How To Properly Install A Water Floor In A Concrete Screed

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

• Pros of a warm floor
• Device methods
• Design and thickness selection
• Required purchases
• Foundation preparation
• Laying the pipeline
• Test activities
• Filling the screed
• Expansion joints

Warm water floors are rapidly replacing more classic space heating options from the market. This is due to the positive qualities that are manifested in the process of the system operation. All of them can be arranged in different ways, depending on the chosen technology. "Classics of the genre" is the installation of a water-heated floor, followed by pouring concrete.

Pros of a warm floor

The technology of laying a warm water floor has a whole set of advantages, which include:

• Comfortable conditions. The heat in the room is distributed evenly over the entire area. Almost no heat loss occurs, which saves on heating costs. The well-known expression "keep your head in the cold and your feet warm" finds its practical embodiment.
• Profitability. The entire space in the room becomes heated, except for the area under the very ceiling. In this case, the surface of the floor does not absorb heat, but rather releases it. If the installation is carried out in a standard room, then the costs are reduced by about 15-20%, and if these are rooms with high ceilings of more than three meters - up to 50-60%.

• High level of adaptability. A floor heating system can be arranged from the radiator heating system. In addition to a separate room taken, everything can be organized throughout the house (for apartment buildings, such options for underfloor heating are not provided, with the exception of new buildings, where this is the basis).

  

• When using conventional radiator heating, we always face convective movement of air masses. This is all due to the presence of suspended dust. A warm water floor does not create such an effect, heating occurs evenly and dust does not move with air masses. This is of great importance in children's rooms, especially when adolescents suffer from various diseases, tendencies to allergies.
• Long period of operation. Much in this case will depend on the material used for the work.
• Ease of installation. Many will say that not everything here is so easy to accomplish. The most important thing is to create a project and display the entire work plan along with the piping diagram on paper. In the future, it remains only to transfer all this to the base of the floor in the room.

Device methods

A screed of a warm water-heated floor is a layer of concrete, which can be arranged in two main ways:

• Use in the work of special building dry mixes in ready-made form.

  

  They can be found in a huge assortment on the construction market. In addition, various additives are attached to them, giving the best qualities of the future solution.

• Self-mixing of a cement-sand screed using cement grade M150 and higher with the addition of PVA glue for plasticity and reliability of the entire structure.

Underfloor heating technology allows you to make a choice in favor of one or another method. The main thing is to adhere to the established rules and recommendations from the manufacturer. If everything is clear with ready-made mixtures - it is enough to add a certain amount of water and fill in them, then self-preparation requires careful and precise observance of proportions.

Not everyone knows how to properly prepare a solution for pouring a concrete screed. The proportions will depend not only on the brand of cement, but also on the use of alternative options instead of sand. For glue, 1 kg will be enough for the whole bag of cement. The main thing is to add the right amount of water so that the consistency of the solution is appropriate.

Design and thickness selection

Most often, laying a water-heated floor under a screed is performed on an old base, on which a layer of insulation is spread. The main thing is to prepare the base for installation. After all, it should be perfectly flat and without errors. Only slight differences in room height are allowed. A layer of heat insulator in the form of foam flon or cork with foil is a must, regardless of whether a water or electric floor heating is installed in the room.

The next component of the entire structure of a warm water floor is the laying of a pipeline. It can be mounted directly on the prepared base, on mats, attached to the reinforcement layer, or it can be placed in special mounting mats with grooves. In the latter case, the installation process takes much less time. The final solution is pouring a concrete screed. The resulting cake will be able to fully warm up the room from the very base, evenly distributing the temperature.

It should be understood that the entire structure must have optimal height parameters. Each layer of the "cake" has its own height, which will be necessary for the quality operation of the water-type floor heating system.

When it comes to a concrete screed, then its optimal height is 40-60 mm. Everything will depend on the type of mixture used, the purpose of the room, as well as the presence of a reinforcement layer or its absence. Self-leveling mixtures have great elasticity, which, moreover, make it possible to arrange thin screeds above the warm floor within a range of up to 20 mm without a layer of reinforcement. In this case, a universal plasticizer or other types of additives are added to the solution. The technology of laying a warm floor of a water type provides for a competent distribution of the height of each layer relative to each other. If everything is done efficiently and with optimal parameters, then the efficiency of the system will be the highest.

Required purchases

In order for the water floor heating to be laid under the screed, the necessary materials should be purchased. The most important thing is the components of the system, which includes pipes, a heating boiler, a manifold group, etc. A layer of thermal insulation will need to be laid under it. Insulation can be used in different ways, but the final layer thickness should be within 80-100 mm.

Only in this case, even a basement without heating will not allow heat to be taken to its side. It will all be directed to the base of the floor in the room.

For the screed, you will need to purchase materials in the form of sand and cement for the preparation of a solution, or ready-made mixtures that greatly simplify the entire pouring process. The cost of additives to the solution is not high, but they significantly increase the reliability and strength of the entire structure.

In addition to this, you might consider hiring a construction team to carry out the work. But in this case, funds must be available to pay for their services. The most important thing is that the result is a high-quality and efficient design of the warm water floor system.

Foundation preparation

The technology of laying a warm floor requires careful preparation of the surface for installation. Initially, a capital screed is arranged to smooth out all the unevenness of the base. This is especially true for cases with a large height difference.

If this is not done, air locks will form, negatively affecting the warm water floor system. After that, additional layers are installed to improve the performance of the system - heat, hydro and vapor barrier. They can be used as polyethylene films, waterproofing mastics, foamed polyethylene insulation, etc.

All components must be located correctly relative to each other. In this case, the technology of laying a water-heated floor under the screed will not be violated, therefore, it will be possible to obtain all the positive properties and characteristics during operation. Even the pouring process will not create difficulties due to the poor foundation, the quality of its preparation.

Laying the pipeline

If you strictly follow the technology of laying a water-heated floor under the screed, then before laying the pipeline, you should make competent measurements and draw up a plan. The latter displays the location of the pipes with the selected pitch and laying pattern. There are also various computer programs that make all the manipulations much easier and better. For this, there is a calculation of the warm floor.

The resulting diagram, to a scale relative to the area of the room, is transferred to the thermal insulation layer. When the underfloor heating mats do not have special grooves for fastening pipes, then a diagram is pre-drawn. You can use a regular marker for this. Additionally, this method will allow you to identify possible errors that were not detected during the design of the circuit.

To ensure that the pipes are securely fastened, you can choose one of the possible methods:

1. Using a reinforcement mesh to which the contour is attached.

2. Polystyrene boards for warm water floors. They have special "bosses", staggered. Pipes are fixed between them.

   

When laying out pipes, the most important thing is to calculate everything, and only then implement it. Before the pipes are laid, it is necessary to connect to the supply manifold, place the pipes directly on the surface of the heat insulator, after which the remnants are connected to the return manifold with cutting off excess sections.

It should be remembered about the choice of the step of laying the pipeline. You cannot take a small step if the cross section is large and vice versa - large for pipes with a small diameter. Overheating of a separate area will occur or heat pits will appear. When a load is created in the room of 48-50 W / m ², the optimal step is 300 mm. When the load rises to 80 W / m ², the step is halved to 150 mm.

In this case, the maximum length of the circuit should not be more than 90 m. Otherwise, you may encounter serious heat losses, as well as a decrease in pressure in the system. If a longer length is required, an additional contour must be created even in one room.

Test activities

To get a high-quality laying of a warm water floor in a screed, the systems should be tested after laying the pipeline and connecting it to the manifold. The tightness of the joints and individual pipe sections located in the future screed is checked.

The system is filled with water or a special coolant such as antifreeze. If there are several circuits in the room, then they must be filled in one by one. One circuit is opened, filled with water, air is removed, after which it is closed, and similar actions are carried out with the second circuit. When all the circuits are filled, they are closed, and the system is supplied with a pressure of up to 4-5 bar. In this case, it is increased from the standard 1.5 times. System operation should continue for two hours, after which it is turned off and left for another two hours. These steps are usually repeated 3-4 times to make sure everything is working properly.

After that, the working pressure of 2-3 bar turns on and does not turn off during the day. In the presence of water leaks, the pressure in the system will decrease, antifreeze - a specific smell. In the latter case, one must be careful, since the coolant contains ethylene glycol, which can lead to poisoning with its vapors.

All these checks on the technology of laying a warm floor in a screed must be carried out without fail and before pouring the solution. If you go through the stage and begin to distribute the solution, create a solid structure, then in the latter it will be much more difficult to identify errors and areas with breakdowns.

Filling the screed

Laying a warm water floor in a screed begins after all the previous stages have been carried out in a clear sequence. Initially, the solution is prepared. Instead of a layer of reinforcement, an additive such as fiber is used, which has even better qualities and properties. A damper tape must be laid along the perimeter, which helps to preserve the screed during thermal expansion.

According to underfloor heating technology, the thickness of the screed over the upper part of the pipeline should be 40-50 mm. The solution is poured onto the base and evenly distributed over the entire surface. All work begins from the far corner from the entrance to the room, and pulls towards the entrance. In this case, it will not be superfluous to use beacons for high-quality filling.

A thin screed will warm up much faster, but this can lead to its cracking, as well as the appearance of a "thermal zebra" effect, when the laid pipeline can be felt on the surface.

To increase the efficiency of the underfloor heating system, the surface should be vibrated to get rid of air bubbles. In this case, the concrete itself will adhere more tightly to the pipes.

You can proceed to the flooring only after the concrete screed is completely dry.

An additional calculation of the thermal regime is made if there is a screed over 150 mm. But even at once it will be possible to face certain difficulties when heating the subfloor.

Expansion joints

To prevent the solution from collapsing after pouring and during operation, the technology of laying the warm floor under the screed must be observed. After casting, expansion joints must be performed under the following conditions:

1. Large area of the premises (over 25-30 m ²).
2. The configuration of the room is very flexible.
3. One of the walls is over 8 meters long. The difference here between the length and width is more than 2 times.

4. Along structural expansion joints.

   

The technology of laying a water floor provides for the division of the entire room, with its large parameters, into separate sections, where seams are arranged to preserve the integrity of the screed over the warm water floor. It is best for this to select simple elements in the form of a square or rectangle.

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