The device of the screed is an integral process when aligning the base of the floor under the laying of many modern flooring. Performance of this work prevents the occurrence of bugs and depadies on the floor surface and allows you to qualitatively set the finish coating. This is especially true of laminate, parquet and linoleum. Now we will tell about the tie of the floor by cement-sandy solution.

Characteristics of cement-sand tie

The composition of the solution to create a screed includes three main components:

• cement;
• sand;
• water.

Some experts recommend to add in cement-sand mixture to the floor plasticizer. Its use will increase the density of the tie and make it more elastic.

If in the future, the floor will be subjected to high mechanical loads, the tie will have further reinforced. If you observe precisely the technology device of cement-sand floors, they can withstand the pressure of 500 N / cm².

The main characteristics when creating concrete ties are:

• consumption of materials;
• ties weight;
• density and thermal conductivity of the dry mixture.

The consumption of materials for the preparation of the solution directly depends on the thickness of the poured screed. Suppose we need to make a screed 5 cm thick in a room of 20 m². We will need 1 m³ of solution.

Based on the fact that it consists of 1 hour cement and 3 hours. Sand, then we need 0.25 m³ cement. The M400 brand cement density is 1100-1600 kg / m³. Accordingly, for the device of the cement-sandy floor, 20 m² is 6-8 cement bags and 18-24 sandbag.

Particular attention should be paid to the weight of the filailed cement-sand tie. Since not any sex can withstand it. In some cases, the most optimal option will be the device dry or semi-dry (with fibrovolok) screed. In the event of a fill of the 5-centimeter screed, the load on the floor will increase by 90 kg / m².

Depending on the density, the cement-sand screed happens:

• easy - up to 1500 kg / m³;
• severe - over 1500 kg / m³.

The tie density directly affects the strength, frost resistance and sound permeability of the solution. For residential rooms, a more suitable option is a lightweight concrete screed.

The cement-sandy mixture does not have sufficient thermal conductivity (1.2 W / m-K). To maintain the normal temperature mode, the room should be used thermal insulation materials.

The advantages of the device of the concrete screed include:

• increased strength;
• prolonged operational period;
• excellent vapor permeability;
• simplicity of installation work;
• the minimum price of the cement-sand tie of the floor.

Preparatory work

The preparation of the foundation consists of four main stages:

• floor cleaning;
• priming surface;
• determining the top point of the screed;
• installation of lighthouses;
• preparations of the solution.

The first stage provides for the removal of an old floor covering. The entire construction trash is removed as a result of dismantling work. Oil and greasy spots are eliminated with the help of special chemicals. Cracks and other surface irregularities are closed. All dust removes the construction vacuum cleaner.

In the presence of an earth basis, it will be necessary:

• carry out the surface seal;
• create a drain layer.

On top of the rammed land, sand is poured by a layer of 10 cm, which is covered with a polyethylene film. A 5-centimeter layer of rubble is poured into the film.

Priming the base of the floor leads to an improvement in the adhesion of a concrete screed with a surface. This is due to the fact that when the solution is dried, the lower part of the screed is prone to shifts. For priming it is better to use the compositions that are processed with a large porosity.

The primer is applied with two layers. The application of the second layer is made after drying the first. After drying the second layer of primer, laying a special damper tape. It solves three tasks:

• protects the screed from destruction when it is dried;
• seals plates of plates;
• protects the places of adjustment of the screed to the walls at temperature differences.

After the final drying of the primer is determined and the location of the upper points of the filled screed is noted, the size of which can be from 3 to 7 cm. The specific thickness of the screed depends on:

• such as finishing flooring;
• presence of insulation materials;
• the degree of irregular surface.

When adding a plasticizer to cement-sandy solution, a screed thickness must exceed 3 cm. And if a warm floor is created, the thickness of the screed must be at least 5 cm.

First you need to set a "zero" point. And it is done immediately on all the walls in the room where the screed is poured. This will require a laser (or water) level and a deduction cord.

For more accurate markup, some experts are recommended to conduct a control line on a meter height from the floor. This line will become a guide line to which equal perpendicular segments are conducted.

A strictly horizontal surface of cement-sand sex in the photo and in reality is created using guide lighthouses. Metal profiles can be used in their capacity. The technology of their installation involves the following actions.

In all the corners of the room at the level of the highest point of the screed, screws are screwed. Between them stretches the fishing line. Using the construction level, the fishing line is exactly stretched along the perimeter of the walls and in parallel one of the walls. When installing, the beacons must perpendicular to ingur at least with three strained fishing racks.

The fixation of beacons is carried out with a concrete solution, which is led under them. The distance between the beacons installed should not exceed the length:

• construction level;
• rules for resurrection of the solution.

The installation of beacons is accompanied by a constant verification of their exact horizontal location. The building level is applied both along the length of the lighthouse and between two adjacent lighthouses.

Usually metal beacons after the fill of the concrete solution are not pulled out. When using wooden rails as a result of the impact of a wet environment, their destruction occurs. They are removed 2 days after filling the screed, and the recesses remaining from the rails are filled with a solution.

After grappling the guides of beacons, you can prepare and fill a concrete solution. For the preparation of a high-quality solution, cement M400 and above, sand (the best option is quartz) and water.

It takes 1 hour. Cement and 3 h. Sand. Water is added as needed. By consistency, the solution should turn out like a thick dough, intended for baking pancakes. The cooked solution needs to be spent over 1-1.5 hours.

Pouring concrete solution

Before starting the fill of the floor surface, it should be moistened with water. Creating a screed starts from the very far corner, gradually moving to the door. The solution is poured between beacons. It takes several punctures. In the middle of the solution should not be air bubbles. Using the rule, the extra part of the cement-sandy solution is cut off.

The implementation of a thorough alignment of the laid concrete will be the key to fast and high-quality laying of the floor covering. Otherwise, you will have to additionally produce the finishing fill of the concrete solution.

The device screed in one room occurs in one day. The fill of the cement-sandy solution in parts is allowed only when creating multistage structures with a mandatory device of damper seams (up to 2 cm) between them.

After completion of the work, the screed is covered with a polyethylene film. After 12-14 hours, it should be carefully examined. If there are bugs or other roughness on the surface, they should be eliminated. This uses a wooden grater and a metal spatula.

Fully screed will type perfect strength for a month. Over the course of this time it is impossible to dry out. Abundant wetting of the new floor water is carried out 2-3 times a day.

Video on the creation of cement-sandy gears: