Floating screed: installation technology and reviews

Repair 2022
Floating screed: installation technology and reviews
Floating screed: installation technology and reviews

Floating screed technology is associated with heat, hydro and sound insulation. Its essence lies in the fact that a monolithic slab based on cement and sand is not based on soil, floor slabs or any other solid base, but on a soft pad. A layer can act as it:

  • bas alt wool;
  • foam;
  • expanded clay.

Use area

floating screed

Concrete surface does not interact with pipes or walls. The structure is separated by a damping gasket or gap. Floating screed acts as a mandatory attribute of the floors:

  • terraces;
  • bathroom;
  • verandas.

Quite often, this flooring technology is used on the first floors of private residential buildings. Floating systems are also relevant for those rooms where it is planned to connect a warm floor. The advantage of such a screed is the ability to dampen vibration, shock and sound vibrations.

The concrete layer will be separated from the structural elements of the building. In this case, the internal energy will be distributed between the floor elements without being transferred to the building structures. High loads are a limitation for such work. Their allowable value reaches 0.2 tons per square meter. If we are talking about household premises, then this tolerance is quite large. For example, in a bathroom, the maximum force is a quarter of the limit.

The need to use an independent tie

floating floor screed

Floating screed is laid with the main goal of preventing moisture from spreading by capillary action, because if this happens inside the building wall, it will negatively affect the durability of the materials. The soundproofing effect is concomitant, however, in some cases, the described type of screed is installed in order to give the room sound-absorbing characteristics.

Floating screed is carried out in those buildings that are fully assembled, equipped with utilities and plastered. A great example would be the bathroom, which fits the bill because it maintains a relatively high local temperature.

All systems in this room are exposed to moisture overload, this should include floors, ceiling and walls. In the bathroom, communications are concentrated by the type of pipes, electrical wiring and channels. Special requirements are imposed on this room, which are expressed insound permeability, waterproofing, as well as mechanical stress.

Floating screed reviews

dry floating screed

Floating screed is a rigidly fixed panels or a monolithic slab, which is laid on the ground or a soundproof base. The role of noise-absorbing materials are usually:

  • expanded clay;
  • foamed plastic;
  • OSP.

To limit the spread of moisture, as users emphasize, the screed is covered with a layer of waterproofing. Additional qualities of sound insulation can be provided by air gaps. According to the owners of the property, they should be located between the floor slabs and the floor, as well as between the walls, heating pipes and the floor.

If you are going to equip a floating floor screed, then you should know that it can be wet or dry. In the first case, we are talking about the use of a cement-sand mixture, with which a concrete surface is created. Such structures are usually located in household premises for household purposes or industrial buildings. At the same time, concrete acquires the ability to endure high loads. This concept refers not only to the types of loads, but also to their parameters.

For example, in rooms that are operated in conditions with high humidity, it is best to equip concrete floors. But they have certain disadvantages, expressed in the possibility of delamination and the complexity of the technology. If the screed is laid incorrectly, then it will “ring”. As they sayhome craftsmen, a dry screed differs from a wet screed in that cement-bonded particle board or gypsum fiber panels are laid on the heat-insulating layer instead of a concrete monolith. They have a technological advantage. According to consumers, it lies in the fact that the sheets are specially designed for dry screeds, for this they provide a mounting lock.

Dry floating floor screed, according to consumers, has another important advantage, it is expressed in functionality. OSB or GWP is a monolith that is not subject to destruction. If you equip a dry screed, then over time it will not flake off and “bubble”.

Preparatory work

floating screed device

The floating screed device provides for preparation and marking. Along the perimeter of the wall at different heights, it is necessary to draw two lines, the first of which will indicate the level at which the floating floor is supposed to be laid. The second line is the mark of the waterproofing layer. The height of the threshold of the door, taking into account the thickness of the tiles, will act as the most suitable level in the bathroom.

The floor surface is washed several times and dried well. If the base is not properly prepared, the material will peel off during operation. In those places where sewerage and heating pipes pass through the floors, it is necessary to make limiters for the concrete mixture, they are made of strips of roofing material and will serve as edges. These edges should be formed in the form of rings, and they need to be fixed around the pipes,stepping back from the walls 11 cm. The pipes are pre-wrapped with foamed polymer tape.

Specialist recommendation

minimum thickness of floating screed

Floating floor screed, the laying technology of which is described in the article, can be equipped even at the stage when the room has no communications. In this case, the floors must be drawn, marking the places of the pipes. They will need to be bypassed, and the minimum width of the strips should be such that the height of the rings is higher than the edge of the screed being laid.

Waterproofing works

floating semi-dry screed

Floating screed, the laying technology of which should be known to you before starting work, involves waterproofing. To do this, you can use roofing material, which is laid on a horizontal surface. A moisture-proof film must be created on the base of the slab or subfloor. For this, a bitumen-based mastic is usually used. Waterproof paints are also great.

The first layer will be moisture-repellent paint, the second will be waterproofing roll material. Maximum efficiency can be achieved if the roll is melted, having previously rolled it over the floor surface. For this, an industrial hair dryer or a gas burner should be used, the latter of which requires a work permit. This method can be replaced by technology, when bituminous mastic is used to fix the roofing material, it will act as an adhesive. The composition is applied with a spatula or brush, only after you can proceed tolaying waterproofing.

Advice for a home master

floating floor screed technology

Before you make a floating screed, be sure to prepare the surface. To do this, after laying the waterproofing, you need to paste over the heating pipes and walls. The width of the strips for this should overlap the height of the screed. On the market you can find modern materials like "Isoplast" and "Isoplen", which have high functional characteristics. The only disadvantage in this case is the high cost.

Soundproofing works

The surface must be checked for unevenness before laying the screed. Pits in the right places are covered with sand, which must be well leveled. After that, you can start laying soundproofing. The following materials act as it:

  • OSB;
  • foamed polymer boards;
  • bas alt wool;
  • DSP;
  • extruded plastic.

When choosing a material, it is necessary to ensure that it has the appropriate state standards of elasticity and compressibility. If work is carried out in a domestic area, then the maximum limit of this parameter is 5 mm. These characteristics correspond to the CP5 panels. The most suitable layer thickness is between 30 and 50 mm. It is important to provide technological gaps of 25 mm at pipes and walls when laying sound insulation boards.

The resulting joints are filled with construction foam. On top of the plates, you can lay a vapor barrier film. When building a multilayercoatings to solve the problem of sound insulation, denser layers are located on top. Next comes the turn of the polyethylene film, the thickness of which can vary from 0.1 to 0.15 mm. Its function is the separation of mortar and sound insulation. With this layer, the formation of thermal bridges can be eliminated.

Pouring concrete mix

The most important step in carrying out the described work is pouring the screed. The simplest recipe for preparing the mixture is the use of M-400 cement and sand. These ingredients should be applied in a ratio of 1 to 3. Of the total volume of the mixture, water is 1/50 part.

You must know the thickness of the floating screed. Its minimum value is 50 mm. If you used modifying polymer additives when mixing the concrete mix, then the thickness can be reduced to 35 mm. As an additional element that acts as a strengthening of the screed, a polymer or steel mesh acts. Reinforcing material is not used in compliance with European standards, but traditional technologies suggest such a need. This is especially true for the screed, which is arranged on the ground.

Semi-dry screed technology

Floating semi-dry screed involves the use of a special solution, which consists of sand, cement and propylene fiber. The proportion looks like this:

  • 1 piece fiber;
  • 3 parts of sand;
  • 1 piece cement.

First you need to work on the manufacture of dry composition, itknead until smooth, and then add water. If it is planned to equip a thick screed, then it must be supplemented with reinforcement in the form of a metal mesh. The semi-dry mixture must be distributed between the beacons and leveled with the rule. With the help of this composition, the entire area is filled, which can then be gradually leveled. To strengthen the screed during grouting, the topping method is used.

Dry screed

Dry floating screed is convenient because it can cover the entire area of ​​​​the room with it in one day. A mixture for dry screed, which consists of fine-grained expanded clay, is poured onto a plastic film. As soon as the floor is half-filled, beacons can be installed, along which the mixture will be leveled by the rule.

Work can be done in sections. On a flat surface, gypsum fiber boards are laid, which have a lock connection. They are fastened together with glue and additionally twisted with self-tapping screws. Panels must be level. In order to prevent spillage of the mixture during installation, partitions from GVL scraps or ordinary boards are installed in the doorways.


The minimum floating screed thickness has been mentioned above. But this requirement is not the only one that should be observed when installing the floor. If, over time, you still hear that the material is “bubbling” in those places where it adjoins the heating system, then this can be caused by vibrations and temperature changes. Such a coating can be repaired by first cutting out a piece of the coating.Then it is well cleaned and filled with concrete again.

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