Maximum And Minimum Parameters For Floor Screed Thickness

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

• Requirements
• Screed selection
• Definition of irregularities
• Minimum thickness
• Maximum performance

The basis for the flooring is the floor screed. To create it, you should make every effort to get a decent result. The surface must be flat and flawless to meet all requirements. For work, you will have to prepare not only materials, tools, but also determine what thickness the concrete floor should be.

Requirements

The choice of the thickness of the concrete floor has an effect on the manifested functions of the screed, therefore it is important to determine the height and material for pouring. This layer is necessary to create not only dynamic, but also static strength, to give the structure a flat surface. The base should be such that it is possible to lay tiles, linoleum flooring or laminate flooring without any problems. If the thickness of the concrete floor is chosen correctly, then the load will be distributed evenly over the entire area. This, in turn, will extend the life of such a foundation.

The selected layer may differ depending on whether you want to create a slope on the surface. This is very important for rooms such as dressing rooms, bathrooms, shower rooms. In any case, the thickness should be such that it can easily withstand the loads not only from walking, but also being placed on the surface of the furniture. Moreover, over the entire base, it should be equally dense. There should be no chips, any defects in the form of cracks, voids inside.

The maximum slope for a flat surface along the floor screed is allowed within 0.2%. Everything will depend on the room itself where the screed is mounted, as well as individual structural elements. The same applies to underfloor heating. Too small layer sizes will quickly warm up, but cool very quickly, which will lead to excessive boiler operation. The thickness will be influenced by the soil, floor slab or other base.

We must not forget that under certain circumstances an additional reinforcing layer should be arranged. Most often it is a steel mesh with a certain element diameter. It will slightly increase the limiting layer of the screed. But there are also modern ways to perform reinforcement - the use of fiber in the work. It has even better qualities, giving the mortar plasticity, strength and the ability to resist fracture, shrinkage and cracking.

The worse the base is flat, the thicker the screed will be. After all, it is necessary to obtain a flat surface with minimal indicators of the poured solution. In some areas, you will have to increase the thickness, and somewhere to make it smaller.

Screed selection

Depending on the thickness, the floor screed has the following layers.

1. Rough screed with minimum thickness. Everyone is probably wondering what kind of layer should be in this case. Most often, dry rough non-leveling mixtures with a height of up to 20 mm are used. No reinforcing elements are required for this type of screed.
2. Subfloor height up to 70 mm. Reinforcing elements are already provided here in the form of reinforcement elements or steel mesh. Most often it is performed from cement mortars or using the semi-dry screed technology.
3. Maximum thickness up to 150 mm. It is a monolith with reinforcement inside. Its main area of application is the foundation of the future house together with the floor. That is, both functions are merged into one.

If concrete pouring is chosen together with crushed stone, then you can forget about the minimum indicators. The crushed stone fraction has a special effect. When it is necessary to arrange a thin floor screed, then self-leveling mixtures are included in the work. The same applies to other types of mixtures, which are mainly used as a device for the finishing layer of floor screed. The layer is not only thin, but also even, capable of being used as a decorative element.

We should dwell a little on warm floors. After all, everyone wants to know how many centimeters should be a screed for a warm floor. The solution should cover all elements of the system, possible cables and wiring. If the average pipe thickness is 25 mm, then the total fill layer is usually taken in the range of 50-70 mm. Large thicknesses are not taken, since the warm floor will not function according to its performance. Experts say that a 40 mm solution is sufficient above the heating elements. Otherwise, the heat supply system inside the room and floor heating will be disrupted. The bulk of the energy will be spent on heating the concrete itself.

It is worth noting that the large thickness of the screed on a warm floor will lead to the fact that it will begin to expand strongly when heated. Consequently, the walls in the room will suffer. This will make it possible to exclude pasting the walls before filling with a damper tape capable of compensating for these vibrations.

Definition of irregularities

No one will independently determine by eye what irregularities there are on the base for pouring the floor screed. For this, the easiest option is to use a bar or a special level. Let's start with the bar.

The size of the bar should be about a meter and a half. Walking them along the surface of the floor, you can find the existing holes between the floor itself and the level. If there are a large number of them or there are significant differences, then you will have to arrange the maximum thickness of the screed under the warm floor. In a new apartment, when replacing the old base with a new one, the screed is taken within 35-50 mm. It cannot be said that the high thickness of the screed will influence the quality of the base. This opinion is erroneous and requires clarification. After all, the screed is only necessary to level the base, and not to raise it to a height.

Thickness of the screed will take a long time to dry and uneven drying may occur during this time. Consequently, the quality of the solution will be lost. When installing the base coat, wait until the base coat is completely dry.

Minimum thickness

Building codes say that the minimum thickness is 20 mm. But in many respects everything will depend on the material used in the work, 5 mm is enough for such a material as a self-leveling floor. And with sand concrete screed, they are usually poured to a minimum height of 20 mm.

These requirements are based on the fact that the base of the floor must be even and level. To save a budget with these indicators, a combination of different types of screeds is possible. A thin self-leveling screed can cope with small irregularities, and concrete with a greater thickness. In turn, the height of the screed will decrease over the entire surface.

There are conditions that must be met when installing a screed with a minimum layer.

A very important point is an even base, the absence of reinforcing elements. If we are talking about technical premises or industrial premises, then forget about the thin screed. The same goes for kitchens, hallways and bathrooms. It is best in such cases to arrange a thick screed.

There are certain requirements and the sequence of work on pouring a screed with a thin layer:

• Crushed stone and sand are poured, which are carefully rammed with a special tool. In this case, everything should be evenly distributed over the entire plane in the room.
• A waterproofing layer is being mounted, for which it will be enough to use a polyethylene film.
• The reinforcement mesh is fixed on the surface, after which beacons are placed for better pouring of the prepared solution. It should be noted that the reinforcing elements should not lie on the base, but “float” inside the future screed. To do this, they rise somewhat above the surface.
• The solution is poured from concrete.

Since the screed layer is generally insignificant and additionally has a layer of reinforcement, then fine crushed stone should be selected from the materials. In this case, the strength will not be lost, and the height from floor to ceiling inside the room will also remain. Plasticizers, when added to the solution, will give it better quality and strength.

Some features of the minimum thickness indicators are provided for water-heated floors according to building codes and regulations. Usually the screed should be 40-45 mm high from the pipe location. But even this distance can be reduced. For this it is best to use a wire mesh with a diameter of 0.3 cm as a reinforcement. The mesh cells should be 10 * 10 cm in size. Then the level of the screed is reduced by about 10-15 mm.

The laid tiles are included in the overall optimal thickness for uniform and high-quality heat distribution over the base of the floor and inside the room. A total layer of 65 mm will be enough. Much will depend on the diameter of the pipe used. Experts recommend a screed thickness of 60 mm when using the MV12 pipe, and 65 mm when using the MV17 pipe.

Before starting work, it is necessary to clarify all the indicators that the floor slab can withstand. After all, a screed arranged in this way over a warm floor can create a load of up to 150 kg per square meter.

Maximum performance

Also, there are no indicators for obtaining the maximum floor screed in the apartment. But more than 150-170 mm, it makes no sense to fill the solution.

This takes a lot of time, as well as effort. It makes sense only if huge loads on the base are constantly created in the room. It could even be a garage. This is influenced by the weight of the vehicle along with the existing equipment. Such a screed will be completely justified here.

The same applies when the screed is part of the supporting structure. This applies to the device of the floor and the foundation in one whole. Even problematic soil will require pouring the solution to a considerable height.

A thick screed is more often used to compensate for significant differences in height indoors. But this is far from the only way to hide irregularities.

Before starting work, it is better to immediately decide what will be used, only a screed, or additionally use crushed stone or expanded clay. These materials are able to easily hide all the differences, reducing costs in financial terms. The high cost is never justified, so you should immediately think about using backfill to reduce the height of the screed.

Performing a screed in an apartment with a height difference of 2 cm requires adding this indicator to the screed. In one of the areas where the height will be higher, a smaller layer of screed should be arranged, and on the other a larger one. To get the optimal solution, everything should be calculated in advance.

To obtain a high-quality result when pouring a floor screed, even on a warm floor system, calculations should be made and the best indicators should be determined. After all, the final result and the strength of the entire structure of the future floor will depend on this. At the same time, it is very important to listen to the recommendations of specialists who have significant experience in carrying out similar work.

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