The choice will mainly depend on the surface roughness.
Leveling the floor in the room (screed) with cement mixture
The floor level in the room is not the same. With respect to the entrance, the surface height difference is 3 cm in the left and 2 cm in the right corner of the room. Alignment required. Self-leveling screed is not effective here. A continuous floor screed will be made with a cement mixture with alignment with beacons.
1. The surface is cleaned (garbage is removed, including small ones). Dust is removed with a vacuum cleaner.
2. To increase the adhesion (adhesion) of the cement layer to the surface, a primer is made. Apply the solution with a brush or roller. This coating should dry for at least five hours.
After that, the surface is re-primed and dries.
3. Using the laser level is the highest point.
4. Beacon installation begins at the highest point in the room. Lighthouses are metal rails along which alignment will take place.
To do this, the lighthouse (equal to the length of the wall) is fixed with a solution (the same material that will be used for screeding) approximately every 60 cm.
Checks the correct installation with a corner (or tape measure) relative to the laser level as it is fixed.
The length of the segment from the line of the laser beam to the lighthouse is measured.
5. By the same principle, the next and all other beacons are installed. The distance between them is about one meter.
6. Preparing a cement mixture. For this, three parts of sand are taken on one part of cement.
Fiber is added to the bucket of cement (approximately 300 mm in volume, just as much is included in the electric socket).
For better ductility, 100 ml of plasticizer is added, which makes alignment easier.
Water is poured. Everything is mixed into a homogeneous mass.
7. The screed starts from the corner of the room farthest from the entrance. The cement mixture is laid out in small portions.
It is leveled by a long "plain".
8. The work ends at the entrance to the room.
9. Beacons are not deleted.
The screed is ready. Its thickness is 35 mm (at a high point).
You can proceed to the next operation (laying the flooring) after complete drying (ripening).
Advantages of this type of screed: not a high price, well-known technology. Disadvantages: a long process of complete formation (maturation) of 28-30 days. If the flooring is laid ahead of time, the screed may crumble.
Expanded clay screed
The room has central heating pipes laid on the floor. To align the finish will require a large volume of the mixture. In some places, the thickness of the screed will reach 10 cm. Therefore, expanded clay is used as a filler to increase the volume and reduce the weight of the screed.
1. Preparation (cleaning) of the surface is carried out with a vacuum cleaner.
2. Using the laser level, we find the highest and lowest points on the surface. When installing the laser on the wall, marking is made with a marker, so that in case of a malfunction, you can easily set the level again.
3. At the highest point, we postpone from the level of 30 mm upwards. Accordingly, in other places in the room, the screed layer will be thicker, and the same segment from the level up. It is advisable to prepare a template to measure this distance.
4. To fix the beacons, the same sand concrete mixture is used as for the screed itself.
5. Lighthouses are fixed on the same level. Damper tape is laid along the walls. It will play the role of sound insulation and thermal insulation.
6. Prepare sand concrete mass. Expanded clay is poured into the same container.The solution should be as thick as possible, otherwise the expanded clay pebbles will float to the surface.
Everything is thoroughly mixed with a hand mixer.
7. For better adhesion of the screed mass to the floor, a double surface treatment with a suitable primer is carried out. It should dry.
8. The mixture is evenly distributed over the surface and leveled.
A layer of sand concrete mortar (without expanded clay) is applied on top of the expanded clay layer. Aligned with the "rule".
9. After about 10 hours, the beacons are removed.
10. Irregularities are eliminated using the “rule”. For better glide, the surface is wetted with water.
11. Roughnesses are smoothed out with a wooden grater.
12. After drying (at least 28 days), the surface is ready for further operations.
Can be coated with laminate, linoleum or other material.
The advantage of this screed: cheap materials. Long hardening can be attributed to the minuses.
Screed "bulk floor"
With a small difference in heights and a fairly flat surface, a bulk floor (self-leveling mixture) is a good option. When using it, there are some nuances.
1. The height is measured on the surface and the height difference is detected. If it does not exceed 10 mm, then this type of screed is justified.
2. After garbage and dust (for this it is better to use a vacuum cleaner).
It is necessary to fill all cracks and crevices. Since the solution is very liquid, it can leak through these holes.
3. Double primer required. The primer can be poured onto the floor and distributed with a roller. Then wait at least an hour and apply a second coat. This will provide good coating quality. The solution will adhere perfectly to the surface. The screed will not crack.
4. Use the resulting mass as soon as possible. She freezes very quickly. The hardened mixture cannot be evenly distributed on the floor. Better to work with an assistant. One person mixes the solution, the other applies it.
The coating is applied as follows: the mixture is poured onto the surface, leveled with a needle roller.
The length of the roller needles should be greater than the depth of the mortar. Otherwise, air bubbles will remain in the screed. In addition, with short needles, the mass is poorly leveled.
5. Work starts from the corner of the room opposite the entrance. Accordingly, they finish at the entrance.
When the floor of the whole room is leveled, a limiter is placed at the exit.
After a few hours (the pour time depends on the thickness of the coating and temperature), the screed is ready. While the floor dries in the room there should be no drafts, the temperature in the room is not lower than +5, the surface temperature should be the same in all the treated areas. Otherwise, serious defects are possible.
If all the work was carried out strictly according to technology, then the surface is very smooth. This is the main advantage of the "bulk floor" coating.
