Features Of Installing A Cement Screed To Level The Base

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Video: Features Of Installing A Cement Screed To Level The Base

Video: Features Of Installing A Cement Screed To Level The Base
Video: How to floor screed with sand and cement - Beginners guide- plastering Guru 2023, October
Features Of Installing A Cement Screed To Level The Base
Features Of Installing A Cement Screed To Level The Base
  • Screed device options
  • Determination of thickness
  • Base marking
  • Lighthouse selection
  • Hydro and thermal insulation
  • Reinforcement
  • Mixing the solution
  • Fill

For laying any type of flooring, a high-quality cement-sand screed should be performed. This is necessary to level the base. Installation of concrete floors takes some time and labor, but at the same time it has a minimal cost. All major components are readily available in the building materials market. In this case, all work should be carried out in strict accordance with the technology of pouring cement-sand floors, which includes certain stages.

Screed device options

When choosing a specific type of concrete floor device, you should start from how much it will affect the base. After all, all the components together have considerable weight. Everything will depend not only on the amount of water, but also on the power of the screed. Each square meter of a 40 mm thick screed will exert a surface pressure of approximately 90 kg. It is depending on the thickness that the division of the device of the cement-sand mortar into types will occur:

Related option. A cement floor with a layer of no more than 40 mm is perfect. It becomes one with the subfloor, as well as with walls and other structures in the room. It is very important to carry out high-quality preparatory measures, on which the strength and strength of the finished version will depend. All deep cracks and potholes must be repaired, debris removed, and the mounting ears are bent with a sledgehammer. If there are minor defects in the base, then they are left in order to better set the solution after pouring

After 20 minutes after mixing, the cement-sand mortar begins to lose its quality. It is during this time that it is best to fill for the best quality.

Not connected to building structures. When choosing this option, the device of floors on a concrete base, adhesion and everything associated with it are not important. But here you need a very smooth surface for pouring the solution. In addition, it must have the property of waterproofing so that moisture does not leave the screed, which will dry out. The thickness of this version of the device is usually 50 mm

In the process of preparing concrete floors, it is impossible to use various primers and mixtures for concrete floors, which increase the level of adhesion.

A floating slab separated from the floor and walls by layers. The thickness of the layer for leveling the floor in this case is from 50 to 70 mm. The future solution is separated from the base with the help of an arranged waterproofing layer. It also separates from the walls using a damper tape made of expanded polystyrene. A reinforced concrete floor will be of high quality if you add reinforcement with a metal mesh or fiberglass. In the latter case, the likelihood of cracks on the surface of the future screed is almost completely excluded due to the positive quality of the component

Determination of thickness

The thickness of the future screed will depend on the prepared base. If it is compacted soil, then usually a layer of mortar is made in the range of 100-120 mm, and when it is installed on a concrete base - about 70 mm. You can go up to 40-50 mm.

With large differences in height in the room, in addition to the cement-sand screed, it will not be superfluous to use expanded clay backfill. This will save money and get a better future surface. To obtain expanded clay concrete, these components should be mixed together. In addition, the level of sound insulation will be at a decent level.

Such a screed has its drawbacks associated with the technology of the device. But even in this case, its popularity remains at the highest level. The direct process will allow you to avoid errors in the work, if you do everything efficiently and consistently.

Leveling the floor with concrete mortar
Leveling the floor with concrete mortar

When determining the thickness, calculations are made according to the amount of solution used. But after all, not everyone knows about what mixtures are used to level concrete floors. The store offers a wide range of them. Of particular importance will be the grade of concrete for pouring the floor. The strength and strength of the finished solution will depend on it.

Base marking

There will almost never be an ideal surface for a cement-sand screed. Therefore, it is necessary to set the highest and lowest points. Here the laser level will act as an assistant, giving more accurate results.

The first mark is applied independently at a level of 1 meter from the surface, where the solution will be subsequently poured. It will serve as the starting point for the horizontal line. Use a pencil or chalk to outline. The main thing is that this level is preserved until subsequent measurements. It got its name - zero level.

Leveling the floor with concrete mortar
Leveling the floor with concrete mortar

A distance of 30 mm in height is set from the highest point in the room and a mark is made on the wall. A measurement should also be made from this point to zero. After that, points are drawn from the horizon downward. The results obtained are combined with each other. It is this line that will become the plane of the future screed. Beacons are set up along it and other calculations are carried out, observing the rules for the construction of floors.

Lighthouse selection

For high-quality leveling of the floor with a cement-sand screed, beacons should be installed. They will allow you to get a flat surface with minimal effort. For them, you can even take pipes with a diameter of 15-30 mm. Each builder chooses a more suitable result to obtain the desired result. There is only one main requirement for them - rigidity and the ability to withstand certain loads.

There are several ways that beacons can be installed:

  1. The threads are pulled at the level of the future screed.
  2. Using a laser level.

    Leveling the floor with concrete mortar
    Leveling the floor with concrete mortar

Using the broken lines, self-tapping screws are drilled. They will be required for each lighthouse, 3 pieces: along the edges and in the middle. The thread is pulled along the self-tapping screws. But it can also sag if there is a long distance. To avoid this, additional supports are installed (timber bars).

Hydro and thermal insulation

You cannot ignore the waterproofing layer when installing a cement-sand screed. There may be cracks in the concrete (foundation) that are not visible during preparation. Water can penetrate into them after filling. To avoid this, special compositions and mixtures should be used for the device of the above layer.

The waterproofing material can be:

  • coating mastic (bitumen, synthetic rubber);
  • roll waterproofing, with which the surface and walls are glued to a certain height;
  • cement-polymer compositions in liquid form.

If these are dry rooms, then it is not always necessary to coat or seal up the entire base. It is enough to pay attention to the joints of the floor slabs. When it comes to baths or toilets, then you should not spare the mixture for work.

Leveling the floor with concrete mortar
Leveling the floor with concrete mortar

When using roll materials, there must be a joint of at least 10-15 cm. It is these areas that will be the most susceptible to negative manifestations. A more expensive option is liquid waterproofing. But the result will please every performer. All these subtleties will allow you to get an answer to what to cover the concrete floor with.

When this layer is established, the floor can be filled with cement. In addition, now you don't have to worry about water getting to the lower floors. You can fill the cement floor on your own, but special attention should be paid to the preparatory measures.


When pouring a cement floor over the ground, a prerequisite is a layer of reinforcement. As a material, metal mesh, reinforcing bars or more modern materials - fiberglass can be used.

Leveling the floor with concrete mortar
Leveling the floor with concrete mortar

It is the last component that has a large number of properties and qualities that make it possible to avoid cracks, shrinkage during drying and other negative manifestations. Moreover, if you make calculations for consumption, then the cost of fiber will be slightly lower than, for example, a steel mesh. For each square meter of the area of the room, about 600-800 grams of such material will be required.

Leveling the floor with concrete mortar
Leveling the floor with concrete mortar

The use of modern technologies to level the floor with cement mortar can significantly reduce the load on the floor slabs. This becomes especially true in the case when a screed is arranged in old buildings, as well as on a wooden base.

There are several options for fiberglass:

  • Basalt. It is used in the reinforcement of gypsum, lightweight concrete, in the production of press materials, plastic products
  • Steel. Increased consumption due to weight - from 20 to 100 kg per square meter, depending on conditions.
  • Polypropylene.

Mixing the solution

The composition of a concrete floor can be completely different. Everything will depend on those components that are selected when mixing. You should know and understand what mixture to level the floor with in order to get a high-quality coating. You can fill the floors with cement as soon as possible, but the main thing is to follow the technology.

There are several options thanks to which you can prepare a solution:

  1. Purchase ready-made bags with a mixture to which you just need to add the required amount of water. But it is worth noting that such bags will cost a little more than preparing everything yourself using the appropriate components.

    Leveling the floor with concrete mortar
    Leveling the floor with concrete mortar

    The leveling mixtures of the floor screed will depend on the brand of cement. It is best to choose at least M400, so that the fortress is the highest.

  2. Ordering the solution in the mixer. In addition to quality, the customer is pleased with the acceptable cost. True, it is very difficult to bring the solution from the mixer to the work site, especially if the area of the room is significant. You can use a concrete pump for a certain cost. This will save labor costs.
  3. Using a recipe for mixing a solution, mix cement and sand together. Additives, such as concrete floor hardener, can be used additionally. This will be the most cost-effective floor leveling option.

If the cement-sand mixture turned out to be with a gray tint, then you can be sure that the quality will be high. All other shades - red, yellow, suggest otherwise. The color can be influenced by plasticizers, which allow the solution to harden better after pouring.


There should be no problem with how to fill the floor with cement. This process takes a minimum amount of time if everything is done sequentially according to the technology. The beginning of all work is carried out from the opposite corner from the entrance to the room. A certain amount of the ready-made solution is poured there, after which it is leveled using the rule towards the entrance. In this case, all gaps must be completely filled.

Leveling the floor with concrete mortar
Leveling the floor with concrete mortar

Initially, the stripes between the lighthouses, located along the side walls, are filled, and only after that, the central sections. When everything is done, you should leave the solution until it hardens. When the mortar sets, the guides are removed, and the voids that appear are filled with a repair compound.

Any resulting irregularities must be knocked down with a metal spatula. After that, grouting with a wooden float is performed. The surface should be uniform and slightly rough.

The drying time of the floor after pouring is usually 10 to 30 days.

During operation, you should know some of the subtleties associated with what to cover the concrete floor so as not to get dusty, as well as how the floor is leveled by grinding.

There should be no question as to why the floor is needed. It allows you to create favorable conditions for the subsequent installation of any type of flooring. But even in this case, you should understand how to properly level the concrete floor.



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