Grinding concrete with an angle grinder with your own hands

Smartkrete Concrete Polish Demonstration


The wet method involves the use of nozzles with varying degrees of abrasiveness. That is, at the beginning, nozzles with a softer coating are used and so on incrementally. This method requires a lot of attachments, so for a home craftsman it will be much more expensive than the dry method.

In addition, if the dry method affects only 2 mm of the top layer, then the wet method removes up to 5 mm. Because of this, during the initial treatment 3-5 days after pouring the screed, a huge amount of wet dust rises into the air, in other words, sludge.

To get rid of it, you will have to use a water pump, but even with its help it is far from a fact that it will be possible to regulate the resulting inaccuracies and shortcomings. All this makes the wet method more expensive than the dry one, so I use it only when processing surfaces covered with marble chips or before applying tiles.

Grinding application

Concrete floor grinding is finding more and more fans among owners of both private properties and administrative buildings and offices.

From private estates, the possibility of creating a floor can be distinguished:

How to Safely Grind Concrete Floors (Quick Tips)

  • In the garage. Grinding significantly increases the durability of the structure and makes it easier to clean up machine oil and fuel oil. The consequences of mechanical influences are reduced: such a floor cannot be scratched with an adjustable wrench, it cannot be damaged by chemical solutions, the smell of gasoline will not be absorbed into it. The service life of such a floor is measured in decades, so a polished floor is often used in the construction and repair of a garage.
  • In living quarters. Residential concrete is far from the best option, but special additives and marble chips can be used. Such tricks make the fill indistinguishable from the marble coating. The aesthetics of such a floor is kept at a sufficiently high level for a long time, while it will not be possible to scratch it with a knife or an unsuccessfully dropped frying pan in the kitchen. In living quarters, under the concrete floor, you can lay a floor heating system and not worry about excessive draft over the floor.
  • In administrative buildings: various types of offices, hospitals, shopping centers. the concrete floor is easy to clean, it is difficult to damage it, and it looks quite aesthetically pleasing, so this type of floor is gaining more and more popularity.
  • In the production premises of small workshops, hangars and large factories, a polished floor is also used. Of course, in industrial buildings, there is no point in expensive additives that make the floor beautiful. But without them, it does not become less practical, since the properties of withstanding mechanical and chemical loads remain.
grinding, concrete, angle, grinder, your

Polished concrete is used in small workshops, hangars

In addition, grinding is one of the stages of material processing, and therefore you can also grind a rough working surface. Subsequent material will more easily fall on such processing, and the screed itself will be much stronger and less susceptible to soaking.

The ways

Distinguish between dry and wet floor sanding.

Tool selection

For home conditions, an ordinary angle grinder with a capacity of 1.2-1.5 kilowatts is perfect. The disc is selected in the size 150-180 mm. You should also take care of a water pump or an industrial vacuum cleaner with a shelter so that dust does not get into the air at all or, if it does, it is immediately removed into a dust bag.

See also  How to Correctly Install Brushes on an Angle Grinder

If everything is more or less clear with the choice of an angle grinder, then everything is not so simple with the choice of attachments. Exist:

  • Disks. Discs are a great option for fine surface finishing. As with any fine finishing discs, discs wear out quickly.
  • Cups. These are disks
  • Frankfurt is only used for the final stages of wet processing.
  • Cutters. Cups are steel discs with welded-on elements.
  • Models from the manufacturer. Each company seeks to imagine something of its own, and therefore many models with strange names exist on the market and will always exist


The dry method is the easiest to perform. It’s not about some sophisticated technologies: just with this method less dust is emitted, respectively, it is easier for the master to regulate the degree of floor processing. Wet method makes it easier to scratch the coating. At the same time, even the dry method generates rather large volumes of dust, so you cannot do without a vacuum cleaner. In addition, it is imperative to protect your face with a respirator with goggles.

Grinding material

There are also a huge amount of materials for grinding. For use within an apartment or a private house, two attachments are sufficient:

  • Diamond cup
  • Abrasive disc.

A diamond cup is needed for grinding concrete with an angle grinder

The rest of the nozzles are either worse, albeit cheaper, or are intended for expensive grinding of large-volume rooms, which is simply useless for a home craftsman.

Particular attention will have to be paid to the choice of concrete filler. These should be soft grades of fine stone. Remember, grinding concrete filled with coarse gravel is impossible without the use of expensive equipment and attachments.

It is also worthwhile to attend to the purchase of impregnation in advance. Thanks to the initial polishing, the top layer is removed, after which the concrete perfectly absorbs the strengthening waterproofing impregnations. It is she who betrays the effect of gloss and strengthens the surface, protecting it from chips, cracks and moisture.

Do-it-yourself concrete grinding with an angle grinder

Sanding is a great way to transform a plain concrete subfloor into a work of art. When sanding, you should be very careful and careful with the angle grinder, especially if the procedure is performed by the master for the first time. How to grind with an angle grinder using various methods and let’s talk today.

Preliminary activities

Grinding is getting rid of minor defects, therefore, before starting the process, you will have to attend to getting rid of major flaws:

  • These are different types of tubercles. If it is visible with the eye, then it is better to cut off with an angle grinder. The maximum allowable tubercle size is 1 mm.
  • Seams. No seams should be visible. No amount of sanding will get rid of a seam or dent in the screed. In this case, you will have to re-fill or pour an additional layer on top.
  • Depressions. It is better to cover the depressions. There should be no visible cracks, depressions, dents.
  • Mark the areas where sanding will take a little longer, i.e. irregularities of the screed itself. To do this, you need to use the level.
  • After that, you need to check the voltage in the network. From a sudden jump or fall, the angle grinder can fail, the sanding will break off, and the hand tremble. Because of this, it may be necessary to create a floor from scratch.
  • The floor itself must be tested for strength. To do this, you will have to make a test run with a grinder. If the floor crumbles too much, you need to take a nozzle with less grain or re-fill the floor.
See also  How to clean air filter on your MotoBlock

If a small but visible crack has formed, then with the help of a diamond disk, the crack is expanded and sealed flush with the floor. Grinding can be started only after such fillings have dried.

Expansion is carried out to a depth of 10 cm, after which a piece of concrete is removed, the surface is treated with a primer and only after that a layer of embedding is applied.

Technology and stages of the grinding process with an angle grinder

  • Preparation: cleaning of surfaces, marking of grinding, sealing of seams, sawing of protrusions, etc. Be sure to take out all the debris before grinding, since it will be extremely difficult to do this during work. Nothing should distract you from your work. The cover on the angle grinder must be put on in advance, as well as turn on and prepare the vacuum cleaner. The attachment of the attachments to the angle grinder is checked.
  • Rough grinding. Rough grinding is performed 3-5 days after the screed was monolithic. It is necessary to remove 2.5-3 cm in order to get rid of the most coarse blemishes, cracks and protrusions. After checking the tool, grinding is performed. The 15-minute rule applies to an angle grinder: work is carried out for 15 minutes, after which the tool is turned off. You can turn on the angle grinder again only after the disc has completely cooled down. The heating temperature of the nozzle should not be felt at all. That is, the disk will reach a temperature approximately equal to the ambient temperature.
  • The next step is impregnation. Special construction impregnations are used to strengthen concrete. The impregnation is literally poured onto the surface of the screed and slightly leveled over its surface. Concrete will absorb this composition for another 10-15 days. The amount of impregnation is calculated in advance. Do not be surprised if, immediately after pouring, a certain amount of liquid remains above the concrete surface. Over time, the concrete will absorb it.
  • Only after this is the final processing carried out. For this, a thinner disc with a higher abrasiveness value is taken. If a disc with abrasive 25 is used for roughing, then for the final one you will have to use a nozzle with an indicator of 40. The glossy effect is revealed only when using tools with abrasive 1400-1500.

How is concrete grinding with an angle grinder

Sanding the floor is not that difficult. The main thing is attentiveness when correcting draft defects, adherence to safety rules and the correct choice of tools.


Grinding the concrete gives it the quality and appearance of an independent floor covering. Smooth surface, aesthetic appearance determine the use of this type of concrete floor for a wide variety of buildings:

  • workshops, household premises of enterprises;
  • halls of airports, railway stations;
  • corridors, foyers of educational, medical institutions;
  • shopping centers, pavilions;
  • water parks, swimming pools;
  • cinemas, exhibition complexes.

There are two methods for grinding concrete screed: wet and dry. The same consumables are used, the tool.

Wet sanding

It is used for the treatment of floors of increased strength with fillers from hard species of decorative stone. expensive: more consumables required.

Sanding removes up to 5 mm of concrete top layer.

Working with hand tools is complicated by dirty splashes, sludge, and interferes with the control of the surface finish. You have to remove dirt, water, dry the floor surface.

When cleaning a concrete pavement, abrasive wheels with solid fine-grained inclusions or particles of different sizes are used.

Grinding concrete with an angle grinder

To obtain a smooth, with a decorative effect, polished floor covering allows concrete grinding with special equipment. After removing the surface layer with abrasives, the structure of the filler from the hard rocks of the decorative stone appears.

Monolithic concrete surfaces without processing have an unsightly appearance, dusty when abraded. A polished floor eliminates the drawbacks of a concrete screed, retains its naturalness, and gives new qualities:

  • decorativeness, appearance of natural stone;
  • increasing the strength of the floor surface by 2. 3 times;
  • resistance to abrasion, exposure to chemicals;
  • no dust;
  • environmental friendliness, safety for humans;
  • ease of maintenance, repair;
  • increase in the service life of floors.
See also  Angle grinder armature sparks how to fix. Failure in the stator winding

Floor preparation. How to remove defects

The cycle depends on the type of the old floor. Easier to perform on the finished monolithic coating. It happens like this:

  • Removal of foreign objects: ends of fittings, wire, irregularities.
  • Cutting of cracks, potholes (to a depth of 2. 3 cm) in the old pavement. Grouting.
  • Installation of beacons from mortar, profiles.
  • Dust cleaning. Impregnation with binders.
  • Pouring screed based on decorative hard rock aggregates (marble, granite, basalt).

When cutting cracks with a grinder, pinching and destruction of the disc is possible.!

The old floor does not have a monolithic screed. The work is done in the following sequence:

  • dismantling the old floor;
  • dumping from incompressible soil (crushed stone, blast-furnace slag);
  • preparation with a thickness of 100 mm from low grade concrete (M 50. M 100);
  • installation of mortar beacons, profiles;
  • impregnation with binders;
  • screed filling based on decorative hard rock aggregates.

Decorative screed thickness. at least 50 mm.

Grinding with an angle grinder

How to grind concrete with an angle grinder? The polishing process begins with primary or preliminary stripping. Perform with a cup with square overlays. Cut off sagging, screed irregularities. With double-segment cups, remove the top layer. Finishing polishing is done with boomerang attachments, turtle discs.

Initial polishing is performed with abrasives with a crumb size of 25. 30, finishing. 40 units. Grain size for glossing. 1500. 3000 units.

The tool with a cover and a flexible hose for connection to an industrial vacuum cleaner will provide a comfortable working environment. It is advisable to equip the machine with two handles. Tighten the nut for fastening the abrasive wheels until it stops.

Before polishing, read the instructions for use of the tool. After that, you can start grinding.

To avoid overheating of the grinder, take breaks from work every 10. 15 minutes! Switch on the instrument after it has completely cooled down.

Grouting fresh screed

There is a technology for working with a fresh screed (less than a day after pouring). To do this, use a trowel. “helicopter”. Seals the top layer, increases strength.

First, a rough cleaning of the concrete is performed. The finish line is started after 12. 15 hours. The introduction of a special impregnation binds the dust on the surface.

It should be remembered that after such processing, the gloss of the coating does not last long.

It is unlikely that an amateur has such equipment. Therefore, you need to give the monolith 10. 15 days so that it gains the necessary strength.

How to use an angle grinder to cut and smooth concrete

Concrete Grinding Tools

When cleaning large volumes of concrete floors, mosaic grinding machines are used. The electric motor, the gearbox constitute the main working unit. The attachments are attached to the gearbox shaft. The cleanliness of the polish depends on the type of attachments. Adjustment of rotation speed is provided. The mechanism is protected from dust. Often models are equipped with a vacuum cleaner, a system for supplying water to the working area.

There are single traverse mechanisms with remote control. There are even self-propelled vehicles. Speed ​​- up to 10 m / min.

Grinding concrete with an angle grinder (angle grinder) is used for polishing small areas, hard-to-reach places.