Water underfloor heating along with electric underfloor heating is increasingly being used in heating systems in private homes. Indeed, it is much cozier in a child's room or bathroom with \"bottom\" heating.
Water systems, unlike electric systems, are considered not as costly if the heating medium in the pipes is provided by a gas boiler - part of the overall heating system. But they are more difficult to install and manage, so before implementing a project on the device of floor heating, you need to study a lot of technical nuances.
In this article, we will talk about how to connect the floor heating with minimal losses and without serious technical mistakes. We offer a clear step-by-step instruction with which you will select the necessary materials, understand the key principles of laying the pipe and finally solve the heating problem in your own home.
- Important factors when installing underfloor heating
- Step-by-step installation instructions
- Step #1 - designing and choosing a laying scheme
- Step #2 - preparing materials
- Step #3 - installing insulation
- Step #4 - fixing the water pipe
- Step #5 - Installing the mesh
- Step #6 - Hydraulic test
- Step #7 - Installing the screed
- Step #8 - Commissioning
- Conclusions and a helpful video on the topic
Important factors when installing the floor heating
Before you start the instructions before we move on to the installation instructions, let us look at a number of factors without which it is not possible to start designing a heating system with underfloor heating.
Private home owners have more options when choosing a heating system: they are autonomous and independent of centralized water supply. Owners of apartments in multi-storey buildings most often do not get a chance to install water type floor heating - only electric.
The following requirements are set for the premises where the water system is planned:
The \"cake\" thickness including screed is usually 10-20 cm, therefore the ceilings should be rather high - minimum 2.7 m without considering the water floor. This also applies to doorways, the height of which should not be less than 2.1 m
Laying water circuits takes place in strict conditions - only on a level, without dips and bulges, the surface. Any differences negatively affect performance, increase the hydraulic resistance and contribute to blowing
Cement screed, the contours with water and other parts of the \"pie\" have a large weight, so the base must be strong, avoiding further deformation. In this regard, \"wet\" and \"dry\" water floors are laid either on the ground or on a cement slab
Laying a warm floor - one of the final stages of construction and equipment of residential premises. It is recommended that all windows be inserted and \"dirty\" finishing work - such as levelling and plastering the walls
The height of the ceilings in the rooms
A flat and clean base surface
Safe base to install the water floor
Preparation work before installation
In general, By the time the heating system is connected, it is necessary to reduce the heat loss as much as possible, i.e. to insulate the house, otherwise both underfloor and radiator heating will be ineffective.
Prepare for the fact that the purchase of components and implementation of the project will be expensive. Installation of equipment consists of several stages, which we do not recommend neglecting. But there is a big advantage: the installation of the floor heating will be more than repaid in a couple of years if you choose a boiler operating on natural gas
Natural gas is still much cheaper than alternative fuels - wood, coal, pellets, and a two-circuit boiler can easily provide heat and hot water to a large cottage
There are two variants of floor heating: \"wet\" and \"dry\". The first differs in that it includes the filling of the cement-sand screed, requires more time to install, but it is chosen more often. The second is advisable to implement if it is planned to lay wooden floors as the final coating.
The best floor coating when arranging warm floors is considered ceramic tile, but more often use laminate, linoleum or carpet with a special mark.
Step-by-step installation instructions
We offer an instruction with 8 steps. Each of them is important in its own way and if you eliminate one of them you might have a malfunction during the operation of the system.
Repairing the underfloor heating is an expensive, long lasting and very troublesome job, therefore it is necessary to be very careful and scrupulous from the very beginning when installing the system.
Preliminary calculations, making an estimate and the procedure will make the installation work much easier. You will know the approximate amount of costs and understand whether you can do everything yourself or will have to involve a working team
The stage includes the purchase of all components: collector, pipes, substrates, dry cement mix. Purchase of parts for the pipeline occurs according to engineering calculations. Tools is also better to prepare in advance to avoid downtime
Thermal insulation is necessary to reduce heat loss to a minimum. It is known that without insulation a large amount of heat escapes through the floor - as a result not heated rooms, and not the base and the ground under it
Pipeline is laid, first selecting the most successful scheme, think through how many circuits are required and how they will be located. It must be remembered that the contours do not install heavy furniture or appliances
Armoring grid creates a kind of framework that protects the pipeline and gives strength to the cement screed. This step should not be neglected, so as not to face in the future with the deformation of the \"pie\" and all the ensuing problems
Do not fill the screed, until you make sure the system works. With the help of pre-testing you can identify errors in calculations, leaks and other weaknesses. This stage - the last chance to fix all the problems
Pouring of cement mortar occurs according to the standard scheme. Screed layer should be a certain thickness - to create a solid base and at the same time not to prevent the flow of heat into the room. Some time will be spent on the \"maturation\" of cement
The final stage, in the course of which performs balancing circuits - adjust the pressure in the pipeline. If the hydraulic tests were successful, and all the shortcomings were eliminated in time, after connection to the in-house heating system the floor heating should not cause any problems
Step #1 - design and choice of layout
Step #2 - material and tools prepared
Step #3 - installation of insulation
Step #4 - securing of water pipe
Step #5 - laying reinforcing mesh
Step #6 - hydraulic test
Step #7 - install beams and pour Screed
Step #8 - Commissioning
We will now explain each step in detail, from the purchase of accessories to the final connection. Our recommendations are not to be taken as the only possible ones - there are many interesting and efficient solutions.
We advise to take the offered instructions as general rules which must be followed during the preparation and installation. The individual details and peculiarities of the arrangement depend largely on the project in question.
Step #1 - design and choice of installation
Planning can be done in different ways: by contacting a company dealing with similar projects or by doing everything yourself. But to make calculations and implement the idea by your own forces requires at least engineering education, sufficient experience and proficiency in computer programs. Otherwise, the successful result is not guaranteed.
These are some of the things you should know when making a project:
- the average comfortable floor temperature in living rooms and bedrooms is 21-27 °C;
- for bathrooms, toilets and combined toilets the parameters are higher - 31-32 °C;
- the temperature of the heat carrier in the floor heating circuits does not exceed 60°C (in comparison: up to 90 °C for radiators);
- the temperature drop in the floor heating piping, i.e. the difference in the inlet and outlet is 10°C;
- the pipe diameter depends on the circuit length: Ø 16 mm - 80-90 m, Ø 17 mm - 90-100 m, Ø 20 mm - up to 120 m.
Ideally all water circuits should be the same length - this makes it easier to balance. But in practice this is almost impossible, so it is necessary to keep at least the same diameter for all pipes.
Pitch spacing is the distance between adjacent coils of one circuit. It depends on the type and diameter of the pipe as well as on the installation site
At the outside walls are the so-called \"cold zones\" , therefore the installation pitch is max. 150 mm, in the center 250-300 mm. If there are no external walls, you can keep the interval within the limits of 200-300 mm in the entire room.
In swimming pools, bathrooms, baths, the floor should be as warm as possible, so the step of layout 100-150 mm. A smaller spacing is not possible without breaking the piping.
There are two basic ways of laying the circuits: \"serpentine\" and \"snail\". \"Snake\" is easier to install, but produces a large temperature difference at the inlet and outlet - up to 10 degrees. It is well used in areas with exterior walls. \"Snail\" is more difficult to execute, but this layout keeps the temperature stable throughout the circuit.
Possible ways to install heating circuits. By arranging the piping, it is possible to set the desired temperature in different zones of one room
It is not uncommon to use combined variants, combining different methods in one room. If properly calculated, the heating will be as efficient as possible.
It is recommended to use a separate circuit for each room. The only exceptions are small rooms next to each other - for example a toilet and a bathroom.
If the space is large and the area is more than 40 square metres, it is recommended to connect 2 circuits. One circuit simply cannot cope with the load on it
Take into account that thermal expansion occurs when heating up. It is compensated by the damping tape that is laid between the loops, in the adjacent rooms and along all walls
We spoke about the laying and connection schemes in our other article. To read this information, please follow this link.
Step #2 - Preparing the materials
Prepare for the fact that the floor heating design consists of a large number of parts, and you should only choose quality products that match each other as closely as possible. Let's take a look at the most significant of these: pipes, insulation and the manifold.
PEX or PERT pipes are best suited for heating circuits:
- PEX - characterized by a \"memory effect\", have an 85 percent cross-linking density, are joined with axial fittings that can be filled with screed;
- PERT - have no memory effect and are joined with collet-type fittings that cannot be filled with cement, but can be used in exposed areas - such as collector joints.
In practice both types of pipes are used.
The least affected by temperature differences are PE-Xa pipes with an EVOH inner layer - a kind of protective barrier of polyvinylene which reduces oxygen penetration
Pipes with Ø 16 or 20 mm are used for private installations. We also recommend that you read the rules for calculating pipes for floor heating.
We recommend not buying cheap dubious analogues, and opt for the products of one of the proven manufacturers: Valtec, Rehau, KAN, Tece or Uponor. Don't forget that the quality of the components determines the service life of the warm floor.
It is advisable to use extruded polystyrene or profile mats as a heat insulating material. The former is cheaper and mats are easier to install
EPS is strong, moisture resistant, low thermal conductivity and has an affordable price. Various sizes of boards are connected to one another by means of grooves.
Special dowels called plate ones are used to fix the pieces of ESPS. They are fixed at the center of the boards if they are large and at the joints
Profile mats are made of dense polystyrene foam. They are covered with convexes on top, allowing the heating circuits to be laid evenly and dimensionally. Mats are more expensive than EPPBs and are usually purchased if finances allow.
The manifold is responsible for distributing the heat transfer medium to the circuits, regulating and balancing it. It is a complex unit made up of a large number of parts including:
- collectors themselves with balancing valves and shut-off valves;
- air vent valves with automatic operation;
- connection fittings;
- drain cocks;
- brackets for fixing.
In the absence of a separate riser, a mixing unit consisting of a bypass, pump and thermostatic valve will be required.
The manifold and the mixing unit are located in a manifold cabinet - a metal box installed in a convenient place for maintenance, preferably at equal distance from all circuits
There is no fixed place for the manifold cabinet - this may be a hallway, dressing room, hallway, small separate room or a recess provided for that purpose.
Step #3 - installation of insulation
Skip all kinds of rough work - the installation of a recess for the manifold cabinet or additional passages in the building structures, proceed directly to the installation of the thermal insulation layer. The substrate must be cleaned and levelled before this.
The sequence of work to lay the EPPP boards:
- Debark the level of the finished floor, mark it on the walls.
- Fill irregularities with sand.
- Lay the boards in grooves starting from the far wall, or better yet, from the corner.
- The joints of the neighbouring boards must not match, that is why they are laid with an offset.
- If a second layer is planned, also lay the boards without matching joints.
- Secure the boards with dowels using a hammer or punch.
- The joints and the seams are sealed with masking tape without leaving gaps.
Large gaps may be filled with small remnants of the boards and blown out with assembly foam from above.
Finish the work with a uniform, even thermal insulation material floor without gaps or dips. One of the conditions for a reliable layer is stability
If the underfloor heating is above the basement, basement or on the ground, cover the base with waterproofing film - polyethylene or 150-200 µm membrane in advance. Roll up the rolls with an overlap of about 100 mm, glue all seams with tape.
Features of laying different types of insulation we discussed in detail in the next article.
Step #4 - fixing the water pipe
Before laying the loops you need to install a manifold cabinet and then start work from the furthest point. The transit pipes running from the collector to the destination are masked in a layer of thermal insulation and additionally placed in polyethylene foam covers - to preserve heat.
At the same stage, fix a damping tape around the perimeter with liquid nails.
Where the pipes exit the outside as well as at the entry point of the concrete screed, a protective corrugation or a dense insulation against deformation is put on each pipe
The assembly procedure of the circuits:
- Wind 12-15 m of pipe from the coil, put the insulation and the manifold fitting.
- Hook the insulated end to the manifold.
- Lay the piping without effort and tension along the planned contours, fixing every 35-40 cm with brackets (in the curves every 10 cm).
- Following the contours, bring the return pipe to the supply pipe, also put a corrugation or thermal insulation on the second end, connect with a fitting to the collector.
- Write the contour length against the respective inlet/outlet on the collector.
Concord the remaining pipe loops the same way. If the brackets fly out during installation, repeat the fixing, but not in the same place, but at least 5 cm from it.
To avoid damaging the insulation or the pipes, use planking of plywood sheets or pieces of chipboard to move around the working areas.
Step #5 - Laying Reinforcing Mesh
Metal wire or plastic mesh is not placed under but over the pipe. Plastic roll mesh is cheaper, lighter and easier to install.
Metal mesh of smooth, thin wire not more than 3 mm thick and 10*10 cm mesh is suitable for reinforcement. Fittings are not suitable because of the corrugated surface that may damage the pipe
The pieces of mesh are placed with an overlap of 1-2 cells, connected with plastic ties or wire, the protruding ends are removed.
Step #6 - Hydraulic Test
All ready to pour the screed, but before that it is essential to check the operation of the system. Water is connected to the supply manifold and a hose to the outlet, taking it to the sewer.
A pressure pump is installed on the line, to one of the outlets.
The purpose of the pressure test is to fill all the circuits with clean water, flush the piping which may have accumulated grease residues or debris, remove air
The procedure to follow when filling the circuits with water:
- block all manifold circuits except the one to be checked;
- pour clean water from the water supply;
- watch the air escape until clean water flows without air bubbles;
- block the filled circuit, move on to the next circuit - and so with all;
- stop the water supply, close the valve.
After that it is necessary to carry out a test using a special pump - pressure pump. It is recommended to involve an experienced master familiar with the process.
The essence of the test: water is fed into the system at a pressure higher than the working pressure - about 6 atmospheres. After that, the pipes are checked for leaks, then the pressure is relieved, and this is repeated at least 3 times. Then the circuits are left under high pressure for a day. If there are no leaks after 24 hours the system is leak free and installed without defects.
Step #7 - Install Lighthouses and Screed Pouring
Pre-screed the pipes with water and working pressure, average 2 bars. Then install the beacons.
We recommend a 28*27 gypsum board profile as the beacons. The height of the beacons is the level of the finished floor without taking into account the finish coating
The distance from the outermost beacon to the wall is 0.3 m, between the beacons - no more than 1.5 m. Accordingly, the length of the leveling rule is 2 m.
After that, prepare the screed mortar. The ideal is an ordinary mixture, but with the addition of plasticizers. The fact is that in addition to mechanical stress screed will constantly experience and temperature differences, so it should be plastic and mobile.
We recommend buying special plasticizers or fibers, which are sold in a large assortment.
Portland cement M400 and higher with an unexpired shelf life is the main part of the mortar. Make sure it is dry, clean and sifted
For each 50-kilogram bag, about a bucket of water. It is better to add the liquid gradually, because plasticizers change the composition.
Playing screed order:
- Remove unnecessary objects from the floor, close windows.
- Prepare a quality mortar, better with a construction mixer than a drill.
- Start screed laying from the far point, in strips, orienting on the beams.
- Correct and level the surface after each strip has been laid between the screeds.
- A couple of days later, after drying, deburr the rough spots, remove the layer of cement up to the screeds.
- Moisten the screed, cover the floor with plastic.
After another day, remove the screeds, mask the gaps that have appeared, splash water on the concrete surface again. It is recommended to moisten for at least 10 days.
Step #8 - Commissioning
The screed takes about a month to mature, and only after that can the balancing proceed, which is necessary to equalise the parameters of the heat carrier in the circuits.
First the normal working pressure is set (1 to 3 bar), then the flow meter of the longest circuit is read and the other loops are adjusted according to the readings, one after the other, in descending order of length.
After balancing, the temperature in the system is gradually increased from 25 °C up to 40-45 °C, increasing daily by 5 degrees.
First time it is advised to carefully supervise the floor heating \"behaviour\", to follow the thermal evolution and, if necessary, to repeat the regulation.
Conclusions and useful video on the topic
How the process and result of underfloor heating installation looks like + overview of the manifold unit:
What mistakes to avoid:
Details on circuit dimensions and pipe laying nuances:
Tips based on personal experience:
Statistically, heating systems with competently installed underfloor heating can save significantly on energy costs. Thanks to clear instructions from component manufacturers and detailed descriptions of the installation process, you can try to install the system yourself. But if you have doubts about your own abilities, we recommend that you contact masters who specialize in the installation of underfloor heating.
Any questions about the rules of connecting underfloor heating? Or would you like to supplement the material with useful tips from your own experience? Write your comments, ask for advice from our experts and other visitors of our website - the feedback box below.