Underfloor heating is a very functional and increasingly valued alternative to classic radiators. What screed should be used for underfloor heating?
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What screed to choose for underfloor heating?
The decision to install underfloor heating should be made at the design stage of the building. This will allow for the optimal use of the possibilities of popular underfloor heating. Laying the heating system requires a decision on the method of installation, selection of appropriate system elements, as well as the type of screed that will tightly cover the underfloor heating. This is extremely important because the creation of free spaces reduces the efficiency of heating. Then, so-called thermal bridges are created. A screed with a liquid consistency will work best. It is easy to apply and will thoroughly cover the entire surface.
When the material is both durable and flexible, it provides the heating system with maximum protection, protecting the pipes from mechanical damage. When looking for the optimal solution for underfloor heating, it is important to ensure that the material from which the screed is made has the right parameters allowing for heat conduction. This is important because the floor will heat up faster and will maintain the temperature longer. This feature will reduce heating costs. Thermal conductivity is marked with the lambda coefficient, and the higher its value, the higher the degree of heat conduction.
The most commonly used solutions are concrete or anhydrite screeds. The choice of which option to use should be considered at the design stage, because the heating system is planned and materials are selected depending on the material.
How much screed for underfloor heating?
The thickness of the screed layer depends 
is on the selected variant. The layer cannot be too thick or too thin. Most manufacturers indicate that the maximum thickness should not exceed 6.5 cm, and the thicker it is, the lower the thermal conductivity. When determining the optimal thickness, not only the heating efficiency is taken into account, but also the load-bearing capacity and the potential risk of cracking. A special concrete additive can be purchased for concrete screeds, which will allow you to obtain the appropriate quality concrete.
The final thickness of the screed depends largely on the materials used. In the case of screed, the thickness will most often be 6.5 cm, although it should be remembered that the final thickness also depends on the maximum temperature that the floor can reach. Another parameter that should be taken into account is the load-bearing capacity of the floor.
Anhydrous screed for underfloor heating
Currently, the most popular method of making a screed on underfloor heating is an anhydride screed. This is a special solution that has been developed in such a way as to maximize the possibilities of underfloor heating. Anhydride screed, also called self-leveling screed, is available in liquid form, thanks to which it tightly fills the space between the pipes of the heating system. In this version, the floor will heat up faster, which is important in terms of savings in heating. Another great advantage is the ease of application.
In the case of a self-levelling screed, its thickness can be reduced without the risk of it starting to crack. This reduces the risk of potential damage to the installation. Using less material means that this solution will work, for example, in a situation where the screed for underfloor heating is to be made on a higher floor. This allows for reducing the load on the building structure. Anhydrous screed is characterized by excellent thermal conductivity properties.
Concrete screed for underfloor heating
The screed for underfloor heating can also be made of cement. However, concrete has weaker parameters than a self-leveling screed. First of all, it is a material that is definitely harder to apply. You have to be very careful not to create thermal bridges. However, a big advantage of concrete is its durability. Ready-made concrete mixtures are available for sale, although you can also prepare the material yourself - however, you need to be especially careful to mix the components in the right proportions, because only then will the whole thing be durable. In the case of a concrete screed, remember to use reinforcing elements with anti-shrinkage properties, so-called micro-reinforcement fibers.
When using a concrete screed for underfloor heating, remember that its thickness should be at least 6.5 cm, because such a layer ensures optimal heat distribution on the floor while ensuring adequate durability.
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