During the construction of the house, workers need to perform a large amount of work and apply a variety of technologies. The construction of the walls is carried out from a variety of materials, and the interior decoration is carried out in the most unusual ways. A distinctive feature of floor leveling is that the owners not only see the result of this stage of construction every day, but also feel it under their feet. All this proves the importance of the correct execution of the base.
Types of floor screed
- Classic method. Wet screed of cement-sand or concrete mortar. This method of leveling the base has been used in construction for a very long time. Working on a wet screed requires a lot of time, as the material must dry completely.
- Dry screed. It is carried out using boards made of chipboard, OSB, fiberboard or plywood. The cost of such work depends on the initial quality of the foundation. The worse it is, the more material will be required for alignment. The strength of some plates does not allow them to be stacked in onelayer, which also indicates the need for repeated alignment work.
- Semi-dry screed. This method is similar to the implementation of the classical base, but fundamentally differs in the minimum amount of water in the sand-cement mixture. It is not poured, but falls asleep on the floor. To increase the strength, polypropylene fibers can be added to the solution, which play the role of a reinforcing frame. A semi-dry floor screed, the technology of which will be discussed below, can be produced in several ways, depending on the differences in the plane of the base.
Benefits of semi-dry floor screed
- No need for additional floor waterproofing as the mortar does not flow.
- During the work it is not necessary to use protective gloves and shoes, since the sand-cement mixture contains only 25% water. This makes it non-marking.
- If the work is not carried out on the ground floor, then there is no risk of leakage of the solution between the floors.
- The semi-dry floor screed device, the technology of which allows you to get a completely even base, also makes it possible to completely eliminate air voids and cracks.
- The term for complete drying of the floor is only 4-5 days. After this time, you can lay the topcoat.
- The weight of a semi-dry base is much less than a wet one. This allows you to reduce the load on the floors of the building.
- Works with mortar can be carried out at temperatures up to -50 °С.
- The special structure of the material allows you to get a floorwith excellent sound and heat insulation performance.
- Semi-dry European standard screeds are produced with special mixtures. A large saturation of the market with such types of materials and services leads to minimal margins for work.
Disadvantages of semi-dry floor screed
- Before compressing the material, the floor area is very dirty.
- When using special equipment, the cost of repairs increases.
- Price for 1 m2semi-dry screed depends on the height where the work is being done. For example, the cost of the floor on the 1st and 20th floors differs by 30%. This is due to the need to lift all materials and equipment.
- Semi-dry mortar is very difficult to mix by hand.
- Often, builders don't know the exact amount of water in the mixture, so they pour too little or too much of it. This leads to a violation of technology and an unexpected result.
- Semi-dry screed must be carefully compacted, otherwise it will constantly crumble and even creak underfoot.
Types of semi-dry screeds
- Screed without backing. The material is placed on a bare concrete base.
- With polyethylene backing. The solution in this case does not touch the rough base and walls. This type of tie is also called "floating".
- With thermal insulation pad. Mineral wool slabs most often act as an additional layer. This is especially true on the first floors of houses and in private buildings.
- Ssoundproof underlay. The sand-cement mixture itself does not transmit sound well. In addition, polyethylene foam or noise damping membranes can be used.
- With reinforced mesh. They give the floor more strength.
- With fiberglass. Such a floor is able to withstand very heavy loads.
Some of these types can be combined with each other, so you get the optimal floor screed for this room. Semi-dry screed device technology is divided into several stages.
Preparing the base for a semi-dry floor screed
- Before starting work, the base is completely cleaned. Garbage is removed with a broom, and small particles - with a vacuum cleaner.
- The zero level is set. It helps to accurately measure the height of the base.
- If necessary, large floor defects are puttied. A semi-dry screed, the laying technology of which allows you to create a flat surface, still does not guarantee penetration into all the flaws in the base. The remaining voids can subsequently cause cracking.
- The entire floor surface must be primed. This helps to bond the new layer to the old one. The primer dries for several hours.
Installation of beacons and waterproofing
Beacons are called guide elements that serve as guidelines for the horizontal level of the future floor. They help the builder lay out the mortar of the desired thickness.
Waterproofing for a semi-dry screed is not required, but walls and columns must be protected from mortar. This is done in order to compress andthe subsequent expansion of the vertical structures did not affect the condition of the floor. Above the level of the future screed, a damper tape is glued to all surfaces, it will prevent cracking of the material. After the floor has dried, it must be removed with a sharp knife.
Semi-dry floor screed, the device technology of which implies the mandatory presence of beacons, allows their implementation in several ways. One of them involves the installation of landmarks on two opposite walls. Lighthouses consist of a compacted mixture. Their height is accurately measured from the zero level.
Lighthouses can also be planks fixed on self-tapping screws or concrete. Their level is usually 8-10 cm higher than the base.
Such beacons are installed in stripes every 180-190 cm, if a two-meter rule is used. With a decrease in its length, the distance between the landmarks becomes shorter. Their height is measured by a thread stretched between the walls from the first lighthouses.
Beacons must not move during floor leveling. To do this, they need to be securely fastened. As necessary, the future floor is reinforced.
Preparation of mortar for semi-dry floor screed
This process can be done in several ways. The simplest of them is to dilute the finished dry mixture with water. In this case, you only need to follow the instructions.
If there is no ready-made mixture, then you can make it yourself. To do this, mix one part of cement and three of purified coarse sand. Added if necessaryplasticizer and fiber. Everything is placed in a concrete mixer, and water is gradually poured into it. A semi-dry floor screed, the laying technology of which will be discussed below, involves obtaining a solution of a certain consistency. Such that when clenched in a fist, it forms a lump, but does not release water.
Semi-dry fiber screed withstands very heavy loads. The required amount of mortar is obtained by constantly adding dry ingredients and water.
Device semi-dry floor screed. Concreting Technology
After finishing the preparatory work, you can proceed to the direct concreting of the surface. Semi-dry floor screed, the technology of which provides for the performance of work by several builders at the same time, begins with pouring the mixture between the guides. After that, the material is leveled by the rule slightly above the beacons. The mixture is pulled towards itself. As necessary, you can perform wave-like movements with the rule, this will help remove excess material from neighboring zones.
Before the concrete mixture begins to dry, it must be compacted and rubbed. All this must be done within 6 hours after leveling. A special machine is used, which allows you to make the surface of the floor even and smooth. During the operation of the equipment, the material settles a little.
Material processing ends with a control check of the horizontality and evenness of the resulting floor. The level must be clean.
Sin order to gradually dry out, the floor surface is covered with polyethylene for 12 hours, this will help prevent moisture from evaporating too quickly. After that, the floor dries for at least four days.
Do-it-yourself semi-dry floor screed: device and work technology
It is possible to carry out work on self-concreting the floor. The only difference is the use instead of a machine to level the usual grout of a large area. For the convenience of working with it, the floor can be covered in small segments. The do-it-yourself semi-dry screed technology provides for the quick and consistent execution of all stages of the process. Therefore, one person can knead the mortar, the second one can lay it down and level it, and the third one can rub it.
Components of the cost of floor screeding
When ordering a screed from a construction company, its final cost will be the sum of the costs of:
- concrete and dry mix;
- transportation and lifting of all materials and equipment;
- additional materials;
- doing work.
Feedback on the semi-dry screed method
Many of those who have done floor leveling work on their own note that the main thing is to choose the right amount of water. The passage of the cement hydration process depends on this. If there was not enough water in the solution, then when moisture gets on the finished surface, the crystals of the material may begin to grow again, and the floor will creak.
Most experts speak of the semi-dry screed methodpositively. However, the maximum service life is not yet known.
Thus, a semi-dry floor screed, the technology of which was discussed in the article, can be produced both by professional workers and independently by apartment owners.
