Grind concrete smooth

Concrete can be machined in many ways mechanically. Increasingly improved and cheaper machines and tools mean that home improvement is now also able to carry out such work, which until now has been rather difficult to implement. Just like concrete sand smooth.

Smooth concrete smoothly: a trend keeps on going

For a long time concrete was only sanded to roughen it. Polishing concrete to get very smooth concrete surfaces was the exception. But in recent years there has also been a trend towards concrete. The artificial stone is no longer considered gray and barren.

From conventional exposed concrete to polished concrete surface

Fair-faced concrete in the private residential environment has long been a firmly established trend. But it's not just the concrete look that people now appreciate. Concrete can also be sanded completely smooth. With the help of various aggregates (gravel in different colors), a smooth sanded concrete surface creates the look of terrazzo or another high-quality soil refinement.

Concrete grinding differs significantly from other materials

However, smooth grinding of concrete is not comparable to grinding work on metal, wood or other materials. Due to the hardness of the material, significantly more steps are required to allow concrete to be smoothed:

  • already consider concrete compaction during concrete pouring
  • Milling concrete
  • Grind concrete
  • Polishing concrete
  • if necessary, treat concrete

The first concrete layer must be milled off

The massive pretreatment is not groundless. When pouring concrete, it is unavoidable that heavy components sink down a bit. At the same time, a layer of concrete sludge, the concrete veil, forms in the upper area of ​​a concrete layer. Even the best compression of the concrete can not completely avoid this.

Not every concrete layer is suitable for smooth grinding

As a result, depending on the quality of the concrete and the subsequent compaction, there is a different deep layer in the upper area, which is not suitable for smooth sanding. This layer must first be milled off. Because this creates a correspondingly rough surface, you have to grind it again several times. Finally, the already very smooth surface of the concrete is polished.

Grind concrete smoothly: Milling, grinding, polishing

When using the tool, the following rule of thumb applies: with each grinding step, the grain size of the abrasive material doubles. So if you start with a grain size of 80, then in the next step you would have grit size 160, then 320, etc. In order to be able to mill and grind a concrete surface, sanding plates are equipped with so-called diamond segments (these are interchangeable).

The tool for grinding concrete

These are claws, which consist of a plastic-diamond stone mixture and ensure correspondingly long service life for grinding and milling. While these works can be carried out - and of course with an enormous amount of force, of course - also with hand-held machines, correspondingly large concrete grinding or milling machines must be used for the absolute smooth grinding of concrete.

Even the recipe of the concrete is crucial

As mentioned before, however, the quality of the concrete during casting is of enormous importance if the concrete surface is to be polished to an absolutely mirror-smooth finish. The mixing ratio of concrete as well as additives and admixtures are crucial here. This also includes coatings from the concrete, for example concrete with steel fibers. Above all, the amount of water is important.

Take care when using too much aggregate water

Concrete does not just become easier to process when more water is added. The cement reacts with the water, and there are also chemical processes directly around the surfaces of the aggregate (gravel). The more water added, the greater the likelihood that the concrete will crack later on curing.

Tips & Tricks

So the absolute smooth grinding is suitable from the house only for experienced DIY or competent professionals. This is further reinforced by the fact that many concrete elements also incorporate a reinforcement. This must remain sheathed to a certain minimum of concrete. It is not just about the changing static, also the protection of the metal reinforcement against corrosion by oxygen must be considered.

To make even smooth concrete look even nobler, it can be treated even further. You can oil or grow the concrete.

Video Board: Smoothing Rough Concrete