Screed laying

The underfloor heating system is gradually becoming an integral part of comfortable modern housing. From the point of view of profitability, durability and high-quality heat distribution, the most attractive is a water-heated floor with a pipe heating system. Despite the fact that laying such a floor in an apartment is associated with certain risks and difficulties, residents apartment buildings do not want to completely find themselves on the opportunity to enjoy the comfort and warmth that gives water system. Let's find out how realistic it is to realize this idea, and how the underfloor heating is laid in the screed.

Possible obstacles

As already mentioned, the arrangement of a water heated floor in an apartment in some cases can be problematic. There are several reasons for this:

• The large length of the underfloor heating pipes can lower the pressure in the entire house system, which affects the quality of heating among neighbors.
• In some regions of the Russian Federation, including Moscow, it is prohibited by law to connect a warm floor to a common water supply and heating system.
• In those regions of Russia where such a ban does not apply, before connecting the underfloor heating system an apartment building requires an examination, which is required to establish that the system will not work broken.
• The high temperature of the water in the heating system (50-75 degrees) is not suitable for the underfloor heating circuit; according to the standards, the surface temperature should not exceed 30 degrees.
• With any leakage in the system, you risk flooding your neighbors.

Solutions

With a great desire, any obstacles can be overcome. Laying water underfloor heating in apartments will become possible if you take the following steps:

1. Installation of an individual heating system - in this case you are guaranteed not to violate the heat circuit of a multi-storey building and you will manage the heat in your own apartment.
2. The inclusion of a circulation pump in the underfloor heating system will also help maintain normal pressure in the system and allow you to pass the necessary expertise.
3. To lower the temperature of the water in the pipes of the underfloor heating, it is necessary to connect through the mixing unit.
4. The guarantee of reliability and protection against leaks will give the use of copper pipes in the underfloor heating system. In addition, leaks are not so terrible to residents of the first floors.

If difficulties do not stop you, try to approach the matter with all responsibility and clearly follow the installation technology to avoid subsequent defects.

Material selection

The choice of material for a warm floor is an extremely important part. The reliability of the entire structure and the service life depend on the right choice.

Choosing pipes

The efficiency and safety of operation of a warm floor is based primarily on high-quality pipes, since filling the screed will repair and replace damaged areas in practice impossible.

• Metal-plastic pipes with a diameter of 16–20 mm are suitable for a warm floor system. They are flexible, conduct heat well, and are practically not subject to thermal expansion. However, you only need to choose high-quality, expensive metal-plastic from trusted manufacturers, an inexpensive pipe due to insufficient protection of the aluminum layer can simply break.

• A good option is to use PE-X cross-linked polyethylene pipes. They are very flexible, but at the same time resistant to stress, serve up to 50 years. Available in large bays, so the circuit is performed without additional connections.
• Copper pipes have excellent thermal conductivity, ductility, serve up to 100 years and have very reliable connections. Unfortunately, they are very expensive and not suitable for everyone.

• The best choice is PEX-AL-PEX pipes, which have all the advantages of metal-plastic and cross-linked polyethylene. The multilayer structure, the oxygen barrier, which prevents corrosion of the aluminum layer, make them very reliable

Important! Pipes for underfloor heating must be designed for pressures exceeding 8 bar.

Screed Material

When buying a mixture for the primary screed, you can choose any composition of a proven brand that matches the brand strength of the base.

To fill the pipes, you can use a standard cement-sand or concrete mixture into which plasticizers are introduced to prevent cracking from temperature changes. You can choose a semi-dry ready-made mixture specifically designed for warm floors - it will not require any additional additives.

The choice of waterproofing

For a waterproofing device that protects against the formation of condensation and protects against leaks, you can choose coating or film type materials.

Coating waterproofing is more reliable, but more expensive. The finished mixture in buckets has a bitumen base, it is well applied with a roller and brush in several layers. Dry - cement waterproofing, requires mixing with water, after being applied with a layer of up to 1 cm.

Film waterproofing materials are roofing material or a dense film. The bitumen material is spread out and heated by a burner or a hairdryer for strong adhesion to the base. The film is spread with an overlap, gluing the joints with tape.

Heat insulating layer

As a heat-insulating layer, polystyrene foam is usually used, the minimum thickness of which is 30 mm. You can choose any foil heat reflector. There is a special substrate for a warm floor with a foil layer, on which there are clips for fastening pipes.

Preparatory Stage

The preparatory stage of laying is as follows:

1. Calculation of the volume of necessary materials, the choice of laying scheme.
2. Rough surface leveling, sometimes with prior removal of the old screed.
3. Waterproofing device after the previous layer has completely dried.
4. Mounting the heat reflector and gluing pipe holders to it. If a reinforcing mesh is used, the pipes can be attached to it; it itself is fixed to the floor with dowels.
5. Gluing the perimeter of the room with a damper tape, for the possibility of expansion of the screed without cracking.

Layout selection

There are two popular styling schemes: the “snail” type and the “snake” type.

• For uniform heating of the floor, the “snail” scheme is better suited, since a cold and warm stream of water alternates in it. Hot water passes through the entire circle of the room, then goes to the second, third, fourth circle with a decrease diameter by 20-30 cm, then in the center changes direction, and returns with an increase in the circle on the left intervals.

• According to a scheme called a “snake”, a pipe with hot water goes along the edge of the room, passes under the windows, steps back 10 cm and runs parallel to the first line in the opposite direction. Another indentation - another row, and so, gradually cooling, the liquid passes through the entire room. For small rooms up to 20 sq.m. the difference in temperature is not very noticeable, unlike large ones.

Laying underfloor heating

After completion of the preparatory phase, laying of the warm floor begins according to the scheme selected and marked on the floor.

When laying pipes, it is necessary to adhere to the following scheme:

• retreat from the walls by 20 cm, from the windows by 15 cm;
• the distance between the pipes from 10 to 15 cm;
• maximum pipe length - not more than 80 meters;
• the end of the pipe goes back to the convector.

Before filling the pipes with a screed, they must be checked by turning on the system. If everything is in order, you can set the beacons on the level, then fill with the mixture and level them, not forgetting to install the floor temperature sensor, which should be between the pipes in the screed.

The inclusion of a warm floor

The first inclusion of a warm floor occurs immediately after its installation, without pouring screed, to check the operation of the system. The second inclusion - only after the screed and topcoat have completely dried. In this case, the water temperature must be increased gradually, starting from room temperature to the required one, increasing by 5 ° C. A good temperature controller will help in this, without it it will be difficult to choose the correct mode of operation of the system.

Finish coat

After the screed has completely dried, you can apply the finish coating - the bulk floor.

When pouring it, it is important to observe the application technology:

• divide the room into zones for pouring with the help of corners and bars;
• primer the surface;
• stick a damper tape around the perimeter;
• use self-tapping screws as beacons;
• use a needle roller to eliminate air;
• the vintage strength of the topcoat should not be greater than the vintage strength of the previous layer, otherwise cracks and bumps may occur after drying.

Under the tile and porcelain tile, the device of the finishing layer of the fill is not required.

If all the recommendations and stages of the technology have been followed, you can enjoy the results of your work for many years.