What Is The Minimum Thickness For A Semi-dry Floor Screed

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54

general information
Factors affecting thickness
Materials used
Surface reinforcement
Thickness selection
The need to determine the minimum
Maximum performance

For leveling the floor in any room, more and more preference is given to a semi-dry screed. This is due to the main features of quick installation and at the same time minimal water use. It resembles a slurry, but it brings less red tape. At the same time, it is important to observe the technology of laying the mortar, choosing the appropriate thickness for work.

general information

In the process of performing a semi-dry screed, dry ready-made mixtures are more often used, which make the work easier and more convenient. As a reinforcing agent, a mesh made of steel material, fiberglass is selected. To reduce the load on the floor and improve the strength characteristics, they acquire fiberglass.

The concrete mix dries much faster due to the small amount of water. The average period is 5-6 days. These indicators are about 5 times faster than pouring a "wet" screed.

The semi

- dry version of the subfloor can be performed both on concrete floor slabs and on a wooden base. The room where the installation is carried out, as well as the flooring used in the subsequent flooring, will not play a role. The main thing is that the technology is followed at all stages.

It should be noted that the thickness of the semi-dry screed is very carefully determined. Certain factors influence the height of the finished cake.

Factors affecting thickness

There are certain conditions that affect the thickness of the floor screed. This is not only the technology itself, but also:

Characteristics of the operation of the premises where the sub-floor is being installed. The greatest loads on the floor are in corridors, kitchens and halls. So you should not think about the minimum indicators in such rooms, but do a little more than what is required.

Semi-dry screed thickness
Floor covering to be laid after the prepared substrate has dried.
The material into which the semi-dry screed is poured, as well as the very condition of this coating. The more irregularities there are, the more you have to arrange a layer of semi-dry screed. If you pay attention to building codes and regulations, then there is a minimum thickness of 20 mm. With such a thin layer, it is very important to think about reinforcement so that over time it does not crack.
Materials for semi-dry floor screed used in the process.

Each of these factors adds or decreases the overall thickness and creates conditions for the use of additional moments in the installation. But it does not mean that a very thin or very thick base will be more effective than each other. At the same time, there are subtleties and nuances. Each specific case should be approached individually.

Materials used

When there is no desire to independently knead the solution for a semi-dry screed, you should think about purchasing ready-made options. Dry building mixtures in their composition already contain all the necessary components to obtain the desired result. They include:

Sand.

semi-dry screed thickness
Cement.
Fiber fibers.
Plasticizer.

It is worth noting that a semi-dry screed with fiberglass has significantly better qualities, so it is easy to use when installing a steel mesh. It gives the mortar plasticity, which allows it to be evenly leveled over the surface of the prepared base. In addition, the result is a smooth subfloor with high strength characteristics.

The brand of semi-dry screed will directly depend on the brand of cement used in the composition. The higher this figure, the better the strength will be in the end. In this case, a semi-dry screed will turn out to be really strong and reliable. From an increase in the brand, the cost of a ready-made mixture for preparing a solution will also increase slightly.

Sand is selected for construction or river.

Its fraction should not exceed five millimeters. You should carefully monitor the humidity, since the amount of water added to the solution will depend on it.

Plasticizing agents are included in the semi-dry floor screed and the composition of the mixture is no different from the outside. But the quality of the finished solution is high. When it is prepared on its own, the plasticizer can be bought separately, adding a certain amount depending on the volume. The plasticizer can be found at any hardware store.

It is also an advantage that a semi-dry floor screed with a ready-made mixture is performed much faster. Besides, you don't have to think about the proportions, which are very important in this case.

Surface reinforcement

When a semi-dry floor screed is performed, the thickness will depend, among other things, on the reinforcing layer. In this case, everyone is familiar with a steel mesh, with a mesh size of 10 * 10 mm. But this is beginning to go aside due to the increase in the weight of the finished structure for the floor.

A semi-dry screed with fiber comes to replace it.

This component is easily "embedded" into all the components of the mixture and a single whole is obtained. As a result, the flooring becomes more durable, stronger and harder, capable of withstanding any loads and flooring flooring without exception.

The steel mesh also increases the overall thickness of the subfloor. The installation process will look somewhat stretched due to the creation of additional stages of work: filling the mixture, laying the reinforcing element, finishing work. With fiberglass, everything is much easier and more convenient.

Thickness selection

First, you should inspect the very base of the subfloor. We will proceed from it when determining the thickness of a semi-dry screed. It will be enough to carefully examine externally. It is not superfluous to hold a rail of metal about a meter long. It will indicate the presence of uneven parts, as well as significant protrusions. Such defects appear not only in old buildings, but also in newly built houses. The accuracy of the work will allow you to complete the laser level.

A cement semi-dry floor screed is based on the preparation of the base. The smoother the surface, the less amount of solution will have to be spent during operation.

The need to determine the minimum

The minimum indicators of the thickness of a semi-dry screed should be determined when there are installed communications or a floor heating system. By making a very large sub-floor layer, the distance from the floor to the ceiling is reduced. This is especially true in low rooms.

Above the level of the warm floor, the minimum thickness should be 35 mm. This level is set immediately after the end of all its elements. A thick floor increases the cost of heating the room, since the screed itself is soaked with heat for a long time, not to mention another obstacle - the floor covering.

The thicker floor puts pressure on the floor.

It appears most often on balconies. And the drying time will instantly increase. The material tends to expand over time. This can subsequently cause pressure on the walls if the layer is too massive.

If the mixture does not include any additional reinforcing substances, then its minimum thickness should be 40-50 mm. You can learn a lot about thickness from the packaging for the mix. Recommended parameters are always displayed there. Manufacturers always worry about the bottom line.

According to SNiP, when laying a semi-dry screed immediately on the floor slab, it must be at least 20 mm thick. In the presence of an additional layer of waterproofing - 40 mm.

Maximum performance

There are no maximum screed limits. Everything will depend on the need to hide communications or any surface irregularities. But you should be careful not to put a heavy load on the floor.

Experts recommend not to proceed from the minimum layers of a semi-dry screed, but to take it slightly larger. A small value will lead to cracks and chips on the surface, which will lead to repeated work.

Since almost every base for a subfloor has irregularities of several centimeters, the screed, in general, will be about 50-60 mm. At each level above the floor, it should be at least 30-35 mm. Some sites will be larger, some at minimal limits. This is also necessary in order for the water to evaporate evenly until it dries.

Plates are not always laid at a decent level. It even happens that the drops are more than 60 mm. In this case, it is best to use sand concrete from a coarse fraction of sand for mortar. In this case, the thickness of a semi-dry screed can be up to 15 cm. If you have to make it even more, then expanded clay will come to the rescue, which can reduce costs.