The device of a floor screed: materials, technology and the basic stages of works

The device floor screed today is perhaps one of the most common technologies for leveling the surface. Home masters and professional builders know a lot of different techniques, among them one should especially highlight the laying of the concrete floor, the installation of a semi-dry screed, as well as the method that involves the arrangement of the floor on the ground.

Why choose a concrete screed

With regard to leveling with concrete, it allows you to achieve a high-strength surface, which will undergo all kinds of load, without losing its quality characteristics. Inviting specialists to carry out such work is not necessary, because the process can be carried out independently.

Preparation of the surface before pouring concrete screed

The device of a floor screed necessarily assumes carrying out of preparatory works. If the floor will be laid on the ground, which is important for the basement and private houses, then first you need to take out the soil, deepening by 500 mm. At the bottom poured 100-mm cushion of sand, which should be well tampered, and on top of a gravel layer.

Then it is possible to carry out the pouring of concrete with the addition of expanded clay. As soon as the base solidifies, it should be waterproofed with a dense polyethylene film or roofing material, which excludes penetration of ground moisture from below. Waterproofing layer should go to the wall. If necessary, another layer of insulation is covered on top, after which it is possible to proceed to pouring the reinforced finish layer of the screed.

Preparation of the floor surface in the apartment

The device of a floor screed in an apartment assumes removal of an old layer of a rough surface. These works are necessary for the reason that old materials can be damaged, have cracks and delaminations. In addition, do not forget about the maximum loads on the slabs. For example, in high-rise buildings of old construction, this load is approximately 400 kg per square meter. As for the dynamic load, it is 150 kg. The weight of a square meter of concrete screed is 100 kg, this is true if the thickness is 50 mm.

If you do not remove the old screed, the ceiling height in the apartment will be even smaller than before. It is possible to dismantle the old layer with a perforator, but it is important to exclude the destruction of the slab. The base should then be inspected. You may need a repair. If you plan to lay a bound screed, then the existing grooves should be cleaned, fix cracks to a width of 5 mm, so that the concrete solution can penetrate there.

Advice from a specialist

If the floor screed device is planned for floating technology, the flaws must be repaired. Under the layer of waterproofing, it is not necessary to leave any voids, since condensate can accumulate there. Fixing of defects can be carried out with repair composition, concrete mortar or epoxy putty. In the presence of quite impressive defects, a mounting foam is used.

It is especially necessary to repair the corners between the floor and the walls, because the water from the concrete solution can easily penetrate deep into the ceiling and leak to the neighbors from below. The surface is treated with a penetrating primer, this will dust the base and increase the adhesion characteristics. Among other things, in this case, the overlap will not absorb moisture from the solution. The primer should be poured on the surface by strips and distributed by a roller. In hard-to-reach places, you can use a brush.

Additional recommendations for training

Before pouring the floor screed in the house, along the perimeter of the walls, it is necessary to glue the damper elastic tape, which will compensate for the expansion of the concrete screed. This will prevent cracking and deformation of the material. Among other things, the screed will not be in contact with vertical structures, columns and partitions.

If the coupler is laid on the separating layer, then the entire surface of the floor is to be covered with a polyethylene film, the thickness of which is 0.2 mm. Cloths should be laid with an overlap of 100 mm, and joints are glued with waterproof construction tape.

Beaconing and reinforcement

The technology of floor screeding in the next stage involves the setting up of beacons. According to them, the master will carry out leveling of the surface of the future floor. It is important to make the markup by determining the zero level. To do this, you need to draw a horizontal line, defining the highest angle of the room. The mark on the wall is a mark, and then, with the help of a water level, it is transferred to all other walls. The distance between the risks should allow to connect the marks with one line. From the value at the highest point it is necessary to take away the thickness of the screed. This parameter can be at least 30 mm. The resulting value will become the zero level.

Marking under the beacons is carried out after applying the zero level. The pitch between the parallel guide and the nearest wall should be 300 mm. Between adjacent guides the distance is not regulated, but it should be somewhat less than the length of the rule for equalizing the solution. For reinforcing, a metal net made of galvanized wire is usually used. Arrange the frame at some distance from the floor. For this, polymeric supports are used.

Filling the screed

Rough floor screed at the next stage involves the pouring of the mortar. The optimum working temperature is considered to be a limit of 15 to 25 ° C. If this value is reduced, the maturation period of the concrete will increase. Work on the fill should start from the far corner of the room, moving to the exit. It is recommended to finish the filling during the day, in this case it will be possible to get the most stable and homogeneous screed.

The finished solution is laid out between the guides and distributed using a shovel or trowel. It is important to maximize the compaction of the solution and the release of air bubbles. To do this, you can use the method of bayonet. On the guides, the rule is established in the next step. Zigzag movements should be carried out so that a smooth surface is obtained. The concrete solution can be added as needed. Its excess at the end of the filling is carefully removed.

Semi-dry screed technology

As an alternative, you can use a semi-dry floor screed. For this, a solution is prepared using fibrous fibers. For 120 liters of sand, you need to prepare 50 kg of cement and 150 g of fiber. If you are going to work with a room, the area of which is 20 m ² , then the fiber consumption will be equal to 0.54 kg.

The ingredients are mixed for 3 minutes, after which water is added, the solution is again mixed and placed on the surface. If the layer is additionally reinforced, then one part of Portland cement will need 3 pieces of sifted sand. The mixture can be prepared on site without the use of a concrete mixer. Water is gradually added to the dry composition. The solution should be semi-dry.

It is thrown over the surface, and the next layer will be a reinforced mesh, which is again covered with a semi-dry mixture. The composition is rammed, and leveling is done using the level and rule. When the irregularities are formed, they are sprinkled with a solution.

The last stage will be grouting and grinding. This allows for perfect smoothness. After hardening, screeds of roughness can be knocked down with a metal spatula. If grooves are formed, they can be filled with a solution of sand and cement in a ratio of one to one. Grout the base with a polyurethane or wooden float. If the semi-dry floor screed is laid using lighthouses, then they should be removed, and the places of their location should be wiped and sanded using a special machine.

Screed on the ground

After excavating the soil from the pouring area of the screed, it is necessary to fill the bottom with sand. The thickness of this layer should be about 10 cm. The quality of the tamping will be improved if we additionally use special mechanisms such as vibration compactors or vibrating rammers. In this case, sand should form a horizontal surface.

The device of a floor screed on a ground at this stage assumes wetting of the basis that will increase a degree of shrinkage of a layer. You can feed water from buckets or hoses. Then a layer of crushed stone is poured, its thickness can vary from 5 to 10 cm. The layer is well trampled. This will increase the load-bearing characteristics of the base.

After preparing a concrete mixture, which can be done independently. The density should be moderate in density. This will allow the concrete to be spilled on its own. As one of the advantages of a liquid mixture, there is no need to use beacons for leveling. The masters will only have to adjust the level slightly in the places where the material is being fed.

The reinforced floor screed at this stage provides laying of the mesh. Fasten the frame to 3 cm from the floor, and then pour the solution. The grid can be formed from wire elements, which are twisted together. If the wire has a diameter greater than 6 mm, it is better to use welding for the connection. However, the optimal solution will be the purchase of a ready-made grid.

Calculation of materials for screed

Calculation of floor screed must be carried out in order not to interrupt work. Forming a 10-cm layer, the cement must be purchased in an amount of 50 kg per square meter. For a more accurate calculation of cement and sand, a concrete example can be considered. If you want to work with an area of 60 m ² , then this value should be multiplied by 0.06 m. This is the thickness of the screed. As a result, it will be possible to obtain 3 m ^{3 of} solution.

Calculation of the floor screed may look like this: for 1 liter of the mixture you will need 1.4 kg of cement. This indicates that in one bag there will be only 36 liters, and the finished solution will be enough for 30% of the volume.

Conclusion

Before starting work it is important to consider whether you will use the services of specialists. If you decide to do the work yourself, then you should evaluate your knowledge and skills. Most often, house masters use the technology of laying a concrete screed, you too can follow their example. But the floor screed in a new building is best laid down by a semi-dry technique.