How To Lay A Semi-dry Screed On A Warm Water Floor

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

• Choice of flooring
• Screed features
• Tools and materials
• Holding the horizon
• Thickness selection
• Foundation preparation
• Installation of a semi-dry screed
• Advice

A semi-dry floor screed has its own characteristics when it is installed on a base in a room. The quality of work will play a huge role, on which not only the strength of the entire structure will depend, but also the durability in operation. If the surface is flat, then even the flooring will wear less. There must be no defects under any circumstances in order to get a truly positive result.

Choice of flooring

When you do the screed of a warm water floor with your own hands, you should glean information about what kind of floor covering you can choose in the future. The main thing is that it has excellent thermal conductivity characteristics. The most ideal option in this case is ceramic tiles or porcelain stoneware. This material is able to serve for a long time, to maintain all performance characteristics.

The heat transfer is good, and, therefore, all the energy from below will show through very well outward. True, such a choice will be convenient for the legs only during the heating season. A semi-dry screed for a warm water floor will be cold in the summer.

Many people make the mistake of laying plastic tiles. At elevated temperatures, heating, it will crack and become unusable over time. So it is better to bypass it when choosing.

Another best option is laminate flooring. Moreover, you can buy in the store a special material designed for underfloor heating. Among manufacturers, Tarkett, Parador and others are popular. Semi-dry cement screed can also withstand linoleum. There is one peculiarity here, which is that the raw materials must be selected natural. Otherwise, various chemicals and carcinogens will be released into the room when heated. This applies to non-woven linoleum.

For a warm water floor, natural materials are also used as flooring - parquet, cork. The main thing is that the products are certified, and they can fit on the warm floor. It is very important to read the manufacturer's recommendations.

Screed features

A semi-dry cement-sand floor screed in particular basically includes all its positive qualities. These include:

• For the price, it will be much less than a concrete solution.
• After finishing work we get a very flat surface as a "rough" floor. Therefore, no further alignment steps are required. This saves not only energy, but also financial resources.
• As a result, factors such as cracks, chips, shrinkage are reduced to zero. Only if the technology of the semi-dry floor screed is violated, they can appear on the surface.
• Due to the low amount of water used to dilute the dry mix, the possibility of moisture ingress into the lower floors is excluded.
• Faster drying and hardening of the ready-made mortar after installation.

• High heat and sound insulation qualities.

  

But this is only part of what is generally available in a semi-dry screed. As mentioned earlier, everything should be done in stages, monitor the quality and proportions of the prepared solution. Then there will be no errors in the work.

Tools and materials

To get the work started and go without distractions, you should think about preparing in advance not only about the tools, but also the corresponding materials. As for the latter, then the proportions of a semi-dry floor screed must be fully observed. It is on the proportions that the basic quality of the finished base for the flooring will depend.

Among the tools, a building or water level is distinguished. The laser level is no less popular. But its cost repels some. There is not always a desire to spend large amounts of money on a single task. Also useful is a tape measure, various containers for mixing the solution and stirring with a drill with an appropriate attachment. In addition, a spatula and trowels are useful in the work.

Depending on the process of performing the installation of a semi-dry screed, any additional tool will also depend. If the beacons are exposed and attached to the base using self-tapping screws with wire, then you do not need a screwdriver, as well as wire cutters.

It has a semi-dry screed of proportions, which are best looked at the instructions for the purchased material. The cement slurry should be homogeneous and free of extra lumps. To avoid possible difficulties with stirring, there are enough dry mixtures in the chain of stores, in which you just have to add a certain amount of water.

True, here the proportions of liquid in relation to the mixture must be appropriate.

When self-manufacturing a solution for a semi-dry screed, the store buys:

• 50 kg of cement. Its brand must be at least M-400.
• For this amount of cement, 200 kg of sand will be required, with a fraction of no more than 0.8 mm.
• 30-40 liters of water. In no case should you rush about water. It is better to fill in a little less than the required amount, and only then add as much as needed. The main thing is that the solution does not turn out to be liquid.
• Plasticizer. It can be found ready-made in stores. Its amount will be insignificant, about 200 grams. Some experts advise adding regular liquid soap instead of an expensive additive. The elasticity of the screed will remain at a decent level.
• The thermal insulation layer is made of expanded polystyrene boards.
• A special metal profile, called "beacon", is taken as beacons. By the way, lighthouses can be performed in other options, of which there are a huge number.

Holding the horizon

To improve accuracy, special tools are used, for example, a building level.

You should find not only the lowest point on the floor, but also the highest. The latter will serve as a starting point for determining the height of the screed.

In modern construction, a laser level has gained popularity. With its help, all points in the room are drawn and landmarks are set for subsequent beacons, along which a semi-dry screed is poured under a warm water floor.

Thickness selection

If pouring is performed on semi-dry floors, the exact thickness of its layer should be determined. It will depend on the evenness of the floor surface, on the existing irregularities, as well as on the presence or absence of communication elements in the apartment. We will have a warm floor with all the components. This suggests that the thickness of a semi-dry screed for a water-heated floor should not exceed 100 mm. The quality of heating the floor covering will also depend on the layer. The smaller the thickness of the semi-dry screed, the faster the floor will become warm after turning on the heating systems in the room.

Thickness also affects cooling. Here everything will be the other way around. Long-term heating of the surface leads to its long-term cooling. If we talk about savings, then this will be the maximum. True, it is not known what bills will come to pay for heating.

All subtleties and the choice of thickness will depend on the customer. He chooses a specific option, which will also depend on the chosen flooring. It is worth noting that if the pipes of the warm floor are laid out on an uneven base, then the thickness of the screed over the area of the room will differ. This will lead to the fact that the heating of the floor will be different in different areas. In some cases, energy overruns will occur.

When thinking about which screed is better for a warm water floor, it is best to make a choice in favor of doing it yourself or seeking help from specialists. All the pros and cons that will have to be faced must be weighed. A poorly executed semi-dry screed will lead to big problems during operation.

Foundation preparation

This stage in the installation of a semi-dry screed on a warm water floor is no different from the standard version. Remove the weight of existing debris and items from previous work. The waterproofing layer had to be made before laying the warm floor, but the damper tape around the perimeter of the walls and any decorative elements is fixed without fail. The main thing is that the underfloor heating itself passes all checks, including work under pressure. If it works fine, you can proceed to the next step.

Installation of a semi-dry screed

Before preparing the solution, you should know its components. Some are trying to save money and expose the steel mesh as a reinforcing element. But modern technologies have proven that it is better not to do this, but to use fibers in the work, which are added during the preparation of the solution. Alternatively, a semi-dry fiberglass screed is used.

When using ready-made building mixtures for semi-dry screeds, care should be taken to ensure that the proportions of adding water and other additives are observed. Otherwise, no experiments are worth doing. The consistency is checked very simply: a piece is taken and squeezed in the hand.

A lot of liquid will be in the event that it seeps between the fingers. The ideal case is that the lump forms a single whole after being compressed. The composition of a semi-dry floor screed should be such that is necessary for work.

The whole room is conditionally divided into so-called zones. The division will be responsible for the beacons for screed warm water floor. A solution is poured between them, which is leveled by the rule. After laying the mortar, it is recommended to tamp the base. It is worth noting that there is a certain time, within which it is necessary to meet. Tamping, sanding, grouting should be performed no later than six hours after the ready-made dry mixture is laid out on the ceiling and underfloor heating. Only in this case, a semi-dry screed under a water floor will eventually turn out to be even and smooth, without negative manifestations.

After finishing the work, attention should be paid to the care of the semi-dry screed. If necessary, it is moistened with a spray bottle in the required amount. Immediately after laying and grouting, the screed is covered with a polyethylene film so that moisture is distributed evenly over the entire area. This can be avoided when there are no drafts or temperature changes in the room.

Advice

It is possible to highlight some of the recommendations of experts, with whom one should agree when performing a semi-dry screed under a warm water floor:

1. The optimum thickness of the mortar layer should be in the range of 50-70 mm. In this case, it is better to use modern means, which include fiber, as a material for reinforcement.

2. When laying boards from expanded polystyrene, their density should be more than 35 kg per m ³. Otherwise, they will not be able to withstand all the loads, collapse over time.

   

3. Before checking the performance of the underfloor heating, it will be better to lay a layer of thermal insulation, as well as a welt tape, which can subsequently compensate for the expansion of a semi-dry screed due to changes in temperature indicators. If the warm floor also works under pressure, you can start pouring the prepared solution, adhering to the required proportions.
4. Turning on the underfloor heating system is possible only after the solution has completely dried. The more time passes, the better the result will be. The cement gains strength characteristics only after at least a month after the end of work.
5. The temperature set for the warm floor must be performed consistently, without jumps. Otherwise, it can lead to cracks at the base of the "rough" floor.

If the technology of installing the floor for a warm version is followed, then the result will be a really high-quality construction. Regardless of the area of the room where the heated floor is arranged, payment will be made only for central heating in an apartment or house.

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