Only inexperienced builders will tell you exactly what should be the minimum thickness of the screed, professionals in the construction business will tell you that it all depends on many factors. Laying can be done on the insulation layer, in which case it should not be thicker than 4 centimeters. If it is laid on the floor slabs, then this value is also 40 millimeters. In such cases, the screed in the apartment should be reinforced with a metal mesh, which contains polypropylene fibers. Such a value is determined by SNIP, so it is better not to violate the state standards. An important factor in determining the value of the height is the material from which it is made, as well as under what exactly the coating. When laying in the apartment, this figure can be higher, but to significantly exceed this value on the balcony is dangerous, then its base simply can not withstand the load.
Dependence on the unevenness of the floor
This factor is also important when laying, because for this you need to determine exactly how uneven the floor is. With the naked eye it is not possible to notice it. It is necessary to take an even bar (it is not difficult to make it yourself) a meter – a meter and a half long, and just gradually pull it across the entire area of measurement. When identifying dents or holes between the bar and the floor a simple conclusion is made – it is necessary to make a screed. In an apartment, it is generally three to five centimeters high. Many people consider a great height a good factor, but experienced builders disagree with this. Laying is not intended to raise the floor, but simply to level it. The floor may be relatively flat, then tighten the high ball seems to be no need, but it is not. At values of thickness less than the minimum, cracks may appear. Also do not just fill the floor with mortar, in which case it will not be possible to level the surface, and it will take longer to dry than usual.
Sand-cement based screeds and others
Sand-cement mixture is quite popular among builders, thanks to her compensate the basis with an unevenness exceeding 20 millimeters. Such solutions contain a variety of plasticizers, so professionals are convinced that the thickness value on the sand-cement base should be at least 3 centimeters. Often there is such an effect as a rapid evaporation of water from the mortar, because of this, in general, it is advised to make the laying 5-centimeter thickness. Sometimes it happens that due to shoddy laying plates level difference is more than 6 centimeters. Then you need to do screed of sand-concrete, which is based on coarse sand. In this case, the thickness of the screed is 10-15 cm. In the worst versions with a huge slope screed thickness in general varies in the region of 150-170 mm, its bottom layer is laid keramsit-concrete. Allow this is not desirable, because then the cost of materials you will be unpleasantly surprised.
Laying the floors with insulation
If you have planned to heat your floor with a water system, keep in mind that then the floor surface will perform the function of heat distribution. To achieve its quality performance it is necessary to use a self-leveling mixture. It hardens faster, but sand-cement mixture is also quite suitable. The thickness of the screed over the surface of the water pipe should be 30 millimeters. Of course, the thickness of even more than 15 centimeters is allowed, but then you need to calculate the thermal regime of the area, take into account all the corrections. The optimal value in this case – from seven to ten centimeters. If the floor is heated electrically – three to five centimeters. It is also worth considering the time for which the surface will harden and dry out. Therefore, not only the thickness of the screed will be the main factor in choosing the right material for laying, but also the waiting period before applying the final coatings.