How to make a foundation slab for a house. Do-it-yourself foundation slab step-by-step instructions: how a monolithic foundation slab is arranged and construction stages. Curing

The best choice when building a new house is to use a strip foundation. This also applies to various outbuildings. But there are certain limitations that relate to the quality and composition of the soil, making it difficult to use just this type of foundation. They also include the proximity ground water. In certain cases, you have to go deep enough to build a monolithic strip foundation becomes unprofitable. In the search for alternatives, attention is paid to the foundation in the form of a monolithic slab. The article will consider the method of its construction and the nuances of the design.

General information

In favor of the use of a monolithic slab as a foundation, the uniform distribution of the load over the area of ​​\u200b\u200bthe soil on which the house is located speaks. This is especially true if the topsoil has a low bearing capacity. Foundation monolithic slab is a fairly simple design that you can build on your own. To implement the plan, correct calculations of the material, as well as the thickness of the monolithic slab, will be required.

A monolithic slab foundation can be called a shallow structure, since under such a structure most often they do not prepare a foundation pit of great depth. This approach is associated with a floating structure, the representative of which is a slab monolithic foundation. If the plate is deepened too much, then it will be rigidly fixed due to lateral pressure. With a slight deepening, a change in the state of the soil under the influence of sub-zero temperatures does not have a catastrophic effect on a monolithic slab. At the same time, the structure is able to level any loads, partially changing the position of the building that is located on it.

The illustration above shows the main components of the slab structure. The first layer of a monolithic structure is the compacted soil. This is the bottom of the pit, along which rammers are additionally passed, leveling and increasing its density. next layer monolithic foundation, which is laid out on the prepared bottom, is sand, it is called a pillow. Its role is to additionally help to properly distribute the load from the entire structure. Due to the special shape of the sand grains, it does not have significant drawdowns. Instead of pure sand, a gravel-sand mixture or several layers of gravel with different fractions is often used. The material is selected depending on the condition and type of soil in a particular area.

Note! Such a pillow is a normal solution that is used for almost all types of monolithic foundations. In addition to compensating for loads from the building, the cushion levels the impact of soil changes due to its swelling.

On top of the prepared pillow for slab foundation dornite, which is better known as geotextile, is laid from the monolith. This layer is an additional waterproofing. Its role is also to reinforce the base. If you do not use such a coating on some types of soil, then sand is easily silted and washed away from groundwater. This is not the only option in which geotextiles can be placed. In some conditions, it is necessary to lay several layers of such material in order to achieve the required strength for a monolithic slab foundation. Another option is pre-waterproofing using geotextiles. If it is performed, then the membrane is laid directly on the compacted soil of the pit.

On top of it is placed a pillow of sand or gravel. This is done in order to prevent mixing of soil and cushion material. This is especially true for swampy areas where the ground can be unstable. In another embodiment, another layer is located between the layers of the backing pad. This is done for better drainage and separation of the backfill layers of a monolithic structure. If good moisture removal is required, then crushed stone is placed below, if greater stability is required, it is placed on a prepared sand cushion.

The presence of the next layer is a surprise to some experienced builders, since it is rarely laid. But a full-fledged pouring of a monolithic foundation slab implies its presence. The fact that this layer is rarely used does not mean that it is not needed. Often it is absent due to lower costs for the construction of a monolithic foundation structure, as well as a reduction in production time. But preconcreting can play a decisive role in the geometry of the entire monolithic slab structure. Even with high-quality tamping of the pillow, it is difficult to achieve the ideal level. This can be done only with the use of an additional concrete layer, which is poured using beacons. In addition, it is easy to lay insulation on the base prepared in this way, as well as to perform final waterproofing for a monolithic slab foundation.

The final layer of waterproofing, which is laid on a preparatory concrete base. As a material, rolled bitumen sheets are used, which are arranged in several layers with overlapping and gluing at the seams in order to achieve the desired result. The pair also uses bituminous mastic, on which the base is glued. The main element of this type of foundation is a reinforced concrete slab. In the usual version, the reinforcement of a monolithic foundation is carried out in two levels with their interlacing by means of vertical metal elements. At the same time, the monolithic foundation is poured in such a way that the reinforcement, which is in concrete, is closed on all sides and the gap to the outer side of the slab is at least 5 cm. This is necessary to protect the metal base from moisture, which can enter by capillary method.

The general scheme of the monolithic structure of the slab foundation may undergo some changes depending on who performs installation work. Most often, the simplest version of a monolithic slab foundation is used, but there are other solutions. The first is a monolithic structure that does not have additional modules and is laid with the same thickness over the entire plane. The classic version is used in cases where the construction of a building takes place on soils with relative stability. This is due to the fact that concrete is poured in a small layer, while the upper boundary often coincides with the ground level. The consequence of this may be abundant penetration of moisture into the blocks from which the walls will be built.

Increasing the thickness of the monolithic slab will give its results, but the costs may increase several times, so another method is used that increases the strength, but the costs increase by a smaller amount. It implies the presence of additional stiffeners, which are poured under bearing walls, as well as under internal. Reinforcing modules can be located both above the monolithic slab and below it. Filling can be done simultaneously with the main structure. The photo above shows how a monolithic foundation will look like with additional stiffeners that are on top. Before laying bricks or other blocks, waterproofing is performed using roofing material and bituminous mastic.

This version of a monolithic structure is especially relevant in cases where a semi-basement is required in a house that is located on a monolithic reinforced concrete foundation. For a tape structure, the solution is simpler, because it is possible to go deep into the ground by digging an additional pit for a basement or garage. If there is a need to raise the slab foundation above the ground as much as possible, but not to lose in rigidity, then the ribs are poured from below. This is also done simultaneously with the filling of the main layer. At the same time, additional recesses are made in the insulation or in the prepared pillow, where the reinforcement is placed.

This version of a monolithic base is a combination of slab and strip foundations. If the internal walls in the house will be ordinary partitions and will not play the role of bearing ones, then the stiffeners are not located directly below them, but are installed over the entire area of ​​\u200b\u200bthe supporting slab parallel to the smaller side of the monolithic foundation. At the same time, the distance between them should not exceed 3 meters, since they will not fulfill the role assigned to them. By using this solution, it is possible to save on consumables. This is due to the reduction in the overall thickness of the slab. In some cases, the size can be reduced by 15 cm. In this case, the bearing capacity of the monolithic structure does not suffer. With such a reduction in thickness, concrete savings will be one and a half cubic meters per ten squares.

When using stiffeners, the process of insulating a monolithic foundation is simplified. The resulting niches due to the difference in the height of the base are easy to fill with extruded polystyrene foam or polyurethane foam. The presence of such a layer is mandatory in the Swedish stove. This technology has become widespread throughout the world. At the same time, heat loss through the floor approaches zero, which allows you to significantly reduce the cost of heating in the cold season and air conditioning in the summer.

The slab foundation can be not only monolithic. In some cases, a modular design is assembled. It consists of separate monolithic slabs, which are mounted on a prepared base. They are placed without a gap with each other. This option is simpler and takes less time to build, but the strength of this design is lower than that of a monolithic one. This is due to the possible deformation of the base due to the influence of various forces on it. For residential buildings, this type of foundation is practically not used due to low reliability, but can be used for outbuildings.

Advantages and disadvantages

With regard to the slab foundation, some theses are put forward that deserve consideration in order to avoid typical mistakes. The main ones are:

• the possibility of widespread use;
• resistance to any fluctuations of the ground;
• no need for geological analysis;
• the impossibility of building multi-storey buildings;
• a quick decision regarding the floor of the first floor;
• ease of work;
• the possibility of using the plate on an uneven area;
• the need for full support on the ground;
• the need for early communication;
• space cost of the project.

A slab foundation is the only option for those types of soil where the top layer has a low bearing capacity. Its use is justified in the case when it is impossible to install a monolithic columnar foundation or a strip foundation with a small depth. This can be found out by conducting a qualitative analysis of soils, which includes not only the composition, but also the tendency to certain changes depending on the season. In some cases, it is allowed to erect multi-storey structures on monolithic foundations of this type.

Often, the advantages of such a solution include the possibility of building a monolithic slab foundation on all types of soils. But actually it is not. This type of foundation does make it possible to level out significant imperfections in certain soils, but it is not able to cover the entire range. For example, it is impossible to say that a slab foundation can withstand the load from a house on any marshy soil. For conditions with high waterlogging, where there is an increased moisture content in soils best solution will be the construction of a pile foundation. In this case, the piles are immersed to such a level that they reach denser soil rocks, for which they can cling.

The floating structure of a monolithic foundation becomes indispensable in conditions of an acceptable amplitude of ground vibrations, but if we are talking about significant changes in the upper layers, then this is an alarming signal for a slab foundation. This is due to the fact that the force exerted by the soil on the plate is uneven in different areas. This can lead to the destruction of the monolithic structure. The reason for the uneven impact of the soil on the slab monolithic foundation is explained by the different rates of freezing and thawing of the soil from different sides of the building. On the south side, the speed of the processes is much higher, and on the northern side, it is lower.

Such internal stress will not necessarily lead to the destruction of a monolithic slab, but deformations will certainly manifest themselves. The consequence of this will be cracks in the walls, a violation of the geometry of the building or the occurrence of a slope. Such changes are critical for brick and block buildings. The effect is not so noticeable on log structures or on frame houses. This is explained by some mobility of the structure. wooden house. V brick buildings the force will increase towards the top of the wall. It has to do with leverage. The above shows how important it is to carry out a qualitative analysis of the soil. Such services are expensive, but it is cheaper than repairing or rebuilding a house after it has collapsed. It would also be appropriate to observe what types of foundations have already been applied in the area where construction is planned. If monolithic slabs are present, then you can apply the same foundation for your home without much concern.

The statement that it is possible to build on a slab foundation high-rise buildings is fair. But this applies to those cases when the calculations and construction of the structure will be carried out by professionals, because otherwise it will not have a positive effect. A fiction is also the limited service life of a monolithic foundation, which is reduced to a maximum of 50 years. The service life largely depends on what materials are used, as well as whether the points described above are observed.

Someone believes that in comparison with a deep strip monolithic foundation, the amount of earthwork is much less in relation to a slab foundation. In some cases this is true, but much depends on the project. For example, on different objects different thicknesses of backfill layers are used. It directly depends on how deep you have to go. In addition, an insulated blind area is being built to the monolithic slab base, it also involves excavation work, which increases the total amount of work. Therefore, it is irrational to make evaluative comparisons of this type.

Note! There is a variant of a slab foundation with a deep foundation. This is done if the owner wants to have an underground garage or basement. In this case excavation will be several times higher than those carried out for a deep strip foundation.

One of the advantages of a slab foundation is the ease of organizing the floor of the first floor. In fact, these operations are combined, since the slab itself can already be used as a subfloor. If you perform a monolithic foundation according to Swedish technology, which involves insulation and installation of a warm floor, then additional laying of insulation is not required. On the one hand, the construction of a slab foundation can indeed be called a simple task, which includes laying all the layers listed above. On the other hand, certain experience is required for each stage of construction to be successful and for a monolithic foundation to have the required parameters.

When building a large building, you can not do without the involvement of special equipment. For example, high-quality ramming over large areas is almost impossible to do manually, so you need to get an electric or gasoline rammer. The rebar that is used for reinforcing the foundation chord often needs to be bent at a certain angle. This means that you will need to come up with a small machine that will simplify the task. When laying rolled waterproofing, in most cases it will be necessary to use a gas burner. In addition, a high-quality slab foundation must be poured in one day. To do this, it is impossible to do without a concrete mixer or pump, which will allow the solution to be delivered to a certain point.

One disadvantage of the monolithic slab design is the need for a relatively flat area. This does not mean at all that such a structure cannot be built on a territory that has a drop. Everything depends on additional waste of forces and material. If there is a difference in level, then it will have to be leveled with a greater thickness of the slab foundation in a certain area. Such a device of a monolithic foundation is not always justified, therefore, pile-based solutions are resorted to.

The bearing capacity of the slab foundation largely depends on how exactly the foundation for it will be prepared. This means that the entire area of ​​the slab must be supported by the ground. If one of the sections is suspended, then it is impossible to talk about a uniform distribution of the load. This approach excludes the possibility of constructing any underground facilities directly under the slab. The problem is solved using the deep-buried monolithic slab method, as described above. Another important nuance of the foundation in the form of a monolithic slab is the need to calculate in advance the method of laying and the length of all communications, since most of them will be located directly in the thickness of the foundation or under the slab. After its construction, its gating to a great depth will be impossible, since this can violate its integrity.

Note! A comparative disadvantage of the slab foundation is its high cost.

This is due to the need for pouring over the entire area of ​​\u200b\u200bthe foundation. In addition, more reinforcement is used for the slab than for the strip foundation, which also eats up the lion's share of the budget.

Settlement work

The construction of any object never starts without quality calculations. They include not only the determination of the amount of material, but also possible risks when laying a monolithic slab as a foundation. The easiest way is to entrust such work to professionals and get ready-made technical documentation in your hands, which will make it possible to do the job in the best possible way. At the same time, there will be a guarantee that the foundation will serve the stated period. When it comes to building a garage or outbuildings, then you can make calculations for the foundation of such buildings yourself. The most important indicator, which is determined in the course of calculations, is the thickness of the slab of a monolithic foundation. If it is insufficient, then the forces will be wasted, because such a foundation will not have the required bearing capacity. With an unjustified increase in the thickness of the plate, additional waste will appear.

Correct calculations are never carried out without a qualitative analysis of the soil where construction is planned. This is done to determine the bearing capacity of the soil itself, on which the monolithic slab will be located. For these purposes, a drilling rig is often used, with the help of which soil is taken at several points of the site for a future monolithic foundation. This is necessary to determine the layers present, as well as the proximity of groundwater. Each type of soil has a variable resistance to load. The unit of measure for the variable is kPa or kilogram of force divided by square centimetre. Indicators for different types of soil are shown in the table below.

The numbers indicate the maximum allowable pressure that can be exerted by the slab foundation and structure per unit area of ​​a particular soil. If the indications are not met, then it is difficult to talk about the quality support of a monolithic foundation. But such indicators should not be considered accurate and final. During the calculations, it is more correct to use not the resistivity of the soil, but the specific pressure on a specific type of soil. This is due to the fact that with low soil resistance, the plate will begin to sink into it. Otherwise, if the pressure is insufficient, then deformation may occur due to heaving of the soil. Optimal pressure values ​​are shown in the table below.

If you carefully compare the two tables, it becomes obvious that not all types of soils are in the second one. This is due to the fact that for soils with sufficient bearing capacity, the construction of a slab monolithic foundation is impractical. It can be replaced with a shallow or deep foundation. With regard to the selected types of soil, additional studies are being done that will make the structure stable. Sandy loams do not always have a reduced bearing capacity. In some cases, they are allowed to erect monolithic tape or pile foundations. In relation to clay soils, there is also a certain danger. It consists in the amount of water in a certain period of the year. If the soil is waterlogged, then its bearing capacity drops. In the case of a moderate moisture content, one can speak of sufficient resistance to the pressure of the foundation on the ground.

From the facts listed above, it becomes clear that for the correct selection of the thickness of the monolithic foundation slab, it will be necessary to determine the total load of the monolithic structure on the ground. After that, it is necessary to subtract the recommended load, which is assumed for a particular type of soil. The resulting difference can be compensated by increasing or decreasing the mass of the foundation or walls by using blocks of a different material. The specific gravity of reinforced concrete is a public fact, so it is easy to calculate the required volume. The foundation area is marked on the plan, so it will be quite simple to determine the required thickness of the monolithic foundation. To simplify the task, special engineering programs have been developed, for example, Scad, which carry out the proposed calculations in a few keystrokes.

The optimal indicator for a slab monolithic foundation is considered to be a thickness of up to 30 cm. In this case, we can talk not only about sufficient bearing capacity, but also about the economic benefits of the project. If after calculations it becomes clear that the thickness of the slab will have to be increased by more than 35 cm, then it is worth considering other available options for a monolithic base. If there is a need for a slab foundation, then it is possible to reduce the thickness, but add stiffeners that compensate for the missing area, reducing material consumption. Such a monolithic structure is built only with the help of professionals.

If after the calculations a negative number is obtained or the result is less than 15 cm, then this indicates that the weight of the building to be built on the site is too large. In this case, additional geological analysis will be required to determine the optimal thickness or type of foundation that can be used in a particular case. When the thickness is calculated, it is then easy to know the amount of concrete that will be used for a particular project. For this, the derivative of the height, width and thickness is found. A 10% margin is also made. If the house is planned brick walls, then it is better to take as a basis the thickness of the slab foundation from 30 cm. If you wish to use gas blocks and foam blocks, the indicator can be reduced to 20 cm. The optimal brand of cement in the case of such a design is M300.

Reinforcement

The number of reinforcement levels for a slab monolithic structure will be determined by its thickness. If we are talking about a monolithic structure up to 15 cm, then only one tier of reinforcement is laid, which is fixed with a knitting wire. In this case, rods with a diameter of 12 millimeters are used. In this case, the reinforcing layer should be located exactly in the middle of the entire monolithic structure. In this case, the required strength will be provided. Double reinforcement is required and possible for implementation only in slab foundations with a thickness of 20 or more centimeters. The step with which the individual elements are laid should not exceed 30 cm. At the same time, a gap of 5 cm is made from each edge of the slab, which will allow the mesh to be completely immersed in the thickness of the concrete.

Advice! When reinforcing a monolithic foundation, the step between the rods decreases in places where the load-bearing walls will be and is rarefied towards the middle of the foundation structure.

Developed general rules, which allow you to choose the correct pitch and thickness of the reinforcement of a monolithic structure. For example, the spacing of rods in a reinforcing mesh for a monolithic foundation in the form of a slab should not exceed 1.5 of the thickness of the slab foundation. If the length of the reinforcing layer exceeds three meters, then the diameter of the rod should be from 1.2 cm.

Construction process

The process of laying the foundation in the form of a monolithic slab begins with marking. The contour of the future monolithic structure is applied to the site proposed for construction with the help of pegs and a rope. Next, earthworks begin. It is easier to carry them out using an excavator, since it will be problematic to overcome the area under the slab manually. The depth of the pit, which is being prepared for a monolithic foundation, is selected taking into account the thickness of the slab and each of the layers that will be covered as a pillow. In this case, it is necessary to take into account that part of the monolithic slab protrudes above the soil surface. 10 cm will be enough. After excavation, the surface of the bottom of the pit and walls can hardly be called even. Leveling can also be done mechanically.

Note! After marking the area for a monolithic foundation, you need to make sure that the corners along the edges are exactly 90 degrees. To do this, you can apply a triangle with an aspect ratio of 3 to 4 to 5, or simply measure the diagonals, which should be equal.

The prepared pit is covered with waterproofing material. The latter cannot be selected to the required area, so the individual elements are laid with a slight overlap, which is 30 cm. The joints should not disperse under the weight of subsequent layers, so they are glued with a moisture-resistant tape. In some cases, the use of mastic is allowed. The overlap is also done on the edges of the pit. Depending on the soil, the next step is sand or gravel for the foundation. If we are talking about sand under a monolithic foundation, then it is backfilled with an incomplete layer at once. The total thickness of the pillow is divided into several layers. They are easier to ram, which will give the desired effect. If you immediately fill the entire volume under the foundation, then the weight will be distributed incorrectly.

Note! The pit must be made larger than the reinforced concrete slab of a monolithic foundation.

Simultaneously with the process of backfilling the pillow, the drainage system is being prepared. It is necessary for the timely removal of excess moisture from a monolithic foundation. To make it correctly, it is necessary to dig a trench around the perimeter of the monolithic foundation. Its depth should be such that it completely fits the plastic pipe that will be used as a drainage channel. Separate pipes around the foundation are combined into a common circuit. In this case, a general slope must be observed in order to divert water to the place intended for this. The space around the pipe is covered with rubble, and holes are made in the pipe itself so that the liquid can freely flow inside.

The thickness of the sand bedding can be different, but not less than 20 cm. When tamping the pillow under the foundation, it is necessary to constantly monitor the horizontal level. A few pegs will help with this, which will be hammered around the entire perimeter. They should be marked with the level to which the backfill will be made. The next layer is crushed stone under the monolithic foundation. The layer of this material should be from 15 cm. You will have to make enough effort to also compact it well and at the same time maintain a horizontal level. Crushed stone will allow timely removal of moisture from under the monolithic foundation, if it is there.

The foundation will be difficult to pour without formwork. Therefore, as soon as alignment is made, the formwork elements are exposed to the crushed stone. They must be well fixed, as they will be subjected to significant lateral pressure. In the case of insulation of the entire monolithic structure, polystyrene sheets of a special configuration are used as formwork. To reduce the chances of moisture getting to the monolithic concrete base, a polymer membrane is laid on the rubble under the foundation. Its purpose is to keep the foundation dry. It is laid in the same way as described for the first layer of waterproofing under the foundation in the form of a monolithic slab. In this case, the membrane must be placed under the slab foundation with the correct side. If this is not controlled, then moisture will collect under the monolithic foundation, and not be removed from it.

Note! in the case of the second layer of waterproofing under the foundation, an overlap is made on the formwork.

Next, the preparation of the concrete solution is carried out, which will be laid under the base of the foundation. In this case, cement brand M100 is suitable. The thickness of the primary screed is a maximum of 7 cm, but not less than five. As soon as it gains sufficient strength, it is possible to perform final waterproofing of a monolithic slab foundation. To do this, the entire surface of the footing is primed with a primer based on bituminous mastic. This is done to bond the surface, as well as to increase the adhesive properties with the waterproofing material. After that, the first layer of rolled material for the foundation is laid out. The material used is a bituminous sheet without powder.

The lower part of the sheet heats up, and it rolls out over the footing area. In order to distribute the waterproofing well under the foundation, it is necessary to walk along it with a metal roller. The next sheet overlaps the previous one. The second layer of waterproofing is laid in the same way. In this case, it is necessary to observe the offset in order to cover all the seams of the previous waterproofing layer. Upon completion of the final waterproofing layer under the foundation in the form of a monolithic slab, insulation can be laid. It can also be placed in multiple layers. In this case, the seams overlap, as in the case of waterproofing.

The next step is reinforcement. The grid for a monolithic foundation can be assembled directly on the area of ​​\u200b\u200bthe future foundation. In this case, you can not use the welding machine. It may be faster and easier, but there will be tension inside the metal, which can subsequently lead to the destruction of the monolithic foundation structure. The crate cannot be laid directly on the insulation. Under it, you can make linings in the form of bricks or special metal legs. It should rise at least 5 cm. The rules for selecting the diameter for the batten rods were discussed above.

Advice! To make it easier to maintain a given cell size, you can make a small template in the form of a metal cross, as you can see in the photo above.

Before concrete is poured into the future monolithic slab, all communications are laid. If we are talking about a floor heating system, then the pipes are fixed to the metal crate of the foundation. In this regard, it is important to remember that the length of one circuit should not exceed 90 meters. Collector units are immediately installed, which combine all the pipes. All conductors must be pressurized to reveal a hole if damaged during pouring. Next, the formwork is carefully examined again. There should be no gaps between the individual elements through which water could escape from the concrete solution.

If one mixer is not enough, then the delivery of concrete is carried out by several machines at once. The solution is poured onto the reinforcing mesh and evenly distributed throughout the territory. To do this, you can use a pump or wooden mops, which are more tedious. Before leveling the surface, vibrator treatment is performed. The purpose of this procedure is to fill all kinds of voids in which there is air. Next, you can proceed to leveling with a rule and grouting the surface with helicopters, which will further compact the thickness of the monolithic foundation. A video about the process of installing a monolithic foundation is below.

Summary

As you can see, the construction of a foundation in the form of a monolithic slab requires certain skills and knowledge. If you take into account all the nuances that were given in this article, then you can succeed in doing the work yourself. For ease of work, it is better to hire several assistants who will allow timely distribution of concrete over the surface before it sets. During leveling, it is necessary to constantly check the level of the future floor.

When building a house, the most important part of it is the foundation, foundation and support of the structure. Exists different kinds foundations. They differ in cost and complexity of installation of the structure, but the most reliable option among the existing ones is a foundation based on a concrete slab. About what this concrete structure is, its features and construction technology will be discussed further.

The comments and expert advice that accompany the article will help you avoid possible errors and make the foundation exactly according to plan.

What is a concrete slab foundation

The foundation based on a concrete slab is a solid structure, poured from concrete, which serves as a reliable support for the house. It is advisable to build such a foundation in such cases:

• If the future house is being built in conditions of "difficult" soil;
• Additional protection against underground and melt water is required.

There are three types of monolithic concrete foundations:

1. Unburied - concrete is poured simply on the surface of the earth.
2. Shallow - the foundation is installed at a depth of 50-60 cm.
3. Deeply buried - the foundation is lowered to the maximum depth of soil freezing (1.5 meters).

The foundation based on a concrete slab is a classic version of the support of any structure. It has its own advantages and disadvantages that should be taken into account.

Advantages of a monolithic concrete foundation

The advantages of a concrete slab are much greater than the disadvantages. To begin, consider positive sides using a solid concrete foundation:

• High degree of stability. Due to the fact that the structure is solid and made of such a durable material as concrete, the resulting structure is very strong and reliable.
• Not subject to the damaging effects of groundwater.
• Does not sag or shift over time.
• A simple monolithic design that is done in one go.
• Well suited for building houses on sandy surfaces.
• It is an ideal support for large, massive buildings.

Sergey Krasovsky, worker construction company"StroyMarket" about the advantages of a concrete slab foundation:

A concrete slab is the most stable and versatile type of foundation that can be installed anywhere and under any conditions. Those shortcomings that exist are insignificant and you can often turn a blind eye to them.

Disadvantages of a monolithic concrete foundation

The disadvantages of this type of foundation, although not many, but they are.

Firstly, concrete slab installation is an expensive process. The cost of building materials and the work itself reaches 50% of the total cost estimate. Here you need to decide what is more important - a solid foundation or the opportunity to save money.

Secondly, before pouring a concrete slab, it is necessary to carry out significant preparatory work. This mainly concerns the cleansing of the territory, which is reserved for the construction of plants and excavation. Depending on the depth of laying the foundation, the volume of soil to be excavated also changes. To do this, use the attracted equipment, which only adds financial costs.

Thirdly, the one-piece construction of the foundation excludes the possibility of arranging a basement under the house. Although this is not as important as the previous disadvantages, it also requires attention so that later there are no unpleasant surprises and disappointments.

Foundation installation technology based on a concrete slab

Process building a foundation on a concrete slab requires special care and precision when making decisions, developing an action plan and in the process of its implementation. The technology of mounting a concrete slab includes several stages.

1. Drawing up a project. If you carefully weighed all the pros and cons of a concrete slab as a foundation and decided to stop on it, it's time to move on to calculating the foundation based on a concrete slab. This process, though not very complicated, but very responsible.

Vitaliy Bondar, design engineer of the construction company "StroimSami" about independent design:

Engineers do not just study for five years to obtain a qualification. If only everything was as simple as some people think... A concrete structure, especially a solid and voluminous one, cannot be corrected and adjusted. As it turns out, so it will stand for the next few decades. The best option is to order a calculation from a professional. Thus, you will protect yourself from risks and be calm about the quality of the future home.

2. Based on the existing plan, you can start working on the ground. First, markup is done. Then a pit is dug according to the markup. A pit for a concrete slab is best done not by hand, but with the help of technology. First, just imagine how long it will take to dig 50 cm deep in an area of ​​50 square meters. What if you need more depth and area? Secondly, while you are digging, the edges of the pit may crumble a little and disrupt the final design of the slab. The excavator will do everything quickly and accurately.

Leonid Molotov, a builder with experience regarding the pit:

Make sure the surface of the pit is level. It is unacceptable to level the bottom in bulk. If somewhere they dug deeper, you need to make the whole pit deeper. The last 10 cm of soil I recommend to choose manually.

3. At the next stage, a formwork is constructed, which will subsequently be poured with concrete.

4. At the bottom of the pit, 15-25 cm "pillows" of sand are poured. To avoid "dehydration" of concrete, a layer of dense film is placed on top of the pillow.

Evgeny Andropov, employee of the StroyService construction company:

Please note that all communications that are laid under the house need to be thought out and leave a place for them in advance. When the foundation is filled, then there can be no talk of any additional pipes in it.

6. A waterproofing material is laid on top of the foundation slab. Insulation of the foundation based on a concrete slab also happens at this stage. To do this, a special foam or polyurethane is placed on top of the waterproofing. Some experts suggest using polystyrene foam for insulation.

7. The most basic stage installation of the foundation on the basis of a concrete slab- direct concrete pouring.

Sergei Krasovsky, employee of the construction company "StroyMarket":

Firstly, when pouring concrete, its quality must be taken into account. Concrete grade M300 and higher is best suited for the foundation. Factory certified high-class concrete will be a guarantee of the quality of the foundation being built.

Secondly, the pit must be filled in all at once. To do this, you need to take care of the concrete pump and mixer in advance, since a lot of ready-made concrete will be needed.

8. The final stage is concrete shaking, curing and formwork removal.

The concrete slab foundation is ready!

The video shows in detail the process of pouring concrete foundation.

The cost of building a foundation based on a concrete slab

The cost of building a foundation based on a concrete slab can vary depending on a number of factors.

V concrete slab installation cost includes the following:

• Drawing up the calculation of the foundation;
• Involvement of construction equipment for digging a pit, pouring concrete;
• The cost of building materials - may vary depending on the quality of the purchased goods.
• Compensation for builders.

If we evaluate the overall cost of concrete foundation, then it will come out more expensive than others, but also much more reliable and durable. Definitely, such a foundation is worth the money and labor spent.

And in the end, I would like to highlight the features of the foundation based on a concrete slab:

1. The most reliable and stable type of foundation of all existing.
2. The service life of a concrete slab is over a hundred years.
3. The foundation is simple, but installation requires special equipment.
4. High price project, however, the result is worth it.

In our time, when the field of building materials is rapidly developing, there are many types of foundations that differ in characteristics, type and purpose. But recently, among professional developers, the slab foundation has become more and more in demand. This type is especially convenient for owners of plots with land in poor condition. And also, this option is considered one of the available. Even an inexperienced person in repair matters can pour the foundation slab on their own, without putting much effort.

Areas suitable for slab foundation applications

The most important feature of the slab foundation is a shallow base, which is made of a concrete pad. This property allows you to fulfill its purpose even on moving soils. Any other type of foundation will be covered with cracks during the movement of soils, therefore, in such areas it is necessary to use exclusively slab foundations.

This base is perfect for building houses where hard materials are used. It prevents deformation of the structure.

Buildings that have low, in comparison with the ground, floors, must be erected using exclusively slab foundations. When using it, there is no need to build a basement and grillage.

Slab foundation advantages and disadvantages

Before you start choosing a particular product, you need to weigh all its pros and cons. Let's start with the positive qualities of the slab foundation:

• It is reliable and durable. And it's hard to argue with that. Interview specialists who are versed in building materials, and all of them will say that tiled is the most reliable type of foundation.
• It has a large area of ​​\u200b\u200bsupport on the ground, and if it is laid correctly, the soil will not adversely affect the foundation in the cold season.
• The slab foundation is universal. The fact is that specifications which it possesses, allow it to be laid on almost any soil. Therefore, this type is most often used in areas where no other foundation could cope with the task.
• The ability to establish a foundation above the depth of freezing of the earth. This plus was made possible thanks to the massive sand and gravel cushion, which prevents the impact of the soil in the cold winter.
• A high level of rigidity, which prevents the house from sagging, and if this happens, then the room will not be significantly damaged.
• No need to install a subfloor.
• The ease of device technology, which allows you to do the work on your own and save on the services of a master.
• Suitable for any type of low-rise building. The only thing to consider is the thickness of the slab (the lighter the room, the thinner the slab).
• Can withstand ground movement. It is possible to build a house on floating lands, since the tiled foundation will not burst and tear, but will simply begin to move along with them. This property is to keep the building intact.

It should be borne in mind that all the previously listed advantages will be valid only if the installation rules are strictly observed. If there are violations of technology during the laying process, then the pros can turn into cons.

As with any foundation, there are some negative qualities:

• One of the biggest downsides that buyers point out is the price. The high cost is justified by the large amount of concrete, reinforcement, sand, and crushed stone, unlike analogues. But on the other hand, the money spent quickly pays off. The tiled foundation will not need frequent repairs, expensive maintenance, moreover, it will function as the floors of the first floor, which will also reduce costs.
• It is not recommended to lay a tiled foundation under the house, which is located on a site with a large slope. In this case, the output will be leveling the ground level, or installing a basement, but this is quite an expensive pleasure.
• There are difficulties with the construction of the basement. In the case of building a basement, you will have to fill in a monolithic slab under it, which will cause significant losses to the owner.
• The occurrence of difficulties during the installation of the foundation in winter days. To pour concrete in sub-zero temperatures, you will need to spend money on heating it and maintaining the warmth around it.
• Difficulties in wiring communications. Consideration should be given to the location of plumbing, electricity, etc. before the start of pouring concrete because after that it will be impossible to do this.

As you can see, the slab foundation has a large number of advantages, and disadvantages can be circumvented, however, this will cost additional costs.

Material calculation

Before starting work, it is necessary to calculate the slab foundation: the dimensions of the formwork, the number and diameter of the reinforcement, the volume of concrete. All these values ​​can be found using a special calculator. To do this, you will need to enter the brand of concrete, the width and length of the slab (in meters) and its height (in cm). Further, the program itself will calculate the amount of materials necessary for arranging the foundation.

Types of slab base

Also, before starting work, it is worth deciding on the type of tiled base. There are several options. The main ones are:

• ordinary concrete pad;
• tape-slab.

This type is used during the construction of buildings with a basement. A hole is dug, a concrete pad is placed, on which the base is subsequently installed. The entire load is placed on the strip foundation.

• base with stiffeners;

It is the best option among all, because it has high strength. Its construction requires more materials and effort, so its technical characteristics are superior to other types of foundations.

Preparation of materials and tools

Preparatory work also includes the assembly of a set of materials:

• concrete;
• steel bars;
• gravel;
• sand;
• material for waterproofing (geotextiles are most often used).

You will also need some tools for the slab foundation:

• saw;
• hammer;
• shovels;
• transport wheelbarrow;
• apparatus for welding;
• Bulgarian;
• roulette.

Construction of a slab foundation

Instructions for the construction of a slab foundation includes several steps:

1. First of all, we carry out a geological study of the earth, determine places with strong elevation changes.

2. We mark the future base.

3. We remove the soil layer and level the area where the construction will be carried out.

The choice of the depth of the pit directly depends on the type of structure (shallow or swollen). If we consider a shallow foundation, then it will be enough to remove 50-70 cm of earth. The dimensions of the pit are selected taking into account that they should be 1-2 meters more than the length / width of the foundation. After digging, be sure to compact the soil.

4. We design and install formwork (strong wooden boards are suitable for its construction).

5. We dig several trenches in the pit and lay waterproofing in them.

6. We lay plastic pipes on top of the waterproofing.

7. We fill the bottom with a mixture of sand and gravel, evenly distribute it and tamp.

8. We assemble a double reinforcement cage and tie it with a special wire.

For reinforcement, only rods with ribs are suitable. They will provide high-quality adhesion of the frame and concrete mix, as well as prevent stretching of the foundation slab. Using smooth rods in the work, the base will crack at the first subsidence of the soil. The reinforcement is laid in increments of less than 30 cm. If you increase the distance, then the strength of the base will decrease significantly.

9. We put plastic pipes in places where various communications will be located.

Before installing them, it is necessary to fill them with sand and carefully compact the backfill. Pipes must be laid before pouring, since it is forbidden to make holes in concrete.

10. Fill the monolithic slab with concrete mortar.

The slab foundation is poured immediately. The concrete solution must be kneaded once and a large amount, so that it is enough for the entire pour. The work is quite laborious, so ideally it should be done by four people. We lay the concrete in uniform, horizontal layers. It is necessary to fill in such a way that the plate does not have deviations from the horizon. To prevent such slopes, we create stiffeners in the lower part. These are strips of concrete, made in the shape of a trapezoid. The last layer must be poured very quickly. Use a mixer or concrete pump for this.

11. Carefully smooth and level the surface.

12. We cover the resulting foundation with a film and leave it for a couple of weeks. Do not forget to moisten the construction during the first five days.

How to mix concrete for the foundation?

To reduce the cost of work, you can knead concrete at the site of the foundation with your own efforts. But in this case, you will need a special concrete mixer. It perfectly mixes all the components without forming lumps. This unit operates at a power of 250 watts or more. At one time, you can get from 50 to 250 liters of solution. But the quantity greatly affects the time of work. If we take a small device as an example, then it will take about 5 hours to create 1 pour cube.

An important point is the location of the concrete mixer, it should be located near the base. This will reduce the amount of force you apply.

Of course, there is an option to independently knead concrete for a slab foundation using a shovel, but this will greatly affect the quality of the future foundation.

Warming

Of course, the best option there will be insulation of the foundation, to achieve a warm temperature in the room all year round. To do this, use various heaters. The most popular among them is foam. Only 10 cm layer will be enough.

Also, there are different types insulation. We recommend using the subfundamental. Insulating material is placed directly under the stove.

Use the tips below to make your job easier:

1. To create a quality foundation, you need to use only durable reinforcement and concrete mix.

2. The use of a shallow base will reduce the cost of Construction Materials, approximately 35-45% of the cost of the underground premises.

3. It is very important to consider the thickness of the slab. For example, choosing a base thickness of 20 cm, you will need to "reinforce" in some places where there is too much load. At 25 cm, it becomes possible to knit a frame of reinforcement uniformly, without resorting to additional reinforcements. A 30-centimeter thickness will help increase the strength and durability of the foundation, but at the same time it will make you spend a lot on concrete.

4. During the manufacture of a cushion of sand and gravel, the material must be laid in layers. One layer should not exceed 12 cm. After each masonry, carefully tamp. If your pillow will consist entirely of sand, be sure to moisten the layers.

5. Before laying the insulation material, the pillow must be covered with a dense polyethylene film to prevent water leakage from the concrete solution. It is advisable to glue or solder the polyethylene at the joints, or overlap the sheets.

After reading this article, everyone will be able to make sure that the construction of a slab foundation is a fairly simple process and is possible when creating it yourself. The main thing is to follow all the rules of pouring and construction technology. If this is done, then your foundation will serve faithfully for many years.

Also, we invite you to look step by step instructions how to properly build a slab foundation video is located after the article.

The laying of the slab foundation begins with the preparation of the soil. For this, it is removed fertile layer soil, a pit is dug out with an additional allowance for the formwork, the surface of the site intended for construction is completely leveled. The depth of the required pit is usually 40-50 cm. Later, a sand cushion 20-30 cm high is laid on its bottom, consisting of sand and fine gravel, which are poured in layers of 5 cm and compacted. A concrete screed of M50 concrete about 10 cm thick is laid on top of them, and then the base is waterproofed. To do this, use a waterproofing or other rolled waterproofing material, the edges of which are released 1 meter from the edge of the concrete base under the foundation in order to subsequently wrap them on the foundation walls and provide additional waterproofing. To insulate the basement, you can put a heater on top of the waterproofing: extruded polystyrene foam - the most the best option for this.

When waterproofing and thermal insulation are ready, a reinforcing cage is mounted, consisting of two meshes - lower and upper, made of metal rods with a cross section with a diameter of 12-16 mm. The ribbed surface of the reinforcement will give it a better bond with concrete, which will affect the higher strength of the foundation. The size of the mesh cells is from 20x20 to 40x40 cm. The lower mesh is installed on supports 5 cm thick, and the upper one is accordingly installed so as not to reach the edge of the finished surface by 5 cm.

After the construction of the reinforcing mesh, the formwork is installed around the entire perimeter of the future foundation. For this purpose, boards of large thickness are usually taken, which can withstand the pressure of concrete and not burst, are well and securely fixed. Next, the concrete mixture is poured so that the reinforcing cage is completely immersed in concrete. To avoid corrosion of the reinforcing cage, all of its bars must be covered with concrete by at least 3 cm. For concreting, concrete of a grade not lower than M300 is used, and special impurities are added to the concrete to increase frost resistance. The concrete mixture is laid tightly and evenly - for this, a deep vibrator is used, which allows you to perform these works more efficiently and efficiently. The surface of the poured concrete is leveled, covered with a film to prevent it from drying out. It is necessary to ensure that the concrete mixture does not dry out too quickly, otherwise it will lose the necessary strength and may even crack. As soon as the foundation has completely hardened, the formwork is removed and the remaining edges of the waterproofing are lifted up, glued together and the surface is waterproofed.

The process of laying a slab foundation is quite simple. The main difficulty of the work falls on digging the pit, installing the formwork and laying the concrete mixture.

For the manufacture of a slab monolithic foundation, a large amount of reinforcement and concrete is used, this affects its price, which is several times higher than the cost of other types of foundation.

The slab foundation can be shallow or deep buried - it depends on the type and characteristics of the soil. For greater depth, it is necessary to carry out additional work, which also affects the cost. But on the other hand, the costs of this type of foundation are fully justified by its bearing capacity and high rates strength, which in certain conditions are absolutely irreplaceable.

It is worth noting that a monolithic slab is very unstable on slopes, so special ribs are made for it, which are buried in the ground and prevent the slab from sliding. Despite the fact that this type of foundation is not supposed to have a basement, there is a way out of this situation - a recessed monolithic slab. For her, I make a deep pit, at the bottom of which a reinforced concrete base is poured. The walls of the basement are built on it, which are waterproofed and insulated, resulting in not only an excellent place for storing various jars, but also for organizing a laundry, boiler room and other household premises. You can also make such a base insulated by mounting all communications in concrete.

To determine the need for this type of foundation, you need to make all calculations of the load of the future house on the foundation at the design stage and correlate them with the characteristics of the soil where construction is planned. It is advisable to choose a monolithic slab type of foundation in areas with a high amount of groundwater or on weakly bearing soils.

The specialists of our company are ready to advise you on this topic, help you make the necessary calculations, design and provide the necessary services regarding this type of work.

Private developers, when choosing a foundation for a house or outbuildings, prefer the tape structure as a reliable, economical and easy-to-use option. But in some cases, the only possible solution is the foundation of a monolithic slab. Such a foundation is required when building on sandy soil, on hard and plastic loams, and plastic clay. The design may also be in demand when building a building on hard and plastic sandy loams, hard clays.

Features of the "pie" slab foundation

The foundation base of the slab type does not require deepening - its ability to “float” and resist the forces of frost heaving is fully manifested precisely when it is laid on the surface.

The basic version of the foundation pie is shown in the illustration:

Foundation layers from bottom to top:

1. Compacted soil - the bottom of the prepared pit.
2. Pillow - made of sand or a mixture of sand and gravel, crushed stone. Fall asleep in layers, leveled and rammed. The pillow dampens ground vibrations, reduces the intensity of the impact of loads from below on the foundation.
3. Geotextile. Dornit fabric protects the pillow from silting, reinforces it. Geotextiles can additionally be laid at the bottom of the pit, between layers of sand and gravel to increase the strength of the cake.
4. Footing. A thin leveling layer of concrete on top of the pillow helps to qualitatively waterproof the foundation and correctly install the reinforcing frame.
5. Waterproofing. Waterproof material protects the reinforced concrete foundation slab from moisture penetration from the ground. Waterproofing of a monolithic foundation slab is traditionally performed from two or more layers of rolled bituminous material.
6. Concrete slab. Actually, the foundation itself, the thickness of which depends on the magnitude of the loads on the foundation.
7. Armature frame. Reinforcement increases the strength of a monolithic structure, takes on tensile-compressive loads, preventing concrete cracking.

Varieties of slab foundation

There are several options for the execution of the slab for the foundation. Most often it is a monolithic slab, the thickness of which is the same over the entire area. The advantages of such a base include ease of installation, the disadvantage is the close location of the upper edge to the ground surface - in this case, the base of the walls may be exposed to moisture, which harms building structures.

In order for the edge of the slab to be located higher above the soil surface, it is not necessary to increase its thickness - this will significantly affect the cost of the foundation. A more practical option would be to equip a plate with stiffeners.

The monolithic structure is a flat base with reinforcing stiffeners protruding above the surface - it looks like a strip foundation on top of the slab. The ribs are located along the perimeter and under the future load-bearing walls inside, if provided for by the project.

The foundation slab with stiffeners upwards makes it possible to build a building with a basement or ground floor. In this case, the monolithic structure must be buried in the ground and grillage ribs of a suitable height should be designed. Subsequently, a layer of waterproofing is laid over the ribs and wall structures are mounted.

To enlarge bearing capacity slab foundation base without its deepening, a monolithic structure is made with stiffening ribs directed downward.

There are two options for the execution of a monolithic slab with stiffeners down:

1. The stiffening ribs are formed by trenches dug in the ground below the level of pouring the reinforced concrete slab. A reinforcing frame is installed in the pits for the ribs, made as a single unit with the frame of the slab itself, after which the concrete mixture is poured.
2. A pit is being prepared with a flat bottom under the stove. A polymer plate insulation is laid on a waterproofed base - stiffeners will be formed in the gaps between the "islands" of the heat insulator and the walls of the pit. Before pouring the concrete mixture, a reinforcing cage is mounted.

Stiffeners should be located under load-bearing walls and capital internal partitions. If the project does not provide for partitions, but it is required to increase the rigidity of the slab, the ribs facing down should be parallel to the short side of the building in increments of up to 3 meters.

Laying a heat insulator, including extruded polystyrene foam under the foundation slab, not only allows you to equip the stiffeners of the required dimensions, but also contributes to the insulation of the foundation base, reducing the cost of heating the house. This type of foundation is called a "Swedish slab". It is often supplemented with a water heating circuit.

Prefabricated slab base

Instead of a monolithic slab foundation, in some cases a precast concrete foundation is used. Finished structures stacked close to each other. But this option can only be used on rocky soils that are not prone to heaving. In other cases, the base may deform over time under uneven heaving loads due to the lack of a rigid connection between the plates.

The base of prefabricated reinforced concrete slabs is used only in the case of the construction of outbuildings, baths, small light houses. A screed is made over the laid slabs. The technology of mounting a prefabricated foundation requires the involvement of special equipment for transporting and laying slabs.

Calculation of the thickness of the slab and reinforcing cage

When installing a slab foundation with your own hands, it is important to correctly calculate the thickness of the slab. Too thin base will not withstand the load. Pouring an excessively thick slab will lead to unnecessary financial costs.

Please note: each centimeter of slab thickness is 1 cubic meter of concrete mix per 10 square meters. m area.

The calculation should be entrusted to professionals or use special program. The value is calculated based on the type of soil and loads on the foundation. Therefore, it is necessary to have geological exploration data on the site and finished project the buildings. The standard thickness of the slab foundation is 200-300 mm.

The reinforcing frame for slabs up to 150 mm thick is made from a single mesh layer located along the central horizontal axis. For slabs of 200-300 mm, two parallel layers of mesh are required, installed with an indent of 30-50 mm from the bottom and top of the future slab. Reinforcement diameter - 12-16 mm, rod installation step - 200-300 mm.

Under the load-bearing walls, the installation step of the rods is reduced due to the more sparse arrangement of the elements in the central part of the slab.

The number of reinforcing bars and clamps for their fastening is most conveniently calculated using a specialized calculator.

Do-it-yourself foundation-slab: step by step instructions

The whole complex of works on arranging the slab base of a house or outbuilding can be done on its own.

Preparatory stage

The area for the foundation is cleared of debris, trees and, after which the future excavation is marked. It is important to ensure that the stretched cords form right angles. For the accuracy of the geometry, the coincidence of the lengths of the diagonals of the marked rectangular section is checked.

On the marked area, it is required to dig a pit, taking into account the thickness of the sand and gravel cushion, footing, waterproofing and the design depth of the slab.

It is required to remove a layer of fertile soil with vegetation from the building spot, the depth of the pit is calculated relative to the prepared surface.

The bottom of the pit should be flat and horizontal, the soil should be carefully compacted. The technology for building a foundation slab may involve the use of geotextiles to create a barrier between the soil and the sand cushion - in this case, the sand does not silt and is not washed out when flood groundwater rises. Geotextile sheets are laid with an overlap of 30 cm and run onto the walls of the pit.

Pillow arrangement

At the bottom of the pit, sand is evenly poured with a layer of 100-120 mm. Then it is wetted with water and compacted with a vibrating plate. Then, according to the same principle, the next layer of sand is poured and rammed. The total thickness of the cushion must be at least 200 mm.

Common critical mistakes: using sand mixed with clay, unloading the entire volume of sand into the pit at once, followed by leveling.

The sand cushion is covered with a layer of gravel or crushed stone 120-150 mm thick. You can pre-lay geotextiles so that the layers do not mix. A layer of gravel is necessary to prevent capillary suction of moisture from the soil.

At the stage of arranging the pillow, it is required to lay all communications that will be brought out vertically through the thickness of the foundation slab.

Waterproofing

Formwork is mounted on the finished pillow along the contour of the future slab. For rigidity from the outside, the formwork is supported with spacers. The design must be airtight so that moisture does not leave the working mixture during concreting.

After the footing has dried, waterproofing is laid from a special polymer profile membrane or two or three layers of rolled bituminous material. Waterproofing should go to the walls of the formwork, the edges of the sheets are glued together with bituminous mastic or fused, heated by a burner.

Foundation insulation

In regions with cold winters, thermal insulation of the foundation slab is practiced when it comes to building a residential building, where it will serve as the base of the floor. The insulation under the foundation slab is laid in an even layer if it is designed flat. When arranging a slab with stiffeners pointing down. From the same insulation, platforms are formed in the designed places.

Reinforcement

Installation of the reinforcing cage begins with the bottom grid. To maintain the required clearance of 30 mm from the base, the reinforcement bars are placed on special plastic stands.

First of all, lay all the longitudinal rods. Then the transverse ones are attached to them with the help of wire twists or plastic clamps. Welding is not used - overheating of the metal at the attachment points weakens the structure.

In order to place the second tier of the lattice at the required height above the lower one, use “spider” stands (they are “frogs”) over the entire area (2 pieces per square meter) and U-shaped edge elements.

Concrete works

The pouring of a monolithic foundation slab should be done within one shift, otherwise it is impossible to achieve the required structural strength. Requirements for the working mixture:

• (strength class B22.5);
• mobility P3;
• water resistance coefficient W8 and more;
• frost resistance class F

It is necessary to provide a convenient entrance for the automixer, take care of the concrete pump or trays for supplying the working mixture to the formwork in advance.

The solution supplied to the formwork must immediately be evenly distributed over the entire plane. To compact concrete, eliminate air bubbles, you can not do without a deep vibrator. The surface is leveled with a rule or with the help of a vibrating screed.

The foundation of a monolithic slab should be covered with plastic wrap to protect it from precipitation, debris and accidental damage. A day later, for 5-7 days, it is required to wet the concrete surface with water. This will prevent drying and cracking of the top layer of the plate. After 10-15 days, the formwork can be removed - the concrete will have time to gain more than 50% strength. The construction of walls is started no earlier than a month after pouring - the concrete must fully mature.

Knowing how to make a foundation slab for a house, you can save a lot of money on building a summer house or country house, garage. In order for the foundation to serve for more than one decade, it is important to strictly observe the technology of work and use high-quality materials.

Monolithic slab foundation technology - video