How to make a floor screed on your own

During the construction or overhaul of a house, when arranging an apartment bought in a new high-rise building, a new floor has to be made. So that its strength is not in doubt, you should choose the optimal type of intermediate layer mounted under the cladding. Do-it-yourself floor screed requires strict adherence to technology and the use of good materials - under these conditions, the floor is durable and does not need additional costs to correct defects.

Regardless of the laying method, the screed has such goals;

• lifting the base to the required level;
• leveling the floor plane;
• redistribution of pressure on concrete slabs, increasing the strength characteristics of the entire system;
• thermal and sound insulation.

The installation method is determined by the type of dwelling, the condition of the base, the humidity of the room and the estimated costs. The following comparative analysis of screeds will allow you to choose an acceptable option.

1. Solid. It is made from a sand-cement mortar, gypsum (anhydrite) or self-leveling mixture. Floor screed in a private house, garage, rooms with a high level of humidity is most often made of concrete (1 volume part of cement and 3 parts of sand): it is resistant to moisture, durable, easy to manufacture and affordable.

Pouring a concrete mixture as the bottom layer will help level differences in height up to 20 cm. A significant drawback is the duration of the process (almost a month). Cement or concrete floors shrink a lot and need additional layers of thermal insulation. Another disadvantage: when hardening, cracks form in concrete if expansion joints are not left. When installing a wet mixture, an apartment runs the risk of leaking to the lower floor, although a new building with large irregularities in the floors most often requires a solid screed.

The gypsum mixture is suitable only for conditions of low humidity, collapsing under the influence of fumes even after absolute drying. The solution layer can be 2 - 10 cm. The advantage of the gypsum version is the absence of shrinkage during drying.

2. Semi-dry. In fact, this is also a solid screed, which has one nuance of the recipe: very little water is poured into the solution. For its preparation, they take coarse sand without clay, cleaned of crushed stone, and M500 cement. Additionally, a reinforcing element is introduced - fiber, which limits cracking and shrinkage. It is difficult to work with the mixture: in order to prepare it and distribute it on the floor, special devices are needed (a concrete mixer and a “helicopter” trowel). Most often, construction teams are engaged in laying, making up to 300 m2 of floor per shift with a screed thickness of 5 to 6 cm. The solution is rapidly hardening, allowing you to walk on the surface earlier than in a day. A semi-dry screed is used if the apartment is being renovated - in this case, the risk of flooding does not threaten the neighbors.

After a rough layer of wet or dry screed, a finishing layer of self-leveling mixture is laid. It smooths out defects and irregularities with a height difference of no more than 3 cm.

3. Dry (team). This is a progressive high-speed screed with a backfill of dry filler (for example, expanded clay), covered with sheet material. If the new building has even floor slabs, then the dry method is suitable for it: it eliminates differences up to 12 cm. On top of the leveled backfill covered with a parabarrier, a Knauf floor screed is mounted - GVL sheets fastened with PVA glue and self-tapping screws.

The advantages of the dry method: quick installation, cleanliness, the possibility of flooring immediately after the screed. Knauf sheets are fire-resistant, have an increased level of noise and heat insulation, do not require height adjustment, and are light in weight. The wide application of the method is limited only by the high price.

Preparation of materials and tools

If you do the floor screed with your own hands, you should acquire the necessary equipment. The home master will need:

• roulette:
• building level-ruler (better than a laser level);
• hydraulic level - needed to detect the slope throughout the room, you can do it yourself from small plastic bottles connected by a flexible hose;
• putty knife;
• trowel;
• rule;
• mixer or drill with a whisk;
• container for the mixture;
• soil roller.

Preparatory operations are determined by the state of the base. The usual course of action looks like this:

• removal of construction waste (in a new house) or removal of a worn coating (during a major overhaul);
• sealing cracks in floor slabs with concrete mortar, into which an additive is introduced to prevent shrinkage (for example, penetron);
• beating the horizontal on the walls using a laser level or hydro level and determining the highest point of the floor (by measurements) is the zero level, from which the beacons are then set.
• priming with concrete contact;
• sealing gaps between the floor and walls with mounting foam.

The average calculation of the material for the floor screed is made after measuring its depth. For this purpose, in different parts of the room, the gap from the zero level to the existing one at this point is measured. The greatest height is taken into account, adding at least 1 cm to it.

For example: screed thickness 6.5 cm, room area 14 m2. The required volume of the mixture is calculated as follows: 0.0065 * 14 \u003d 0.91 m3. According to the norms, a cube of concrete mortar contains 410 kg of M500 cement. This means that 410 * 0.91 \u003d 372 kg of cement (about 27 buckets with a capacity of 10 liters) will be required for work. Accordingly, three times more sand is taken - 80 buckets or 960 kg. The rate of water per 1 kg of cement is from 0.45 to 0.55 liters, and in total it will take about 186 liters.

The calculation is completed by determining the required weight of the fiber (it is introduced with a screed thickness of more than 5 cm) and beacons. Fiber is added at the rate of 0.9 kg/cubic meter of the mixture. Beacons are placed at intervals of about 0.8 m (it should be shorter than the rule by 0.3 - 0.4 m).

How to make a screed yourself

The universal cement-sand mixture adheres well to a stone, brick, concrete base - first it is moistened or primed. Further work is carried out sequentially.

1. The first beacon profile is set at the zero point, aligned in length with plastic spacers, “glued” to the base with a quick-drying gypsum mixture. In parallel with the first beacon, the rest are laid out, due to the spacers of the required thickness, they are set along the initial profile, checking the position with the building level. All lighthouses are fixed with plaster.

2. A mortar is made manually or with a mixer, gradually adding water to the sand mixed with cement. If you pour too much of it, the brand of the mixture will decrease.

3. In order for the screeding process to be continuous, it is advisable to work in pairs: one member of the team mixes the mortar, and the second closes the spaces between the beacons. The first batch of mortar (several buckets) is laid out along the wall opposite the door. As a rule, it is pulled along the lighthouses for about half a meter, while leveling the site. The solution is lightly tamped with a trowel. The laying time in one room is adjusted so that it does not last longer than a day without interruptions. Spread the next portion of the mixture and continue to level further. Gradually, the entire floor is leveled in stripes.

4. Wet screed stabilizes for about 4 weeks. In the process of drying, every 5-6 days it is moistened with water so that the concrete dries evenly and sets better. For the same purpose, the floor surface is insulated with a dense polyethylene film. Doors and windows do not open to avoid drafts.

After a month, laying of parquet, laminate, linoleum is allowed. For tile cladding, you should wait at least another week for the strength to become sufficient.

The screed of a warm water floor is somewhat different in the installation sequence. At the bottom there is a heater (polystyrene) and a parabarrier film. Then the reinforcing mesh is mounted. It is important that the wire is free of scratches and does not scratch the water pipes laid on top of it. Conduct a hydraulic test of the heating system, checking it for leaks. Beacons are mounted and a wet screed with a thickness of at least 3 cm is laid - otherwise the floor temperature will not be the same when heated, and the concrete may crack.

Cost of floor screed

The market price of the finished concrete solution M200 is 3,700 rubles/m3. For a room of 14 m3 and a layer thickness of 6.5 cm, the cost of concrete is 3,360. The required amount of fiber will cost 160, 6 lighthouses cost about 300 rubles. The total cost of a wet screed is 3,827, and the price of 1 m2 is 273 rubles.

The price of a screed with expanded clay and Knauf sheets consists of the following items:

• backfill bag - 195 rubles. (this is enough for 1m2 with a thickness of 4 cm);
• KNAUF-superpol (thickness 2 cm) - 400 rubles (assuming that 1 sheet of 0.72 m2 costs 287);
• waterproofing, glue, self-tapping screws - 50 rubles.

With independent installation, the final price per square meter of dry screed is 532 rubles.

When comparing prices, it is worth considering all the advantages of the prefabricated method. In comparison with it, the complexity of pouring is much greater - this is due to the large weight of the components of the solution.