In this article, we will analyze in detail the design and construction of a monolithic concrete floor on the ground. Under the "floor on the ground", further in the article, we will understand the concrete floor, made inside the contour of the foundation, right on the ground. Let's take a look at common questions related to this floor and the structure itself from ground to finish.
With what types of foundations can you make a floor on the ground
A concrete floor along the edge can be used with a strip foundation, and with a columnar foundation (or a foundation using TISE technology). The slab foundation itself (by its design) is immediately a floor on the ground. With a strip foundation, the floor structure, as a rule, adjoins the foundation wall.
Rice. 1. Adjoining the floor on the ground to the strip foundation
Rice. 2. Adjoining the floor on the ground to the columnar foundation with a low grillage
With a columnar foundation or a foundation using TISE technology, the floor structure on the ground can be adjacent to the grillage (if the grillage is low), or located below the grillage (if the grillage is high).
In the case of a high grillage, the gap between the floor structure and the grillage is closed when the floor is filled, for example, with boards (can be unedged). These boards remain in the structure, they are not removed, Figure 3.
Rice. 3. Adjoining the floor on the ground to the columnar foundation in the case of a high grillage
The height of the floor device on the ground relative to the strip foundation
Rice. 4. Floor on the ground on the tape extension
Rice. 5. The floor on the ground is adjacent to the wall of the strip foundation
Rice. 6. The floor on the ground is located above the foundation tape
Rice. 7. Floor on the ground adjacent to the top of the tape
There are no constructive mandatory recommendations regarding the mark (height) of the floor device on the ground. It can be arranged at any height shown in Figures 4-7 above. The only thing you need to pay attention to when choosing this option is where the front door will be in height. It is advisable to attach to the mark of the bottom of the door so that there is no difference between the bottom of the door and the floor, as in Figure 8, or so that you do not need to then cut an opening in the tape under the door.
Rice. 8. Height difference between the floor on the ground and the doorway
Rice. 9. Floor on the ground flush with the doorway
Note: It is better (more correct) to provide an opening for the front door at the stage of pouring the tape. Just do not flood this place, insert boards or polystyrene there, so that an opening remains in the tape. If you forgot to leave the opening, then you will either have to make the entire floor higher (and this will increase the cost of backfilling), or cut an opening in the finished tape, cut the reinforcement in it, loosen it, etc.
Thus, if the opening under the front door is made correctly (at the stage of pouring the tape), then we arrange the floor on the ground so that the top of the floor is flush with the opening under the door (taking into account the finishing coating). In order to correctly calculate the thickness of the floor structure, and determine from what mark you need to start its construction, you need to understand what all its layers will be in thickness, what it depends on. More on this later.
There are no such cases. Even when the groundwater level is high, it is more correct to arrange a monolithic floor on the ground than a floor on logs, for example. The type of soil, seismic, freezing level - all this also does not affect the possibility of constructing such a floor.
Note: We do not consider situations when the house is raised above the ground on piles, it is clear that then such a floor is not suitable.
Floor construction options on the ground
Rice. 10. Floor construction on the ground at ground water level higher than 2 m (with waterproofing)
Rice. 11. Floor construction on the ground at low groundwater level, below 2m, with backfill
Rice. 12. Floor construction on the ground at low groundwater level, below 2m, without filling, with pouring instead of a rough screed
Rice. 13. Floor construction on the ground at low groundwater level, below 2m, without filling, with a rough screed
Rice. 14. Floor construction on the ground in combination with a warm floor
Note: Figure 14 shows underfloor heating pipes and a reinforcing mesh above them. Between the floor pipes and the reinforcing mesh, - no gap, just drawn for clarity.
Description of the main layers of the floor on the ground
Let's analyze the main layers (pie) of the floor on the ground. We consider the design from the bottom - up. We will describe all the layers that may be, without reference to a specific pattern.
- compacted soil- the basis for the device of a floor, has to be qualitatively condensed;
- Backfill layers(sand 7-10 cm and gravel 7-10 cm). Backfill layers can be made to protect against capillary rise of water and can be made as a leveling layer. Crushed stone in the bedding layer should be of a fraction of 30-50 mm (large). The sand in the bedding layer can be any, both river and quarry (ravine). It depends on the purpose for which the backfilling is done, whether it is possible to replace crushed stone with expanded clay, you can read about this in the paragraph Is it possible to replace crushed stone with expanded clay, in the same article, below. It is important that the layers of backfill are well compacted. There are conditions when a bedding device is mandatory, and when it is not. You can read about this in the paragraph What determines the design of the floor on the ground, in the same article, below;
- Rough floor screed on the ground. This is a layer on top of the bedding or compacted soil. It is carried out on a plastic film (it spreads on the ground or bedding), the thickness of the rough screed is 5-7 cm. It can not be reinforced. Sometimes a rough screed is replaced with a spill. About spilling - in the next paragraph, about when it is possible to replace a rough screed with a spill - in the paragraph Is it possible to replace a rough screed with a spill, in the same article, below. Crushed stone in the design of the rough screed should be a fraction of 5-10 mm (fine). The sand in the design of the rough screed must be river, not quarry (ravine);
- Spilling (filling) the floor on the ground. It is arranged by spilling a layer of bedding with a solution. The thickness of the pouring is equal to the thickness of the bedding layer. It is arranged without a plastic film;
- Waterproofing. It is arranged from roofing material, 1-2 layers. Roofing material can be taken the most common, without sprinkling. There are conditions when waterproofing is required. You can read about this in the paragraph What determines the design of the floor on the ground, below;
- . We recommend using EPS with a density of 28-35 kg / m 3, or polystyrene with a density of 30 kg / m 3 and higher as a heater for the floor on the ground. The thickness of the insulation is determined by calculation (depending on the climatic zone);
- Finishing screed. The thickness of the final screed is 7-10 cm. The crushed stone in the construction of the final screed should be a fraction of 5-10 mm (fine). The sand in the construction of the finishing screed must be river, not quarry (ravine). A finishing screed (unlike a rough screed) is necessarily reinforced. Reinforcement is carried out with a mesh with a wire diameter of 3-4 mm. How to choose, 3 mm or 4 mm, is written in the paragraph What determines the design of the floor on the ground, below;
- Finish coating. Finishing floor covering on the ground can be any. Accordingly, the details of the device are different for each type of coverage.
The presence and sequence of floor layers on the ground
What determines the design of the floor on the ground:
- From the level of occurrence of groundwater;
- From whether these floors will be with heat carriers (warm) or not;
- From operational loads on the floors.
How exactly the construction of the floor on the ground depends on these factors, we will analyze below.
1. By the presence of waterproofing. Our recommendations: to arrange waterproofing from roofing material (1-2 layers), if the groundwater level lies closer than 2 m from the bottom of the floor along the ground. In addition, when the groundwater is located closer than 2 m, we recommend that you make sure to add sand and gravel, Figure 10. If the level is lower than 2 m, then you can make the floor without waterproofing. At a level lower than 2 m, sand and gravel filling is not required, Figure 11, 12, 13.
Note: You need to focus on the highest groundwater level that can be on a particular construction site. That is, to watch how high the water rises in spring, during floods, etc., and this is the level to take into account.
2. If there are heat carriers in the floor structure on the ground, it is necessary to make a gap between the walls and the floor, 2 cm. This requirement is the same for both water and electric underfloor heating. The gap is made at the level of the finishing screed (with coolant). All layers below the finishing screed are placed to the walls without a gap, Figure 14. You can read more about installing a water-heated floor in the article.
3. If it is planned that something heavy (heavier than 200 kg / m 2) will be placed on the floor on the ground, then we reinforce the finishing screed with a mesh with a wire diameter of 4 mm. If the load is up to 200 kg / m 2, then it can be reinforced with a wire mesh with a diameter of 3 mm.
Important points when installing a floor on the ground
I would like to analyze these important points on the basis of questions that, as a rule, readers of our portal have when installing a floor on the ground.
Can interior walls be placed on this floor?
Yes, on a 4 mm wire-reinforced screed, you can put internal walls made of brick (in brick), from a partition block (100 mm), and walls half a block thick. By "block" is meant any block (expanded concrete, shell rock, aerated concrete, foam concrete, etc.)
Can crushed stone in the bedding layer be replaced with expanded clay?
Backfilling is performed, as a rule, in order to break the capillary rise of water. Expanded clay swells from water, and, as a bedding material, is not suitable. That is, if the bedding was planned as additional protection against water, such a replacement cannot be done. If the backfill was planned not as a protection, but simply as a leveling layer, and the water is far away (deeper than 2 m from the base), and the soil is constantly dry, then crushed stone can be replaced with expanded clay for flooring on the ground.
Can crushed stone in the bedding layer be replaced with broken bricks, building materials waste?
It is forbidden. If the backfill was planned as an additional protection against water, then broken bricks and other waste will not fulfill their task in the backfill. If the backfill was planned not as a protection, but simply as a leveling layer, then we also do not recommend such a replacement, since these materials are of different fractions, it will be difficult to compact them with high quality, and this is important for the normal operation of the floor structure.
Is it possible to replace crushed stone in the bedding layer with expanded clay, pour more of it, and then not put insulation?
To replace 50-100 mm of EPPS (that's how much on average is needed to insulate the floor on the ground), you will need 700-1000 mm of expanded clay. Such a layer cannot be compacted with high quality, so we do not recommend doing this.
Is it possible not to reinforce the screed?
You can not reinforce the rough screed. It is imperative to reinforce the finishing screed.
Is it possible to reinforce the screed with a non-mesh? Is it possible to put just metal bars in the screed instead of a reinforcing mesh, without tying them together, or other metal parts?
No, in order for reinforcement to work, it must be performed by a mesh.
Can waterproofing be laid directly on the layers of backfill?
No, waterproofing must be laid on a flat and solid base (in our case, it is a rough screed), otherwise it will quickly become unusable due to uneven loads.
Is it possible not to make a rough screed and put waterproofing or insulation (if there is no waterproofing) directly on the layers of backfill?
For waterproofing dismantled in the paragraph above. Insulation must also be laid on a flat and solid base. This base is the rough screed. Otherwise, the insulation may move, and subsequent layers too, and this may lead to cracks in the floor.
Is it possible to do a spill instead of a rough screed?
Let's analyze what we mean by "rough screed" and "pouring". A rough screed is a layer on top of the bedding or compacted soil. It is carried out on a polyethylene film (it spreads on the ground or bedding), the thickness of the rough screed is 5-7 cm. The thickness of the pouring is equal to the thickness of the bedding layer. It is arranged without a plastic film. Now about whether it is possible to replace the rough screed with a spill. If the water is closer than 2 m, and the bedding (sand and gravel) was carried out as a layer that prevents capillary rise, then watering cannot be done. Because the spilled rubble will not cut off the capillary rise of water. If the backfill was carried out for leveling purposes, and the water is deeper than 2 m, then you can do the spill instead of the rough screed. If there is no backfill at all, and the screed is carried out directly on the compacted soil, then both a rough screed and a spill can be done. It only turns out that it makes no sense to do the pouring, since for it you still have to pour sand about 3 cm and crushed stone about 10 cm, and the sand in this case is river, and the crushed stone is about 10 mm fraction. In general, it is easier to perform a regular rough screed.
Does polyethylene under the rough screed replace waterproofing?
The function of this layer is to prevent concrete milk from going into the layers of backfill or into the ground. This layer is purely technological, it does NOT replace the main waterproofing (roofing material over the rough screed). If the water is deeper than 2 m, then waterproofing (roofing material) is not needed, but this does not mean that we “replaced” it with polyethylene. It's just that these layers have a different function, and do not replace one another. When installing a rough screed and water deeper than 2 m, a layer of polyethylene is still needed.
Where is it correct to place the reinforcing mesh in the finishing screed?
Does it matter where exactly the reinforcing mesh is located in the finishing screed layer (bottom, top or center)? If the screed is without heat carriers, then the mesh should be located 3 cm from the top of the screed (that is, approximately in the middle). If the screed is with heat carriers, then the mesh must be on top of the pipes, plus 2-3 cm of the protective layer.
Rice. 15. Finishing screed without coolants, reinforcement
Rice. 16. Reinforcement of the finishing screed with coolants
If earlier concrete floors on the ground were used only for unheated premises, then the emergence of new building materials and technologies has significantly expanded the scope of their use. Now such floors are being installed in all rooms, and the degree of protection against heat losses in concrete floors is almost as good as structures made of traditional materials. And for the duration of operation, concrete floors have no equal. Another advantage of such structures is that they can serve as the basis for all types of floor finishing.
Concrete floors can have several varieties, but all are subject to the same technical specifications. requirements. Regulatory recommendations for the design and installation of concrete floors are prescribed in the provisions of SNiP 2.03.13-88. Compliance with these provisions guarantees the durability of the use of structures.
SNiP 2.03.13-88. Floors. Download file (click on the link to open the PDF file in a new window).
Table. Basic regulatory requirements for concrete floors.
| Name of indicator | Regulatory requirements |
|---|---|
| Physical indicators of soils should not allow the possibility of deformation of the concrete floor due to natural subsidence or seasonal expansion of wet earth. In residential premises, it is taken into account that the temperature does not fall below zero. It is forbidden to use soils that are not compacted according to SNiP 3.02.01-87 as a base for floors. |
| Fillings can only be used after thorough mechanical compaction, the underlying layer of concrete must have a concrete class ≥ B 22.5. The indicators of the underlying layer in thickness are selected taking into account the maximum possible loads. Deviations of the bottom filling from the horizontal are not ≤ 15 cm per 2 m of the floor length. The bedding is done with sand or gravel. |
| Provided by the underlying, used in cases where the floor is located in the zone of capillary water. At the same time, the height of moisture rise through the capillaries is taken in the parameters of 0.3 m for coarse sand, 0.5 m for fine fraction and 2.0 m for clay. The height of the groundwater, as many amateurs say, does not have any effect on the height of the rise of capillary water. |
| The thickness of the thermal insulation of concrete structures is regulated by the provisions of SNiP and depends on the specific purpose of the room. Concrete floors on the ground, installed in heated rooms, must have a heat-insulating gasket along the perimeter of the junction with the foundation or walls. This gasket additionally compensates for the thermal expansion of structures. |
| It is provided if it is necessary to level the surface of the concrete layer, to cover various engineering networks, to reduce thermal conductivity and create slopes (if necessary). The thickness should be 15-20 mm more than the diameter of engineering pipelines. For self-leveling coatings with polymers, the screed is made of concrete ≥ B15, the strength of light (semi-dry) concrete is ≥ 10 MPa. With an increase in floor loads in individual sections, the thickness of the screed is calculated taking into account the exclusion of deformation and loss of integrity. |
Technical requirements are adjusted taking into account the characteristics of the premises and project documentation.
Step-by-step instructions for the construction of concrete floors on the ground
For example, consider the option of arranging a concrete floor in a residential area. To save building materials, it is recommended to install hydroprotection.
Step 1. Calculation of parameters and number of layers of concrete floor. Before starting work, you need to decide on the zero level. If the house is being built according to the project, this parameter is indicated on the drawings. Zero level - the level of finishing the floor, everything below this level is indicated on the construction drawings with a minus sign, everything above is indicated with a plus sign. In most cases, the floor is located at the level of the foundation, but there may be deviations.
If you do not have a project, which is very bad, then we recommend equipping the concrete floor in such a way that the concrete surface is in the same plane as the foundation. Now we need to do the pie calculations.
- Sand layer. For a private house, it is enough to make a pillow about 10-15 cm thick. Gravel can be omitted, the load on the floor in residential premises is not so high.
- A layer of primary concrete under the base. The thickness is about 10 cm. If there is a desire, then the primary layer can be reinforced with a metal mesh with mesh sizes up to 10 cm and a wire diameter up to 3 mm.
- Insulation. It is recommended to use modern extruded polystyrene foam. It can withstand significant loads, does not absorb moisture, and is not afraid of rodents. The thickness of the thermal insulation is within 10 cm, it is impractical to do less due to low efficiency.
- Top screed concrete floor. The parameter depends on the load, in our case the screed should be more than 7 cm.
The thickness of the waterproofing layers is not taken into account. Now summarize these dimensions - this is exactly the distance that should be from the ground to the upper plane of the foundation tape.
Step 2 Ground leveling. Measure the level of soil under the floor, decide how much to throw out or pour according to previously made calculations. If there is a lot of land, then it should be removed, you will have to dig with a bayonet shovel, no equipment can work in the perimeter of the strip foundation. If there is not enough land, then the missing amount should be poured. Constantly check the ground level.
Loose soil must be rammed. This can be done with a mechanical unit (frog, vibrating plate) or manually. The first option is much better - the work is noticeably accelerated, and the quality of the rammer is improved.
Practical advice. If you do not have a vibrating plate, then experienced builders strongly advise you to pour plenty of water on the compacted earth and leave it for several days for natural shrinkage. The resulting recesses after shrinkage are additionally leveled and re-rammed. If the earth is loose, then uneven shrinkage of the concrete floor cannot be avoided, and this is an extremely unpleasant phenomenon.
You can independently make the simplest device for tamping the soil. Take a bar 100 × 100 mm about 1 m long. Nail a wooden platform from a board trimming with a square side of about 20–30 cm to the lower end, fasten the handles to the upper end. It’s not worth making a large site: the larger it is, the less tamping force, you will only level the top layer of the earth, and not compact it. If the layer of earth exceeds 10 cm, then it is necessary to ram in several stages, after each of them fresh bedding is done.
Step 2 On the inner perimeter of the foundation tape, mark the location of the layer of sand, insulation and the final concrete layer. During work, do not allow deviations from the marks made by more than 2 cm.
Step 3 Pour sand, constantly level and compact each layer. We remind you once again that its stability largely depends on the quality of tamping of the concrete floor base.
Step 4 When the sand cushion has the calculated thickness, the first layer of concrete can be poured. The material is prepared based on one part of M 400 cement, two parts of sand and three parts of gravel. Gravel and sand should not contain clay, it greatly impairs the properties of concrete. Calculate the approximate amount of material. First, determine the cubature of the layer, this is easy to do. Next, use the practical data. For one cubic meter of M100 concrete, you need about 3 bags of M400 cement, for M150 concrete you need 4 bags of cement. Accordingly, sand will need twice as much, and gravel three times as much. The calculations are approximate, but in practice no one measures fillers up to a kilogram. Concrete can be prepared with a concrete mixer or manually. Briefly describe the technology of both methods.
Making concrete with a concrete mixer
You should not buy a large concrete mixer; for private construction, it is quite enough to have a unit with a bowl volume of 0.5–0.75 m 3. Store sand, gravel and cement next to the concrete mixer, place the materials in such a way that it is convenient to throw them into the bowl. Water is always poured first, for a stirrer with a volume of 0.75 m 3, at least three buckets are needed. Then you need to throw about 8-10 shovels of gravel into the water and pour cement. Gravel breaks all small lumps of cement to a homogeneous mass. When the cement is completely dissolved in water, sand and gravel can be thrown until the concrete of the desired grade is obtained. Water is added as needed. At first, the inclination of the bowl should be approximately 30 °, then, as it fills, it can be lifted. But do not increase the angle too much - the larger it is, the worse the ingredients are mixed.
Prices for electric concrete mixers
electric concrete mixer
Making concrete by hand
This is hard physical work that requires certain practical skills, but for small volumes you can prepare material in this way. How to prepare concrete by hand?
- Prepare a flat, solid platform about 2 × 2 m in size. For the base, it is better to use a steel sheet, if not, then you can make a wooden box with low sides. The height of the sides is within 20 cm.
- Pour sand, gravel and cement into one pile in the form of a pyramid. During the pouring of the pyramid, alternate all materials, the amount should correspond to the recommended proportions.
- Throw a pyramid with ingredients with a shovel to a new place and back again. Double transfer will ensure uniform mixing of cement with sand and gravel.
- In the center of the pyramid, make a funnel deep to the bottom, pour water into it. Take the prepared ingredients in small portions with a shovel and mix them with water. Move in a circle, make sure that the barrier shaft of dry material does not break through. Water is also added as needed.
Concrete must be prepared in portions, taking into account the speed of its laying.
Step 5 Fill the surface of the compacted sand with concrete in portions. Control the height along the lines made on the foundation. Concrete is first leveled with a shovel, and then with a rule. There is no need to make lighthouses; only the last layer of the concrete floor should withstand exact horizontality. Level the mass with a long rule, periodically check the flatness of the coating with a level. If significant deviations from horizontal are found, problem areas should be corrected immediately.
Practical advice. Professional builders recommend making the first layer of the floor from a semi-dry mass. It has several advantages: significantly less thermal conductivity than ordinary, manufacturability and ease of installation. In terms of strength, the semi-dry mass is inferior to the wet one, but this is not critical for the floors in the house. The semi-dry mass is prepared in the same way as the wet mass. The only difference is that the amount of water decreases.
Step 6 Install waterproofing, work can begin after the concrete has set, this will take at least 48 hours. If the concrete layer was made in dry and hot weather, then it must be abundantly moistened with water at least twice a day. Earlier in this article, we already mentioned that waterproofing for concrete floors on the ground in houses is not always considered a prerequisite. If the thickness of the sand cushion is sufficient to interrupt the capillary retraction of moisture, then waterproofing is not needed. In addition, waterproofing is also not required on all gravel bases. Gravel does not draw water through the capillaries. But for reinsurance, waterproofing can be done, use an ordinary plastic film with a thickness of about 60 microns for this. This material is inexpensive, and in terms of efficiency it is in no way inferior to expensive modern non-woven materials.
Step 7 insulation layer. It is recommended to use extruded polystyrene foam. It has excellent performance in all respects. The only drawback is the high cost. To reduce the estimated cost of concrete floors, expanded clay or slag can be used as a heater.
Important. These heaters react extremely negatively to an increase in humidity. For them, the presence of waterproofing is a prerequisite. Moreover, waterproofing should be done both from above and from below.
Step 8 Cover the concrete surface with sheets of expanded polystyrene. Do not allow gaps between the sheets, insert them with little effort. The material is perfectly springy and when the load is removed, it independently eliminates cracks. Expanded polystyrene is well cut with a mounting knife. You need to cut it on a flat surface under a ruler or a flat rail. If you have an electric cutter, great, if not, then work manually. First, the sheet is cut on one side, then exactly along the cut line on the other. After a slight bending force, the notched sheet breaks. Expanded polystyrene can also be cut with a hacksaw for wood with fine teeth.
Step 8 Regulations do not provide for the need for waterproofing polystyrene foam, but practitioners advise not to skip this stage of work and cover it with plastic wrap or another type of waterproofing agent.
Step 9 Install a soft heat insulator along the inner perimeter of the foundation tape. These can be strips of foam about one centimeter thick or special foam rubber tapes. The heat insulator performs two tasks: it eliminates the possibility of heat leakage from the concrete floor to the foundation strip and compensates for the linear expansion of the concrete floor.
Step 10 Install beacons. The final layer of concrete must have a flat surface. Beacons can be installed in various ways, but the fastest and easiest way is to make them from metal bars.
- Throw a few small piles of cement-sand mixture on the surface. In order for it to set faster, you need to increase the amount of cement by one and a half times. The distance between the piles is approximately 50-60 cm, the main criterion is that the bars should not bend under their own weight. The distance between the lines of beacons should be 20–30 cm less than the length of the rule.
- Install the two extreme beacons under the level. Carefully check their position, the upper plane of the beacons must coincide with the plane of the foundation tape.
Practical advice. In order to speed up the setting of the cement-sand mixture, sprinkle it with dry cement several times. Remove the wet cement and sprinkle the heaps under the bars again. Cement very intensively absorbs moisture, after such procedures, you can continue to work without waiting for the solution to completely harden.
- Pull the ropes between the two extreme beacons and do the rest on them. Do not forget to check the position, it is very difficult to correct errors in the future.
After all the beacons are exposed, start making the top layer of the concrete floor.
Step 11 Throw concrete between the beacons in small portions. First, level the material with a shovel and trowel, and then with a rule. Work carefully, do not allow the appearance of depressions. To improve the performance of the top layer of concrete, add plasticizers during preparation. The specific brand doesn't matter, they all work great. The main thing is to follow the proportions and technologies recommended by manufacturers. For the top layer, add four parts of sand to one part of cement.
This completes the work, allow time for the screed to completely harden and then proceed to the final coating of the concrete floor. As a finishing floor, you can use lumber, ceramic tiles, linoleum, etc. We have considered the simplest concrete floor, but there are options with electric or water heating, it will take much more time and knowledge to equip such structures.
In private housing construction, the technology of constructing a concrete floor on the ground is widely used. This type of floor is the most popular because of its ease of execution, strength, low cost and general availability of concrete. Concrete flooring on the ground is usually carried out in commercial premises, less often in residential ones. In order to cope with this task with your own hands, you need to understand what layers the pie of this building structure consists of.
Layers of the concrete floor structure on the ground:
- Underlayment;
- Waterproofing;
- Thermal insulation;
- Concrete base slab;
- Screed;
- Floor covering.
In order for the concrete floor on the ground to serve in the house for many years, you need to properly operate it - make sure that the air in the building is warm. In the absence of heating in the house for a long time, the floor structure may be deformed, with the appearance of cracks and gaps due to the heavy load from frozen soils on the floor pie.
Ground floor technology
First you need to set the zero level in the room. To do this, marks are made along the perimeter of the walls in the lower part of the entire room, focusing on the bottom of the doorways. Thus, by lowering or raising this line, it will be possible to make the required thickness of the cake. The thickness of the concrete pour is controlled by a rope stretched over the nails, which serves as a level.
To prepare soil bases, we remove the vegetative layer of soil, clean it with our own hands from debris and tamp it down. We level the surface as much as possible.
Usually the concrete floor cake is about 350mm thick. Therefore, from the zero line, it is necessary to dig the soil to this thickness. If the soil level is below 350 mm, then it is necessary to remove a layer of fertile soil, tamp and fill in dry sand to the required level with its subsequent compaction. After that, tamping and leveling of the surface is performed. For this, the best tool is a special vibrating plate. In its absence, tamping is carried out with your own hands and for this you can do with a simple log or a flat board, to which handles are attached for ease of use. Concrete floor on the ground is a technology that requires the most leveled surface at the stage of laying each layer.
For additional waterproofing of the future structure, you can first make a layer of clay. If the clay is dry, it is necessary to spill it with water, compact it with your own hands, fill it with sand and then compact it. In addition, clay makes the base warmer.
Advice! To indicate the required height of the backfill, you can drive several pegs of the desired length into the ground. The main thing is that the marks are clearly marked on the level. After all dry layers have been poured, the stakes will need to be removed before the concrete is poured.
We fill in the first layer (thickness 50-100 mm) with gravel, followed by pouring with water and tamping. The second layer (about 100 mm) is filled with sand, also followed by tamping. As a result, we get a warm pillow for the concrete base of the floor cake in the house.
Hydro and thermal insulation device
Various technologies are used to create waterproofing, where heated bitumen casting and polymer membranes are often used). We recommend waterproofing with a special waterproofing polymer membrane, but if you want to save money, you can lay your own ordinary plastic cake film with a thickness of 200 microns. The film is laid with an overlap of 10-15 cm, and the joints must be made airtight and glued with adhesive tape.
Important! Waterproofing should be carried out over the entire area of the house, the edges adjacent to the walls must be bent along the wall a few centimeters above the zero line.
A huge number of different types of thermal insulation materials are presented on the modern construction market, for example:
- expanded clay;
- mineral wool;
- Styrofoam;
- extruded polystyrene foam;
- isolon.
Each type of insulation has its own installation technology, the observance of which will make it possible to get a warm floor in the house.
Reinforcement of the concrete floor structure on the ground
In order to give the floor structure strength and protect it from destruction during operation, it is necessary to perform its reinforcement. For this purpose, plastic or metal reinforcing meshes or reinforcing bars can be used. If we use rods, then they must first be fastened with flexible steel wire into a mesh with a cell from 100 to 200mm (the higher the load on the floor, the smaller the mesh cell size should be). In order for the reinforcement to work effectively, it is necessary that the reinforcement on both sides be protected by a layer of concrete - for this, the reinforcing mesh must be laid on stands about 20-30 mm high. It is not difficult to do this with your own hands, just put the bars under the grid and raise it to the desired height.
Creating formwork and guides
Boards, beams, metal profiles, reinforcement bars, etc. can be used as guides. With the help of guides, we divide the surface into several platforms with a width of about 2m. It is important that the guides are laid at the same level. We fix the guides with lime-cement mortar or in another way.
To make formwork, you can use boards or moisture-resistant plywood. We place the formwork for pouring concrete between the guides. As a result, cells are formed - the so-called "cards", which must be filled with concrete. The same guides can serve as beacons for leveling cement during pouring. Throughout the process of laying the concrete floor, it is important to ensure that the surface is even, guides and formwork must also be checked with a building level before proceeding with pouring. Irregularities in the formwork are eliminated either by squeezing the upper part of the boards or by placing the remains of bars, plywood, etc. under them.
Before pouring concrete, do not forget to treat the formwork with oil - this will allow you to easily remove the wooden elements from the hardened concrete.
Pouring concrete
Concrete pouring followed by a rough concrete screed. To prepare a concrete solution, we use the following ratio of components:
- cement grades M400-500 -1 part;
- sand - 2 parts;
- gravel - 4 parts;
- water - 0.5 parts.
We mix all the components with a concrete mixer, or manually and pour a concrete solution of a homogeneous consistency simultaneously into several “cards” in 1 step, in extreme cases in 2, helping ourselves with a shovel in a more even distribution over the surface.
Advice! Pouring with concrete mixture should be carried out from the corner of the wall opposite the front door so that you do not have to walk on concrete.
After filling in several cards, you can start rough alignment. To do this, we use a rule about two meters long. Moving the rule towards us along the guides as if on rails, we distribute the concrete into “cards”, thus removing the excess concrete mass and filling the voids.
When the entire area of \u200b\u200bthe room has been treated in this way, you need to give the concrete time to harden (about a month), covering it with plastic wrap. To prevent cracking of concrete, be sure to spray it with water periodically.
The video clearly illustrates the technology of the rough screed device:
Finished concrete screed
The device of a concrete floor on the ground ends with the stage of creating a final concrete screed. The most effective option is to use self-levelling screeds based on gypsum or cement and special additives.
An important parameter of the screed is its weight. Therefore, if you need to reduce the load on the ceiling, use lightweight screeds - self-leveling floors. A feature of this coating is the speed of installation - it can be done in 1 day, it is well suited for hidden communications and underfloor heating.
Some may say that the concrete screed is not very reliable and always remains cold. And its advantages include, perhaps, efficiency, environmental friendliness and fire resistance. It used to be like this, but the use of modern materials and advanced technologies makes the service life and reliability of the screed much higher, and heat insulators provide a comfortable surface temperature.
The arrangement of a concrete screed on the ground is not always a rational solution. There are certain restrictions that must be taken into account:
- no basement or basement;
- groundwater flow at a depth of at least 4-5 meters;
- the presence of heating in the house, since freezing of the soil can lead to deformation of the screed due to a higher load on the foundation.
Having decided to create a concrete floor on a soil base, you need to make sure that flooding does not threaten the house. It is possible to start arranging the screed only after the construction of the walls and roof of the structure.
A concrete pavement on an earthen base consists of several layers, each of which performs an important function. Layers are created from various materials, as a rule, the "pie" includes the following components:
- sand layer;
- crushed stone or gravel layer;
- waterproofing material;
- draft concrete floor;
- steam and heat-insulating layer;
- clean concrete floor.
Any commercially available material that corresponds to the stylistic direction of the interior and most harmoniously fits into the design of the home can act as a finishing floor covering.
In no case should you start pouring concrete directly onto the ground, because the first two layers of the “pie” prevent the penetration of moisture from the soil into the floor covering, which can occur by capillary action. Creating a concrete screed is not the easiest and fastest process. The main difficulty lies in the fact that the work takes place in several stages. It’s not worth messing around, because as a result, a high-quality coating should be formed that is not prone to dust formation, airtight and resistant to loads.
The layered structure is the key to a long service life of the screed and its wear resistance. The modern technology of creating a concrete screed can be divided into two large stages: preparatory work and the immediate arrangement of the concrete pavement. Each of these stages consists of several parts.
Video - Floor screed on the ground
Preparation for the arrangement of concrete screed on the ground
Preparatory work is a mandatory step in creating a concrete floor, it is they who take the lion's share of the time in the process of arranging the screed. But it is not possible to do without them, unless, of course, you want to get a low-quality result.
filter layer
First of all, it is necessary to deal with the compaction of the earth at the base, which will help prevent its subsidence and, accordingly, possible cracking of the screed. Concrete floors on the ground are often equipped in combination with a strip foundation with a depth of at least 1-1.5 meters, filled with sand inside.
But this approach is not acceptable if the house is on a clay plot. After all, clay retains moisture, therefore, if there is sand inside the foundation, water stagnation forms and a real “pond” appears under the building. That is why in clay areas it is necessary to arrange drainage.
The best course of action in this case is:
- clay extracted during the creation of the pit is filled with its lower part;
- the internal thermal insulation of the house and the external insulation of the foundation are carried out. These actions are aimed at leveling the heaving of the soil even in the absence of heating in the building;
- gravel is poured onto the prepared earth, and then carefully compacted. The quality of the rammer is very important in this case, since it is a question of preventing the formation of voids. It is carried out with the help of special ramming mechanisms;
- sand is poured onto the gravel, which is also carefully rammed and smoothed.
The thickness of the filter layer depends on the characteristics of the soil, as a rule, sand and gravel pads are not thicker than 15-20 cm each.
Waterproofing layer and rough screed
After backfilling the foundation, you can begin to arrange the waterproofing of the future screed. The most popular materials for this purpose are polyvinyl chloride and bitumen-polymer membranes. If the moisture level for the house is within the normal range, then you can get by with a conventional polyethylene film 250 microns thick, which is laid in two layers.
The edges of the waterproofing material should be slightly higher than the expected level of the finished concrete screed. Particular attention should be paid to laying waterproofing in the corners, since it is through them that moisture most often penetrates. If the material does not completely cover the perimeter of the room, then its elements are overlapped and fixed with adhesive tape.
The optimal material for a rough screed is "lean" concrete, in which crushed stone is added. The resulting surface does not have to be perfectly flat, and there are no high requirements for it. It is quite enough if it does not have differences in height of no more than 4 mm. At the same time, its thickness should be about 4 cm.
Thermal insulation layer
Insulation of a concrete screed is an important stage, so a lot of attention is paid to the choice of heat-insulating material. It must have the following qualities:
- high strength;
- low thermal conductivity;
- fire resistance;
- ease of use.
Most often, preference is given to foam, polystyrene foam or a layer of mineral wool. The required thickness of the material is determined by the location of the house. For example, in central Russia, slabs 10 cm thick can be used for insulation, in less warm regions - up to 20 cm.
The laid thermal insulation material must be covered with a polyethylene film on top, which performs two purposes at once: it prevents the penetration of concrete mortar into the space between the insulation elements and provides vapor barrier.
Stages of arranging a concrete screed on the ground
Preparatory work ends after the creation of a heat-insulating layer. However, it is impossible to immediately proceed to pouring concrete - you need to take care of the strength and reliability of the future structure.
Screed reinforcement
The next step is the laying of reinforcement, which will give the concrete surface additional strength and durability. Traditionally, a road mesh is used for this purpose, the diameter of the bark bars varies between 5-6 mm. The dimensions of the cells in this case are 100 * 100 mm or 150 * 150 mm. Such reinforcement will prevent the appearance of cracks on the screed during shrinkage.
It is best to place the reinforcing layer a few centimeters above the thermal insulation material, as this will be inside the concrete cover. If the operational load of the floors is very high, then a reinforcing cage is used to strengthen them.
The photo clearly shows the mesh laid on the waterproofing
Formwork creation
Before starting the arrangement of a finishing concrete screed, guides and formwork are mounted. This technology allows you to more accurately maintain a given level. The available area is divided into equal segments, the width of which does not exceed 2 m. After that, guides are installed, their height should correspond to the desired level of the screed. Guides are fastened with a cement mortar, in which clay and sand are introduced.
Then, formwork is laid in the space between the guides, thereby dividing the base into rectangular parts, which are subsequently filled with cement mortar. Guides and formwork are brought to the desired level and aligned horizontally, serving as a guarantee of evenness of the future coating. After pouring, they will be removed from the concrete, which is quite difficult to do, therefore, to simplify this process, they are covered with special oil.
In order to obtain a monolithic surface, the screed is poured in several passes:
- work begins from the corner located on the opposite side of the door. After filling several rectangles, the solution is distributed with a spatula over the entire area;
- then comes the time for rough leveling, which is carried out by moving the rule towards itself, while removing excess concrete;
- on the treated areas, the formwork and guides are removed, and the voids that appear are filled with a cement mixture.
This procedure is maintained until the entire floor area is filled. To compact the concrete surface, you can use a special vibrator, which will speed up the process and remove all voids. When the screed is completely ready and leveled, it is kept under the film for 3-4 weeks and moistened periodically. On the finished monolithic surface, it is possible to pour a leveling screed made of concrete M-100 and higher.
Creating a floor screed on the ground is a task subject even to home craftsmen. The modern technology of the process is maximally facilitated, the main thing is to follow the stages of work, do everything with high quality and listen to the advice of specialists:
- the screed level is set taking into account existing or planned doorways. The marking of the level must be carried out around the entire perimeter of the base. Stretched cords will help simplify orientation;
- if a clay layer is involved in the preparatory work, then it should be moistened and then compacted - such an obstacle will become almost insurmountable for groundwater;
- a concrete screed on an earthen base - a multilayer "pie", each of the layers in which must be carefully aligned horizontally;
- the thermal insulation characteristics of the concrete floor can be improved with expanded clay, cork or plywood layer;
- the thickness of the rough screed should be about 8 cm, and the heat-insulating layer should be at least 10 cm;
- when creating a reinforcing cage for a concrete floor, which will have to withstand serious operational loads, it is best to use rods with a diameter of 8 mm;
- the concrete surface is prone to cracking; in order to avoid this trouble, expansion joints are created on the coating. After cutting, they must be sealed;
- to prevent the appearance of dust on the screed, special impregnations are used, which are applied no later than 7 hours after the compaction of the concrete layer.
It is very important to use high-quality materials when arranging a concrete screed, especially for the “stuffing”, that is, insulation and waterproofing. If they fail, then the whole structure will lose its strength and will not last long. You should not save on materials for the screed, otherwise you will later have to spend much more money on repairs.
The result of the implementation of competent work with high-quality materials will be the appearance of a reliable and durable concrete floor. It will not only withstand high operating loads, but will also serve as an ideal base for applying any of the topcoats on the market today.
Floors with a properly equipped concrete screed will last more than one year, or even decades. Observing the technological sequence and paying due attention to all its stages, an amateur who has very modest knowledge about the repair process and possesses minimal skills will also cope with the creation of a screed.
tables
| Concrete brand | Mass composition, C:P:Sh, kg | Volumetric composition per 10 l of cement P/Sch, l | |
|---|---|---|---|
| 100 | 1: 4,6: 7,0 | 41/61 | 78 |
| 150 | 1: 3,5: 5,7 | 32/50 | 64 |
| 200 | 1: 2,8: 4,8 | 25/42 | 54 |
| 250 | 1: 2,1: 3,9 | 19/34 | 43 |
| 300 | 1: 1,9: 3,7 | 17/32 | 41 |
| 400 | 1: 1,2: 2,7 | 11/24 | 31 |
| 450 | 1: 1,1: 2,5 | 10/22 | 29 |
| Concrete brand | Mass composition C:P:Sh, kg | Volumetric composition per 10 liters of cement P/Sh, l | The amount of concrete from 10 l of cement, l |
|---|---|---|---|
| 100 | 1: 5,8: 8,1 | 53/71 | 90 |
| 150 | 1: 4,5: 6,6 | 40/58 | 73 |
| 200 | 1: 3,5: 5,6 | 32/49 | 62 |
| 250 | 1: 2,6: 4,5 | 24/39 | 50 |
| 300 | 1: 2,4: 4,3 | 22/37 | 47 |
| 400 | 1: 1,6: 3,2 | 14/28 | 36 |
| 450 | 1: 1,4: 2,9 | 12/25 | 32 |
| Styrofoam | polyurethane foam | Min. plate |
|---|---|---|
| open cell structure | There is both open and closed cell structure | Fibers randomly arranged in vertical and horizontal directions |
| Poor moisture permeability | Almost impervious to moisture | Almost does not absorb moisture |
| Lightweight material | Lightweight material | Medium-light material |
| Medium strength | Low strength | Low/medium strength |
| Average compressive strength | Low compressive strength | Low to medium compressive strength |
| Non toxic | Non-toxic, emits carbon monoxide and carbon dioxide at a temperature of 500 degrees | Non toxic |
| Not suitable for high load use | Not all slabs are suitable for high load applications |
Floors on the ground are an economical option for building a country house on a strip foundation. When arranging, costs are minimized, as publicly available materials and tools are used. Concrete as a building mix for screed is the most popular because of its availability, low cost, ease of manufacture, high strength and durability.
Requirements for a concrete floor on the ground
Despite the absence of the need for special skills, some requirements are imposed on the installation of a concrete floor:
- Soils should be dry and immovable with a minimum level of groundwater - 4-5 meters.
- It is recommended to first determine the magnitude of the planned load.
- Choose the pouring technology: conventional on the ground or concrete screeds with lags.
When groundwater occurs closer than two meters to the foundation, waterproofing with coarse gravel is required. If underfloor heating technology is used, a thermal gap of 20 mm between the concrete floor and the wall will be required in order not to damage the casting during operation.
on the ground should be built only in a heated country house. Otherwise, soil freezing may occur, which will cause deformation of the structure due to increased loads. It is recommended to pour the floor when the walls and roof are erected, which will improve the quality of the work performed.
Advantages of the floors
Advantages of screeds, equipped on the open ground:
- cost-effectiveness compared to conventional designs;
- simplicity and ease of installation;
- high reliability, strength and stability;
- increased frost resistance;
- ease of arranging a warm floor.
Manufacturing technology
For concreting floors on soils with your own hands, you will need a mixture of cement, sand, crushed stone or gravel. To calculate the amount of mortar required, multiply the area of \u200b\u200bthe room by the thickness of all layers of the structure. The concrete mixture is prepared in a ratio of 1: 2: 3 (cement: sand: gravel or). Ready mix concrete can be used. To do this, one volume of cement will require 6 volumes of crushed stone with a fineness of 20 mm and 3 volumes of sharp-angled sand.
To prepare large quantities of concrete, you need a concrete mixer. First, dry components of the mixture with the above composition are poured into the mixer for 2/3. After thorough mixing, water is added in portions until a sufficiently plastic solution is obtained. The next servings can be started by pouring water. At the end of construction work, the concrete mixer must be cleaned and rinsed.
Level markup
The zero level of the concrete floor is deposited in two stages:
- From the bottom of the doorway, 1 meter is measured, which is transferred to all perimeter walls.
- From the drawn upper line, 1 meter down is again measured, and beacons are placed for the future floor.
Filling is carried out to the obtained zero level. For easy orientation along the edges, nails are hammered into the corners, on which a steel thread is pulled.
Clearing and compacting the soil
Preparation of the site for pouring is carried out in several stages:
- Cleaning the soil from debris.
- Removal of the top layer of the earth corresponding to the thickness of the future multilayer floor - 30-40 cm.
- Careful tamping of the surface with a vibrating plate. In the absence of special equipment, ramming is carried out with an ordinary board or log. When there are no deep footprints, the ground is considered sufficiently compacted.
If the thickness of the removable layer of earth is more than 40 cm, sand should be added after compaction to the desired level.
To increase, the soil is covered with clay, which is watered and carefully rammed. Then sand is poured. Such a "cushion" will prevent leakage of groundwater.
Laying layers with gravel, sand and crushed stone
Cushion of gravel, sand and crushed stone for the floor in the garage. The next layer is a gravel layer 5-10 cm thick. For a more accurate determination of the required level, pegs of the desired height are driven in. The resulting layer is watered, compacted, the beacons are removed. Then ravine sand 10 cm thick is laid (possible with impurities). The reservoir is watered and rammed.
The next layer of crushed stone with a grain of 40-50 mm is only compacted. There should be no protruding edges on the surface. All layers of the concrete floor are aligned horizontally with a building level.
Waterproofing and thermal insulation
In order to improve the waterproofing properties of the concrete floor in a country house, an additional layer of 0.02 cm thick polyethylene film should be laid. As an alternative, a waterproofing membrane is used. It is necessary to isolate from possible ingress of moisture the entire area of the room with an overlap on the walls of 2 cm and between the sheets. The joints are sealed with adhesive tape.
There is a wide range of materials to improve thermal insulation: polystyrene foam, expanded clay, ordinary or extruded polystyrene foam, stone-basalt or mineral wool, perlite, cork products, isolon in rolls, thick moisture-resistant plywood. Thermal insulation is laid after waterproofing.
Reinforcement
The required strength of the concrete screed is achieved by reinforcing with a metal or plastic mesh. You can also use reinforcing bars or wire. For laying the reinforcing frame, it is necessary to build supports 2-3 cm high.
Installation of guides and formwork
Guides and formwork will most accurately maintain the level when pouring concrete. For this, the area of the future floor is divided into equal segments. Boards or bars are laid on the markup flush with the zero level. The guides are fixed with a thick solution of sand-cement and clay. The formwork is mounted between boards made of moisture-resistant plywood to form honeycombs. With their help, concrete pouring will correspond to the zero mark. It is recommended to coat the formwork and guides with special oil, which will facilitate the process of their dismantling.