Screed on a warm water floor: what and what thickness is best done

Comfort in a house, apartment or cottage depends on the proper arrangement of communications, an important element of which are heated floors. Their functioning completely depends on whether the screed is made on a warm water floor.

And no matter how the work will be done - with the involvement of the brigade or on its own. The main thing is that all processes are carried out correctly and in accordance with current regulations.

The content of the article:

  • What could be a screed?
    • Species by application method
    • The difference in material production
    • Features of the choice of layer thickness
  • Wet-type screed installation
  • Nuances of the control check
  • Conclusions and useful video on the topic

What could be a screed?

Pipes with water or other coolant used for arranging heating are hidden inside the floor structure. Water floor heating assembled like a cake from several layers, among which there is a screed designed to protect the main line from mechanical damage and ensure uniform heating of the entire surface.

Species by application method

Depending on the consistency of the substance used for the arrangement, they emit a wet, dry and semi-dry screed. The first option is made of available materials - most often it is sand and cement. Moreover, you can try to implement it yourself - you need to practice a bit and make an effort.

The peculiarity lies in the correct preparation of the mixture and its uniform distribution. The consistency will be liquid, which facilitates application and leveling.

Wet version of the screed is good for tile

Wet version of the screed is ideal for finishing marble, ceramic or other decorative coating. The layer conducts heat well and transfers it to natural stone, which gives it as much as possible to the room, ensuring warming

The dry method is quite simple to install and can be implemented on its own. All components can be bought - manufacturers offer a dry backfill from composite materials and ready-made gypsum-fiber boards. The filler will have to be placed over the entire surface and cover the top with a self-tapping screw.

To perform the third type of tie will need additional equipment. It is a pneumosupercharger and other automatic devices. To evenly distribute the semi-dry mixture, you need experience in performing such work.

Equipment can be rented - construction organizations present it for rent. However, without skills to cope with the work will be difficult. It is better to buy the mixture already finished - independent production will be difficult due to the inaccessibility of individual components. Yes, and manufacturers do not rush to share the correct recipe.

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Dry screed

Backfilling tightly compacted, as much as possible filling all voids. Top covered with gypsum sheet. True, the dry version is afraid of moisture

Wooden modules for underfloor heating

Wooden modules are attached to the base, and metal plates are inserted into special grooves - grooves -. Then put the trunk pipe there. This is a dry method, which can hardly be called a screed.

Moist Mix

A semi-dry mixture is difficult to mix and distribute over the surface. It is advisable to order it already finished, and serve to perform a pneumosupercharger.

Wet type screed

For laying a watery solution requires skill. But if you want, you can learn. In the extreme case, over a slightly uneven screed can be applied to the final coating, which itself is able to align

Dry screed

Dry screed

Wooden modules for underfloor heating

Wooden modules for underfloor heating

Moist Mix

Moist Mix

Wet type screed

Wet type screed

The choice of arrangement depends on the characteristics of the room, skills and budget. In any case, deciding to make the floor warm, you can not save on quality. Even the best material can ruin hand curves.

Moreover, the system is being made for more than a decade - the expenses are justified and will pay for themselves in the coming years. If you invite cheap shabashniki and do not control every process they perform, you can end up paying double the price.

The difference in material production

To perform the screed can be used various mixtures and materials. The solution can be prepared independently, buy a dry mix and mix it using the manufacturer’s recommendations, or order ready-made material, which will be delivered at a specified time.

Most often used such options:

  • concrete - it can be ordered or made;
  • a solution of sand, cement and additional additives to improve the properties of the future coating;
  • ready mix cement with mineral fillers such as Ceresit CN 85 and others.

When choosing ready-made materials for the device screeds, you should carefully follow that they were designed for underfloor heating and strictly follow the recommendations of manufacturers.

Not all ready mix can be used in the bathroom.

Especially it is necessary to comply with the requirements regarding the thickness of the coating being arranged - as a rule, this indicator should not exceed 10 mm. This mixture dries quickly, but it can not be used in wet areas and outside the building.

For the device of a coupler atop floor heating in the bathroom more suitable concrete or sand-cement composition, made in appropriate proportions. Moreover, his recipe can be improved by creating a more malleable mixture that is most suitable for arranging a floating screed.

To do this, buy a special liquid - plasticizer for concrete. This substance is added in the proportions indicated by the manufacturer on the label. It allows you to get a plastic solution that is resistant to damage after drying.

You also need polypropylene fiber - this is a filler used to reinforce the mixture. With it, it is possible to create a composition that is as resistant to cracking as possible.

Preparation of the solution

For the preparation of the solution is better to take cement brand M300 or M400. In the extreme case, the M200 will do, but not less. Sand should be chosen pure, not containing large fractions.

It is important to remember that any mixture other than dry should be used immediately. Its storage is unacceptable - the process of solidification will begin. And this can happen in 2-4 hours, unless otherwise specified in the manufacturer’s recommendations.

Features of the choice of layer thickness

One of the key points is to choose the thickness of the screed for arrangement of a water heat-insulated floor. It is bad as too small a value, and vice versa. In the first case, the coating will quickly crack all over the surface and simply fail. Yes, and uniform heating will not work.

Optimal screed layer

Too thin a layer will not allow heat to evenly distribute, so it must be at least 30 mm. If the heat passes through a fairly thick layer of concrete, it will take a long time to reach the surface.

In the second - too high a layer above the pipe with a coolant will warm up for a long time.

In addition, in addition the user will receive the following disadvantages:

  • uneven heating - heat bands alternate with cold ones, especially if there are pipes with a diameter of 16 mm below;
  • high consumption of materials, which turns into unnecessary waste;
  • long time for arrangement - a thick layer will dry for more than 1.5 months, which is not always acceptable;
  • a significant elevation of the floor will reduce the overall height of the room.

It turns out that the choice of the optimal thickness should be approached responsibly. Moreover, if you look at the recommendations of manufacturers of equipment and materials for arranging a heated floor system, they advise you to make a layer of screed on average 40-45 mm above the pipe level.

The choice of thickness is directly influenced by the following factors:

  • laying step;
  • diameter itself floor heating pipes;
  • the type of mixture to be filled;
  • ceiling height in the room;
  • overlap strength.

With the features of the calculation of water-heated floors and the definition of the optimal step of installation will introduce next article, which we highly recommend.

Given the initial data, the parameters of the future layer are to be determined. Moreover, less than 30-35 mm can not be taken, and the maximum limit is 100-120 mm. These are recommended restrictions for living rooms.

Screed device

When the device is screed, it is often carried out in 2 stages - first, the pipes are poured, having covered the floor with them. Then put the second layer of the desired height (+)

In the case of production premises, the approach will be radically different - everything depends on their purpose and loads, which have to stand - whether visitors will dance if it's a cafe, or loaders ride when it comes to storage supermarket. We are talking about the thickness of 200 mm.

More popular material for arranging the screed is concrete or cement-sand mortar applied by a wet method. Here it is important not to forget about the need to perform expansion joints, which will provide a quality complete layer over the pipes with water.

For this procedure, a 10 mm wide polystyrene foam pad is used - a damper. It allows you to get a floating floor that is not associated with the walls of the room, so no effect on them has no effect when heated or cooled.

Rules for performing expansion joints depend on the characteristics of the room. The most basic requirement is to lay a damper tape of elastic material around the perimeter of the room. It is important to do this before laying the screed.

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Highway moves from room to room

When the trunk goes from room to room, a deformation seam is made in the doorway using an elastic band. This will avoid cracking the screed.

Large room

For a room with an area of ​​60 m2 and more, it is imperative to carry out a breakdown into sections of 30 m2. Otherwise, cracking of the coating will be ensured.

Long room

If the room is long, then it will also have to be separated by an expansion joint. The maximum allowable length on one side is 8 meters

Complex room

For rooms of complex shape, even if they do not exceed 30 m2, it is advisable to do the separation with a damper tape. The concrete will be deformed during drying and the plastic tape will take it all on.

Highway moves from room to room

Highway moves from room to room

Large room

Large room

Long room

Long room

Complex room

Complex room

Wet-type screed installation

You can make a sand-cement mortar on your own. It is easy to prepare it at home. Moreover, the purchase of additional inclusions will improve the strength and plastic characteristics of the mixture, making it look like concrete.

The recipe for preparing a wet working mass is simple: you need to take 3 parts of sand, add 1 piece of cement to it. To improve the properties that contribute to a better distribution of the mixture, you need to pour in a plasticizer, and for reinforcement you need to introduce fiber.

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Sand and cement for mortar

Sand should be bought sifted, and cement brand M400 or M300. Such components allow you to get a quality mixture

Plasticizer for concrete

Plasticizer buy one that is intended for concrete. It should be added based on the recommendations given by the manufacturer on the package.

Polypropylene fiber

Fiber is better to take polypropylene. It will need 0.9-1 kg per 1 m3 of solution. When added, this component is gently mixed with the dry ingredients, ensuring uniform distribution in the mixture

Ready mix

In the finished working mass, all components must be qualitatively distributed. When using a reinforcing mesh, no fiber is added to the solution, limiting it with a plasticizer and water.

Sand and cement for mortar

Sand and cement for mortar

Plasticizer for concrete

Plasticizer for concrete

Polypropylene fiber

Polypropylene fiber

Ready mix

Ready mix

Before the preparation of the composition to be determined, in how many layers to implement the tie - in two or one? From this will depend on the volume of the mixture, which will need to be prepared.

First you can pour laid on insulation layer pipes, getting at the exit surface flush with their placement. The second layer, which will be above them, is to be done after the first one has dried. Or immediately form a layer of the desired height. For the self-taught master, the second option is simpler and more convenient.

To perform it, you will need to mark the height of the future layer in the room. Here you need to use a laser level and metal guides, called beacons.

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Drilling holes

It is necessary to drill holes for the installation of dowel-nails along a flat line - the installation location of the lighthouse

Driving dowels

The dowel with a diameter of 8 mm is more tightly held in concrete than 6 mm. We put a washer on it in advance to ensure a tight pressure on the foam. We drive in plastic dowels along the entire length of the room

Determining the height of the screed

With the help of a laser level, we mark the height of the future screed - it is precisely at this depth that the nails will have to be hammered. It is important to consider the thickness of the lighthouse when installing it on the dowel, so as not to be mistaken with the height

Install beacon

It remains to mount the metal rail on the prepared fasteners and check the installation with the help of laser marking - the line should be perfectly flat

Application of the solution under the profile of the lighthouse

It is time to fix - we impose a solution without gaps along the line of placement of the future beacon lath, trying not to damage the pipe contour

Immersion of the beacon in the solution

In order not to bend the rail, with smooth, directional movements, immerse it in the solution. It should be performed confidently and gently along the entire length of the lighthouse.

Leveling the solution flush with the beacon

It is necessary to level the solution under the rail. To do this, in places where there are gaps between the surface and the lighthouse, you need to add another mixture and carefully level it. Excess solution should be removed with a slight slope.

The solution is firmly fixed beacon

Further work can be continued through the day, when the mixture grabs and firmly fix the placed beacon.

Drilling holes

Drilling holes

Driving dowels

Driving dowels

Determining the height of the screed

Determining the height of the screed

Install beacon

Install beacon

Application of the solution under the profile of the lighthouse

Application of the solution under the profile of the lighthouse

Immersion of the beacon in the solution

Immersion of the beacon in the solution

Leveling the solution flush with the beacon

Leveling the solution flush with the beacon

The solution is firmly fixed beacon

The solution is firmly fixed beacon

The beacon variant is the most reliable assistant in obtaining the correct surface of the screed. Moreover, the damper tape at this stage should already be glued around the perimeter and in all places where it is required to make a deformation seam. Without it, even the best styling technology does not justify itself - the surface is covered with cracks.

A day after the installation of the beacons when using a wet solution, you can continue to work. It is necessary to fill the mixture on the pipe.

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Start from the corner

First put the solution from the angle farthest from the entrance to the room. This should be done gradually, working with a small area.

Rule to smooth

To smooth the surface, you can use a long rail - the rule. Excess solution should be wide side of the device, and the sharp is designed to remove excess when plastering walls

Adding solution to the troughs

In places where there is not enough volume, you can safely add a little solution, evenly distributing over all irregularities

Re-alignment rule

It remains to tighten the processed area once again, focusing on the level set by the lighthouse rake. Pre-fixture should be cleaned from excess solution

Start from the corner

Start from the corner

Rule to smooth

Rule to smooth

Adding solution to the troughs

Adding solution to the troughs

Re-alignment rule

Re-alignment rule

Similarly, to fill all areas of the room, gradually moving to the exit. It is important to have time to do the work, until the mixture has lost its properties. We are waiting for complete curing of the laid layer. This will take at least 28 days, unless otherwise specified in the instructions.

If you used a mixture purchased from one of the manufacturers and intended to cover the floor heating pipes, the waiting time may vary. Here we have to adhere to the recommendations of a particular manufacturer, whose brand of solution was used.

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To cut off all flows and splashes from the walls

It is necessary to cut off all flows and splashes of sand-cement mixture from the walls. For this you can take a spatula

Remove surface irregularities

The sharp side of the rule is to remove irregularities from the surface of the dried screed. It is necessary to go in different directions around the room, evenly pressing the rail to the surface

Remove all trash

It's time to remove the formed debris from the leveling. You can use a vacuum cleaner for this purpose or use a simple broom.

Make a grout and check evenness

It remains to check the flatness of the surface. Well, if the gap does not exceed 4 mm, otherwise the work is not done in the best way.

To cut off all flows and splashes from the walls

To cut off all flows and splashes from the walls

Remove surface irregularities

Remove surface irregularities

Remove all trash

Remove all trash

Make a grout and check evenness

Make a grout and check evenness

The surface is ready for tile laying. But for linoleum or laminate need grinding. To do this, pour water over the screed, take a polisher and rub it thoroughly. The procedure allows to get a perfect evenness at the output.

Such a result can please not every beginner performing the first tie. Here a self-leveling mixture will come to the rescue, which is designed to remove all differences. It is used as stated in the manufacturer’s recommendations.

After the application, it will remain to wait for it to dry and no grout will be necessary - as a result, a smooth and smooth surface, ready for decorative finishing.

Nuances of the control check

When arranging a wet-type screed made of concrete or cement-sand mixture, the hired brigade should not rush and pay for their services immediately. It is necessary to wait for the complete solidification of the artificial stone. And the first 2 weeks the surface is covered with a film, periodically moistened with water in order to maximize moisture.

Then you need to wait for the time, and this is about a month, so that the composition that covers the floor heating pipes crystallizes. The term depends on the thickness of the layer - it is an individual indicator for each case.

As soon as the allotted time for hardening has expired, it is possible to conduct an audit of the surface, the arrangement of which was engaged by the hired team. There are some nuances that should be checked when accepting their work.

Cracks in the screed

First of all, time should carefully inspect the surface - the presence of cracks clearly indicates errors. This work can not be taken

During the inspection, it is necessary to pay attention to each section of the screed in all rooms - the presence of gloss is undesirable, the top layer should be even, uniformly gray, without chips and cracks.

Then the evenness of the surface is checked with a two-meter rail - the rule. It is applied in several places to the screed. Normal, if the gap does not exceed 4 mm. This is SNIP 3.04.01-87, table 25.

Checking the quality of the screed on a warm floor

You should check the slope on the horizon - it is permissible with a length of 4 meters deviation from the horizontal is not more than 0.2 percent. It turns out that in this case the permissible level of slope is 8 mm.

For tapping, it is better not to take a hammer, but to knock a wooden bar and butt. The entire surface is checked - the sound is the same, ringing. If deaf, there are detachments of the screed from the base.

If the surface withstood the test with honor, the work can be accepted and paid to the brigade honestly earned money. If this is the result of independent work, then they can be proud of.

It now remains to conduct thermal tests. It is important to remember that they are launched in a month, not earlier. Begin at 25 with a daily increase in temperature of 5 degrees until it reaches the design value, not forgetting to follow the pressure loss.

Rules and examples of calculations of water floor heating system given here. We recommend to get acquainted with the useful systematized information.

Conclusions and useful video on the topic

The technology of laying screed in the video:

Detailed video with explanations of the minimum and maximum allowable screed thickness for underfloor heating:

On the choice of the type of mixture and the rules of its manufacture for arranging the screed:

Existing methods for creating screed for floor heating pipes allow you to choose the most suitable option for your room.

Engage in these works independently or invite a brigade - the decision depends on the chosen method and characteristics of the equipped room. In any case, knowledge of the nuances is useful to check the quality of the surface at the end of the work.

Want to talk about how to make a screed for your floor heating system? Is there any useful information for visitors to the site? Please leave comments in the block below, post a photo on the subject of the article, ask questions.

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