Polished Concrete has been grinding its way to commercial and industrial locations all over America. But one of the biggest locations has been in the Baltimore region, and the surrounding state of Maryland, and even Pennsylvania, New Jersey, and Delaware.
Polished concrete has become too unnoticeable to ignore, and brings to light some hardening questions about the floor: what is polished concrete, and what are its benefits?
Polished Concrete is the result of a successive grinding phases over a concrete slab. Each proceeding grinding phase has finer diamond heads, that ultimately polish the concrete slab. A comparison that is easy to consider is sanding wood. Start with a heavier grade of sand paper, and keep increasing the grade, until the wood is nice and fine, similar to grinding concrete.
Polished concrete is completed with a diamond grinder. The diamond heads are installed on the rotating arms beneath the motor. See picture below:
The diamond grinder is handled like a lawn mower, except on larger and heavier scale. Here is PennCoat, Inc. polishing a floor:
There are 4 separate phases to polishing concrete:
- Grind the concrete (which is typically 3-4 grinding steps)
- Apply densifier
- Polish concrete (which is typically another 3-4 polishing steps)
- Burnish with a semi-penetrating topical sealer and high-speed propane burnisher
The grinding steps prepare the concrete. Sometimes, the concrete can be new, or it can be old and pitted. If it’s older, then it will need to be started with a more aggressive grinding process. And the more aggressive the grinding process, the more aggregate will be exposed through the surface. This may or may not be a desired look, so it is important to understand what the expectations are for a concrete slab.
The densifier is filled with lithium silicate. The lithium silicate slowly reacts with the compounds within the concrete, and allows it to gradually become harder. This helps create an impervious substrate, which grants polished concrete the privilege of being an easy-maintenance flooring solution.
After the densifier has cured, the next steps are to begin polishing the floors with either a resin or copper bond head. These heads are installed the same way as the metal bonds. But instead of grinding into the concrete, they begin to smooth, level, and polish the concrete. There are typically 4-6 steps involved in the polishing, depending on the condition of the concrete slab, and the level of sheen and luster that the customer is desiring.
And once the polishing is completed, a sealer needs to be burnished onto the surface with a high-speed propane burnisher. The burnisher needs to rotate at least 2500 RPMs. Otherwise, the pads won’t generate enough heat that allows the sealer to bond to the substrate. Additionally, the burnisher needs to be equipped with 1500 diamond impregnated burnishing pads. The impregnated pads will add a final level of micro-polishing to the floor, while sealing the substrate to create a completed showroom finish.