The technology of floating screed is associated with heat, hydro and sound insulation. Its essence is that a monolithic slab based on cement and sand does not rest on the ground, floor slabs or any other solid foundation, but on a soft laying. As it can be a layer:
- basalt wool ;
- polystyrene foam;
- expanded clay.
Area of use
The concrete surface does not interact with pipes or walls. The design is separated by a damping pad or gap. A floating screed acts as a mandatory attribute of the floors:
- terraces;
- bathroom;
- the verandas.
Quite often, this technology of flooring 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 damp 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 elements of the floor, not transmitted to the building structures. A limitation to such work is high loads. Their permissible value reaches 0.2 tons per square meter. If we are talking about domestic premises, then this tolerance is quite large. For example, in a bathroom, the maximum force is a quarter of the limit parameters.
The need for an independent screed
A floating screed is laid for the main purpose, which is to prevent dampness from spreading by the capillary method, because if this happens inside the wall of the building, 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. An excellent example is the bathroom, which is suitable in all respects, because a relatively high local temperature is maintained here.
All systems in this room are exposed to humidity overloads, including floors, ceilings and walls. In the bathroom, communications are concentrated by the type of pipes, electrical wiring and channels. This room has special requirements, which are expressed in sound permeability, waterproofing, as well as mechanical stress.
Floating screed reviews
The floating screed is a panel rigidly fixed between each other or a monolithic plate, which is laid on the ground or soundproof base. In the role of sound-absorbing materials usually are:
- expanded clay;
- foamed plastic;
- OSB.
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 with air gaps. According to the owners of real estate, they should be located between the floor slabs and the floor, as well as between walls, heating pipes and the floor.
If you will be equipped with a floating screed floor, 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 domestic premises for industrial purposes or industrial buildings. At the same time, concrete acquires the ability to undergo high loads. By this concept is meant not only the types of loads, but also their parameters.
For example, in rooms that are operated in conditions of 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 not laid correctly, it will “ring”. According to home craftsmen, a dry screed differs from a wet one in that instead of a concrete monolith, a cement-bonded particleboard or gypsum-fiber panels are laid on a heat-insulating layer. They have a technological advantage. According to consumers, it consists in the fact that the sheets are specially designed for dry screeds, for this they provide for 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 which is not subject to destruction. If you equip a dry screed, then over time it will not exfoliate and “cobble”.
Preparatory work
The floating screed device provides for the preparation and marking. Two lines must be drawn along the perimeter of the wall at different heights, 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. As the most suitable level in the bathroom, the height of the door threshold will be given the thickness of the tile.
The surface of the floor is washed several times and dried well. If the substrate is not properly prepared, the material will exfoliate during operation. In those places where sewage and heating pipes pass through the ceilings, 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, departing from the walls of 11 cm. The pipes are pre-wrapped with a tape of foamed polymer.
Specialist recommendation
A floating floor screed, the laying technology of which is described in the article, can be equipped even at the stage when the room does not have communications. In this case, the floors must be delineated by marking the places of the pipes. They will need to be circumvented, and the minimum width of the strips should be such that the height of the rings is higher than the edge of the stacked screed.
Waterproofing
A 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, mastic on a bitumen basis is usually used. Water resistant paints are also great.
The first layer will be water-repellent paint, the second will be waterproofing roll material. Maximum efficiency can be achieved by fusing the roll, having previously rolled it on the floor surface. An industrial hair dryer or gas burner should be used for this, the last of which requires work permits. This method can be replaced by technology, when bituminous mastic is used to fix the roofing material, it will act as glue. The composition is applied with a spatula or brush, only after you can start laying waterproofing.
Home Master Tips
Before you make a floating screed, be sure to prepare the surface. To do this, after laying the waterproofing, you need to glue the heating pipes and walls. The width of the strips for this should overlap the height of the screed. In the market you can find modern materials of the type "Isoplast" and "Isoplen", which have high functional characteristics. The only negative in this case is the high cost.
Soundproofing
The surface before laying the screed must be checked for unevenness. Pits in the right places are covered with sand, which needs to be well leveled. Then you can start laying soundproofing. The following materials act as it:
- OSB;
- foamed polymer slabs;
- basalt cotton wool;
- DSP;
- extruded plastic.
When choosing a material, it must be ensured that it possesses elasticity and compressibility corresponding to state standards. If the work is carried out in a domestic building, then the maximum limit of this parameter is 5 mm. These characteristics correspond to the CP5 panel. The most suitable layer thickness is a limit of 30 to 50 mm. It is important to provide technological 25 mm gaps at pipes and walls when laying soundproofing boards.
The joints obtained are filled with construction foam. A vapor barrier film can be placed on top of the plates. When a multilayer coating is installed to solve the problem of sound insulation, more dense layers are located on top. Next comes the turn of a polyethylene film, the thickness of which can vary from 0.1 to 0.15 mm. Its function is the separation of the solution and sound insulation. Using this layer, the formation of temperature bridges can be eliminated.
Concrete pouring
The most important step in carrying out the described work is to fill the screed. The simplest recipe for preparing the mixture is the use of cement brand M-400 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 should know the thickness of the floating screed. Its minimum value is 50 mm. If you used modifying polymer additives when mixing concrete, then the thickness can be reduced to 35 mm. As an additional element that plays the role of strengthening 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 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 is as follows:
- 1 part of fiber;
- 3 parts of sand;
- 1 part cement.
First you need to work on making a dry composition, mix it until smooth, and then add water. If it is supposed to equip a thick screed, then it should be supplemented by reinforcement in the form of a metal mesh. Semi-dry mixture must be distributed between the beacons and level 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
A dry floating screed is convenient in that the entire area of the room can be covered with it with one help in one day. A mixture for a dry screed, which consists of fine-grained expanded clay, is poured onto a plastic film. Once the floor is filled up to half the thickness, you can install beacons, according to which the mixture will be leveled by the rule.
Work can be done in sections. Plaster boards made of gypsum fiber, which have a castle connection, are laid on a flat surface. Between them they are fastened with glue and additionally twisted with screws. Panels must be level-aligned. In order to prevent spillage of the mixture during installation, partitions from GVL scraps or ordinary boards are installed in the doorways.
Conclusion
The minimum floating screed thickness was mentioned above. But this requirement is not the only one that must be observed when installing the floor. If, over time, you still hear that the material “coils” 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 a piece of the coating. Then it is well cleaned and again filled with concrete mortar.