Floor screed above foundation. How to make a concrete floor on the ground in a country house? Types of rough screed

From this article you will learn:

• What are the advantages of a subfloor on the ground
• What layers should the rough floor on the ground consist of
• How to make a rough floor on the ground with your own hands
• What do professionals advise regarding the subfloor on the ground

Building a house in Moscow is a long and multi-stage process, including work of a completely different nature and complexity: laying the foundation, erecting walls, roofing, finishing and a host of other processes. Among the main stages of construction is a rough finish, in particular, pouring the screed. Its essence is to create a base on which a finishing coating with finishing materials will subsequently be installed. Despite the fact that the draft floor on the ground is often subject to a builder of any qualification, it has a number of nuances and requires various types of work. This article will talk about them.

What does a draft floor on the ground mean?

This method is applicable to any type of soil, regardless of the proximity of groundwater. A high-quality and reliable rough screed on the ground is provided with concrete grade M300 and higher. In particular, a higher grade of concrete should be used for floors that are expected to be heavily loaded or if the soil properties are unsatisfactory. In this case, a reinforcing mesh is also required.

All recommended parameters of the necessary materials are indicated in the design estimates. If there are none, it is necessary to make the appropriate calculations yourself, taking into account all the conditions for the further operation of the floors.

Benefits of a subfloor on the ground

Among the advantages of carrying out a screed on the ground, the following are distinguished:

Subfloor layers on the ground

In order for the filling of the subfloor on the ground to be of high quality, it is necessary to take into account all the following layers:

• compacted base;
• a mixture of purified and sifted river sand with gravel;
• rough concrete screed;
• vapor barrier membrane or other insulating material;
• insulation made of expanded polystyrene or other similar material;

• polyethylene film;
• reinforced concrete screed;
• flooring, which, if necessary, can be laid on a special substrate.

This diagram is not the final version. The stages may vary depending on the characteristics of the soil, types of flooring and other nuances.

Do-it-yourself rough floor on the ground: step by step instructions

Step 1. We prepare the base.

First of all, the zero point is searched using a level (and adjusted for the relief and surface level). This will make it possible to objectively assess the scope of the forthcoming work with the soil. The surface of the earth is carefully compacted in order to reduce the risk of subsidence of the soil and cracking of the finished floor.

• the first layer should be 25% higher than necessary;
• the poured layer is moistened and rammed, due to which the thickness comes in line with the original calculation;
• compaction is carried out by means of a vibrating machine or a roller.

A layer of gravel or expanded clay is poured on top of the sand, which will make the sand layer denser and become a solid foundation for the following layers.

Step 2. We produce sub-floor concrete.

The first layer of the subfloor is lean concrete. It performs technical functions, being the basis for vapor and waterproofing. For the rough screed, lean concrete (class B 7.5-10) with crushed stone filler (fraction: 5-20 mm) is used. When using gravel bedding, the screed can be poured with concrete of class 50-75.

Filling the first screed is not troublesome and does not require adherence to precise technology. The thickness of the rough layer should vary between 40-50 mm and not exceed 4 mm horizontally in accordance with the level.

Step 3. We carry out waterproofing of the rough base.

To eliminate capillary suction of moisture from the soil, waterproofing of the floor should be carried out.

• The most suitable for waterproofing will be bitumen in rolls or a polymer membrane. Sometimes a gasket made of a single piece of thick polyethylene film is allowed. If the material is joined, it must be overlapped, followed by sealing the seams with construction tape. It is necessary to inspect the surface of the materials for integrity damage or manufacturing defects.
• The insulating sheet is displayed on the walls by about 15-20 cm. After laying the finishing screed, excess material fragments are removed.
• Sometimes it is impossible to lay waterproofing in front of the rough screed. In this case, a concrete base is poured, on which a coating waterproofing layer of bitumen or polymer is applied.

Step 4. Insulation of the subfloor on the ground.

The next step is the installation of a vapor barrier layer. The most suitable material for this is a polymer-bitumen membrane, based on fiberglass or polyester. Despite the high quality and durability, the price of such material will pleasantly surprise you. A more expensive analogue of such a material is a polyvinyl chloride membrane. However, in this case, a high price is by no means an indicator of durability. In practice, such material is subject to rotting and other damage.

The vapor barrier layer will help save a lot of money on space heating, because the level of heat loss during its use is reduced by 20%. The laying of this layer is the key to creating warmth and comfort in the house.

Warming is carried out using materials such as:

• Extruded polystyrene foam is one of the best insulation options, protecting the floor from frequent deformations during compression and withstanding heavy loads.

• A variety of polystyrene foam is PSB50 and PSB35 class foam. The first option is intended for garages, warehouse or industrial premises, the second - for dwellings. To avoid damage to the foam plastic with cement mortar, foam sheets are sheathed on both sides with a polyethylene film. Such insulation will be quite reliable.

• Another common option for insulation is mineral wool. However, such a material is able to quickly absorb moisture from the cement layer and screed. Therefore, as in the case of foam, mineral wool must be insulated on both sides with a polyethylene film.

Step 5. Reinforcement.

It is important not to confuse the rough floor screed on the ground with the foundation, which experiences loads from heaving forces. In this regard, a single-layer reinforcement with a welded mesh of rods with a diameter of 3-5 mm will be sufficient.

It is important to take into account some of the nuances:

1. The mesh should be laid as close as possible to the base of the structure (in the concrete tension zone).
2. The thickness of the protective layer should be from 1.5 to 2 cm, so the mesh is mounted on polymer or concrete pads placed on polystyrene foam.

Along the perimeter, the structure must be protected with a similar layer. Most often, cards with a cell from 10x10 to 15x15 cm are used. In this case, the overlap must affect at least one cell. The contour of the warm floor is placed on the grid and fixed with nylon clamps.

Step 6. Damper layer and fill.

The screed is separated from the walls, grillage, plinth and foundation by means of a damper layer. It is formed from strips of expanded polystyrene installed on the edge, which are placed along the perimeter of the enclosing structures. Another option is to stick a special tape on the walls also around the entire perimeter. The height of such a damper must exceed the thickness of the subfloor on the ground. Excess parts will be cut off at the stage of installation of the plinth.

It is worth noting that the screed of the subfloor on the ground is done in one step to ensure the greatest resource of the structure. For large areas (over 50 m2), expansion joints are created from a special profile.

To make it easier to level the layers, plaster beacons are often used, which are attached to a quick-hardening solution of gypsum or starting putty.

Then a mixture is applied between the beacons, which is leveled by the rule. Beacons can be left embedded in the floor or removed after the mixture has set a little. The resulting gutters can be filled with concrete and leveled again. To prevent cracking, the surface must be moistened periodically during the first 3 days.

Answers from professionals to popular questions about finishing screed

To save money in general and ensure better performance in particular, some builders sometimes try to replace the recommended materials for a rough floor screed on the ground with others.

• Is it advisable to change crushed stone to expanded clay for adding screed?

Such an original solution can provide additional thermal insulation. However, professionals do not recommend using expanded clay for soil with closely spaced groundwater, which can lead to wetting of this material.

• Can crushed brick or other construction waste be used instead of gravel?

The use of such materials is strongly discouraged. Brick is not a waterproof material, it absorbs water and quickly collapses. Consequently, such a draft floor on the ground will lose its strength and integrity. In addition, waste and broken bricks have a different fraction, so it will not be possible to compact them tightly.

• Is it possible to install hydroprotection only under a rough screed and not to use it in the future?

The answer is negative. Firstly, the polyethylene film is responsible for other functions: it prevents the cement laitance from leaving the mortar. Secondly, after some time, the waterproofing loses its tightness and breaks under the influence of uneven point loads on the floor.

• Is it possible to replace the rough screed by pouring the floor on the ground?

Spilling involves spilling onto the bedding under the rough screed with a special layer of liquid solution. Its height depends both on the thickness of the bedding layers and on the intensity of compaction. If the bedding is very dense, the liquid solution will not be able to penetrate more than 4-6 cm. As a result, the bearing performance of the floor base will be reduced. Thus, the answer to this question must be given, taking into account the possible loads on the floor surface.

Draft floor on the ground for a warm floor

The design of a warm floor on the ground will be optimal subject to the following steps:

How much does a rough floor on the ground cost

The detailed cost of work on the rough floor on the ground is displayed in the price lists of various construction and repair organizations. They can be found on the websites of these companies. You can also find out the price and get additional advice by phone. In addition, many companies offer a free visit of a measuring consultant to your facility in order to calculate the price as accurately as possible, taking into account all possible nuances and wishes.

Cooperate with the company "My Repair" - it is reliable and prestigious. The specialists working here are professionals of the highest level. The company "My Repair" operates throughout Moscow and the Moscow region.

Such a screed is made in private houses, garages, outbuildings, industrial and warehouse premises, in large trading floors, at bus stations, etc.

The method is considered universal, it is used on all types of soils, regardless of the location of groundwater. For pouring, concrete of grade not lower than M300 is used, if the loads on the floor are large and the physical characteristics of the soil are unsatisfactory, then the grade of concrete increases and a reinforcing mesh is necessarily used.

All indicators for the thickness and characteristics of materials are prescribed in the design and estimate documentation. If it is not there, then the calculations must be done independently, while taking into account all the factors that affect the operating conditions of the floor coverings.

1. The rough screed is located below the ground, adjacent to the strip foundation at the level of the tape expansion. Such a scheme is used if there are underground rooms under the house for storing food or other needs.
2. The rough floor screed on the ground is located approximately at ground level and is adjacent to the side inner wall of the strip foundation. The most widespread situation is used not only in housing, but also in industrial construction.
3. The rough floor screed is located above the foundation tape. It is used during the construction of buildings on waterlogged soils, in areas with flood risks, etc.

There are no universal recommendations for the location of the rough screed, it all depends on the operating conditions and architectural features of the house. The only requirement is that the position of the door frame must be planned even before the start of the rough screed, the level of the finished floor should be at the level of the threshold.

Options for arranging a rough screed on the ground

The specific option is chosen by the builders, taking into account the maximum load on the structure and the proximity of groundwater. The classic solution is compacted soil, a layer of sand and gravel of various thicknesses, polyethylene film and a rough screed with or without reinforcement.

This method is recommended in cases where groundwater is located closer than two meters to the surface. Groundwater is much lower - you can simplify the construction scheme. It is allowed to pour a rough screed directly on the ground, use only sand or gravel as backfill. In some cases, it is possible to pour a subfloor directly onto the ground without using a plastic film. For a rough floor screed, the film is used not so much for waterproofing (concrete is not afraid of moisture, on the contrary, in conditions of high humidity it increases strength indicators), but for retaining cement laitance in a mixture. Without a film, it will quickly leave the concrete, which will have a very negative effect on strength.

What factors affect the construction technology of the rough screed

If they come closer than two meters to the surface, then be sure to backfill with sand and gravel. The backfill serves to prevent moisture from being drawn in by soil capillaries. If there is a backfill, then the use of a film to retain cement laitance is required. If a rough screed is made immediately on the ground, then the film can not be laid.

Important. The location of groundwater must be determined in the spring, it is during this period that they rise the most.

If the floor structure assumes the placement of heat carriers, then the rough screed should have compensation gap between the foundation. Such structures eliminate the negative impact of thermal expansion and exclude the possibility of cracking or swelling of the rough screed.

If the planned load on the floor can exceed 200 kg / m2, then reinforcement is mandatory. Reinforcement parameters are selected individually for each case. The same approach is needed in cases where it is planned to install interior partitions on the floor. You should not rely only on the reinforcement of the finishing screed, its physical characteristics do not allow it to withstand heavy loads.

A few frequently asked questions about the rough screed

Inexperienced builders often try to replace the recommended materials for adding a rough screed with others in order to save money or improve performance.

1. Is it advisable to replace the crushed stone bedding with expanded clay bedding for a black screed? At first glance, it may seem that this is an original solution that allows you to simultaneously insulate the floor. Professional builders recommend using this material only for those cases where groundwater is low, and expanded clay is excluded from getting wet.
2. Can gravel be replaced with broken bricks and other construction waste? Absolutely not for several reasons. Firstly, the brick draws in water, when wet, it quickly collapses, the base of the rough screed loses its strength and stability. Secondly, waste and broken bricks have different linear dimensions, it is impossible to carefully compact them because of this.
3. Is it possible to put waterproof protection only under the rough screed and not use it anymore? No. We have already mentioned that the polyethylene film performs other tasks - it does not allow cement laitance to leave the solution. Over time, the waterproofing breaks its tightness, under the influence of uneven and point loads, it will definitely break.
4. Is it possible to do a spill instead of a rough floor screed? Quite a difficult question. First you need to define what a spill is. Pouring - a layer of liquid solution, which is poured over the bedding under the rough screed. The thickness of the pouring depends not only on the thickness of the bedding layers, but also on the quality of their compaction. If the bedding is dense, then the liquid solution will not penetrate deeper than 4–6 centimeters. As a result, the bearing performance of the base for the floor is significantly reduced. Conclusion. The decision should be made taking into account the loads on the floor.

Now that we have dealt with most of the questions on the features of the rough screed device technology, we can give step-by-step instructions for pouring it.

Instructions for the manufacture of a rough screed for the floor on the ground

Consider the most complex and time-consuming option using all layers of backfill.

Step 1. Make measurements. First, on the foundation tape, you need to designate the level of the finished floor.

To do this, use a laser or hydro level. The size is determined according to the design and technical documentation or working drawings for the object. Further down, you need to put marks on the thickness of the floor, depending on its design, the thickness of the finishing screed, rough screed, gravel and sand layer.

Step 2 Remove the soil to the estimated depth, clean the site, prepare for backfilling with sand. Tamp loose soil or carefully clean the base with a shovel.

Step 3 Pour in the sand. As a rule, the thickness of the layer varies within ten centimeters. If a large amount of sand is required, then it must be poured in stages, each layer should be rammed separately. The quality of ramming will improve significantly if the work is carried out using special mechanisms: vibrorammers or vibrocompactors. During tamping, care must be taken that the sand has a more or less even and horizontal surface.

Ramming is a very important stage in arranging a rough screed on the ground, there is no need to rush. All the pits are filled and rammed again, the tubercles are cut off.

Step 4 Pour a layer of crushed stone with a thickness of ≈ 5–10 cm, carefully compact it. Crushed stone is better to take several fractions of op sizes. A larger one is poured onto the sand, and a fine one under the rough screed. In this way, the bearing characteristics of the base are improved. Part of the engineering communications can be hidden in the layers of backfill or directly in the rough screed. There is no need to strive to install all the pipes and electrical networks there, in case of emergencies it is very difficult to get to them for repair work.

Independent production of concrete mix

You can do it yourself using a concrete mixer or order it ready from construction companies. You need to choose yourself, both options can be optimal under certain conditions. It is recommended to calculate the cost of materials in both cases, evaluate your material capabilities and physical strength, the number of workers.

Concrete mixture should be below average in density. Such indicators allow concrete to independently spill over the floor area. One of the advantages of using liquid concrete is the absence of the need to install beacons and perform time-consuming work on its alignment with manual rules.

Workers only need to slightly correct the level in the places where the material is poured. If reinforcement is required, then a mesh is placed at the same time. Building regulations require that it be installed in such a way that the thickness of concrete on all sides exceeds five centimeters. Otherwise, the structure will not work as a whole, the actual strength of reinforced concrete will be much less than the calculated one. The consequences can be the saddest.

What will be the final floor chooses the developer. Regardless of the option chosen, builders recommend making reliable waterproofing on top and laying insulation. On top of these structures, a finishing screed is made under the tiled floor or wooden logs are laid under other options for finishing floor coverings. Such schemes make the floors warm, which is very important given the current prices for heat transfer fluids. At the same time, the implementation of the recommendations of professional builders significantly increases the operating time of floor coverings.

Is it profitable to make a rough concrete screed on the ground

The issue worries all developers without exception, it should be considered more carefully. We will compare with the use case for these purposes factory reinforced concrete slabs.

Installation of slabs with a truck crane

The simplest calculations, taking into account the cost of slabs and additional work and materials and rough screeds on the ground, show savings of up to 25%. And this is only the most approximate calculations. Payment for expensive loading / unloading equipment, delivery shoulder, etc. were not taken into account.

Video - Rough floor screed on the ground

But it is not without a number of shortcomings. If you forget to make vents in the strip foundation (or incorrectly calculate their cross section), then over time this can lead to problems. Due to insufficient ventilation of the underground, wooden logs become covered with fungus, mold and rot. Excess moisture in the basement also leads to the destruction of the concrete floors of the floor of the first floor.

To avoid this, you can replace traditional vents with a closed ventilated underground. This is detailed in the article. “Do I need air in the basement” . But there is another option - to abandon the underground and build a floor on the ground on the basis of a strip foundation, as FORUMHOUSE experts advise.

Floors on the ground: what is itsuch

This design is a monolithic concrete base (screed). Here is the arrangement of the floor on the ground: the screed is poured inside the perimeter of the strip foundation onto well-packed soil, with which the sinuses of the foundation and the insulation layer are covered. Underfloor heating can be installed together with a concrete base. This design accumulates heat, so it is well suited as an element of an energy-efficient home.

The composition of the floor on the ground for a residential building.

There are the following options for floors on the ground:

1. On the prepared base (well-compacted soil), a floor slab is poured, rigidly connected to the strip foundation;
2. A floor slab is poured onto the prepared base, which is not connected to the strip foundation, the so-called "floating" screed.

Let's take a closer look at the pros and cons of these options.

Michael1974:

- If you fill in a “floating” screed, then the construction of the tape and the floor is “untied”. If shrinkage occurs, then the floor screed structure on the ground will “play” regardless of the foundation, cracks will not appear in the structure, because. no stress. This is a plus. But there is also a minus - the design "lives its own life", separate from all other structures.

Floor device on the ground.

With a rigid structure, the foundation / screed unit works as a single unit. The screed will not shrink, because lies on the foundation. But if the soil is not compacted well enough, after a while it may sink, and the screed will “hang” in the air. With a heavy load, if there are walls, partitions, supporting elements on the screed, this can lead to deformation of the base, cracks and loss of the bearing capacity of the entire floor structure on the ground.

How to make a floor on the ground

Both screed options have both pros and cons. The quality of the concrete floors on the bulk soil depends largely on the quality of the compaction of the bulk soil and on how correct the design will turn out.

Michael1974:

– When pouring a “floating” screed, the “foundation wall/screed” assembly must really be untied, otherwise the structure may be pinched in the tape frame. Those. the floor inside the tape frame must move relatively freely, otherwise the whole point of the floating screed is lost.

To do this, a damper is made of an elastic material between the screed and the foundation (wall), which restores its original shape after the load is removed - in this case it is appropriate to place an isolon with a thickness of 8-10 mm. This will allow the concrete screed to “float” freely and compensate for its thermal expansion.

A common mistake is to tie all nodes as tightly as possible. As a result, increased loads occur in the structures. In the case of a floating screed, the "floor" and "foundation" elements work independently of each other.

Ground floor: device.Basic principles

An important rule: a well-prepared base is the key to a long service life of the entire structure. The filling base (the best backfilling of the floor on the ground is sand) must be spilled with water and carefully compacted in layers of 10-15 cm.

Due to the backfilling of crushed stone, when the rammer passes through it, a local impact occurs, as a result, there is a deep additional compaction of the soil layers lying at the lower levels. It is worth building up attention on the correct method of tamping sand.

- In all the instructions for vibrating plates it is written that the plate rams sand to a depth of 20-30 cm, but how well this layer is compacted, I doubt that it is enough. Therefore, I believe that for reinsurance it is better to compact the sand in layers of about 10 cm. It looks like this:

• We spread the sand in a layer of 10-15 cm;
• We pass through the sand with a vibrating plate "dry";
• Spill sand with water from a hose. It is necessary to do this not with a jet of water, so as not to break the layer, but through a spray nozzle;

It is necessary to spill water so that the sand is wet, but not oversaturated with moisture. If the amount of water is too large, then the sand base is practically not rammed.

• We pass through the moistened sand with a vibrating plate 2 times with a change in the orientation of movement;
• Spill the sand with water again;
• We pass along the moistened sand with a vibrating plate 2-3 more times with a change in the direction of movement.

What kind of waterproofing to put on the floor on the ground

After thorough preparation of the base, we proceed to laying the hydro-vapor barrier, which will protect the floor structure from moisture. It is often asked whether it is necessary to make a footing before laying this layer. After all, welded or glued waterproofing, in order to avoid damage, must be placed on a flat, rigid base.

Building a house is a long-term process and includes a huge number of works in various directions. This is the erection of walls, and the construction of the roof, and a host of other types of work. One of the mandatory steps is the filling of the rough screed. It is necessary to create the primary base, on which the finishing screed or finishing coating will then be laid. A rough screed does not require special qualifications of the builder, but, nevertheless, it involves a large number of works associated with its creation.

Creating smooth floors in a new home is not the easiest thing to do. And it is the construction of a rough screed that is the main stage on the way to a flat base suitable for laying various types of coatings. It ensures the reliability of the base and its strength. This is a rather time-consuming and time-consuming process, but at the same time financially quite economical.

As a rule, laying a rough screed on the first floors is carried out directly on the ground. And most often, an ordinary concrete mixture made from sand and cement is used as a base material.

However, the process of creating a rough screed cannot be called quite simple. The fact is that it involves laying several layers of various materials and several preparatory stages:

• soil preparation - it must be carefully compacted;
• laying sand and gravel;
• flooring of waterproofing material, insulation;
• installation directly of the rough screed itself;
• installation of finishing material.

Thus, the floor consists of several layers. And this design has its own name - the pie of the floor. It may also contain . Reinforcement is necessary to increase the strength of the screed.

Important! A rough screed can only be built on dry ground. On a wet, full-fledged one, it will not be possible to create it, since problems with waterproofing may arise. Also, a rough screed can only be mounted if groundwater occurs at least 4 m to the surface.

Also, during the installation of a rough screed, an underfloor heating system and other communications, if any, are necessary according to the house construction project.

In general, a concrete floor on the ground in private construction is probably the most acceptable option for creating a foundation. It is often laid inside garages, on terraces, verandas, in warehouses and others.

On a note! Most often, concrete floors on a soil base are equipped where there is no severe cold in the winter, that is, in the middle or southern strip of the Russian Federation. In cold regions, it is recommended to use wood to create the base of the floor.

In the photo - crushed stone bedding

Main advantages

If we consider the main advantages of creating a floor on the ground, then we can determine the following.

1. Ease of all work. In general, creating a floor cake with the right approach takes only a few hours.
2. High strength and resistance to deformation will ensure a long service life of the floor finish.
3. Such a base has good indicators of heat, hydro and sound insulation. Such a floor, even in cold weather, will not critically freeze, which will keep the house warm and comfortable.
4. One of the factors is economy. Arranging a rough screed is not as expensive as it might seem at first glance.

Thanks to all these advantages, many future home owners choose it as a base, and not created from any other materials.

Types of rough screed

Rough, like a regular screed, can be of different types. It all depends on the laying technology and the materials used. It can be done both dry and wet.

Dry floor screed- this is a kind of multi-layer cake, where vapor barrier (or waterproofing) material, expanded clay or sand act as layers, acting as a dry “cushion”, as well as any leveling material such as chipboard, OSB, plywood or gypsum fiber, depending on the wishes of the owner of the future home. Often, the material can be laid not in one, but in two layers, while individual sheets are fastened with self-tapping screws.

Wet screed It is made on the basis of a cement-sand mixture, which will be poured over previously laid other layers and carefully leveled. A waterproofing layer and insulation can be laid under it, without fail - a sand cushion.

On a note! There is also a semi-dry screed. If in the previous version the mixture during preparation and use will resemble sour cream in consistency, then in the version with a semi-dry screed it will look like wet sand.

Rough screed device diagrams

Depending on the level at which groundwater occurs, as well as depending on the level of the soil and the position of the screed relative to the foundation, there are several types of it.

Table. Types of arrangement of the rough screed.

In general, there is no universal scheme for arranging a screed - depending on the design of the house, it can be performed in any of the above options. However, it is important to accurately design the location and level of doorways even before construction begins, so that you do not have to correct the mistakes made later.

Foundation preparation process

All work on the arrangement of the rough screed begins with a thorough preparation of the soil base. To begin with, it is important to identify, taking into account the level of the soil and the evenness of its surface, the highest and lowest points. The laser level will help determine their values. This procedure is necessary in order to evaluate the entire scope of work for yourself, as well as determine how much building materials may be required.

It is also important to pay attention to the thorough compaction of the soil. To do this, you can use special construction equipment - for example, a roller or a vibrator. The procedure is necessary so that in the future the soil does not significantly subside and this does not entail cracking of the rough screed, which will undoubtedly have a negative impact on the finishing flooring.

After the soil has been carefully compacted, a sand and gravel cushion is laid. It can also be made from clean, washed and river sand. The thickness of this layer should not be more than 60 cm. In the latter case, a layer of gravel or expanded clay is also poured on top, which will make it possible to create a more solid foundation.

Attention! Before the soil is compacted, it is important to cut off the entire fertile layer, if any, from it. He can find a more worthy use than burial under the house. The soil layer is removed by about 35 cm.

It is also recommended to fill the pillow not all at once, but in layers - for example, 20 cm each. In this case, each layer is well rammed separately. The procedure will make the base as dense as possible. Before tamping, the pillow is wetted with water. The thickness of the expanded clay layer can be at least 10 cm. This layer is also separately rammed.

Prices for popular models of electric vibrorammers

electric vibrorammer

Rough screed layer and waterproofing

Another important step in creating a rough screed is its waterproofing. If it is neglected, then the moisture seeping out of the soil will “undermine” the concrete screed and, as a result, the base will become unusable and collapse, or at least it will last a very short time.

For waterproofing a rough screed, roll materials are usually used - others in this case will be ineffective. The ideal option is to use rolled bituminous material or a waterproofing membrane. Less commonly, but still used dense polyethylene. The material must be laid in one large piece. If it is necessary to form joints (in the case of large areas), then they are carefully sealed - soldered or glued with construction tape so that water does not have a chance to penetrate to the base.

Attention! The waterproofing material should not have defects - holes, otherwise it will not fulfill its role.

It is important to lay the waterproofing material in such a way that it extends 15-20 cm onto the walls. If necessary, after laying the finishing screed, the excess can be cut off. If the waterproofing material cannot be laid for some reason, then the final screed must be treated with coating materials that can resist moisture and retain it.

thermal insulation

In order to make the floors as warm as possible, it is important not to skip the thermal insulation stage. Expanded clay, basalt wool, extruded polystyrene foam are used as a material that helps to keep warm. Laying the material is simple - the plates or layers of any of them are mounted butt-to-butt, without gaps, on a surface insulated from water. Thus, it will be possible to obtain a base that retains the heat as much as possible, which tends to leave the house.

Attention! After laying the insulation material, it is recommended to lay another layer of waterproofing. This will allow you to evenly pour the screed and protect the insulation from getting wet as much as possible in case of flooding. Wet insulation often loses most of its properties.

The most convenient and simple option, but not the cheapest, is polystyrene foam. In addition to its thermal insulation functions, it makes floors stronger. Styrofoam can also be used as a heater. In this case, PSB50 grade material is used for garage and storage premises, and PSB35 grade for residential premises.

It is important to protect the foam from getting cement on it, which can destroy the material. To do this, the foam must be closed with plastic wrap. But mineral wool has one drawback, which sometimes scares off builders - it tends to absorb moisture, which is why waterproofing measures should be carried out especially carefully.

Reinforcement

Reinforcement is an additional reinforcement of the rough screed by laying a reinforcing mesh in it. This material, created from metal rods or plastic, is able to significantly strengthen the base and allow it to withstand maximum loads. The mesh is laid on top of the previously mounted layers on small supports so that during the pouring of the screed, it seems to be inside the cement-sand mixture, and not under it. If the mesh has not been raised, it will not perform its functions of strengthening the base. The approximate height of the mesh level is about 2-3 cm. It is recommended to use a mesh with a mesh size of no more than 10x10 cm. The smaller the cell size, the stronger the base will be, this is especially true for plastic mesh, which is also often used in construction.

Fiberglass for concrete screed - replaces reinforcement with metal mesh

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.

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.

1. 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.
2. 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.
3. 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.
4. 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?

1. 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.
2. 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.
3. 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.
4. 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.

1. 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.
2. 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.

1. 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.