Laying underfloor heating pipes: installation + how to choose a step and make a less expensive circuit

Evgenia Kravchenko
Checked by a specialist: Evgenia Kravchenko
Author: Alena Slepakova
Last update: April 2019

The performance of water floor heating depends on the scheme and the step of laying the pipes. Therefore, it’s not enough just to buy accessories for the system device, you also need to calculate the heat transfer, choose the best option for the location of rings or turns of the pipeline.

Agree, no one is attracted by the prospect of investing money and not getting the planned effect. You will learn all about the design of floor heating and the schemes according to which the underfloor heating pipes are laid, from the article we presented.

Acquaintance with the information checked and systematized by us will help to arrange a perfectly working warm floor. The basis for the information we offer is the requirements of building regulatory directories.

We described in detail the principle of operation of floor heating circuits, described device options and technologies for their implementation. Visually confirm the data presented and facilitate the perception of the process of informative photos and video guides.

Underfloor heating system

A distinctive feature of warm floors is that they do not have external heating structures, and the system itself accumulates and radiates the heat generated.

With the correct distribution of heat on the surface of the flooring, you can save on a coolant flow rate of 30% or more.

Types of underfloor heating
The floor heating system can be represented by one of the varieties: water, electric, film, rod or electric. The latter is considered an innovation, but due to an extensive number of advantages, has already managed to win a lot of fans

For the rational use of the floor heating system, we consider additional ways to help save:

  1. The length of the fluid circuit does not exceed 70 m. When choosing the optimal step for laying pipes, the heat carrier is transported almost without loss.
  2. Mixing hot and cold streams. The use of water from the return makes it possible to spend less energy on the boiler.
  3. Drawing up a detailed layout of the contour with an accurate calculation of the pitch. Preliminary distribution of furniture positions will save on consumables, and, accordingly, on the circuit itself.
  4.  With maximum system heating, reduce the temperature by 20 ° C. This action will help save 13% of the coolant.

In order to get the best result, you must strictly adhere to the installation technology. The heating mechanism of such a system consists of several layers, each of which has its own function.

Foundation preparation
Arrangement of the heating system using underfloor heating is carried out in stages. Work on each of them will take a certain time, for example, after pouring, subsequent work can be started only after 2-4 weeks

High-quality heating of the room by laying a liquid heated floor is organized in several stages:

  1. Waterproofing. This layer eliminates the appearance of products formed as a result of condensation. For the substrate, even a plastic film can be applied.
  2. Thermal insulation. The main task is to eliminate heat leakage to the lower part. In most cases, a sheet-type insulation is used. The thickness should be selected based on the conditions of the room - whether there is a basement or basement in the house. The colder the climatic conditions, the thicker the thermal insulation.
  3. Foil or heat reflecting element. Foil film, contributing to the maximum redirection of heat flow up. Laying this material allows you to save up to 5% on the flow of coolant.
  4. Pipe installation. The main device of the whole mechanism. A heated fluid flows through the pipes. If you choose the right step between the turns of pipes when laying a warm floor - this will make it possible to efficiently heat with the lowest heat consumption.
  5. Screed. Provided that all the previous layers were laid on a flat surface, the screed thickness will be minimal - 3.5 cm. Often, pouring from an ordinary cement-sand mixture with a thickness of 50 mm is often used. The heat conductivity of such a material is 0.4 W / (m * K).
  6. Flooring. The liquid floor allows the laying of any material. Nevertheless, the best characteristics, namely thermal conductivity and maximum efficiency, have ceramic tiles.

Mounting technology involves the initial arrangement of the collector assembly. Only then can one start laying individual layers of the system.

The role of the collector node

Not everyone knows that underfloor heating with a water circuit can function normally without a collector. But, how it looks in practice, they know even less.

Pipes no longer than 70 m
Manufacturers recommend using pipes with a length of not more than 70 m. If the coils are arranged with a maximum pitch gap, then this length will be enough for only 7 m2, which will ensure the arrangement of three contours in a room with an average area

However, in most cases, the underfloor heating system is installed in several rooms. In this case, without a collector unit, it is impossible to ensure uniform distribution of the coolant.

The installation of underfloor heating without a collector has several disadvantages: the heat carrier can be supplied only with the same temperature as in the general heating system, automatic air outlet is not possible, the same applies to pressure regulation.

Collector connection diagram

The choice of a finished mechanical or automatic collector model depends on the characteristics of the heating system.

The first type of control module is recommended for underfloor heating without a radiator, the second can be used in all other cases.

Manifold for underfloor heating
Valtec collector groups are the most popular. The manufacturer gives a 7 year warranty on manufactured products. The installation circuit of the fluid circuit collector is already included in the package of the finished mixing unit

According to the scheme execution distribution comb assemblies for underfloor heating as follows:

  1. Setting the frame. As a mounting zone for the collector, you can choose: a prepared niche in the wall or a collector cabinet. It is also possible to mount directly to the wall. However, the location must be strictly horizontal.
  2. Connection to the boiler. The supply pipe is located at the bottom, the return pipe at the top. Ball valves must be installed in front of the frame. A pumping group will follow them.
  3. Mounting a check valve with temperature limiter. After it, the collector is mounted.
  4. Hydraulic system test. Check by connecting to a pump, which helps to pressurize the heating system.

In the mixing unit, one of the required elements is a two- or three-way valve. This device mixes water flows of different temperature and redistributes the trajectory of their movement.

Stop valves
On both pipelines, return and supply, connected to the collector installation, shut-off valves and fittings are designed to balance the volume of the heat carrier, as well as to block any of the circuits

If servomotors are used to control the thermostats of the collector, then the complete set of the mixing unit is expanded bypass and bypass valve.

Rules for calculating the length of pipes

You can calculate the footage of elements for assembling heated floors after drawing up a diagram of the entire system.

When calculating the following nuances are taken into account:

  1. In places of furniture, overall floor equipment, household appliances pipes are not laid.
  2. The length of the contours with different cross-sectional sizes should correspond to the following parameters: at 16 mm should not exceed 70 m, 20 mm - no more than 120 m. The location of each circuit corresponds to an area of ​​15 m2. If you do not adhere to such recommendations in the heating network, the pressure will be low.
  3. The discrepancy between the length of the lines is not more than 15 m. For a large room, several heating branches are made.
  4. Subject to use effective heat insulating materials, the optimal pitch of the pipes is 15 cm. If the house is located in an area with harsh climatic conditions, where the temperature drops below -15 ° C, the distance should be reduced to 10 cm.
  5. If a laying option was chosen in increments of 15 cm, the material costs are 6.7 m per 1 m2. Pipe laying with a gap of 10 cm - 10 m per 1 m2.

Underfloor heating can only be equipped with a solid pipe. Depending on the meter, several or one bay with pipes for the water circuit. Then produce its division into the desired number of lines.

Pipe Bay
At the time of pipe laying, hydraulic losses must be taken into account, which increase with each subsequent turn. It is believed that circuits exceeding 70 m should not be used.

Work on the arrangement of heated water floors always starts from the coldest side of the room. The question of choosing the optimal route for the thermal carrier is very important - the water temperature decreases closer to the end of the circuit.

The nuances of choosing the optimal step

The degree of efficiency and cost of the entire circuit depends on the correct choice of the step between the laid pipes of the warm floors.

However, its calculation depends on many factors. The standard distance between the contours is 100-200 mm.

A variable or constant step is also possible:

  1. If the heating load is less than 50 W per 1 m2, the pitch of the contour will be constant and equal to 200 mm.
  2. With increased heating load of 80 W per 1 m2 and more distance will be 150 mm.
  3. In other cases, it is necessary to apply a variable step. For example, along the perimeter of one or two external walls, laying the water circuit will be with the smallest step of 100 mm.Moving to the center of the room, the gaps will gradually increase to 200 mm.

In practice, if it is planned to heat the floor economically, a step of 150 mm is used. This indicator is optimal in almost any environment.

If the heat loss of the building exceeds the heat transfer, you should think about its effective insulation - in this case, reducing the step will not solve the problem.

A detailed algorithm for calculating pipes for a warm floor is described in this article.

Layout schemes of the water circuit

Schematically, pipe laying for the arrangement of a liquid circuit can be performed in one of the following ways:

  • coil;
  • double coil
  • snail.

Coil. The method of laying such a contour is the simplest and is performed by loops. This option will be optimal for a room divided into different zones for which it will be convenient to use different temperature conditions.

Installation of the first loop is carried out around the perimeter of the room, then a single snake is allowed inside. Thus, in one half of the room, the most heated coolant will circulate, in the other - cooled, respectively, and the temperature will be different.

The turns of the coil can be arranged evenly, but the folds of the water circuits in this case will have strong creases.

Pipe laying with a snake
The serpentine method of placing pipes is ideal for rooms with minor heat loss. They are used not only for apartments and private houses, but also for industrial facilities where there is a need to heat all year round

Double coil. In this case, the supply and return circuits are located next to each other throughout the room.

Angular coil. It is used exclusively for corner rooms where there are two external walls.

The advantages of a serpentine form include a simple layout and installation. Disadvantages: temperature differences in one room, pipe bends are quite sharp, so you can not use a small step - this can cause a pipe break.

Angular coil
When laying the contour in the marginal zones of the room (the floor area where the external walls, windows, doors are located), the step should be smaller in comparison with other turns - 100-150 mm

Snail. Using this arrangement, the supply and return pipes are mounted throughout the room. They are placed parallel to each other and are installed, starting from the perimeter of the walls and moving to the center of the room.

The supply line in the middle of the room ends with a loop. Then, in parallel with it, a return line is installed, which is laid from the center of the room and along its perimeter, moving to the collector.

The presence of an external wall in a room can cause double laying of pipes along it.

Snail laying method
Due to the alternation of two lines during laying by the cochlea method, the temperature fluctuation in the supply and return lines can be up to 10 ° C

The advantages of this method include: uniform heating of the room, due to smooth bends, the system has a small hydraulic resistance, and the savings in consumables can reach 15% in comparison with the serpentine method. However, cons are also present - complex design and installation.

The main methods of pipe installation

There are only two pipe laying methods for arranging a warm floor - flooring and concrete. In the first method, ready-made materials are used for the base: insulation-polystyrene and panels of modular or rack type. There is no wet work that requires a long drying time, so laying is quick.

When using the second option, the heating network is walled up with a screed. Depending on the thickness of the concrete, the time to dry completely is calculated. There is an endurance of 28 days to strengthen and only after that it is allowed to mount the selected floor covering. This is the most time-consuming and financially expensive way.

# 1: Laying on profile heat-insulating boards

Arranging a warm floor system using this method is the easiest. As a basis, mats of polystyrene insulation are used here.

The standard parameters of such plates are 30 * 100 * 3 cm. They have grooves and low columns on which the finishing material is laid.

Polystyrene insulation mats
Polystyrene mats are not hygroscopic, therefore, under the influence of moisture they do not lose their original characteristics. Even though this material belongs to polymers, there are no harmful components in its composition.

In this case, pouring concrete screed is optional. If tiles or linoleum will be used for flooring, initially gypsum sheets will be laid on the base. The thickness of such plates should be at least 2 cm.

# 2: Device for modular and rack panels

In most cases, such panels are used in houses built of wood. Fastening of pipes for the arrangement of a warm floor is carried out on a draft basis.

The modular system is equipped with 2.2 cm thick chipboard panels, on which heating lines are laid. These modules are equipped with channels for accommodating aluminum fixing plates. With this laying method, the insulation layer will be located in the wooden floor.

All strips are placed with a distance of 2 cm. Based on the applied step between the pipes, strips of the corresponding length (15-30 cm) and width (13-28 cm) are used.

To reduce heat loss on the plates, latches for pipes are installed. If linoleum was chosen for the finish coating of the floor, one layer of gypsum-fiber boards is laid on the pipes, if the laminate or parquet board do without them.

Modular slabs
Laying a modular floor is carried out with prefabricated elements, which are wood chipboards. They are equipped with grooves for fixing the coolant pipes

The rack system of the flooring is almost identical to the modular one, however, it does not use panels, but strips with a minimum width of 2.8 cm.

Laying is done directly on the logs with a step of 40-60 cm, and the distance between the rails is at least 2 cm. For thermal insulation, choose extruded polystyrene foam or fibrous mineral wool.

Modular slabs
Laying of heat-conducting lines is carried out by placing pipes in intermediate holes between chipboard sheets on aluminum plates equipped with grooves

Both methods are more suitable. for wooden floors. In other cases, choose a more complex option with a concrete screed.

# 3: Installation of the pipeline through the screed

Despite the complexity of the process, the installation of a heating network with a concrete screed is the most popular.

The process consists of the following steps:

  1. First of all, the basis is prepared. Roughnesses in the subfloor are eliminated with a punch.
  2. The first layer is waterproofing material. It spreads in stripes so that the edges overlap each other by 20-30 cm. Also, the film should go into the base of the walls by 15 cm. Joints are glued with construction tape.
  3. Thermal insulation spreads over it.
  4. A damper tape is glued between the future fill and the walls. This action is required to compensate for screed expansion when the floors are heated.
  5. Laying reinforcing mesh. It helps to increase the strength of the screed.
  6. Pipes are attached to the reinforcement according to the selected scheme using plastic puffs.
  7. Verification of the warm floor system is carried out by filling it with liquid and crimping.
  8. Next, the guide beacons are installed.
  9. Finishing stage - pouring cement screed.

For rooms with a large area, the sector division method should be used, with cells no more than 30 m2. For each of them it is necessary to equip an individual circuit.

Styrofoam with cells

If the lower floor is heated, then polystyrene foam 20–50 mm thick is used as insulation.When there is an unheated basement or basement below, the thickness of the insulation should be 50-100 mm. Filling of heated floors with concrete-sand mixture can be performed on or without reinforcing mesh.

If the role of insulation is polystyrene foam boards with connectors for the contours, the use of a mesh is optional.

When a standard heat-insulating material will be used, a thin polymer or metal mesh is used to fix the heat-conducting line.

On our site there is a series of articles devoted to the design, installation and connection of water heated floors.

We advise you to familiarize yourself with:

  1. How to make a water-heated floor with your own hands: a step-by-step guide from design to assembly
  2. Water underfloor wiring diagram: versions and device manual

Conclusions and useful video on the topic

How not to make a mistake with calculating the optimal step for arranging the circuit with the least cost:

How is the laying of the contour of warm floors, the main methods, their disadvantages and advantages:

Difficulties that you may encounter when choosing pipes for a warm water floor:

The service life of the water heating circuit is about 50 years. However, such high rates are possible only if you follow all the rules when laying them.

Do not forget that the right choice of the optimal step will significantly save on the purchase of materials, as well as reduce heating costs during operation.

Share with your readers your experience in laying the contour of a water heated floor. Tell us which method and installation scheme you used. Please leave comments on the article and ask your questions. The feedback form is located below.

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Visitors Comments
  1. I myself made a warm floor in the living room. I constantly have children there, so I decided that it would not hurt. Although I was frightened by the familiar “experts” that the coating over the warm floors cracked, that pipes might burst and the like. I did everything myself. I can say that everything is fine. Nothing burst, the floor is intact, and most importantly, warm. Gas consumption for heating a house, I noticed, decreased by 30 percent for sure. Well, and the main thing is to do everything correctly so that there are no problems.

  2. Sveta

    There is a desire to make a warm floor to your home. Even while not a desire, but more a dream. Of course, I wondered how much it would cost, but so far only superficially. She herself saw such a floor from a friend from work when she was visiting her, and the impression was very positive. Sooner or later, children will appear, and it’s nice to walk on the warm floor ourselves. Someday I’ll get together and do it!