How To Properly Fill The Solution For Underfloor Heating Screed

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

• Purpose
• What to fill?
• Pre-fill activities
• Installation of expansion joints
• Choosing the optimal thickness
• Fill on beacons
• Semi-dry screed
• Contraindications
• Avoiding screed

Water heated floor is much preferable to radiator heating. But it is worth noting that it costs a lot of effort to install it. Particular attention should be paid to the material for preparing the solution for pouring the water floor over the pipes, as well as the screed itself. It is very important here to fully comply with the laying technology in order to achieve the desired result. When distributing the solution, it is necessary to first determine what thickness of the screed will generally be and what goals it pursues. All pipes and efforts will be in vain if you violate the elementary requirements and recommendations for installation work. In addition, when performing the installation of a warm water floor by workers, it is better for you to show your competence so that they cannot cheat.

Purpose

Screeds of a warm water floor are necessary in order to create a protective barrier for the entire circuit of the system from external influences. In addition, various communications can be placed in it so that they do not spoil the appearance of the room where the work is carried out.

Pouring a water-heated floor can be arranged in several options, each of which will differ in layer thickness. In some cases, a thin screed with minimal parameters will be enough. But then there should be no significant loads on the base. Otherwise, she will not be able to fulfill her mission.

Each type of flooring requires a certain quality of filling and some subtleties of installing a warm water floor. It is worth paying attention to this in advance, when the procurement materials are still posted. You should also know about how to fill the warm water floor, what components to use for this.

What to fill?

They come to the screed of a warm water floor when the system piping is laid. There are two main options to consider here for how to fill. There are methods and in each of them the components from which the solution will be mixed are slightly different:

1. Concrete screed. The solution is based on cement.
2. Semi-dry screed. To prepare the solution, ready-made construction dry mixes are used, to which it is enough to add a certain amount of water.

They all have their positive qualities and disadvantages that can be encountered in the process of preparing the solution. For the final choice, you should weigh the pros and cons. The features of each option will help you make the right choice in favor of filling.

The most popular is ready-made sand concrete M300.

In addition, it is better to add a plasticizer to the concrete solution, which improves the strength of the entire structure after pouring the screed onto a warm water floor. In this case, the latter will not crumble during operation. Its quantity is approximately 0.6-1.0 liters for each m2 ^{of the} poured area. It can be noted here that the thickness of the screed in this case will be reduced by up to 30 mm. A similar power for the same concrete screed without plasticizer is comparable to a thickness of 50 mm.

Some are worried about the question of whether it is possible to fill in a water-heated floor without a reinforcement layer. In this case, it is worth first deciding which room is in front of us. If the area of the room is more than 40 m ², and also has a complex configuration, then as an alternative to the metal mesh, fiber fiber can be used, which is constantly gaining popularity among performers of warm water floors. The addition of fiber makes it possible to distribute the mortar evenly during the pouring process, while maintaining all the qualities necessary to maintain the strength of the screed.

Before distributing the mortar, the areas with the location of the expansion joints should be determined. They are needed to compensate for thermal expansion. The concrete will retain its original appearance for a long time. On the site it is possible to calculate the amount of concrete for the screed using an online calculator.

Pre-fill activities

Before the start of the preparatory measures for the installation of a screed for a warm water floor, other types of work should be carried out, such as plastering the walls in the room.

You should also install windows and doors in the room, lay all possible communications (electrical wiring, sewerage, water supply, etc.). The entire surface for the subsequent installation of a warm water floor system must be not only even, but also very clean, without defects.

There may be cases when the plastering of the walls in the room was carried out after pouring the concrete solution. In this case, the surface is thoroughly cleaned from pieces of solution. For this, BSL can be used. To prevent plaster from getting to the base of the floor, it can be covered with polyethylene film.

An angle of 90 degrees must be maintained between the walls and the base. Otherwise, it will not be possible to achieve a tight fit of the insulation under the warm water floor to the walls and surface.

When one contour is located in the room, a discrepancy in the surface level is allowed, but not more than 5 mm. Otherwise, you can face pipe deformation and the appearance of air locks. If a branded damper tape is used in the work, which has an adhesive layer for mounting on the wall, then putty a part of the wall to a height of about 40-50 cm. This will improve the retention of the tape.

Installation of expansion joints

If not a rough, but a final finish of the subfloor along the contour of the heating system is performed, expansion joints should be made. The same applies to rooms that have large areas of more than 40 m ².

For insurance, seams are made every 20 m ^{2 of} the room area. They do not allow the screed to crack due to constant temperature fluctuations. A rough screed avoids such events, since a layer of insulation is located between the warm floor and it, which makes it possible to avoid this.

Where the seams are arranged, the water floor pipe must pass in a corrugation. Its diameter should be slightly larger than that of the pipe itself, so that it is better and easier to put it on. There are enough diagrams indicating the correct and incorrect location of expansion joints in the room where the screed is poured onto the underfloor heating system through the pipeline.

Choosing the optimal thickness

The thickness of the underfloor heating screed is essential. Indeed, not only its durability will depend on the layer, but also the efficiency of heating the room. A screed that is too thin will quickly crack due to temperature effects and even normal walking. But even a thick layer will not bring any desired result - a warm floor will spend a lot of energy and resources to warm up the entire "pie". Consequently, spending on heating costs will increase noticeably, which can be read by the heating cost calculator.

The optimum thickness for a concrete screed is 50-70 mm. If, instead of a layer of reinforcement, we take and add fiberglass, then it can be reduced in general to 30 mm. The same applies to the use of various plasticizers. They can be supplied with the purchased dry mix.

We must not forget that in addition to this, self-leveling mixtures can be used in work for the device of a screed for a water-heated floor. In this case, the layer can be only 20 mm, and the strength will be sufficient to withstand serious surface loads.

The specific filling option and the choice of the optimal screed layer thickness will depend on the specific situation and customer requirements. It is worth approaching this stage with all responsibility, so that the warm water floor as the main heating system of the house can serve as long as possible.

Fill on beacons

After carrying out test measures for the performance of the water-type floor heating system, you can think about direct pouring. By level, beacons are pre-set. But it is very difficult to call them as such, since they are presented in the form of ordinary mortar slides, on which a metal profile is fixed.

A solution for lighthouses can be prepared from alabaster, concrete. It will not be superfluous to first build the formwork so that they do not spread during the pouring process. The main thing is that nothing should be placed on the water floor pipeline.

After that, you should make an even distribution of the solution over the floor surface with pipes. For this, the rule is perfect, allowing you to pull it in the chosen direction. Pouring should start from the far corner into the room, so as not to walk on the surface of the distributed solution later.

This technology of pouring concrete for warm water floors is identical not only for the rough screed for laying the contour, but also for finishing along the pipes. It should be observed and not sidetracked, even with the slightest doubt. The practice has developed over the years and this is how a really decent result is obtained.

We must not forget about concrete ramming. This allows air bubbles to be expelled from it. If you do without this event, then in the future the thermal conductivity of the poured screed will be significantly reduced. When you are not confident in your abilities, it will be more profitable to seek help from specialists than to redo and dismantle the entire structure of the warm floor.

Semi-dry screed

As soon as the heating circuit has been installed, you can choose a semi-dry screed instead of pouring concrete underfloor heating with your own hands. The pipe fasteners must be reliable, and a damper tape must be arranged around the perimeter of the room.

But with what solution to fill warm floors in this situation? A large number of dry ready-made mixtures are commercially available, in which you only need to add a certain amount of water.

The pouring process is not much different from the concrete screed device. Also, you cannot do without beacons if you want to get a horizontal surface. During the filling process, the pressure in the pipeline must be raised to 0.3 MPa. A mixture is distributed between the installed beacons, which is mixed with water. The thickness of the fill layer above the pipes must always be kept under control. The minimum level should not be lower than 30 mm. This distance is measured from the top of the underfloor heating circuit. The solution should be laid evenly and as tightly as possible, in which there is significantly less water than in a concrete screed. When a space is formed under the rule when distributing the mixture, the required amount is added there and the distribution is performed again.

Grouting of the mortar is required, and should be carried out after about half an hour after the final filling of the mixture. You can perform work with improvised means or use a special trowel. In order not to purchase it for a one-time installation of the screed, it will be easier and more profitable to rent it for the duration of the work. If you miss the half hour that is supposed to be, then it will be much more difficult to grout. Complete setting of the mixture is 6 hours. After this time, it makes no sense to grout the surface, since it can no longer bring any result.

It is impossible to turn on the heating completely until the semi-dry screed is completely dried. In the future, the first working day of the system should not maintain a temperature of more than 25 degrees. The next day, the temperature rises by 5 degrees, and so on, until the warm water floor is fully operational.

This version of the screed device has some advantages over concrete:

• Lower cost than ready-mixed concrete.
• The drying process takes much less time. Also, the setting process is shortened. After 6 hours you can walk on the surface without fear.
• At the end, it is not necessary to additionally level the base, since the surface acquires a horizontal level.
• No cracks form after drying, as well as areas of subsidence. And there are almost no other screed defects.
• The likelihood of water flowing to the lower floors is minimized, since much less water is used in the composition.

• Heat and sound insulation qualities are increased due to the porosity of the entire structure of the screed.

  

Contraindications

There are certain requirements, how you should not pour the screed on the underfloor heating pipeline at all. If an ordinary cement-sand mortar is used, then it will not be able to bring any efficiency.

We must not forget to carry out all the steps of the installation of a warm water floor, and especially the installation of the screed. All necessary steps must be present here - heat and waterproofing, insulation and other elements. Absolutely not to do without the damper tape fasteners. Otherwise, the service life of the warm floor, or rather the screed above it, will not be great.

When installing beacons, all measurements must be calculated several times before the final version. Do everything strictly according to the building level. There won't be enough marks on the walls. The lighthouse itself must be adjusted to them before laying the metal profile.

Avoiding screed

Some people are thinking about how to do without such a process as floor screed. And here there is one very effective solution - a decking system.

The warm water floor is placed in special metal plates, after which the flooring begins immediately. Just keep in mind that you should place a moisture-proof mat in the form of polyethylene or other alternative material between these two components. Everything will depend on financial capabilities and preferences. In any case, everything can be found in the assortment on the construction market, including dry ready-made mixtures for the semi-dry version.

Each of these options, be it a concrete or semi-dry screed, or a "dry" method, have their own positive qualities. What to choose in each specific case is the decision of the contractor. The most important thing is that the result is a really high-quality construction of a warm water floor, made in strict accordance with the technology.

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