process, as they add many valuable benefits:
- Reducing dust and efflorescence.
- Sealing the surface to prevent and resist staining and marks like tire treads.
- Creating a non-membrane forming barrier that won’t discolor or peel.
- Improving light-reflectivity and gloss to enhance visual appeal.
- Easy cleaning that actually serves to protect and enhance sheen over time.
Densifier products are now being made with safer, less hazardous chemical solutions. By increasing the hardness and density of the concrete slab, densifiers ensure a more durable, long-lasting floor, making them an important part of the grinding and polishing process.
How long does concrete polishing take?
The question of time depends on a number of variables, like the area size, condition of the concrete, the number of obstacles to work around, and the desired level of shine or gloss. Our estimators will give you a solid assessment of the time and cost for your project so you can plan accordingly.
The process can be condensed into 3 general steps:
Step One – Remove stains, small pits, old coatings and other flooring imperfections to prepare the surface for further polishing.
Step Two – Polish to the desired level of gloss, generally in a few steps using increasingly finer grit each time.
Step Three – During the polishing process, we apply a concrete densifier to harden and protect the surface for enhanced resilience and reduced maintenance.
One desirable time-saving benefit of concrete polishing: Floors can generally be returned to full service as soon as the process is completed, no post-process drying or curing time required.
Polished concrete is a popular choice for brightness, durability, and low maintenance. Our flooring professionals are happy to discuss your concerns and desires to help you achieve your flooring goals for both appearance and functionality.