Before laying any modern floor covering, it is necessary to have a level floor. In order for the surface to be perfectly flat, you need to fill the floor screed.
From the article you will learn how to fill the floor screed step-by-step technology of the work performed.
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Like any other repair work, pouring the floor screed begins with preparatory work. To begin with, the surface should be cleaned of dust and dirt.
Seal cracks in the floor with a cement-based mortar.
It is desirable to maintain the temperature in the room in the range from 10 to 25 degrees.
To prevent cracking of the screed during thermal expansion, a damper tape is used. Most often it is made of foamed polyethylene.
It also acts as a sound insulator and reduces shock loads transmitted from the floor to the walls.
In small rooms, damper tape is attached around the perimeter of the room. For private houses and other premises where the screed area is very large, it is necessary to lay the damper tape in the screed itself.
insulation
In nurseries, bedrooms and other rooms where you spend a lot of time, it is worth considering the option of floor insulation.
Styrofoam plates 5 cm thick are suitable as a heater. For better heat and sound insulation, polystyrene foam plates have a special mounting lock.
It is necessary to lay the insulation tightly to the base in a checkerboard pattern and, if necessary, fix it with dowels.
vapor barrier
For steam and waterproofing, you can use an ordinary plastic film, the sheets of which are overlapped on top of each other with a call to the walls and fastened together with adhesive tape.
An important point during the preparation is the installation of beacons. It is almost impossible to level the floor without them.
Beacons are rigid metal guides, and you can also use a profile for installing drywall as beacons. Wood is categorically not suitable as beacons, as it absorbs water when it dries.
The lighthouses are set parallel to each other at a distance slightly less than the length of the rule with which you will perform the mortar screed.
The first lighthouse is placed at a distance of 20-30 cm from the wall in small piles of cement. Following parallel to the first, the height is adjusted using a level or a simple level.
The remaining beacons are installed in the same way.
The solution with beacons must be allowed to harden, usually 12 hours is enough.
The second way to install beacons from a profile without mortar on dowels with self-tapping screws. To do this, mark the lines where it is necessary to install beacons and, in increments of about 80 cm, drive in dowels with self-tapping screws.
The height of the screws is adjusted using a laser level. A profile is laid on the self-tapping screws and, as the filling is completed, they can be easily moved along the self-tapping screws.
To prevent the appearance of cracks and overall reliability, a special reinforcing mesh is installed before pouring the floor screed.
More often, a metal mesh with a mesh size of 10 or 15 cm is used for reinforcement. They are attached to the concrete base with dowels.
Now the reinforcing mesh made of composite materials (plastic) is gaining popularity. It does not react with moisture and therefore retains its properties longer. In addition, it is not electrically conductive and does not affect the distribution of the WiFi signal in the room.
Also, the mesh during reinforcement can be replaced with fiber, it is added to the screed solution. The fiberglass provides greater strength and prevents the screed from cracking when it dries.
Now you can start preparing the solution for pouring the floor screed.
To prepare the mixture, sand, cement and water are used. To mix the components, it is better to use a concrete mixer or a drill with a special nozzle.
Cement to take brand M400 or M500.
The required proportions of the screed mortar are 1 part cement, 1 part water and 4 parts sand. First, mix cement with sand, and then add water.
To increase the strength of the solution, add plasticizers. They prevent the appearance of cracks in the screed.
Pouring process
Before you start the process of pouring the floor screed, draw a diagram or photograph all communications that will be filled with mortar. This will help to find them and not damage them during subsequent repairs.
Start pouring from the corner of the room, which is opposite to the exit.
The solution is poured between two beacons so that its level is slightly higher than the beacons and zigzag movements with the help of a rail (rule) are leveled, removing excess. In the irregularities, add the solution and again level the rule.
Repeat the process until the entire floor is covered. It is advisable to fill the floor screed in one room in one day to avoid cracks and joints.
You can walk on the floor after 1-2 days. If the beacons are installed removable, then pull them out and close up the remaining traces. But this does not mean that it is possible to mount the finishing floor covering, since the screed must “ripen”.
In order to correctly make a floor screed based on cement mortars and concretes, the screed must correspond to the purpose of the room and have the necessary parameters for this.
The screed can become a solid foundation for the floor in any room of the house. Cement screed is not afraid of moisture and it is convenient to use it as a base for floors in wet areas, as well as outside the house - on terraces, in the garage. The device of a heat-insulated floor in rooms also does not do without a coupler.
Screed solutions
Cement - sand mortar for screed
For the installation of screeds, a traditional cement-sand mortar of a grade not lower than M75 is used. To prepare the solution, a mixture is prepared from one part of cement and three parts of sand. The strength of the finished screed is increased if the screed mortar has a thick consistency.
Cement-sand mortar is easier to prepare and easier to lay in a screed than concrete. But the consumption of cement for a screed device of the required strength is greater than for concrete. That's why, mortar screed is more expensive than concrete.
Lime should not be added to the solution. Although lime increases the plasticity of the solution, it reduces the strength of the screed.
Concrete of normal, thick-plastic consistency
For the installation of screeds, concrete of class B10, B15, B20 is used. Crushed stone, gravel is used as a concrete filler. The size of the filler granules must be at least three times smaller than the thickness of the screed.
Concrete for semi-dry screed (carving)
To prepare concrete for a semi-dry screed, much less water is used than usual. A semi-dry screed has a higher compressive strength (up to 35 MPa) than mortar and plastic concrete screeds. In addition, it is less susceptible to shrinkage, which reduces the risk of cracking in the screed.
Semi-dry screed is suitable for underfloor heating. It is convenient to prepare concrete for a semi-dry screed at the construction site in a special concrete mixer - mixocrete, which prepares the concrete and immediately delivers it with a pneumatic pump through a flexible pipe to the place of installation.
The composition of cement mortars for concrete floor screed
Cement mortars and concretes can be prepared at the construction site. It is recommended to include additives in their composition to increase plasticity, accelerate setting and reduce the water permeability of the screed.
To obtain concrete of the required compressive strength class, It is recommended to use the following grades and quantities of cement:
During storage, the cement loses its activity. The consumption of cement indicated in the table is indicated for cement with a shelf life of no more than two months. The consumption of cement with a shelf life under normal conditions of more than 3 months is increased by 20%; more than 6 months - by 30-40%.
Cement with a shelf life of more than 12 months is not recommended.
When using stale cement, the mixing time is increased by 2-4 times. It is recommended to introduce additives that accelerate the hardening of concrete.
For the preparation of medium-strength concrete, a mixture of 1 part (by volume) of cement, 2.5 parts of medium-sized sand and 4 parts of aggregate - gravel or crushed stone, is used.
The specified ratio of the ingredients of the mixture is approximate and depends on many factors. For example, the amount of sand in the mixture should be sufficient to fill all the gaps between aggregate granules. With large granule sizes, the amount of sand is slightly increased, and for fine aggregate, on the contrary, it is reduced. Cement consumption is also adjusted depending on its brand, shelf life and required concrete strength (see table above).
The prepared cement mortar must have good plasticity and mobility. Such a solution is easier to level and compact better. To increase plasticity, special additives are used - sulfite-yeast mash (SDB) in an amount of 0.15-0.25% by weight of cement; mylonaft (M1) - 0.1-0.2% by weight of cement, and others. At home, craftsmen often add a small amount of grated laundry soap to the concrete mixer.
The mobility of the concrete mixture also depends on the ratio between sand and crushed stone. The best mobility is achieved at some optimal ratio, at which the thickness of the cement paste layer is maximum. When the sand content in the aggregate mixture exceeds this value, the concrete mixture becomes less mobile, which is explained by the increase in the surface area of the aggregate mixture.
To give the concrete mixture plasticity, much more water is often added to the concrete than necessary (40 ... 70% by weight of cement). Concrete should not be made too liquid, adding a lot of water. A screed made of such concrete will dry for several months, have reduced strength and frost resistance. The risk of significant shrinkage and cracking of the screed increases.
Excess water that has not entered into a chemical reaction with cement remains in the concrete in the form of water pores and capillaries or evaporates, leaving air pores. In both cases, the concrete will be weakened by the presence of pores, and the more water, the more pores and thus the less strength and frost resistance of concrete.
Dry mixes for floor screed
The best option, although more expensive, is to use ready-made dry mixes for the screed device. Such mixtures are commercially available on the construction market. The composition of the mixture already includes the necessary additives.
Manufacturers can include microfiber in the mixture - fibers that perform the function of reinforcement. Microfiber screed is more resistant to shrinkage and cracking.
There are mixtures specially designed for underfloor heating screed. This should be indicated on the packaging of the mixture.
There are fast-setting compositions. Floor tiles can be laid on a screed from such a mixture after 24 hours.
The packaging of the dry mix should contain information about which screeds and laying conditions it is intended for, what compressive strength of the screed will ensure the use of the mixture.
For residential premises, the compressive strength of the screed must be at least 12 MPa, for a garage - at least 20 MPa.
Types of floor screeds
By design, screeds can be connected to the base on which they are laid, or laid on a separating layer, or floating.
Ties connected to the base are performed if the base is also made of concrete. For example, a screed on a reinforced concrete floor slab or on a concrete floor preparation. To ensure adhesion of the screed to the base, the surface of the latter is specially prepared - dedusted and primed. The minimum thickness of the screed is 2.5cm.
In screeds on a separating layer between the concrete base (reinforced concrete slab or concrete preparation) and the screed, a layer of waterproofing film with a thickness of at least 0.2 mm is laid. The edges of the film panels are laid with an overlap of at least 10 cm and sealed with adhesive tape. The edges of the film are wrapped on the walls.
The separating film layer prevents water leakage from the freshly laid concrete. Dehydration of concrete reduces the strength of the screed. The screed concrete must be laid on a separating layer of film in all cases where it is possible for water to leak from the concrete into the screed base.
The minimum thickness of the screed on the separating layer is 3.5 cm.
floating screed laid on a layer of insulation or sound insulation, for example, when installing or Minimum screed thickness 4.5 cm. subject to reinforcement. Floating screed with a thickness of more than 7-8 cm. it is allowed not to reinforce.
Floor screed technology in a private house
The screed is laid at a temperature of the base and air above +5 degrees C. The technology of laying the screed does not change whether cement-sand mortar or concrete is used for laying, including semi-dry consistency.
Work is performed in the following sequence.
Perform the preparation of the base on which the screed will be laid. For the screed associated with the base, the surface of the base is cleaned of debris, dusted with a vacuum cleaner and primed.
For the installation of a screed on the separating layer and floating - a layer of sound and heat insulation is laid, a separating layer of waterproofing film is laid on top.
Styrofoam strips or polyurethane foam edge tape 1-2 thick are fixed to walls and other vertical structures. cm. to create an expansion joint.
Guide rails - beacons - are laid on cakes of fast-setting cement mortar. Beacons are laid over the entire surface of the base in parallel rows with a step of approximately 1.5 m. and at a distance of 20 cm from the walls. Wooden slats or various metal profiles, pipes are used as beacons.
On sale there are special galvanized steel profiles for beacons. Profiles are convenient in that they do not need to be removed from the screed layer. But such profiles have low mechanical strength, increased flexibility and require careful alignment when mounted on cakes and accuracy when pouring concrete.
The upper surface of the beacons is leveled in one plane. If necessary, provide the required slope of the plane.
The solution prepared in a concrete mixer is fed to the place of work, and moving towards the door, it is evenly distributed between the beacons so that the thickness of the solution is slightly higher than the level of the beacons.
With a grater, the solution is pre-distributed between the beacons and compacted. Finally, the solution is leveled with a wooden or metal rail - as a rule, moving it along the lighthouses in zigzag movements towards itself. If shells remain behind the rail in the screed, then they are filled with mortar and re-aligned with the rule.
After the solution begins to harden and can withstand the weight of the worker, beacons are removed from the screed. Do this in a timely manner until the solution has finally set, and carefully so as not to damage the screed. If a semi-dry screed is laid, then it will be possible to remove the beacons in 3-4 hours.
The gaps in the screed remaining after the removal of the beacons are filled with mortar and leveled with a grater, making circular motions.
Until the solution has completely hardened, furrows are made in certain places of the screed, cutting the solution with a spatula to the required depth. After setting the solution, such grooves will have to be cut with a power tool with a diamond blade.
Expansion joints in the screed
The wall expansion joint separates the screed from the walls and other vertical structural elements of the building - columns, stair supports, etc. The seam is necessary in order to exclude the mutual transfer of stresses between the screed and the structures of the house. Stresses can arise as a result of thermal expansion of materials or their shrinkage, as well as as a result of deformations under the action of loads.
In addition, the seam improves the sound insulation of rooms, making it difficult to transmit sounds from walls to floor structures and vice versa.
To arrange a seam along the walls and other elements of the building, an elastic tape with a thickness of 1 cm. to the full height of the screed.
When placed in a screed of underfloor heating pipes with an expansion joint for the entire thickness of the screed, adjacent fields of underfloor heating pipes are separated.
In addition to the expansion joint at the walls, cuts are made in the screed, which divide the screed into smaller rectangular sections. One side of the plot should be no larger than 3-6 m. In narrow corridors, compensation cuts are made across the corridor, every 2-2.5 corridor widths.
In addition, compensation cuts are made at the junction of different floor coverings, as well as at the border of the change in the thickness of the screed, in doorways and in other openings at the border of different rooms of the house.
Compensation cuts are necessary to compensate for the shrinkage of the screed material during drying. Without them, cracking of the screed may occur. Incisions are made to a depth of 1/3 - 1/2 of the thickness of the screed. The width of the cuts depends on the thickness of the screed and the presence of underfloor heating pipes in the screed.
If the screed is reinforced with a mesh, then the expansion cuts should be located above the joints of the individual sheets of the mesh.
If the floor covering along the screed is tile, then the expansion cut must coincide with the joint of the tile.
The expansion slots can remain empty if the flooring is parquet or laminate. The cuts are filled with waterproof silicone sealant if the flooring is tile.
How to properly reinforce the screed
Be sure to reinforce thin screeds with a thickness of 4.5-5 cm on a separating layer of film. Floating screeds, the base of which is a layer of insulation (sound insulation) or compacted soil, are reinforced with a screed thickness of 7-8 cm. and less.
If the screed has a thickness greater than that indicated above, then the need for reinforcement is determined depending on the operational load. For example, it is recommended to reinforce the floor screed in a garage for a car or on an open terrace on compacted soil with a screed thickness of up to 10 cm.
Screeds made from a ready-made dry mix containing microfiber reinforcing fibers in many cases do not require additional reinforcement.
Typically, the screed is reinforced with a steel wire mesh with a diameter of 3-4 mm. The grid must have cells sized 100x100 or 150x150 mm.
The steel mesh is laid on the spacers so that it is approximately in the middle of the screed layer. The protective layer of concrete up to the grid must be at least 2 cm. indoors, and at least 4 cm. when the concrete screed comes into contact with the ground.
On top of the grid, as usual, beacons are installed on the cakes from the solution and leveled.
The thickness and level of the screed in the premises of the house
When choosing the thickness of the screed, the strength of the base on which the screed is laid, the presence or absence of reinforcement of the screed and the operational load are taken into account. In addition, there are restrictions on the minimum thickness of different types of screed (see sections of the article above).
In different rooms of the floor, the thickness of the screed, chosen for structural reasons, may be different. For example, the thickness of the screed in rooms with underfloor heating should be such as to cover the heating pipes with a layer of at least 3 cm.
In the house it is convenient to have floors located in all rooms of the floor on the same level. Only in rooms where water can be spilled on the floor - in the bathroom, toilet, it is recommended to make the floor level lower by 1 cm. than in neighboring rooms.
To make the floors in the rooms at the same level, it must be taken into account that the floor covering that is laid on the screed in the rooms can have different thicknesses. For example, the thickness of porcelain stoneware in the kitchen is different from the thickness of parquet in the living room.
In order to determine the level of the screed surface in the room, first outline the level of coverage of the finished floor on the floor. To do this, choose a room where the total thickness of the screed and flooring is greatest. The level of the finished floor in this room is taken as the level of the finished floor of the floor.
Then, the selected level of the finished floor of the floor is transferred to other rooms. The level of the screed in the room should be lower by the thickness of the floor covering.
In the premises of the floor, the thickness of the screed, selected from design considerations, is adjusted to a given level. If possible, then adjust the level of the base of the screed, for example, change the thickness of the heat and sound insulation under the screed. Choose the most economical option.
To determine the levels of surfaces when working on the installation of screeds in the house, it is convenient to use a laser device - a level gauge, or a hydraulic level - a transparent tube filled with water. The use of a rail with a bubble level will not provide the necessary accuracy.
Screed laying
Laying the screed in the room is carried out in one go, without interruptions. When planning work, it is taken into account that the traditional solution must be laid within two hours after preparation. The time of suitability for laying solutions prepared from ready-made mixtures is indicated on their packaging.
The solution is placed outside the doorway by a few centimeters, and then the excess is cut off along the border of the expansion joint.
The surface of the screed is rubbed with a trowel 8-10 hours after laying, until the concrete has finally set. Semi-dry concrete screed, laid with a concrete pump, rubbed after 3-4 hours. Smoothing eliminates small roughness on the surface. It is not necessary to rub the screed if tiles will be laid on the screed.
Screed Care
The screed must remain damp for a week after installation. At this time, the screed must not lose moisture, otherwise the strength of the screed will decrease. To prevent the screed from drying out, it is covered with plastic wrap or sprayed daily with water.
After seven days, the film is removed, the room is ventilated and the screed is left to dry. After another three to four weeks, tiles can be laid on the screed. Moisture-sensitive floor coverings are laid on the screed after four to six weeks, when the moisture content of the screed is less than 3%.
Floating screed in the floor on the ceiling
On the reinforced concrete floor between floors, a floating floor with a concrete screed is arranged. The floor is called floating, because the screed does not have a rigid connection with the structures of the house.
The floating screed is separated from the walls and floors by a layer of elastic mineral wool. This floor design provides sound insulation between the rooms of the house, and also allows the screed to move with changes in temperature and humidity.
If the ceiling is dry, with a humidity of no more than 3%, and the lower room is heated, then soundproofing slabs can be laid directly on the ceiling concrete. Otherwise, a vapor barrier film is laid between the ceiling and the soundproofing slabs.
How to choose material for soundproofing -
A layer of sound insulation from mineral wool slabs is covered from above with a construction polyethylene film. Film panels are brought onto the walls, to a height of about 20 cm. The strips of film are overlapped. Overlap 20 cm.
The film prevents the penetration of cement laitance from the freshly laid mortar into the sound insulation layer and into the edge tape.
A reinforcing mesh of steel wire with a diameter of 3 - 4 is laid on the film mm. with cells measuring 100 x 100 mm. or 150 x 150 mm.
In the floor screed, you can place heating pipes to radiators, as well as pipes with electrical wiring. Pipes are laid over the reinforcing mesh and attached to it with plastic clamps.
It is recommended to wear covers made of corrugated plastic pipes on heating pipes and wires. In covers, heating pipes will be able to move freely when the temperature changes. In addition, corrugated pipes protect the communications laid in the screed from mechanical damage when pouring the cement mixture.
To level the cement mortar in the screed, beacons from pipes or other profiles are laid on the reinforcing mesh. Lighthouse pipes are laid in increments of about 1.5 m. and level it horizontally with a level. The position of the beacons sets the thickness of the screed. The recommended thickness of the screed for residential premises is not more than 6 cm.
A cement mixture is laid in the space between adjacent beacons. By moving the rule or edged board along the beacons, they distribute the mixture and level the surface.
Eight to ten hours after laying, the surface of the screed is smoothed (rubbed). Grouting can be omitted if ceramic or stone tiles are laid on the screed.
After the cement mixture has hardened, the parts of the edge tape and construction film protruding from the screed are cut off.
Watch the video, which shows in detail how to mark the level and thickness of the screed in the premises.
Features of the screed for underfloor heating
If pipes will be laid in the screed, then it is better to use a ready-made dry mix specially designed for this purpose to prepare the solution. The finished mixture for underfloor heating contains additives that increase the elasticity of the solution.
If the mixture is prepared independently, then an emulsion is added to the solution to increase elasticity. For example, home craftsmen add PVA glue at the rate of 2 l. for 1 m 3 solution.
The screed should cover the underfloor heating pipes with a layer of at least 4-5 cm. Thus, the total thickness (taking into account the diameter of the tubes - 1.6 cm) will be – 6–8 cm.
Care for the warm floor screed for the first three weeks is the same as usual. Before laying the top coat on the screed, the screed must be thoroughly dried. To do this, 21 days after laying the screed, turn on the heating and increase the temperature daily by 5 °C until it reaches the limit - 24 °C.
This temperature should be maintained for 14 days and then lowered daily by 5 °C. Therefore, the heating of the screed lasts another 23–24 days, which should be taken into account when drawing up a schedule for finishing work.
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A standard do-it-yourself screed is quite simple. However, if we are talking about laying the base on the ground in a private house, then the manufacturing technology of the concrete “pie” is different, since in this case it is taken into account that the floor should remain warm, so you need to clarify the groundwater level and other features of the soil.
To prepare the flooring for future flooring on your own, you must first determine how many layers you need to make a screed.
Scheme of floor screed on the ground
In order for the floor screed in a private house to be correct and meet all the requirements of SNiP, it is performed in 8 stages. The result is a "pie" of the following layers:
- prepared clay. This layer must be filled to create a barrier to groundwater.
- Sand pillow. Sand in this case, you can use any, even unwashed.
- Crushed stone fractions 40-60 mm.
- A polyethylene film that does not allow the solution to be poured onto the pillow. The material is laid without cutting it, a kind of sleeve, so in fact you get two layers of polyethylene.
- Rough screed, not less than 80 mm thick. For the solution, a mixture is prepared from washed or quarry sand, crushed stone (fraction size 10-20 mm) and CPU, grade not lower than 300. Reinforcement for this layer is not necessary, just add steel fiber to the solution.
- Waterproofing with roofing material.
- Insulation. As a thermal insulation of the screed in a private house, it is necessary to use only EPS (extruded polystyrene foam) with a thickness of at least 50 mm.
- Fine concreting. For the final pouring of the floor screed, a mixture is used, which includes exclusively river sand and concrete of a higher grade. Also, this layer must be reinforced.
Important! The order of the layers should not be changed, because if you pour sand on top of the rubble, after a while it will begin to sink down, which will certainly lead to subsidence and destruction of the entire floor.
The first three layers allow you to cut off the capillary rise of water. First, the clay takes the “main blow”, then the sand weakens the water rise and reduces pressure, and the gravel does not allow rise at all. If you are interested in how to properly screed the floor to the ground, then lay out each of these layers with a thickness of at least 100 mm. It is also necessary to take into account tamping, which is usually performed using home-made devices weighing up to 80 kg.
If you make a floor screed for the house with your own hands in compliance with this sequence, then any “sex” material can be laid on the resulting slab.
For more information about screed layers, see the video:
Important! An additional 50 mm must be added to the total height of the entire cake.
However, before you make a floor screed with your own hands in a private house, it is necessary to clarify the steps for creating the floor.
Foundation preparation
The first stage of preparation is the creation of the base. To do this, it is necessary to determine the level for the finishing layer of the floor. Usually, in this case, they are guided by doorways in a private house, taking into account the thickness of the coating that will be laid on the floor. Also, before pulling off the floor, using chalk, draw the level of the future screed on the walls in 50 mm increments.
After that, do-it-yourself concrete floor screed is performed as follows:
- Cut off fertile soil from the soil and moisten the surface abundantly with liquid glass and water, in a ratio of 1: 4.
- Lay down a layer of clay.
- Level, moisten with water and tamp the resulting area. For tamping, you can use a bar 200 x 200 mm with a length of about 1.5 m. It is even better to make a home-made device from a piece of pipe (sand must be poured into the pipe), to which the channel is welded. The lower zone of the channel should be 200 x 300 mm.
- Moisten the clay layer with concrete milk (2 kg CPU per 10 liters of water).
- Wait a day for the clay to react with liquid glass.
Rough screed, hydro and thermal insulation
It is best to wait about 10-15 days before performing subsequent work, since this time is required for the crystallization of liquid glass.
Thereafter:
- Pour the sand in several layers (approximately 200 mm) and carefully moisten and compact each of them. In this case, it is advisable not to walk on the first layer.
- Lay out crushed stone (expanded clay can be added to it) and tamp it down as well.
- Lay polyethylene with a bend of 20-30 mm on the walls. At the same time, you should not walk on the film in boots with hard soles.
- Perform a rough cut. Before pouring it, prepare a “weak” concrete solution from CPU, sand and gravel, in a ratio of 1:3:4. It is also recommended to add steel fiber to it to get reinforcement. For 1 cubic meter of concrete, 1 kg of fiber is required.
- Wait 48 hours and “harden” the hardening concrete with liquid glass and water, in a ratio of 1:10, as well as cement, which must be practically rubbed into the slab with a thin layer.
- Treat the surface with liquid bitumen and lay roofing material with an allowance of 30-50 mm.
- Solder the joints of the roofing material with a building hair dryer.
- Take EPPS 30 mm thick to create a heat-insulating layer and glue the joints with specialized adhesive tape. It is better to lay two layers of material at once.
Remember that the room loses up to 35% of heat through the floors, so the heat-insulating layer must be given special attention. In pursuit of savings, you will, in the long run, simply overpay for heating your home.
Finishing screed
The final floor screed should be done as follows:
- Glue a special damping tape 1.5-2 cm thick along the entire perimeter of the room so that it “hooks” on the XPS boards.
- Using a mesh with cells of 10 x 10 cm and a wire thickness of about 3 mm, lay the reinforcing layer. At the same time, it fits on stands (corks from ordinary plastic bottles are suitable).
- Dilute the solution of CPU M 500 and sand (ratio 1:3).
- Pour the final layer and smooth it out using a rule or trowel.
After that, the layer will “ripen” for about 35 days, during which the surface must be moistened daily with water so that it does not crack.
In the process of creating a screed described above, there is no stage for installing guides. The fact is that if you do a floor screed along the lighthouses, you will have to create an unreliable and rather cumbersome building. In addition, the beacon can change its position due to the reinforcement. Therefore, it is easiest to navigate along the chalk marks on the walls during the formation of the “pie”, and after the concrete has completely solidified, cover the floor with a self-leveling compound.
In custody
Before starting work, it is additionally recommended to watch a video on how to properly pour the screed onto the ground. Also keep in mind that each of the layers of the screed plays a very important role, on which the comfortable living of the residents of a country house will depend.
The most common way to create a smooth floor covering is a concrete screed. It can be made using mixtures of various compositions, in one or two stages. The screed can perform specific functions, have additional reinforcement, be applied to different types of coating - soil, concrete slab or wooden floors. Consider some types of work and technology that will allow you to independently carry out all the work with a little effort.
Briefly described, there are four main types of screed.
- adhesive screed. A layer of a new cement-sand mixture is applied to a material similar in parameters. Most often - on an old screed or concrete slab.
- waterproofed. The screed is laid on the insulator layer. Most often it is polyethylene. This ensures good protection of the lower layer from moisture penetration. This method is often used when applying a screed to an absorbent base - sand or soil.
- Thermally insulated. The screed is very thin, fragile, a layer of thermal insulator is laid under it, sometimes also a waterproofing agent. Similar work is carried out before laying the "warm floor" systems.
- Reinforced coating. Such a screed is similar to a reinforced concrete slab in miniature. A wire mesh is located inside the mixture layer. Sometimes a binder additive - microfiber fiber - is added directly to the concrete composition.
All four types can be combined with each other. Which option to choose depends on the conditions of construction. However, the most common method is a simple adhesive screed.
Screed technology
Required tool:
- hydraulic level or laser pointer;
- standard spirit level;
- a pair of two-meter rules, one with a level, the other with a pen;
- shovel;
- container for mixing the mixture;
- powerful drill or puncher;
- nozzle "mixer";
- roulette.
Necessary materials:
The very first step in the laying work is a thorough cleaning of the existing coating. It is necessary to remove all debris and dirt, if possible - vacuum. If it is not possible, carefully work with a broom, trying not to raise dust and wetting the surface.
The stage of marking the room to the level of the future floor should be done carefully and slowly. If there is laser level, work will be easier. You just need to put the device in the middle of the room and mark the received marks on the walls.
Working with the hydraulic level is more difficult. It is better to do it together. First, the highest point of the existing floor is determined empirically. The rest of the screed is marked from it - one person holds the end of the hydraulic level, the second departs sequentially along the surrounding walls and puts marks at a distance of about 50-100 cm.
It is easy to quickly determine the highest point.
- At a height of about a meter from the floor, a mark is made in any corner.
- Using the hydraulic level, the same marks are made in the remaining corners.
- All the points obtained are connected in any way possible - using a long rule, with a thread smeared with blue.
- With the help of measurements with a tape measure, the highest point is determined. It is where the distance from the lines to the floor will be minimal.
Lighthouses are placed at a distance of 100-150 cm from each other. The easiest way is to use self-tapping screws. A plastic stopper is embedded in a pile of mixed plaster, and with a screw it is easy to adjust the height by simply twisting or unscrewing it. The uniformity of the installation is controlled using a spirit level or a long rule. The lighthouse must be level.
After checking each beacon and the total area (the direction of the level setting is perpendicular to the beacons), the gypsum mixture must be allowed to dry.
Perimeter waterproofing
If there are gaps between the wall and the floor, you need to protect the lower room from water. The perimeter can be smeared with mastic, a strip of film can be laid, or gaps can be filled with mounting foam. They do the same if there are through holes in the floor, for example, a hole in the center of the room for lighting wires or a crack in the slab.
Preparing the base for pouring
If the screed is made in an adhesive way on a concrete slab or an existing cement-sand mixture, the base is primed. Usually use the same penetrating primer as for painting or gluing ceramic tiles.
In the case of insulated screeds, a spacer layer is laid for thermal protection or waterproofing. For a steel wire-reinforced coating, a mesh of rods is laid at a distance from the existing floor level. As "props" you can use the same gypsum - small piles of approximately equal height.
The mixing process is easy. The main thing is thoroughness.
First, dry ingredients are gently mixed with a trowel. After a little water is added. Here you can already interfere with the help of a drill and a mixer nozzle. We add water little by little until the solution acquires the consistency of thick sour cream. If you take a handful and lightly squeeze in the palm of your hand, a lump of stable shape should form.
It is better to start work from the sector farthest from the door. A layer of the mixture is applied between two beacons and carefully smoothed out with a rule. At the first stage, the level is filled flush with the beacon profiles. To finish, a small layer is applied that will hide them. This work is best done using a rule with a pen, overwriting several sectors at once.
Exposure time
If a mixture based on cement and sand is used, it must be remembered that the drying time is quite long - about 12-14 days.
In order for the screed to acquire maximum strength and not crack, you need to evenly spray the surface with a small amount of moisture every day. So the coating will acquire the best characteristics.
However, the rapid drying of the screed is also dangerous. If the room is high temperature, low humidity or excessive ventilation, it is better to wet the surface and cover with polyethylene to slow down drying and prevent cracking.
To level the surface and prevent the appearance of fine dust due to abrasion, final finishing is carried out. Using a circular grinder, the surface is freed
from small irregularities and unstable inclusions.
Notes on Coating Performance and Additional Precautions
The minimum thickness of the screed, excluding additional conditions, is 30-50 mm. It is not recommended to make a thinner coating, even if we are talking about a thermally insulating screed for a “warm floor”.
Concrete screed is very durable. This is its advantage and at the same time a disadvantage in some cases - the coating may crack. This happens from a temperature difference, and especially from the shrinkage of a building or structure. To avoid such a danger, security channels are made. These are cuts that are made using a stone circle and a grinder. You can use a special rail, which is laid at the pouring stage.
It is necessary to make cuts or security channels around columns, wall ledges and along the perimeter of the room. The depth should be between 30 and 50% of the thickness of the screed. You can make a grid of channels over the entire area and cover the recesses with sealant to maintain a solid surface.
Some recipes for concrete mixtures
- The most common and accepted. 3 parts sand to 1 part concrete. Add 0.1 part lime. Mix everything thoroughly before adding water until a mixture of uniform color is formed.
- Economy option. For work in several layers, for example, floor construction on the ground or in conditions of large elevation changes, it is possible to make the bottom layer of the screed from a coarse-grained composition. Mix 2 parts sand to 1 part concrete. Add to three parts of medium or fine gravel. Mix with water.
- Recipe for thick ties. If the mixture layer is planned to be very large, cement can be replaced with modern lightweight counterparts. Or mix in equal proportions, for example, expanded clay and standard concrete-400. This will reduce the final weight.
- Ready mixes. Today, there are enough options for ready-made dry mixes for creating a screed. They have a number of advantages:
Screed mixes
Building mixtures are divided into starting and finishing. The first ones are more coarse-grained and are used to create the main thickness of the screed. The surface is rough and uneven. It is "brought to condition" with the help of finishing mixtures that form an even and smooth layer. The same series includes "self-leveling" screeds - this is a very fine composition that spreads and forms the floor level on its own without the need for leveling.
Concrete screed is one of the most popular bases for laying finishing floor coverings. Tiles, linoleum, carpet, laminate, parquet and parquet board are laid on the screed.
In relation to the bath and sauna, a concrete screed is made before laying the tiles, and also as an intermediate layer when installing a warm wooden floor.
The bonded screed has the greatest strength, which is laid directly on the base coated with a primer to improve adhesion (concrete slab, subfloor, etc.).
The screed on the separating layer implies the presence of waterproofing materials (roll, coating or painting) on the basis. If there is thermal insulation in the "pie", they talk about a screed with an insulating layer. Additional layers greatly reduce heat loss, but such a screed has the lowest strength and can collapse under significant loads. But if you are going to make the floor in your own bath, then no special loads on the floor are foreseen (as a rule, the stove that is installed creates the greatest load).
To increase the strength of the screed, a reinforcing metal mesh is laid in increments of 40-50 mm or fiber is used. It is difficult to say how expedient it is to strengthen the screed in the bath. If the bath is small, then there is no need to additionally strengthen the floor.
Preparatory work
If there is an old concrete base, you first need to decide whether to remove it or not. If you plan only to repair the concrete floor screed, the old base does not have large cracks and fits snugly to the base, you can treat the surface with a primer and proceed with the installation of beacons or guides.
If the old base crumbles, has swellings and other obvious defects, it must be removed (for this, a puncher, a jackhammer or a chisel with a hammer are used). After completion of work, the surface is cleaned (using a construction vacuum cleaner or a conventional broom), treated with a primer and allowed to dry. The base is ready.
Wood floor preparation
A concrete screed on a wooden floor has its own nuances: it is necessary to carefully repair all existing defects (replace rotten boards or at least turn them over, seal the joints with epoxy putty, and if necessary with mounting foam, treat the joints with sealant on top), cover the wooden floor with a primer with moisture protection or moisture-resistant paint, lay a layer of waterproofing and only then proceed with the installation of beacons.
The use of a bonded screed is unacceptable here: the wood deforms with temperature changes, which will lead to the destruction of the screed laid directly on the floor boards.
Setting the zero level
The main stage of the preparatory work is the determination of the zero level of the floor screed. If you have a laser, no difficulties are foreseen - just turn it on, install it and make marks on the walls along the beam.
The second method is much more labor intensive. It will require a water level or level. Mark a point on one of the walls at an arbitrary height. For example, 150 cm from the floor. Use a water level to mark other walls (at least 2 marks on each). Then, using a chopping paint cord (you can buy a cord and powder paint for it at a hardware store), connect all the dots. We got a line at the same level relative to the horizon (not the floor).
How to work with the water level, see this video
Now, having measured the height from the floor to the line at several points, find the minimum thickness of the screed, which will make it possible to eliminate all irregularities. Usually the measurements will be different. If you take the largest and smallest value, subtract them, you get the same desired value. Please note that minimum thickness of concrete floor screed 7 mm. With a smaller thickness, cracks will soon appear, the concrete will begin to crumble.
Having found the required thickness of the screed, subtract it from the height of the drawn line. For example, the screed should be 4.5 cm. We subtract 4.5 cm from 150 cm, we get 145.5 cm. We measure this distance from the drawn line and draw another line that will serve as a guide when laying beacons and leveling the screed. This line is called the zero level. Beacons or guides are then aligned along it.
Installation of beacons or guides
In order to make the floor as even as possible, use guide rails, or, as they are also called, beacons. These are wooden or metal strips that are installed on the base so that their upper part coincides with the found zero mark.
What are lighthouses made of?
As guides, you can use smooth pipes or special metal flats with perforated edges. They are sold in specialized stores, and they are called "beacons".
It is not recommended to use wooden slats: they absorb moisture from the solution, which negatively affects the strength of concrete. In addition, wood can deform from moisture, which can cause height differences when leveling the screed.
How and what to put
Guides are laid along the walls perpendicular to the one in which the door is located. The distance between them should not exceed the size of the rule used: it slides along the guides, leveling the laid out solution. When leveling the solution, it will need to be moved from side to side, so leave another 10-20 cm in reserve (with a rule length of 150 cm, place the guides through 110-120 cm).
Lay the beacons on the floor at the required distance, prepare the materials that will serve to level them. The selected rails must be installed at the same level so that their top coincides with the found zero level. For this, some materials are placed under the rails.
Someone uses broken bricks, someone uses plastic or metal plates. The use of cardboard, plywood, wood is not recommended due to the moisture content in the solution, which leads to deformation of these materials. Having been saturated with moisture, they can change the thickness, which will cause a warp. The distance between the fasteners should be such that the beacons or guides do not "walk" and do not sag.
When using special screed beacons, they can be leveled with dowels. They are perfectly attached to the existing ledge. In the necessary places, drill holes in the base, insert self-tapping screws. Rotate them to set the required height.
You can use the "grandfather" method. At some distance, "spots" of the solution (thick) are laid. By pressing or installing additional plates, align the bars at the zero mark (using the building level) and give time for the solution to “seize”.
Attention! The floor in the steam room and washing should have a slope that will divert water to the drain - keep this in mind when installing beacons. Can be oriented to the top.
Primer
After the beacons are fixed, the solution on the spots is a little frozen, the base can be primed. This will improve the adhesion of the concrete to the base.
The primer is poured onto the base, then spread over the surface with a roller or a wide brush.
If the mortar will be laid on a waterproofing film, carefully seal all joints before installing the beacons, check the entire surface for holes and holes. In this case, the use of dowels is impossible - the tightness is broken, and all work on installing beacons and laying the solution will need to be carried out carefully, without damaging the integrity of the film.
Solution preparation
To make a screed, you can use a self-prepared mixture of cement and sand or buy one of the ready-made compositions. When using ready-made mixtures, dilute it in strict accordance with the instructions. This will guarantee its high reliability.
Ready-made dry mix for floor screed "Diola D-342" Screed materials
The proportions of sand and cement depend on the brand of cement and the required concrete characteristics. Below is a table that lists them.
| Grade of cement | Proportion | Solution brand |
| 600 | 1:3 | M300 |
| 600 | 1:4 | M200 |
| 500 | 1:2 | M300 |
| 500 | 1:3 | M200 |
| 400 | 1:1 | M300 |
| 400 | 1:3 | M150 |
| 300 | 1:1 | M200 |
| 300 | 1:3 | M100 |
Now about the purpose of the grades of the solution and their scope:
- M100 is used to create rough screeds, as well as for pillows under the blocks;
- M150 - for the manufacture of concrete;
- M200 - most often used in private housing construction, used for pouring foundations, screeds in heated rooms, etc.
- M250 - for severe operating conditions - for fences, paths, etc.;
- M300 - has water-repellent and frost-resistant properties, therefore it is most widespread: from pouring foundations to installing repair supporting systems (at);
- M350 - for creating beams and load-bearing walls in multi-storey construction;
- M400 and above are used to create heavy-duty structures.
Below is a table that shows the proportions of concrete using two aggregates: sand and crushed stone. Perhaps someone will want to use such concrete.
A typical mistake in concrete work is to exceed the recommended proportion of cement. Its quantity is increased, in the hope that the concrete will become stronger. The result is the opposite: it cracks, crumbles and quickly collapses. This happens due to the fact that he did not have enough aggregate and / or water to gain normal strength. Therefore, the recommended norms should not be changed.
How to mix
If you want to use the usual mixture of cement and sand, then take 1 part of cement (400 marks) and 3 parts of construction sand for floor screed. First, dry sand and cement are mixed until a uniform color is obtained. Then water is poured into the container (0.5 parts of water per 1 part of cement or 1 liter per 5 kg of the mixture), the mixture is poured, stirring thoroughly (with a trowel or shovel - depending on the volume).
For small volumes, to obtain a homogeneous composition, you can use a construction mixer or a drill with an appropriate nozzle; for large volumes, you need a concrete mixer. Mechanized mixing is necessary according to technology: this is the only way to achieve a uniform distribution of all components.
Note. The strength of concrete made using a concrete mixer or a mixer is 50% higher than concrete, the rasters for which were kneaded with a shovel.
As a result, the solution should have a uniform structure and the same color. After finishing mixing, you need to let the composition stand for a while, then knead it again with a mixer.
To obtain a homogeneous mortar, use a construction mixer or a drill with an appropriate attachment You can check the density by taking a little solution in your hand and clenching your fist. After the hand is unclenched, the solution remains in a lump - it does not flow or crumble. If you pour the solution on the floor, it should spread, but not spread. This consistency is perfect.
Prolonged exposure of the finished solution to air is undesirable. Ideally, as soon as one part has been used, the next one should be ready. This is achievable with an assistant. While one aligns one portion with the beacons, the second prepares a new one. So the screed will be strong and uniform.
Laying mortar and curing concrete
Start laying the solution from the corner farthest from the door. Right or left, everyone decides for himself. A portion of the solution is laid out between the guides, slightly leveling. Then they take the rule and, resting it on the beacons / guides, stretch the mixture, leveling it along the way.
You can simultaneously apply the rule a little to the right and left. So it's a little easier to distribute the composition evenly. Having achieved the filling of all voids, leveling the solution according to the level, lay the next portion, gradually filling the entire space. During work, it is advisable not to take long breaks so that the edges do not have time to harden and “grab”.
If guides were laid, as soon as the concrete becomes hard enough to retain its shape, you can pull them out. Some time later (about a day after laying), the holes remaining after pulling out the guides are sealed with mortar. When using beacons, they are left in the floor and no additional work is required.
Curing
In order for the screed to be strong, concrete needs to harden, not dry. Therefore, the first three to four days at normal humidity and low temperature, the surface of the screed is moistened with water - 2-3 times a day. At high temperatures, the surface is covered with polyethylene foam. It is also necessary to take care that there are no areas with different temperatures: sunlight should not fall (close windows), if work is carried out in winter, heating should not work.
It is advisable to leave the floor unloaded for 3 weeks, but the minimum period is 1 week. If there is a desire to increase the strength of the screed and speed up its "readiness", you can add a plasticizer.
This is the whole process. As you can see, you can make a floor screed with your own hands even without much experience in construction. The most difficult and troublesome thing is to set up and fix the beacons. The rest of the work is quite simple.
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