Mounting foundation. Installation of the foundation of the house: highlights. Foundation installation procedure

The foundation is one of the most important structural elements of the house. In construction, it is necessary to responsibly and competently approach the foundation of a country house. If you lay a mistake at the very beginning of construction - by saving or incorrectly designing the foundation for a private house, you will get global consequences for the whole house: foundation distortions, material overruns, vertical and horizontal deformations, uneven settlements, cracks in supporting structures.

By design features, the following types of foundations are distinguished:

1. Strip foundation

Strip foundations are the most common and versatile type of foundation. The strip foundation is used for any type of structure, be it a bathhouse, a cottage, or an apartment building. Such a foundation is the easiest to implement - for its arrangement it is necessary to dig a trench, the walls of which will act as formwork.

Strip foundations are made in the form of belts buried in the ground to which the load is transferred from the load-bearing structural elements of the house, such as walls, columns. The belts are supported on distribution pads, so-called foundation slabs. This makes it possible to transfer forces from the walls and columns to a large area of ​​the soil and allow the use of the soil without special preparation for work.
A strip foundation is acceptable as a foundation for a one-story house or a foundation for a two-story house with or without a basement, with load-bearing multilayer walls or brick walls and reinforced concrete floors. The pressure under the foot of the foundation is from 10 t / m².

Nowadays, pile foundations are becoming increasingly popular in the construction of houses. However, opinions on the use of this type of foundation are very different. Some believe that it is short-lived and extremely limited in use, while others believe that this type of support for the house is universal. Therefore, we will try to describe the pile foundation, its characteristics, types, as well as pros and cons.

Pile foundation: pros and cons
A pile foundation is used in construction on a specific soil, which is characterized by unevenness, looseness (solid or supporting soil is very deep, and the surface layer is sand or peat soil), on land with groundwater, plastic and fluid soil, clay, but can be used and on rocks. The great advantage of this type of foundation:
o installed at any time of the year without special soil preparation and geodetic reconnaissance;
o piles that have already been in use can be unscrewed and screwed in again, the work does not require much time. On average, it takes 2 days to prepare and install piles;
o versatility, another advantage. Modern technologies make it possible to use them both for country houses and for multi-storey buildings. They can withstand huge loads - 5-6 tons per pile;
o one of the indisputable advantages of this foundation in comparison with the tape one is the low cost for building a house and installing them;
o if you are building a summer cottage, then environmental friendliness will be an important advantage - the absence of garbage on your site and the preservation of the landscape;
o the possibility of free ventilation of the underground of the house and the construction of a basement. Pile supports have a big plus - they can be easily repaired and reinstalled. In parallel, you can work on conducting communications to the house.
Undoubtedly, the pile foundation has great advantages in comparison with the strip foundation, but, unfortunately, there are also disadvantages. These include:
o the possibility of uneven settlement of the foundation, which happens, as a rule, due to poor-quality materials or due to the heterogeneity of the soil;
o due to the same low-quality material, pile corrosion may occur, which of course is compensated by the possibility of their replacement;
o there is a difficulty in installing a brick structure on piles;
o the service life, after which the obligatory replacement follows, is 100-120 years, but it is up to you to attribute this to the minuses or pluses of pile foundations;
o there are opinions that piles are not suitable for the construction of large buildings, in houses of this type, it is difficult to make a basement, and the traditional construction of foundations is much more reliable.
Considering the minuses and pluses of the pile foundation, it is necessary to note what types this foundation is; the choice of one or another type will depend directly on the type of soil.

The most common types are:

Based on the above, we can conclude that the advantages of the pile foundation will be the ability to install them on "difficult" soils, efficiency and the ability to quickly complete the work. The disadvantages of the pile foundation can be low-quality material and, as a result, corrosion and the need for replacement. Relatively short service life (100 -120 years). But it is worth paying attention to the fact that the selected piles for the type of soil will serve you for a long time, and the construction will be very fast.

3. Foundation slab

Sometimes, on the site for the construction of a house, soils with uneven deformations (heaving, subsidence) or with a high level of groundwater lie. In this case, the most acceptable type of foundation for a house will be a monolithic slab (sometimes such a foundation is called a "Swedish slab".

Distinguish between shallow and buried slab foundations; foundation slab with or without stiffeners; reinforced or simple (without reinforcement); insulated or not.
The principle of operation of the slab foundation is to evenly distribute the load on individual sections of the foundation due to the distributed amaturn frame, embedded in concrete of the design thickness.

Preparatory work
After removing and removing the soil with grass cover, the building site should be leveled. The site is made a little larger than the foundation contour, then the foundation is broken down and an excerpt of the foundation pit. It is important that the bottom of the "trough" is strictly horizontal. It is recommended to cover the bottom of the pit with geotextile. The roll material will not only keep the bedding material from penetrating into the ground, but also remove excess moisture. Before installing a sand or gravel bed (h = 20-30 cm), it is necessary to install underground elements of water and sewerage pipelines and, if necessary, a drainage system. In some cases, a preparation of 10 cm thick concrete is performed on top of the pillow.

Concrete foundation construction
All stages of the construction of a monolithic foundation slab take place in a certain sequence:
... The foundation reinforcement consists of the bottom and top row of meshes. The diameter of the reinforcement of the periodic profile should be 14-16 mm, the pitch between the rods is 20-22 cm, the distance from each mesh to the lower and upper plane of the foundation is 5 cm. For the convenience of installing the upper mesh, special supports are used. The connection between the bars of the meshes and the frame can be either "knitted" or "welded".

Concreting. In order for a monolithic reinforced concrete foundation slab to be reliable and meet the required technical parameters, the concrete grade must be ─ М 350-М 400. It is advisable to use cement with a water resistance coefficient w 8. For frost resistance, concrete must correspond to the F-200 grade. For a country house, the optimal thickness for a monolithic pillow is 40-50 cm. Below ground level, 10 cm is often laid, and above it is 30 (40) cm. The concrete mixture should be poured continuously and thoroughly tamped / vibrated each new portion.

Waterproofing. After dismantling the formwork and setting the foundation of 70% strength, a waterproofing layer is made on top of the monolithic slab. Waterproofing is carried out either by coating with bitumen or bitumen-polymer mastic, or by gluing roll materials.

Foundation slab with grillage (plinth)
Many developers, along with the foundation reinforced concrete slab, also fill the monolithic basement with their own hands. The reinforcement frame of the basement is made of the same reinforcement as the frame of the slab and must be connected to the frame of the monolithic foundation. Erection of a plinth on a slab significantly increases the rigidity of the entire foundation structure. The basement volume inside the house also increases. This space is used for routing communications, as well as for placing an additional heat-insulating layer in it.
When installing a monolithic foundation, the risk of cracks in the foundations and the appearance of deformation processes in the building structures of the building is eliminated. The device of a monolithic slab is characterized by a long construction period, massive foundation and significant consumption of materials and money. However, this type of foundation has priority advantages ─ convincing reliability and durability.

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Installation of foundations and basement walls, which are the main elements of the underground part of buildings, is the most critical stage of construction. Errors made here can complicate the installation of overlying structures and reduce the strength of the entire building. Therefore, before starting work on the installation of foundations, it is necessary to make sure that the layout of the building axes and the marking of the foundations are correct.

The axes of the building are broken up and fixed on the cast-off by surveyors and other engineering and technical workers. The breakdown of the axes of the foundations begins with the transfer of the axes to the base, prepared for the construction of the foundations. For this, axial strings are pulled along the cast-off and, with the help of plumb lines, the points of their intersection are transferred to the bottom of the pits and trenches. From these points, the design dimensions of the foundations are measured and their horizontal plane is fixed with fixed (control) viziers.

During work, one installer moves several meters behind one of the control lines and, looking over the horizon, gives instructions to the other installer about the depth of driving the pegs. The top installed with such metal pins so that the wire mooring stretched between them is 2-3 mm further than the side edge of the strip foundation. When installing free-standing foundations for pillars and columns, not only the points of intersection of the axes are transferred with plumb lines to the bottom of the excavation, but also the directions of the axes, along which the edges or corners of the foundations are immediately marked. These points are also fixed with pins.

Usually the foundation for the foundations is a leveling sand layer, unless the project provides for other preparation. The sole of the base (soil) in pits and trenches is leveled according to the design marks. Do not leave loose or loosened soil on the sole of the base. It must be removed and crushed stone or sand filled in instead. Depressions in the sole of the base more than 10 cm are filled with concrete or masonry.

To check the horizontality of the base at the beginning and end of the foundation section, control stationary sight-lines are installed so that their top is above the base mark by the length of the portable - running check sight. The level of the control line is checked daily with a level or cast-off. After placing a rule with a level on the hammered peg, the installers check the horizontalness of the base and level it, adding or cutting off, if necessary, an appropriate layer of sand. In this case, the planning of the base is performed so that the rule, applied in different directions, fits snugly against the sandy base. The width and length of the sand base are made 200-300 mm larger than the size of the foundations to prevent the blocks from hanging from the sand cushion.

The foundation blocks are laid according to the scheme of their layout in accordance with the project in such a way as to ensure in the indicated places gaps between the blocks for water supply pipes, sewerage and other inputs. Installation begins with the installation of lighthouse blocks in the corners and at the intersection of the walls. After laying the lighthouse blocks, the mooring (stretched on the edge of the foundation tape) is raised to the level of the top of the outer edge of the blocks and all intermediate blocks are laid on it.

During installation, the foundation blocks are lifted by four loops with a four-branch sling. By turning the boom of the assembly crane, the block is moved to the place of laying, guided and, at the command of the link installers, is lowered to the base. Slings are removed only after checking the position of the block in plan and vertical. If the block is not laid in the plan along the mooring cord, then it is lifted by a crane and put back in place.

The top of the lighthouse blocks is checked with a level, and the rest - along the berth or sighting on previously installed blocks. If the block is laid with deviations exceeding the permissible norms, it is lifted by a crane, taken to the side, the base is re-leveled, and only after that the block is put back on the base.

Foundations, consisting of several elements (for pillars and columns), are mounted sequentially: first, cushion blocks are laid on the base, after their alignment, the following blocks and a foundation glass are installed on the solution. The mark of the bottom of the glass is checked with a level. At the intersections of the walls and at the corners, when laying ordinary foundation blocks with a beveled part, a void is formed, which is filled with rubble masonry or concrete.

After the foundation blocks are laid, the sinuses between them and the slopes of trenches or pits are covered with soil to 2/3 of the block height. This prevents the blocks from dislodging and washing out the sand in the rain. Installation of basement walls. Basement wall blocks (wall blocks) or technical underground are started to be installed after checking the position of the laid foundation blocks and the waterproofing device. Usually, as insulation on the cleaned surface of the foundations, a layer of mortar with a thickness of 20-30 mm is spread, which at the same time serves as a leveling layer.

Wall blocks are marked with letters and numbers. For example, SB-4-24 or SB-4-4, where the letters indicate the type of block (SB - wall); the first number is the nominal width, and the subsequent ones are the length (all in decimetres). Before the installation of wall blocks on the foundations, the main and intersectional axes of the building and the boundaries of the walls are marked, which are fixed with appropriate risks. The marking is carried out using wire axes, cast-off in the same manner as when marking the foundations. Further, according to the installation diagram, mark on the foundations the position of the wall blocks of the first (from the foundations) row, marking the places of the vertical seams.

Installation begins with the installation of lighthouse blocks in the corners and intersections of the walls. The block, raised by two loops, is fed by a crane to the installation site, deployed to the design position and lowered onto the bed from the solution. If the position of the block after the check turned out to be incorrect, it is raised again, the lower edge of the mortar is cleaned and the mortar bed is restored, adding the solution at the side of the bed into which the block bent. When preparing the bed, the solution is served with a shovel-bucket, and leveled with a trowel. The best quality of the bed is obtained when the mortar is leveled with a rail along the frame, which ensures the bed is horizontal and fixes its thickness.

After mounting the lighthouse blocks at the level of their top and at a distance of 2-3 mm from the side edge, pull the wire mooring (or the mooring cord) and fix it with brackets. The rest (ordinary) blocks are installed on the solution along the berth. During the lowering of the block, it is guided into place, holding it by the slings or the upper side rib, but not by the end face. It is dangerous to grasp the end with your hand - you can press your hand with the mounted unit to the previously installed one.

The correctness of the installation of ordinary blocks is controlled by the berth, plumb line, sighting at previously installed blocks and by marking risks on the foundations. If the block is inaccurately planted, it is straightened with mounting crowbars, moving the block in the desired direction. The blocks of the outer walls of the basements are aligned along the plane facing the basement, and the blocks of the inner walls are aligned along one of the planes.

To move blocks on the bed, they use three main methods: a paw away from oneself, a paw to the side and a paw towards oneself. When the paw is taken away from itself, the drawn end of the scrap is wound under the block and the scrap is squeezed away from itself onto the block, which at the same time rises somewhat and, sliding off the paw, moves forward. In the reception with the paw to the side, the drawn end of the scrap is brought under the block at an acute angle to its front edge. Pressing then on the crowbar and turning it on the heel of the paw to the side, raise the block and move it. In the reception with the paw towards itself, the drawn end of the scrap is wound under the block and, pressing on the end of the scrap, the block is lifted and moved towards itself. With a large seam thickness, instead of receiving with the paw from oneself, they use the technique with a sharp end from oneself. The movements when performing these techniques are the same.

The subsequent rows of blocks are mounted in the same sequence, making the layout of the layout of the blocks on the underlying row.

The first two rows are installed from the laid foundation blocks, the next - from the scaffold.

Immediately after installation and alignment of a number of blocks, the vertical seams between them are sealed with mortar. The grade of the mortar on which the blocks are to be mounted is indicated in the project.

The foundations and walls of the basement are assembled by a link consisting of four workers: a crane driver, an installer of the 4th category (link) and two installers of the 3rd category. One installer picks up and slings blocks, checks the fastening of the mounting hinges, monitors the lift and gives signals to the crane driver. The other two installers set the blocks to the design position.

The erection crane, depending on its type, can be during work on the edge of the excavation, and then all the foundation, and then the blocks of the basement walls, are mounted on the grip. If the crane is installed in a pit, then the foundations are mounted in small sections, and the walls of the basement in these sections are erected immediately to their full height, since the assembly crane will not be able to re-enter the area where the blocks are already mounted above the ground level. When installing foundations and other structures of the underground part of buildings to the mark of ± 0.000, or the zero cycle of the building, rail jib cranes are also used. Such cranes provide the supply of parts to any point in the basement. They are used for the installation of the underground part of residential buildings of any type: block, brick, panel, frame-panel.

One of the types of construction work is the installation of a foundation from blocks. In Russia, prefabricated foundations are widely used for any buildings. This foundation has a large margin of safety, and it can easily withstand a private house or cottage.

A foundation from blocks can be made in a few days, so building from them is preferable when there is little time for the installation of monolithic structures.

Block structures do not need time to gain strength; walls can be built immediately after their construction. It is not difficult to lay such a foundation; you can cope on your own. In this case, the installation of formwork and reinforcement are not required.

Installation of a block foundation is more economical than other types of similar buildings. Calculating the amount of building materials is easy to do. Although a cubic meter of blocks is slightly more expensive than a cubic meter of concrete, you will save money on formwork and knitting. If you build an intermittent foundation, or use used blocks, the savings will be more significant.

Foundation blocks come in a variety of sizes. The choice depends on the size of the future home. Blocks can have a width from 300 to 600 mm, a length from 780 to 2380 mm, but all have a height of 580 mm. There are grooves in the side parts, which are clogged with concrete mortar during installation. Installation of foundations is best done with blocks having a length of 2300 mm. The construction of foundations from them assumes greater structural strength and fewer vertical seams. In addition, making a foundation from such blocks is faster and easier, and the costs are minimal.

For the installation of a block foundation, the following tools and materials are needed:

• blocks (preferably with ready-made holes);
• cement or concrete mix;
• sand;
• laser level;
• rope;
• shovel;
• reinforcing mesh;
• waterproofing material;
• concrete mixer;
• Construction crane.

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The main stages of installation

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Foundation design

For the choice of material, planning the dimensions, some calculations should be made. You need to know the features of the soil. Then you need to calculate the maximum allowable weight of the house in order to know if the foundation will withstand the load. To do this, add up the weight of all building materials, including finishing materials, as well as the approximate weight of furniture and household appliances.

It is important to determine the depth of the building into the ground, since the size of the foundation will affect the cost. Some soils allow for the usual meter deep, it is more difficult to build a structure on clay soils.

It is also necessary to take into account the depth of freezing: the installation of a water purification station and the method of carrying out communications will depend on whether the soil is buried or not buried. You also need to know the level of groundwater.

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Masonry technology

Before laying the blocks, make a leveling base of coarse sand. It should be at least 10 cm thick. For convenience, a frame is made of wooden blocks inside the pit, the width of which is 20 cm wider than the width of the foundation sole. Using a laser level, the frame must be aligned horizontally, then filled with sand, moistened and tamped. Excess sand must be removed with a flat plank. Do not forget about waterproofing the foundation, especially if the house will be with a basement.

Corner blocks for external walls are laid first. Then a line is drawn along the sand along which the rest of the blocks will be laid. If the installation of the base is done correctly, the unit will fit well. It is advisable to lay blocks in two. First, you should build the outer walls, then start laying the inner ones. Vertical joints must be filled with concrete. It is difficult to make an additional block from whole blocks, so it is better to make a monolithic insert.

The subsequent rows are laid on a mortar with a thickness of about 1.5 cm. The ligation of vertical seams is 25-60 cm - it depends on the soil: the higher its properties, the less it will be. If the dressing recommendations cannot be followed, a masonry net should be laid. During the construction of the foundation, it is necessary to make holes for the sewerage and water supply to the house.

Factory blocks manufactured in compliance with technological standards and requirements are highly durable. Nevertheless, the hanging of the brickwork from the foundation is limited: if it is done on both sides - up to 6 cm, if on one side - up to 10 cm.

If the site on which the house is being built has weak soil, you need to increase the width of the base for the foundation. To do this, a row of special pillows should be made, between which there should be a distance of no more than 70 cm. When laying the first row of blocks, place pillow blocks under the vertical seams. The gaps between them are covered with soil and tamped. If the soil has poor bearing capacity, then to give the foundation more strength, a monolithic belt is poured over the blocks, the thickness of which is 20-30 cm. Its frame is made of 4 reinforcement threads with a diameter of 1 cm.

If the soil has good bearing capacity, and the house does not have a basement, installation with intermittent laying of blocks is possible, which will not be laid in continuous rows, but with a gap between them. This method allows you to reduce the consumption of blocks and reduce costs. The gaps must be covered with soil and tamped. Vertical seams should be strictly above the previous block. Installation of a discontinuous foundation involves a preliminary calculation, which depends on the project of the house. In any case, the gaps between its elements should not exceed 50 cm. Such structures are not made when building houses with more than 2 floors, but lightweight brickwork should also be made for low-rise houses.

The strip foundation is most in demand in private housing construction. During construction, it is important to take into account the design features and avoid mistakes, which will negatively affect the strength of the finished object. In what cases is this type of foundation used and how can it be built with your own hands?

Strip foundation - what is it?

A strip foundation is a foundation consisting of a closed contour. In fact, this is a reinforced concrete strip that is arranged under all supporting structures, distributing the loads along the entire perimeter. Such a foundation is capable of resisting the swelling of soils, blocking distortions and subsidence of the object.

The benefits are revealed as follows:

• the possibility of erecting any buildings - from monolithic to wooden houses;
• saving building materials;
• low volume of earthworks;
• lower cost compared to other types of bases.

Such characteristics make the structure most in demand in private housing construction. On its basis, dachas, country houses, baths, garages are being built.

• monolithic rubble on cement mortar / concrete - 150 years;
• prefabricated concrete-based - 75 years;
• brick tapes - 50 years.

Device technology

The device of the strip foundation (technology) begins with the construction of a sand and gravel cushion, on top of which a waterproofing layer is laid. This eliminates the erosion of the base by groundwater. If the weight of the object under construction is small, for example, it is a garage or a country house, the arrangement of this layer can be neglected.

The upper plane of the system, on which the above-ground parts of the building will be located, is the surface of the foundation, the edge; the lower plane is the sole.

Supporting structures of this type are applicable:

• when erecting buildings with brick, stone, concrete walls, with a density of no more than 1300 kg / m³;
• for objects with heavy floors (reinforced concrete, metal, monolithic);
• when implementing work on heterogeneous soils. The structure will redistribute the loads and the house will not give deformations and cracks.

There are simply no universal recommendations for the selection of a brand or class of concrete. It all depends on the geology, construction conditions, reinforcement, the possibility of using just such concrete.

Technology by type of foundation

According to the construction method, two types of base are distinguished.:

• monolithic;
• prefabricated - with the same thickness as the monolith, the strength of prefabricated structures is 30% lower. In addition, they cannot be reinforced with additional reinforcement, since the blocks are produced according to a standard design.

The construction of a monolithic structure involves welding or tying the reinforcement system and the subsequent pouring of concrete solution directly at the place of implementation of the work. This allows you to achieve the integrity, continuity and strength of the monolith. The prefabricated structure involves the fixation of reinforced concrete blocks using a reinforcement system and cement.

Device - basic principles

When building a foundation, according to current technology, the following must be taken into account:

• the width of the walls of the structure should not be narrower than the width of the walls of the object being erected. This avoids excessive stress;
• for the most stable position, the width of the tape should be at least 10 cm greater than the width of the walls;
• stronger buildings are erected when the foundation strip expands towards the base, when the cross-section resembles a trapezoid;
• in private housing construction, the base often has a rectangular cross-section;
• to avoid lateral loads, the height of the tape should be at least twice its width;

Materials used

This type of base can be created based on the specified materials.:

• rubble concrete - a mixture of coarse stones and sand-cement mortar. Suitable for construction on rocky and sandy soils, but unacceptable on clay soils;
• reinforced concrete - a mixture of crushed stone, sand, cement and a reinforcement system. Suitable for the implementation of work on any type of soil. The base width depends on the width of the walls.
• brick - requires solid waterproofing. Suitable for the construction of brick and wooden buildings (up to 1.5 bricks). A foundation of this type is not used when it is necessary to deeply lay and with a high level of groundwater;
• slabs and blocks are pre-fabricated reinforced concrete products. They can be used on all types of soil, for the construction of any buildings.

Reinforcement

The main loads carried by the base are longitudinal... This is due to the forces of soil swelling and the uneven load of the building itself on the foundation. Longitudinal reinforcement must be ribbed, with variable cross-sections. This will help ensure the best possible bond between concrete and steel. Smooth rods can be used as transverse reinforcement in the frame.

In the production of the reinforcing cage, it is necessary to especially strongly strengthen the corners, which are very susceptible to various types of deformation, fractures and chips.

The calculation allows you to determine the size, volume of concrete, formwork, quantity and diameter of the reinforcement used. The calculations take into account the following parameters:

• concrete grade;
• tape width;
• belt height;
• tape thickness;
• tape length;
• the brand of concrete used.

Depth of laying

If we consider the types of foundation in terms of depth, then it can be deep and shallow... The choice of a specific depth depends on the expected loads and bearing properties of the soil.

As a rule, in the construction of frame and light houses made of wood, foam concrete, shallow placement (50-70 cm) can be dispensed with, and heavy monolithic houses (above two floors) require the structure to rest on denser soil layers (30 cm below the depth soil freezing).

By equipping such a foundation, you can lay a basement or basement, which implies the removal of the top layer of soil. If the basement is not needed, the topsoil can be left in place, thereby reducing the amount of excavation required.

The device of a shallow strip foundation is subject to the following principles:

• implementation of earthworks. The construction site is leveled, the topsoil is removed with a margin of 2 m on each side. To control the height difference, a building level is used;
• according to the design data, the markup is outlined. The main elements are marked with stakes and a rope. If the object is rectangular, the stakes are hammered in the corners. More complex shapes require the designation of all sections of the joint or turns of future walls. All angles must be 90 degrees;
• a trench is pulled out (depth 50 cm, width exceeds the width of the walls);

• the walls of the trench are lined with a waterproofing layer;
• a sand-and-gravel cushion is set up (15-30 cm thick, depending on the type of soil). Experts recommend using coarse sand;
• implementation of reinforcement. Four rods with a diameter of 10 mm are driven into the corners. The length of the rods should be 5 cm less than the height of the base. If necessary, intermediate rods are driven in with a step of 1 m. In the lower and upper parts of the frame, horizontal rods (12 mm) are tied or welded. The distance from the pillow to the bottom layer should not be less than 5 cm;
• installation of formwork. You can use a flat edged board 6 m long. The system is knocked down from the outside, which will ensure the integrity of the foundation surface. The height of the shields is taken as 50 cm, counting from the ground level. Shields are securely fixed to each other and reinforced with spacers. The walls of the system must be flat;
• pouring concrete. The solution can be prepared independently or brought to order. The mortar is poured in one layer, which prevents cracking of the finished structure. The filling is compacted with a vibrator;

• the upper part of the fill is leveled with a trowel;
• so that the walls are as even as possible, after pouring, you can knock on the formwork with a hammer;
• when the concrete has gained the given strength, the formwork is removed;
• waterproofing - carried out 7-10 days after the concrete is poured. For work, bituminous mastic is used, with which the walls of the base are processed and waterproofing material is glued;
• backfilling - carried out with medium-sized sand with watering and ramming.

The hardened foundation needs maintenance. In hot and dry weather, it is moistened, in rain it is protected from moisture penetration.

Strip foundation and technology of its device

The strip foundation, the device technology of which is widely used in private housing construction, is a universal design for almost any buildings.

Installation of strip foundation

The basis of any building is a foundation, strength and durability depend on its quality. At the same time, despite the different types of foundation, the most demanded today is the strip foundation. This type of foundation is used in the construction of baths or houses from a bar. But, despite this, do not forget that the foundation is selected depending on the type of soil, physical activity and wall structures of the future structure. For example, if you plan to build a small bath from a bar, then you can get by with a built-in concrete slab. If this is a multi-storey bathhouse or a private house, then you need to use a strip foundation.

This is due to the fact that small building objects can be subject to different variations. When planning a normal living space, you should not save on such an important stage as preparatory work, installation of the foundation, as well as the use of high-quality material.

Acquaintance with the strip foundation

The strip foundation was widely used due to its high strength and durability. Even in spite of the fact that its installation is not the easiest one, nevertheless, the technology allows you to automate the process and get a good result.

In order to opt for this particular type of foundation, you should pay attention that it is a reinforced concrete strip, which has the same cross-sectional shape, along the entire perimeter of the building, laid not only under the outer, but also the inner walls of the room.

This design allows you to evenly distribute the load even with uneven foundation settlements. In addition, it is recommended to use such a foundation for buildings that will have heavy floors or walls of dense material. You can use such a foundation if the plan provides for a basement or basement.

Preparation and calculation of materials

You can get a solid strip foundation only if you follow the recommendations and use really high-quality materials.

So, for the construction and device, the following materials are often used:

• concrete, which includes sand, cement and crushed stone. Such concrete is designated as rubble concrete, used for sandy or rocky soil;
• reinforced concrete is also used for sandy terrain. The composition of such a solution includes not only cement, sand and crushed stone, but also reinforced metal rods;
• the use of a brick foundation is intended for light buildings, since such a material is hygroscopic, therefore it is not recommended to install a strip foundation;
• foundation blocks are a common material that has high strength and reliability. This material can be used for any construction site, regardless of the type of soil.

Types of strip foundations

It should also be borne in mind that the strip foundation is divided into several types: monolithic and prefabricated. In this case, the monolithic, in turn, can be shallow and buried. Installation of this type of foundation is carried out directly on the construction site, it is carried out in the form of a rigid reinforced concrete frame, which is located along the entire perimeter of the object.

No less popular is the prefabricated and strip foundation, the construction technology of which provides for the use of reinforced concrete slabs and blocks that are produced in the factory. To carry out the installation of such a foundation, you must use a special technique.

Distinctive features of a monolithic and prefabricated foundation

After carrying out calculations, experts found that the foundation assembled from concrete blocks is less strong than a monolithic one. So, the strength of the foundation made according to the monolithic technology is 30% higher, in addition, such a foundation can always be reinforced with reinforcement. In addition, a monolithic system is cheaper for the developer, because in order to build a prefabricated foundation, you need to attract specialists and hire special equipment. But, there is also such a moment as timing, so if the foundation needs to be completed in a short period of time, then the choice will fall on the prefabricated foundation, since you can start erecting walls almost immediately after its construction.

Installation rules for a monolithic strip foundation

If you plan to build a wooden house, then a monolithic foundation will be an acceptable option.

At the same time, the technology for erecting such a foundation is quite simple, for this it is necessary:

• carry out preparatory work, calculations and purchase of material;
• arrangement, which includes digging a trench under the foundation, for this type of work, you can use special equipment or do the work manually. After the trench is dug, it is necessary to lay the cushion, which will consist of sand and gravel, this will make it possible to make high-quality waterproofing;
• formwork device, boards or panel board folding iron formwork are used;
• installation of formwork, carried out at the stage of arranging the formwork;
• preparation of concrete, which is poured in several layers, after preliminary compaction;
• waterproofing and filling the sinuses between the soil and the foundation. Such work is carried out manually, since it is very important not to violate the integrity of the waterproofing.

Installation of strip foundation

The basis of any building is a foundation, strength and durability depend on its quality. At the same time, despite the different types of foundations, the most demanded ...

Monolithic strip foundation for the house

A monolithic strip foundation is a one-piece structure made of steel reinforcement and concrete strip. It is located around the perimeter of the building and under all load-bearing walls and elements. If the technology is followed, the structure becomes a single whole - a monolith - and has a very high reliability and strength characteristics. For this reason, it is popular both in the construction of multi-storey buildings and private cottages.

It is advisable to use a monolithic strip foundation with a low level of groundwater: when they are located below the required depth of the foundation. Otherwise, it is necessary to organize drainage, and this is additional (and considerable) funds.

This is what the finished monolithic strip foundation looks like.

Device and types

In terms of depth, strip foundations are shallow and deep. Shallow ones can be used on calm, non-powdery soils with good bearing capacity for buildings with a small mass - made of wood and erected using frame technology.

In this case, the tape should go 10-15 cm into a solid layer, which is located under the fertile one. At the same time, according to the standards, it cannot be less than 60 cm.

Types of strip foundations by depth

Deep-laid monolithic strip foundations are made for heavy, massive houses. In the general case, they are lowered 10-15 cm below the level of soil freezing for a given region. In this case, the sole must be supported by a layer with good load-bearing capacity. If this is not the case, you have to go deeper below. For example, if the level of freezing of soils is 1.2 m, and the fertile layer ends at 1.4 m, then you have to drop below 1.4 m.

With or without formwork

In general, the technology for erecting a monolithic strip foundation provides for the installation of formwork. These are panel structures that shape the concrete and prevent it from flowing. It is clear that the formwork is an additional cost for materials, as well as additional time for its assembly and installation.

Formwork - a structure made of boards or plywood, which gives the foundation a shape

Sometimes, in order to save money, on good soils, a foundation pit is dug exactly along the markings - to the required width and depth. And concrete is poured into these holes without formwork. Such technology cannot guarantee the required degree of reliability; the result cannot be predicted. The fact is that concrete requires a certain amount of water to gain normal strength. Without formwork, water, although a little, is absorbed into the soil, which can affect the quality of the concrete stone itself. In the worst case, it can crumble.

They get out of the situation by spreading plastic wrap in the trench. But then they walk on it - you need to do the reinforcement. Both rods and boots damage the film more than once. As a result, moisture still goes away.

A foundation without formwork is a risky undertaking

In some cases, such foundations can last a number of years without problems. But sooner or later, cracks appear or concrete begins to crumble. The second difficulty in working with such a foundation is its far from ideal geometry. In order to reduce heat loss, the foundation is insulated, and most often with foam plates or extruded polystyrene foam. Try sticking them on an uneven surface. The same situation with vapor barrier: it is very difficult (almost impossible) to stick the film on uneven, porous concrete with interspersed soil. Whether this approach is justified or not is up to you, but such a foundation can only be recommended for a fence or a shed.

Basement in a house with strip foundations

The basement can be the same area as the house, or it can only take up part of the space. And you need to decide on its size before the design.

If the basement takes up only a certain part of the space, it will be possible not to remove all the soil, but to dig only trenches for the tape. They also dig the basement according to certain rules. Its placement and arrangement can also be developed at the design stage.

Monolithic strip foundation with a basement - a difficult design task

If it was decided to make the basement later, then you need to choose a place and determine the depth so that when you draw lines from the base of the house at an angle of 45 °, they do not pass through the voids.

If the basement is located under the entire area of ​​the house, then the entire soil is removed to the required depth. In general, such a project cannot be called a budget project: there is much more work and costs. Firstly, reinforced wall reinforcement and their greater thickness are required. Since there will be no soil inside, the walls of the basement will need to resist the pressure of the soil from the outside. Therefore, the thickness of the tape will be much greater and the reinforcement is needed more powerful, it fits with a smaller step, and the number of reinforcement belts will also increase. As a result, the consumption of reinforcement will increase only on the foundation. Secondly, concreting will be required and, possibly, reinforcement of the basement floor over the entire area. And these are materials again - concrete and reinforcement. Third, effective ventilation will be required to remove underground gases. You cannot design such a structure on your own. A professional with extensive experience should work.

One of the options for building a foundation for a house with a basement

Monolithic strip foundation: construction stages

Even if an organization or a team will build a house, the developer needs to know the technology: this is the only way to control the process and be sure of the quality of the work.

In general, the technology is as follows:

• Site marking.
• Land work.
• Base compaction, base bedding and ramming.
• Marking the tape.
• Waterproofing.
• Formwork assembly and installation.
• Armature knitting.
• Pouring and vibrating concrete.
• Curing.

Some clarification is required. Double markings - plot and tape - are needed if the house will have a basement under the entire area of ​​the house. The first time you mark out the area of ​​the house, taking into account the allowances for the installation of the formwork. Here you can’t do without it. Then, after the pit is dug and the bottom is poured and tamped, it will be necessary to mark the tape. These marks will then be used to install the formwork, which will form the "profile" of your house.

Now a little more detail about each of the stages.

Site marking

Since the soil was examined in a certain area for design, it must be tied tightly. The underground structure is often heterogeneous and a displacement of half a meter can be critical: suddenly there are subsiding rocks or a cavity. It is hardly worth positioning with an accuracy of a centimeter, but it is advisable not to miss too much.

So you can make a markup for the foundation on the site

Earthworks

Their volumes and the technique used depend on whether you will have a house with or without a basement. If not, then you marked the tape - this is how you will need to remove the soil. Only with a margin for the installation of the formwork - and this is sometimes 50 * 80 cm on each side. For the shields, spacers are needed that will prevent them from falling apart.

If the house has a basement, all the soil will need to be removed. The dimensions of the pit are 2-5 m larger than the dimensions of the foundation. This is the same stock for formwork struts.

If the house has a basement, the foundation pit turns out to be large

For large volumes, it is better to use a special technique. Renting it costs a lot, but the work of a team of "diggers" for several days will not cost less. The speeds are disproportionate.

The top fertile layer is laid separately, it can be immediately distributed throughout the garden. The rest of the soil is dumped in a heap: partly it will go to backfilling, partly it will need to be taken out.

For a house without a basement, dig less

Compaction of the bottom of the excavation and bedding

After the bulk of the soil has been removed, the bottom must be leveled and compacted. When working with an excavator, it often happens that some areas are 20-30 cm deeper than necessary. All these irregularities must be corrected: fill up and tamp.

Tamping and leveling is needed over the entire area of ​​the excavation or trench. Moreover, not with the help of a deck. It can be used if you are building a fence. Even during the construction of a bathhouse or summer cottage, it is better to use a vibrating plate.

Let's figure out why. The entire load of the building falls on this level. Even small voids and unevenness can cause uneven shrinkage and cracking. And the bottom after the excavation of the earth is uneven. And this can be eliminated with a rammer. It is even better if a layer of sand with medium to fine grains is poured onto the bottom. Due to its smaller size, it aligns better. But for a better and faster ramming, it needs to be moistened (pour water to wet its entire volume). The vibrating plate creates a force that compacts the sand by 15-20 cm. It is this layer that needs to be poured at one time. If, according to the project, a layer of sand is 30 cm, then you first need to pour 15 cm, shed and tamp it to a high density. Then pour in the second one and spill and tamp it too.

There are even narrow rammers for compacting soil in a trench.

Often the project requires the creation of sand and gravel bedding. Then another layer of crushed stone with a fraction of 30-60 mm is poured over the compacted sand. And it is also compacted. The thickness of this layer of backfill is 10-15 cm. It also needs to be poured in small layers of about 5 cm and each tamped.

In this case, the soil is not only leveled, it becomes even more dense: crushed stone is driven into the underlying rock, increasing its bearing capacity. Since the slab hits the pebble with great force, the compaction occurs to a depth of 40-50 cm. And this is very good.

Formwork for a monolithic strip foundation

The formwork is made from boards with a thickness of at least 40 mm, low-grade plywood or OSB. Plywood is inexpensive, special - formwork. On the one hand, it has lamination - there is a protective film. Therefore, it can be used several times.

Shields made of sheet materials are reinforced with transverse and longitudinal bars. From the boards they are fastened with crossbars. The assembled shields are exposed according to the marking of the tape, fixed from the outside with bevels, and spacers are installed inside. All these fasteners must give the formwork the given dimensions. They will not allow the shields to fall apart or bulge out when pouring concrete: the mass will press on the walls a lot, therefore the fasteners must be reliable.

Formwork is an inapplicable attribute of a high-quality foundation

Reinforcement

Due to the structural features - large length and small width - the strip foundation is influenced mainly by forces that try to break the strip across. Therefore, it must be strengthened along the long side. They use powerful ribbed reinforcement from 10 mm in diameter and more. All transverse reinforcement only stabilizes the longitudinal rods in space, therefore, it can be taken smooth and used with a small thickness - 6-8 mm.

Strip foundation reinforcement scheme

Moreover, in most cases, regardless of the depth of occurrence, two reinforcing belts are sufficient: at the top and bottom of the tape. The exception is the construction of the foundation with a basement under the whole house.

A diagram of the reinforcement of a strip monolithic foundation is shown in the photo. At each connection point, the reinforcement is tied with a special wire. This is done manually using hooks or automatic devices - knitting guns.

There is another way: welding. But its use is not always justified. The work is faster, but the connection is tight. When tying with wire, the reinforcement has some freedom. And it helps to compensate for some deformations without breaking the concrete. When welding, the joints are rigid, which is not bad on the one hand, but on the other, too rigid a structure can cause cracks.

And this is how the reinforcement looks live

One more point: the weld always starts to collapse first. Although the reinforcement is located in the thickness of concrete, and therefore does not corrode (oxygen does not penetrate to it), in case of any disturbances and the flow of oxygen, the welded joints are destroyed first.

At this stage, the ventilation ducts and ducts are laid through which engineering communications will be supplied to the house. If you forget about this, you will have to destroy the monolith and this is very undesirable: the fewer flaws, the stronger the structure will be.

Pouring strip foundation

When building a more or less large house, it is easier and better to order the delivery of ready-mixed concrete to the site in a mixer. Then the filling can be done in one day.

You can make concrete yourself. But this will require a concrete mixer. It is impossible to ensure the proper degree of homogeneity by manually mixing the components in troughs.

For pouring a large foundation, it is easier to order a ready-made solution.

For manual pouring, you will need at least three people: one mixes the concrete in a concrete mixer, the second distributes the finished portion, and the third vibrates the area that has just been poured.

Vibration of concrete is carried out using hand-held or portable submersible vibrators. This process removes all voids and distributes the aggregate more evenly. As a result, the strength characteristics of concrete are much improved, it acquires frost resistance due to the fact that it absorbs water much less. Therefore, do not skip this stage: with the same components in the solution, the result is concrete of a higher grade.

To make the concrete more homogeneous and acquire additional frost resistance, treat it with a vibrator

Another point: when pouring from the machine, you need to use special gutters. Firstly, it is easier with them to deliver concrete to the desired point, and secondly, the solution should not fall from a great height. If the drop height exceeds 150 cm, it delaminates. The result is low strength.

Curing

If the work was carried out in hot dry weather, the tape must be covered with plastic wrap or any other material that prevents rapid evaporation of moisture. Since the depth of the concrete is large, wetting the surface will not give tangible results. The main thing is not to let the top dry out and the film copes with this task perfectly.

If the temperature during and after pouring is kept in the region of + 20 ° C, three days after pouring the concrete will gain a strength of about 50%. And on the fourth day, the formwork can be removed and proceed to further work.

At lower temperatures, you need to wait longer: at + 10 ° C it is already 10-14 days, and at + 5 ° C the setting process practically stops. In such conditions, it is necessary either to insulate the formwork, or to heat up the concrete.

The monolithic strip foundation is ready, but there is still work to be done on its insulation and waterproofing. Only after that they fall asleep (backfill).

Monolithic strip foundation: device, structure, construction procedure

When building private cottages on heaving soils, a monolithic strip foundation is most often used. It takes a long time to build, but it is highly reliable.

The foundation is tape. Strip foundation device technology

This article will focus on the strip type of foundations. We will tell you in what cases a strip foundation is used for a house. Consider the device of the strip foundation under the house. We will give a calculation of the cost of a strip foundation and describe the main mistakes during its construction.

What is a strip foundation

Every person probably knows what the foundation of a house is. The foundation in the concept of construction is the underground part of a building (structure) that receives loads and transfers them to the foundation. The base is layers of dense soil.

The upper plane of the foundation, on which the above-ground parts of a building or structure are located, is called the surface of the foundation or the edge, and its lower plane, which is in direct contact with the base, is the base of the foundation.

The strip foundation is a reinforced concrete strip that runs along the perimeter of the entire building. The tape is laid under all internal and external walls of the building, keeping the same cross-sectional shape along the entire perimeter of the foundation.

The technology for building a strip foundation is quite simple compared to a slab or pile foundation. But it is characterized by increased labor intensity and high material consumption in comparison with the columnar type of foundations (more concrete volume, more formwork, the obligatory use of a crane).

Strip foundations are applicable:

• for houses with concrete, stone, brick walls (the density of which is more than 1000-1300 kg / m3);
• for houses with heavy floors (monolithic or prefabricated reinforced concrete, metal);
• in the event that there is a threat of uneven settlement of foundations, due to the heterogeneity of the soils on the site (for example, the site is complex in one part with sands, and in the other with heaving loams). The strip reinforced foundation will work as a whole, redistribute efforts and the walls of the house will not crack and deform;
• if a basement or basement is planned in the house, while the walls of the strip foundation form the wall of the basement.

When planning the construction of a house, it is very important to responsibly and competently approach the choice of the type of foundation for the future structure, since this is one of the most important structural elements of the building. A mistake made at the beginning of construction, an incorrectly designed foundation, saving building material, as a rule, leads to serious negative consequences during the operation of a house. Such problems as foundation distortions, material overruns, vertical and horizontal deformations, uneven settlements, cracks in supporting structures arise. Many qualities of the building, as well as its capital and durability, depend to a great extent on the reliability of the foundation.

Remember, the zero cycle of the construction of a building (preparation of the base, construction of foundations) is an expensive process and, as a rule, accounts for a third of the cost of the entire building. It is better to order the project to experienced designers, and then ask if something happens from them, having drawn up a contract correctly. In the project, the contractor organization will competently and reasonably choose the type and material of the foundation for you.

Service life of foundations.

The service life of strip foundations, depending on the material used, can be:

• monolithic concrete and rubble on cement mortar up to 150 years;
• brick tapes - 30-50 years;
• prefabricated concrete - 50-75 years.

Strip foundation design

By design features, strip foundations are:

1. monolithic, which are carried out directly at the construction site;
2. prefabricated, which are made of standard reinforced concrete blocks produced at the plant and assembled at the construction site using a crane. Prefabricated foundations are made of reinforced concrete slabs - pillows and concrete blocks.

Construction of a strip prefabricated foundation made of reinforced concrete slabs

Construction of a discontinuous precast foundation made of reinforced concrete slabs

The design of the strip monolithic rubble concrete foundation

Rubble stone strip foundation construction

Depending on the magnitude of the load, a shallow and buried strip foundation is distinguished. The shallow and recessed strip monolithic foundation is a horizontal rigid reinforced concrete frame that runs along the entire perimeter of the building, which ensures the stability of the house in conditions of slightly heaving and heaving soils. At the same time, a rational ratio of "strength - efficiency" is achieved. The budget costs for such a foundation are 15-18%. from the cost of the entire construction.

A shallow foundation is well suited for light houses (wooden, aerated concrete, frame, small brick). A shallow foundation is being set up on slightly abyssal soils. The depth of its inception is 50-70 cm.

Recessed strip foundations are built in houses with heavy walls or ceilings and, as a rule, on heaving soils. Also, the device of a buried foundation is necessary if a basement or garage is planned in the house. The depth of such a foundation is usually 20-30 cm below the depth of soil freezing. A deepened strip foundation requires more material consumption. Under the walls inside the building, you can make a shallower foundation by 40-60 cm.

A deepened strip foundation, in comparison with a shallow one, is more durable and stable, due to the fact that its bottom is below the freezing level of groundwater and it is not subject to deformation. But at the same time, the consumption of materials and labor intensity increase.

These foundations are usually laid during the warm season. At the same time, the use of expensive equipment is not required, a concrete mixer and small mechanization are enough.

On dry or sandy soils, the strip foundation can be laid above the freezing depth, but not less than 50-60 cm from the ground level.

On highly swelling and deeply freezing soils, strip foundations are very rarely used.

The main structures of monolithic foundations are shown in the figure.

Monolithic strip foundation design

Installation diagram of the formwork of a monolithic strip foundation

Prefabricated strip foundations are widely used not only in industrial and civil construction, but also in the construction of cottages and individual houses.

The positive aspects of using these foundations include a reduction in construction time and the ability to load structures after a short time delay after the completion of installation. It should be borne in mind that such a foundation will cost more than monolithic ones and requires the use of lifting equipment and skilled workers.

Negative sides: the strength indicators of a prefabricated foundation (with the same thickness) are 20-30% lower than that of a monolithic one. A foundation made of prefabricated blocks does not have such rigidity as a monolithic one, since it consists of separate elements. The precast foundation cannot be reinforced with additional reinforcement. After all, the blocks are produced according to a standard design. Reinforcement of a prefabricated foundation can be achieved with the help of grids laid between the rows of blocks, but this does not give the same result as the spatial reinforcement of a monolithic foundation.

It is possible to reduce material costs for a foundation of this type for low-rise housing construction by laying foundation wall blocks and pillows not in a continuous row, but with some run-up - these are the so-called intermittent foundations. Intermittent foundations will save up to 20 - 25% of blocks, which affects the cost of construction.

Strip foundation construction from foundation wall blocks and pillows in a non-continuous row (discontinuous foundations)

It must be remembered that if your site is peaty, silty and soils with a weak bearing capacity, discontinuous foundations are not acceptable.

Remember that a strip foundation made of precast concrete blocks loses in strength and other performance characteristics to its relative - a monolithic foundation. The main structures of prefabricated foundations are shown in the figures.

Monolithic foundation block for prefabricated strip foundations

Prefabricated strip foundation construction from foundation blocks and foundation pads

Material for strip foundations.

The most popular materials for strip foundations are rubble concrete, reinforced concrete, bricks, reinforced concrete foundation slabs and blocks.

1. Reclaimed concrete strip foundation. This is a mixture of sand-cement mortar and rather large stones (no more than 30 cm in length, with two approximately parallel surfaces weighing up to 30 kg.). It turns out a fairly reliable foundation. With a good supply of large stones and if the site has light soils (sandy) or rocky, then this is suitable for you. If your site has clay soils, it is better not to use this material, since a foundation made of rubble concrete can crack or be completely torn apart. The width of the foundation can be from 200 mm to 1000 mm, depending on the load of the building. Such a foundation requires a sand or gravel pad with a thickness of at least 100 mm to level the soil surface and make it easier to lay the concrete mixture.

2. Reinforced concrete strip foundation. This is a mixture of cement, sand and crushed stone reinforced with a metal mesh or reinforcement rods. It is the most popular foundation material. It is cheap enough, durable, allows the creation of monolithic structures of complex configuration. If you have a concrete vibrator, then you get a very reliable and strong foundation. If your site has sandy soils, then this is the material for you. The width of such a foundation is chosen depending on the thickness of the wall. For example, choosing a wall thickness of 2 ceramic bricks (510 mm), a foundation width of 600 mm, with reinforcement with AIII class reinforcement rods with a diameter of 12 mm, will be enough for the reliability of the house.

3. Brick strip foundations are suitable for both above-ground and underground parts of the foundation and basement parts. It must be remembered that the brick is very hygroscopic and in a wet state it is easily destroyed even by light frosts, therefore it must be protected from moisture by waterproofing. If you have a house with walls 1-1.5 kiripcha or with a frame made of wood, then this material will suit you. The high level of groundwater and the large depth of laying exclude the use of brick foundations.

4. Foundation slabs and blocks. For prefabricated foundations, foundation slabs such as FL 12.12, FL14.12, etc. are used. and foundation blocks 0.9, 1.2 or 2.4 m long, type FBS. These reinforced concrete products are manufactured in the factory. They are durable, reliable and practically suitable for all types of soil and types of buildings.

Perhaps, when building a house, you will have to deal with such a concept as "underground utilities". What it is? Underground engineering communications are linear structures with technological devices on them, designed for the transportation of liquids, gases and the transmission of energy. They consist of pipelines for supplying cold and hot water (heating), gas, cable electric and telephone lines.

In order to have an idea of ​​such communications, it is necessary to obtain a topographic survey of the construction site from the local authorities, where all underground communications are indicated. If the building falls on such communications, you will have to move them or otherwise tie the house on the site. It must be remembered that the construction of a house above or next to underground utilities causes additional loads on their structure and may lead to a man-made accident.

Such communications can pass through the site if it is located in an existing village or on the outskirts of the city.

If the construction project is developed by professionals, then you will know about all possible problems and ways to solve them.

Strip foundation technology

In this section, we will consider the technology of the device of a shallow strip monolithic foundation. Reinforced concrete and rubble concrete are considered as materials. This type was chosen for consideration based on several considerations:

• it is most often used in private construction
• the technology of its device is more complicated than that of the prefabricated one, and therefore, within the framework of this article, we decided to talk about it.

Since effective control over the progress of construction work can only be carried out by those who are at least a little versed in construction technology. Therefore, let's get acquainted with the technologies for the construction of a monolithic strip foundation.

The selection of workers is an important step. Now many construction organizations, and just teams, individuals offer their services. Do not rush to make a choice, chat with friends, acquaintances who have passed this stage, heed their advice. Contact 2-3 construction organizations, analyze their proposals, ask to acquaint you with the objects they have erected, talk to the owners of these houses. This information should be sufficient to select a contractor. Remember that a properly drawn up contract with a contractor will allow you to avoid troubles in case of any complications during construction.

The construction of a shallow foundation includes the following main stages:

1. Preparatory work

Provides for the clearing of the site for construction, the delivery of building material. On the ground, a marking of the axes of the house is applied, the location of the main elements of the foundation is fixed with the help of stakes and a cord (wire). This operation requires great precision and attention. If the area is flat, then measurements are easy. On areas with difficult terrain, slats and a level are used. It is imperative to check the corners of a rectangular or square foundation, they must be strictly straight at 90 degrees. Be sure to check the elevation of the bottom of the trench with a theodolite, at least at the corners of the house and at the intersection of the bands. Prepared for construction, the leveled site should be 2-5 m in each direction larger than the dimensions of the house;

Marking the axes of the house with stakes and wire

2. Digging a trench for the foundation and its arrangement.

The trench is dug with an excavator or manually. If dug with an excavator, then the bottom of the trench must be cleaned up and leveled manually. Protect the pit. At the bottom of the trench, a pillow of 120-200 mm made of fine gravel or sand should be laid (pouring water on it must be carefully tamped). A polyethylene film (or other waterproofing) is laid on the pillow or poured with cement mortar so that water does not leave the concrete into the ground and thereby does not deteriorate its strength characteristics.

Installation of a trench for a strip foundation and its arrangement

3. Installation of formwork with spacers.

The formwork device for the strip foundation is made of boards planed on one side (installed inside the trench) with a thickness of at least 40-50 mm. It is also good to use collapsible iron formwork. The installed wooden formwork, cleaned of debris and shavings and abundantly moistened with water, must be rigidly fixed with spacers to the walls of the trench so that the wall does not bulge. Carefully check the verticality of the formwork walls with a plumb line, as the durability of the foundation depends on this. The formwork is taken out 30 cm (maybe more) above the ground surface. The height above the ground will become the base of the future house. Do not forget to immediately leave holes for water and sewer pipes, so that later, cutting through them, does not violate the integrity of the monolith. After the construction of the monolith, the top of the foundation is covered with waterproofing materials, this will protect the walls of the house from capillary moisture entering them. How to perform such waterproofing, and what materials, you can read in the articles Waterproofing. Foundation, basement, basement waterproofing device and waterproofing. Types of waterproofing when building a house.

Formwork device for strip monolithic foundation

Formwork device with spacers for a strip monolithic foundation

Simultaneously with the installation of the formwork, reinforcement assembled into frames is mounted along the entire perimeter. The diameter of the reinforcement bars, their number and location are indicated in the project. If there is no project, then, as a rule, the frame consists of two rows of vertical reinforcement, fastened with horizontal reinforcement, the number of which depends on the depth of the foundation. The step of reinforcement installation is 10, 15, 20, 25 cm. An example of frame knitting is shown in the picture.

Installation of reinforcement strip monolithic foundation

The reinforcement, after pouring it with concrete, makes it possible to obtain a reinforced concrete monolithic foundation, the strength properties of which are very high. The frame is laid over the entire height of the foundation. It tightly ties the bottom and top of it.

The frames are made by welding or wire knitting. Connections of reinforcement into frames by welding, for convenience, are performed outside the trench. The resulting sections of the frames are installed at the bottom of the trench and welded together. If there is no welding machine, then it is possible to mount frames made of reinforcing rods directly inside the formwork, fastening them together with a knitting wire. Careless installation of reinforcing bars must not be allowed. They should be placed according to the project, strictly observing the pitch of the rods, their diameter, and the class of reinforcement. Maintain a protective layer (distance from the edge of the foundation to the middle of the reinforcement bar) of the reinforcement of 35-70 mm (depending on the conditions of the preparation material) while firmly fastening together. To support the reinforcing bar, when placing concrete, it is not recommended to use incomplete bricks, as well as to use any auxiliary materials. This can lead to a decrease in the strength of the concrete.

5. Pouring concrete into the formwork.

The concrete is poured gradually, in layers about 15-20 cm thick. Each layer is rammed with wooden rammers to exclude voids in the concrete mass, and the walls of the formwork are also tapped for this. The best and most reliable way to do this is to use a concrete vibrator. It is very important that the concrete is of the same consistency and does not split into layers. Quality problems often arise associated with the use of excessively liquid concrete (after all, it is easier to drain it from a concrete truck). In such concrete, the aggregate can settle at the bottom, which leads to its stratification and a decrease in its strength. A simple rule says - if you rake a concrete solution with a shovel, and at the same time it easily flows around obstacles, then the concrete is liquid. To obtain concrete of high strength, the concrete solution must be sufficiently rigid and considerable efforts must be made to move it with a shovel.

Laying the concrete mixture into the formwork of a strip monolithic foundation

If concreting is carried out in winter (which in itself is not the best option), the concrete must be insulated when it sets (with straw, sawdust, glass wool or other improvised materials) or warmed up. How to do it correctly can be found in the article Preparing the soil, concreting, masonry in winter.

It must be remembered that the concrete mix is ​​prone to delamination when it is poured from a height of more than 1.5 m. It is advisable to use portable gutters or other devices for pouring the mix.

If rubble concrete is used as a material, it is necessary to ensure that rubble stones are tightly joined to each other. Such a foundation requires significant costs, since stones must be precisely selected and adjusted. The masonry technology consists in the alternation of operations for laying layers of rubble stone, their compaction, spilling binder concrete between them. In this case, the concrete should be with fine aggregate - crushed stone, fine gravel, sand.

6. Foundation waterproofing device.

After 7-10 days after pouring concrete (or upon reaching 70% of the design strength, the formwork can be removed). For waterproofing the foundation, bituminous mastic is used, with which the outer walls are coated and the waterproofing material is glued. Roofing material is well suited for this. After a while, the quality of the gluing is checked. It is necessary to ensure that the waterproofing does not fall off, exfoliate from the wall of the foundation. Identified gaps, holes in the insulation are eliminated. There is an easier way to arrange waterproofing, for which the sinuses of the foundation are covered with clay, while it must be well tamped. If you want to be one hundred percent sure of the durability of the structure, treat the soil adjacent to the foundation with binding polymer mixtures;

7. Backfilling.

After the waterproofing device, backfilling of the foundation sinuses is performed. It is carried out with sand of medium size with its layer-by-layer compaction and pouring of water. This operation is carried out manually, taking care not to damage the waterproofing. It is possible to protect the waterproofing with a drainage membrane or a layer of geotextile. If there are basements and they are planned to be insulated, then a layer of insulation (for example, extruded polystyrene foam) can be glued on top of the waterproofing, and then it will protect the waterproofing from damage by backfilling.

Estimated cost of strip foundation

To calculate how much a strip foundation costs, you need to understand that the cost of a strip foundation device depends on the main two cost items - work and material. Below are the main types of work and materials for an approximate calculation of the price of a strip foundation device.

Note from the editor: Prices quoted in this article are at the time of 2009. Be careful.

• preparation of a trench 100 g / m3 or 12 dollars USA;
• soil cleaning and sand bed installation 70-80 g / m2 or 10 US dollars;
• execution of concrete preparation 380-400gr / m3 or 50 dollars. USA;
• assembly of the formwork of the support cushion 40gr / lm. or 5 dollars. USA;
• binding of the reinforcing cage and pouring concrete of the support pad 1000-1200g / m3 or 150 US dollars;
• installation of blocks, taking into account crane work 250gr / block or 30 dollars. USA;

Material for strip foundation:

• concrete up to 400-600 g / m3 or 50-75 dollars. USA;
• reinforcement 4500-5000gr / t or 560-625 dollars. USA;
• FBS 24-5-6 200-400 g / block or 25-50 dollars. USA;
• crushed stone fr. - 90-130 - 200 UAH / t or 25 dollars. USA;
• river sand - 110-120 UAH / t or up to 15 dollars. USA;
• expanded clay - 320-350 UAH / m3 or up to 44 dollars. USA;
• clay - 100-120 UAH / t or up to 15 dollars. USA;
• cement - 750-789 UAH / t or up to 97 dollars. USA;
• waterproofing of concrete - 20-40 UAH / kg or 2.5-4.0 US dollars;

Possible errors in the design and construction of the strip foundation

Note: the errors below will negatively affect the quality of any type of foundation, not only tape.

1. When performing exploration work, the properties of the soil, namely, heaving and its subsidence, were not fully taken into account. The level of groundwater and the depth of soil freezing have not been precisely determined. Due to the mistakes made in the project, mistakes were initially incorporated that negatively affect the quality of your house - the foundation will crack, large settlement.
2. In the course of work, builders used building materials of a lower quality than provided for by the project to save money and time. For example:

• cement used for concrete of a lower grade;
• for greater mobility of concrete during the preparation process, excess water was added;
• with careless preparation of concrete, it partially mixed with the ground;
• used split foundation blocks;
• when knitting a metal frame, reinforcement of a smaller diameter was used.

3. Poor quality of work.

• the axes were incorrectly taken out, the corners of the building turned out to be not straight. it
• can lead to a skew of the foundation;
• did not dig up the pit to the design level;
• could not stand the thickness of the cushion in the trench;
• waterproofing was not installed everywhere on a pillow under the concrete, as a result of which the water from it went into the ground and its strength indicators worsened;
• when concrete hardened in winter, the temperature regime was not maintained - the concrete did not warm up, as a result of which the strength of the foundation decreased;
• did not withstand the required time for the concrete to gain the design strength, and the formwork was removed;
• when backfilling the trench, the waterproofing was damaged or even knocked down. As noted above, this operation must be done very carefully and with special control.

All these mistakes lead to a decrease in the quality of the foundation and, ultimately, to the longevity of your home.

This is where you will again need the knowledge gained in this and other articles on construction. And most importantly, do not forget to constantly monitor all stages of the work.

If you do not have the opportunity to do it yourself, then it is better to involve a technical supervision specialist or a specialist from another organization independent of the contractor.

All of the above examples are directly related to the selection of qualified professionals for survey and construction work and are a very important stage in preparation for future construction. Now many construction organizations, and just brigades, individuals offer their services in private construction. Do not rush to make a choice, chat with friends, acquaintances who have passed this stage, heed their advice. Contact 2-3 construction organizations, analyze their proposals, ask to acquaint you with the objects they have erected, talk to the owners of these houses. This information should be sufficient to select a contractor.

It will not be superfluous to remind you that a correctly drawn up construction contract with a contractor will allow you to avoid troubles in the event of any complications during the construction process. The contract, as a rule, must stipulate the scope of work, the timing of their implementation, the contractor's responsibility for the quality of the work performed and his warranty obligations, the conditions for the acceptance of the object by the customer (if necessary, broken down by stages), the procedure and terms of payment for the work. Good lawyers will help you with this.

The foundation is tape

This article will focus on the strip type of foundations. We will tell you in what cases a strip foundation is used for a house. Consider the device

Build a house from scratch on your own is a difficult task, but doable. Careful calculations, competent selection of building materials and high-quality implementation of each process will help to cope without the involvement of specialists. The most important stage is the laying of the foundation, because the durability and reliability of any building depends on the strength of the base. It will take about 2-3 months to make a foundation for a house with your own hands.

Do-it-yourself foundation for a house

For the construction of residential buildings, a strip foundation is most often used. It can be shallow, if the house is one-story and small in area, or standard - laid at a depth of 1.8-2 m. The width of the base tape is usually 40 cm, but it can be increased depending on the specific load of the building. When designing a house, one should immediately take into account possible extensions and arrangement of basements and semi-basements. The presence of a common base will significantly simplify the installation of a veranda or other structures that may be needed later.

In order not to be mistaken with the parameters of the foundation, you need to carefully calculate the total load per square meter of soil and compare it with the permissible values.

When calculating the load, the following factors are taken into account:

• material for the construction of walls;
• type of insulation;
• type of roofing;
• the number of floors in the house;
• type of soil on the site;
• ground water level;
• region;
• snow and wind loads.

Cross section of strip footing

Calculations are made using special tables, for each factor separately. After that, all the loads are summed up, which determines the depth of the foundation in this area and the permissible width of the base of the base.

Base marking

Now measure the distance from the corner of the facade to the corner of the back wall and mark the points on both lines, and then pull another rope, parallel to the first. The intersections of the ropes form the corners of the building, and it is from these points that the diagonals of the resulting rectangle must be measured. If the diagonals are equal, the markings are correct. After that, the inner boundaries of the foundation tape are designated, stepping back from the marking lines 40 cm inside the perimeter. The pegs should be positioned outside the perimeter to better define the corners of the base. The last ones are the internal load-bearing walls, the base for the veranda or porch.

Trench preparation

The walls of the trenches must be leveled vertically, if the soil crumbles, props are installed. After excavation, the bottom must be checked against the horizontal, all irregularities are cut off with a shovel, excess soil is removed. The location and width of the trenches must fully comply with the project. The next stage is the installation of a sand and gravel cushion, designed to reduce the load from the building on the base of the soil.

The arrangement of the sand and gravel layer is as follows:

• the bottom of the trenches along the perimeter is covered with a thin layer of coarse-grained river sand;
• spill sand with water and ram it thoroughly;
• another layer of sand is poured and compacted again;
• fine gravel is poured and leveled with a layer of 15 cm;
• tamp the surface.

For a shallow basement, the inner surface of the trenches is lined with geotextiles before backfilling with sand. This material protects the sand bed from erosion by groundwater and siltation.

Formwork installation

Installation of foundation formwork

When installing the formwork, you will need:

• edged boards from 2 cm thick or plywood sheets;
• polyethylene film;
• roulette;
• screws or nails;
• hammer and screwdriver;
• bars for spacers.

Strip foundation formwork

Boards are fastened into rectangular boards, securing with transverse bars from the outside. Self-tapping screws are screwed in from the inside to make it easier to dismantle the formwork. For the same reason, it is recommended to use screws, not nails. When assembling, you should consider the location of the sewer holes and make cutouts of the appropriate diameter in the boards. At the end, the shields are covered with a film that will not allow the tree to absorb water from the solution.

The formwork is installed in parts on both sides of the trenches, and then reinforced with transverse bars every half a meter. Shields are placed strictly vertically, observing the same distance between opposite sides along the entire length of the perimeter. Outside, the formwork is propped up with timber struts. There should be no gaps between the lower edge of the boards and the upper edge of the trenches, otherwise the mortar will flow out.

Reinforcing frame installation

Reinforcing frame installation

For work, you will additionally need:

• knitting wire;
• building level;
• Bulgarian;
• trimming a plastic pipe;
• roulette.

The armature is cut with a grinder along the length and width of the trenches, after which a lattice with cells from 30 cm is knitted from it.To do this, 4-5 longitudinal rods are fastened with transverse sections every 30 cm.

It is categorically not recommended to use welding for the connection, since it weakens the attachment points and promotes corrosion of the rods. The frame should be three-dimensional, therefore horizontal gratings are placed at 3-4 levels, tying up with vertical rods.

Reinforcing frame installation

When the grating is fixed inside the formwork, the concrete pouring level is indicated on the inside of the panels. You can do this using a fishing line: small nails are stuffed at the ends of the formwork and a fishing line stretched strictly horizontally is fixed on them. It should be located 5 cm above the edges of the reinforcement mesh and run along the entire perimeter at the same horizontal level.

Pouring concrete mortar

Pouring concrete mortar

It is recommended to fill in the solution at a time, but not with the total mass, but in layers. Each layer should be no thicker than 20 cm; this will allow it to be evenly distributed between the reinforcement cells and to reduce the amount of air voids. For the manufacture of the mixture, they take cement M400 or M500, fine-grained crushed stone and coarse-grained river sand.

It is very important to correctly observe the proportions when mixing, otherwise the quality of the solution will be below normal. 1 bucket of cement requires 3 buckets of sifted sand and 5 buckets of rubble. Water needs to be taken about half of the total volume, add it in portions so as not to overdo it. The mortar should be neither too liquid nor too thick: high-quality concrete has a uniform consistency, when the shovel is turned over, it slowly slides down in total mass.

After pouring the first portion, the solution is leveled with a shovel and pierced along the entire length of the trenches with a piece of reinforcement to release the air that has accumulated in the solution during mixing. It is very effective to compact concrete with a vibrator; it increases the strength of the monolith several times. The remaining layers are poured in the same way until the surface of the concrete is leveled with the stretched fishing line. The formwork is tapped with a hammer, after which the top of the mortar is leveled with a rule or a trowel.

It takes about a month to strengthen the foundation.

Video - Do-it-yourself foundation for a house

With your own hands

DIY strip foundation

Building a house starts with a foundation. Building materials for its construction are often selected given regional availability. In some areas, the cost of a strip foundation is commensurate with a reliable foundation structure erected from granite. Such a foundation firmly holds any house of any size, built even on black soil and other unsteady soil. Taking into account modern requirements for construction, the main goal of the review is to talk about innovative approaches and how to make a strip foundation guaranteed to be reliable.

If there is no possibility of constructing a "safety cushion" for a house made of increased strength material, the masters recommend that novice builders use ready-made foundation blocks. This construction option will help to avoid a number of mistakes that, for a number of reasons, are not taken into account in cases where the strip foundation is being erected by hand.

Classic mistakes when building a strip foundation

The strip foundation is still the most affordable option for building the base of a house with your own hands and recommended for the construction of light houses. Meanwhile, the strength of the foundation depends not only on the conditions of its construction, but also on the territorial features of the area. Consider the main mistakes when erecting strip foundations, as well as how to avoid them.

Geological and hydrological works

Before starting work, it is recommended to obtain data from geological and hydrological surveys, which, when developing a project, will make it possible to make calculations with reference to the terrain. Most of the typical projects are quite expectedly made without taking into account the characteristics of the soil, therefore, in some regions, abnormal behavior of the base can be observed.

Strip foundations installed on black soil are not considered a solid foundation for any residential structure. Usually, areas of chernozem under the foundation are selected, covered with sand in layers, thoroughly rammed with water and covered with a pillow of crushed granite.

Features of extreme design

When building a house on your own, you can conduct a soil analysis on your own. To do this, you need to grind the site in 2-3 places and check the depth of the fertile layer, water, clay and sand. It will be useful to ask your neighbors about the features of foundations that have stood for several decades:

• to what depth the foundations were buried;
• types and materials used for the device;
• about the presence of a drainage system near the house;
• about cases of soil creep on slopes.

Errors during work and installation

Installation of foundations in the autumn-winter time

Foundations are not installed on waterlogged and frozen ground, as well as on snow. The construction of a concrete foundation in winter is undesirable or should be carried out according to strict technology using construction equipment. When concrete is poured into a trench on the snow, voids are formed, filled with water.

Heavily soils and their features

A common mistake is the lack of soil when digging a trench for the foundation to the design level. According to SNiP, in heaving soils, it is allowed to deepen the base of the foundation below the calculated freezing depth.

On heaving soils, pile and belt-buried (belt-pile type) foundations are not installed. The piles hold the foundation in place, and the heaving forces push it to the surface, as a result it is very likely that the concrete tape will crack or the pile will come off.

Reducing the likelihood of soil heaving on any soil

To prevent heaving, drainage is laid under the base of the foundation, clay is selected and the foundation pit is covered with sand and crushed stone, excluding the source of heaving. On such soils, the blind area is necessarily insulated, which prevents the foundation from freezing and excludes the condition of heaving.

Pasting and thermal insulation of the outer side allows the dew point to be shifted beyond the foundation, which excludes the influence of tangential heaving forces.

Foundation protection includes:

• gluing a waterproofing film;
• installation of XPS expanded polystyrene (high density);
• shelter with 2 layers of dense polyethylene;
• additionally, PSB 25 polystyrene sheets are pressed against the foundation by filling the soil.

Principle: the forces of heaving of the soil crush PSB 25, which moves up the polyethylene, without damaging the main thermal insulation. After thawing, the structure regains its sandwich structure.

DIY strip foundation photo: step by step instructions

The main structures of the strip foundation: their type and device diagrams

Depending on the characteristics of the soil and the type of building, choose the design of the future concrete base of the house. In the construction of houses on black soil, buried and deeply buried modifications are used. When building on black soil, the depth of the foundation depends on the thickness of the black soil layer. In some cases, it reaches 2 m.

Foundations for gazebos and light household buildings

T-shaped foundation with a heel for frame and timber houses

Recessed foundation for fertile soils

Deep buried foundation for construction in fertile areas

Monolithic foundation

Trench and concrete waterproofing

Communications

Simultaneously with the sampling of soil for the foundation, communications are being prepared, which must be brought to the house. At this stage, special attention should be paid to the local sewer pit and the waste disposal device. If water is supplied from a well, it is necessary to simultaneously prepare communications, since the laying of water supply pipes is carried out at a depth of 1.5-2 m.

Concrete waterproofing

Laying a reinforcing belt

Formwork and additional elements

• install sleeves in the reinforcement belt for entering communications into the cottage or carry out simultaneous piping;
• 40 cm from the blind area in the formwork of houses with beamed ceilings, it is necessary to provide for the installation of void-forming devices in order to ensure ventilation of the subfloor, prevent corrosion, decay and ensure the removal of harmful radon. The dimensions of the ventilation openings should be a total of 1/400 of the basement of the house.

To fill the foundation, use ready-made or home-made formwork. Shields can be made of OSB-boards, plywood or boards. The shields are fastened with an internal tie, as shown in the photo. The ready-made formwork allows concreting structures with complex shapes.

Pouring the foundation

For foundations, it is advisable to use ready-made concrete. In this case, it is possible to carry out winter work, since for these purposes a special brand of solution is used, hardening in the cold. The brand is chosen depending on the type of building:

• M100 - for wooden houses and outbuildings;
• М150 - for buildings made of foam concrete;
• M200 - for one- and two-storey cottages with light floors;
• М250 and М300 - for buildings up to 5 floors, as well as for monolithic floors;
• М400 - for multi-storey buildings (up to 20 floors).

It is not recommended to fill a layer of no more than 60 cm at a time. Deep-buried foundations are poured in several stages, keeping a break between them for no more than 2 hours. Pouring of concrete can be carried out after 12 hours, but the surface film is brushed off or removed by the pressure of water. The concrete in the trench must be laid with a vibrating compactor. Loose concrete does not gain the declared grade strength.

The formwork is removed no earlier than after 3 days. During this period, the upper part of the tape is moistened with sawdust or rags moistened with water, which will ensure the desired level of strength, and also avoid the formation of craters and cracks.

Waterproofing

When laying a concrete foundation, it is undesirable to neglect vertical waterproofing (base walls), this will help keep it from damage and ensure long-term operation. This is especially important for those areas that are characterized by winter thaws, when during which the foundation is moistened and several freezing cycles go through.

Do not neglect horizontal insulation, the absence of which can lead to the appearance of fungus on the walls and high humidity, since moisture from the moistened foundation will be absorbed into the walls of the first floor.

DIY strip foundation video

How to make a strip foundation with your own hands video: monolithic slab

In conclusion, we present one of the modern solutions. As you know, one of the types of strip foundations is a monolithic slab. The technology of the device of a monolithic insulated Swedish plate (USP) is an innovative development that is gaining more and more popularity. And it can also be done by hand.

The base of the house is a reliable sandwich structure that provides the necessary strength to the base of the house and its insulation. This technological solution is used for the construction of passive houses, in which the internal heat of the building is stored in order to reduce energy consumption. Above you have shown how to make a foundation with your own hands video, now we offer the technology of construction of the USWB.

The construction issue is covered in detail in the video.

DIY strip foundation - step by step instructions

Disadvantages and advantages

• Versatility is perhaps the main advantage of this design. It is suitable for the construction of both private and apartment buildings.
• Possibility of building buildings on unstable soils, as well as on slopes.
• Installation can be carried out in all weather conditions.
• The draft of the building is minimal.
• Comparative ease of construction.
• With the correct calculation and adhered to technologies, you will receive a reliable and durable foundation.

• Although the process itself is not too complicated, a fairly large amount of materials and equipment are involved in the construction, which makes the process not the most economical.
• Due to the massive structure, the volume of land work also increases.
• It is not recommended to use this type on horizontally moving ground.
• Problematic of the construction of a basement or underground garage (for foundations with a shallow foundation).

Often, such structures are used when there are no conditions for the construction of columnar foundations, for example, when building on a slope or slope, relief terrain, where the lateral pressure of the soil is of great importance. The strip foundation technology allows you to control and compensate for the uneven impact of the soil, since all its elements are firmly connected to each other in the transverse and longitudinal directions.

In what cases is it advisable to use a strip foundation?

• if there is uneven soil on the site and there is a possibility of its shrinkage;
• when heavy floors will be used in the structure of the building - concrete blocks, bricks;
• if the walls of the structure have a density of 1000 to 1300 kg / m 3.

Modern strip foundations, depending on the amount of work, are distinguished into prefabricated and monolithic.

Monolithic strip foundation

Holistic technology allows you to build a fairly wide, strong and reliable foundation, which will be the support of the building. Solidity is achieved by fastening the reinforcement frame with concrete mortar. If screw piles are used as a base, then their rows are also combined with each other, after which they are poured with concrete.

Precast strip foundation

This technology involves the assembly of blocks of concrete and reinforced concrete, and then fastening them together with cement mortar. It must be said that the reliability of such a foundation is 30% lower than that of a monolithic one.

There is also a precast-monolithic principle of laying the foundation, when the pile field is first connected, and reinforced concrete blocks are laid on top of it.

The depth of the strip foundation

This value largely depends on the type of building, the type of soil and the materials used.

Shallow and deeply buried foundations are distinguished.

Shallow, despite the number of new technologies, it still holds the position of the most popular. Its prevalence is due to a fairly high bearing capacity, as well as an acceptable cost.

Calculation of the strip foundation

The determination of the minimum width of a shallow foundation is based on the main principle: the specific load per unit area of ​​the soil located under the concrete foundation should be less than its bearing capacity. Namely, this difference should be at least 30% in favor of the soil. The design soil resistance is determined at the construction site, according to tabular data from SNiP 2.02.01-83 "Foundations of buildings and structures".

Below are a few examples of ready-made calculations based on the type of building.

Bathhouse, barn. The provided load is 20 kN / m2. Belt width depending on the type of soil:

• stony soil, hard dry clay, loam - 25 cm;
• dense clay and loam, which is molded in the hand - 30 cm;
• dry, caked sand, sandy loam - 40 cm;
• soft sand, sandy loam, silty soil - 45 cm;
• very soft sand, sandy loam, silty soil - 65 cm;

Summer cottage, two-storey house with a load of 50 kN / m2

• Stony soil, hard dry clay, loam - 30 cm;
• dense clay and loam - 35 cm;
• dry, caked sand, sandy loam - 60 cm;
• soft sand, sandy loam, silty soil - 65 cm;
• very soft sand, sandy loam, silty soil - 85 cm;
• peat - a different type of foundation is required.

A cottage of two full floors and a covered carport. Load - 50 kN / m2.

• Stony soil, hard dry clay, loam - 25 cm;
• dense clay and loam - 30 cm;

• Stony soil, hard dry clay, loam - 65 cm;
• dense clay and loam - 85 cm;
• for other types, an individual calculation is required, and for peat - a different type of foundation.

Important: the width of the foundation must necessarily exceed the thickness of the walls.

Tabular data will help to determine the depth of laying:

• stony rocky ground - 45 cm;
• clay - 75-100 cm;
• sands, sandy loams, loams - 45-90 cm.

The minimum depth depends on the location of groundwater, the level of heaving of the soil. The deeper the soil freezes in winter, the more water it contains, which means that the closer the moisture is to the surface. The heaving force directly depends on this, which will squeeze the concrete from all sides, pushing it to the surface. To reduce the effect of heaving, the foundation must be deepened.

But there are also more modern ways of dealing with heaving - this is the insulation of the foundation from the outside, as well as the creation of a cushion of coarse sand, not subject to heaving, under and around the structure.

Strength characteristics are calculated based on the expected load on them, namely: the weight of the roof, load-bearing walls, floors and the estimated weight of precipitation on the roof in winter. Most of this data is taken from tables, which group the estimated weight calculations based on the material of construction.

What distinguishes "samostroy" from a professional approach to the design process? Of course, the blueprint.

After the calculations are completed, a drawing is made for the strip foundation, with the help of which you can visually calculate the amount of cement-sand mixture, reinforcing rods, the cubic capacity of future earthworks and formwork material.

Strip foundation device

Main structural elements:

• Planned and prepared site.
• Outer wall.
• Base / plinth.
• Blind area.
• Waterproofing layer.
• Finishing floor.

When the development of the project is completed and the choice of the location is made, they begin to independently erect the foundation.

1. Splitting along the axes is carried out using a cord with pegs or a theodolite (for more complex buildings).
2. Using a mini-excavator with a small bucket, they dig a trench under the base.
3. The trench is filled up to 15-20 cm with sand, forming the so-called "sand cushion".
4. Gravel or crushed stone is poured on top of another 15-20 cm.
5. A "footing" is being carried out - the cement mortar is poured with a layer of 5-10 cm, and within a week it gains about half of its strength. Only after that do they proceed to further stages.

• Reinforcement of the strip foundation

Previously, before starting the installation of reinforcement, a waterproofing layer (for example, roofing material) was used, however, with today's technologies, this step can be omitted.

The rods with anti-corrosion coating are tied with wire, performing longitudinal and transverse reinforcement in 3-8 rods. If it is decided to weld the reinforcement, it must be remembered that the welding places will corrode.

Depending on the severity of the walls and ceilings, a complicated armature frame with vertical reinforcement is made.

• Formwork for strip foundations

Regardless of the type of foundation chosen, it is impossible to bypass the process of pouring concrete. To achieve the best result, reinforcement and formwork are made, which are quite realistic to do with your own hands.

1. The first stage is the construction of the formwork. For this, plywood, edged and unedged boards, slate or metal formwork are used. It must be said that boards 2-3 m long and 25-50 mm thick have become the most widespread.
2. The formwork consists of the actual decks and their fasteners. It is necessary to strictly monitor the horizontal position of the formwork - there should not be depressions, bumps and other irregularities under it.
3. The distance between the elements must correspond to the design width. For parallel fixation of the boards from the inside, wire and spacers are used, which can be wooden bars 50 x 50 mm. Outside, although the boards are held by the ground, they can deform from the pressure of concrete, so they are additionally fixed with pegs driven into the ground. the height of the formwork exceeds 20 cm, then special stops are used to secure the structure.
4. Nails are driven into the formwork from the inside, then bending the sharp ends downward.
5. The concrete grade is chosen in accordance with the weather conditions. If they are favorable - M200 and higher, if not - M300-M400. In addition, in the cold season, special substances are added to concrete that affect its frost resistance, plasticization and accelerate its hardening. The amount and proportions are observed according to the instructions, usually such additives make up 1-2% of the total amount.
6. For the construction of a bath, it is better to use lightweight concrete mixtures: slag concrete, expanded clay concrete or wood concrete - they are good heat insulators.
7. To find out how much mixture is needed, multiply the height, length and width of the future foundation and get a cubic unit.
8. The ratio of cement to sand and crushed stone is 1: 3: 5. This proportion can vary, however, gravel is always taken twice as much as sand. The previously dry mass of cement is diluted by 60% with water. In the cold season, heated water is used for these purposes, and on hot days, on the contrary, chilled water is used to slow down the setting.
9. The mixture poured into the formwork is pierced in several places with a probe, and outside it is tapped with a hammer. This is done in order to release air bubbles.
10. After two to three weeks, the formwork is removed, and as soon as the concrete has gained sufficient strength, they begin the stage of waterproofing and construction of the basement.

Important: water, sand and gravel should not contain clay and earth.

If the soil at the construction site turns out to be very heaving or you find that the groundwater is too high, it may be worth avoiding the use of a strip foundation and resorting to a pile or pile-rostver foundation.

DIY strip foundation - step by step instructions and photos

The most budgetary option to prepare the foundation for your own house is to equip the strip foundation with your own hands. Step-by-step instructions, photos and diagrams on this page will help you with this.

And by the way, even if you do not want to make a strip foundation with your own hands, step-by-step instructions, photos and diagrams will still come in handy for you. Because the best option is when the customer knows what his contractor has to do.

Agree, if you do not know all the stages of the work, how can you control the correctness of their execution by the construction team that you hired to arrange the foundation for your house?

That's just it. No way. Therefore, in any case, whether you order the arrangement of the foundation for the brigade or make a strip foundation with your own hands, step-by-step instructions, photos and diagrams in any case should be thoroughly studied by you and be at hand at any time during the production of foundation work.

Why strip foundation?

So why do we choose the strip foundation? Because for a relatively light private house, this is an ideal budget option. Now adherents of USP or screw piles will begin to object that their options stand almost the same, but much better.

Wait a second! Each season has its own vegetable, so each soil has its own foundation.

• If you have soft soils, peat or raised bog, then nothing better than a slab will keep your house “afloat”.
• If there is a good foundation under the soft soil, then screw piles are perfect here as a foundation.
• Well, if you have the most ordinary light soil, sand or sandy loam or even loam, then why bother with this whole vegetable garden? Pour in the tape and start building a house.

Second point. If you decide to build a house from a relatively heavy material - brick or expanded clay concrete. In this case, only the tape will allow you to increase the strength of the foundation on a relatively budgetary basis by increasing its height and thickness of the tape.

For all other types of foundations, this process in the budgetary plan will be much more painful.

Step-by-step instructions for the construction of a strip foundation

So, let's start building a strip foundation with our own hands. Here, at certain stages, it is possible to attract construction equipment, or you can do with a couple of shovels.

Excavation of soil for the tape. It is produced to the depth laid down in the design of the foundation. Naturally, the entire fertile layer folds neatly to the side - it will still be useful to you.

Sand pillow under the tape. It is poured to the thickness that was laid down during the design. Backfilling is carried out in 2-3 stages with pouring and ramming. It is better to ram it with a mechanical rammer - you can rent it for 2-3 days.

Installation of formwork under the tape. You can do it the old fashioned way, pound the formwork from an inch board, and then reuse this lumber after dismantling. And you can use the outside in the form of formwork sheets of 50 mm foam, which do not go anywhere and then serve as external insulation of the strip foundation.

Laying the film on the pillow. It is done so that the concrete milk does not flow into the sandy pillow. It can be formed from the film "trough" with a rise along the edges. The film can be glued with ordinary tape or stapled.

Knitting / welding of fittings. At this stage, we knit or weld the reinforcement cage for the strip foundation. The diameter of the reinforcement is selected based on the project. To boil or tie the reinforcement with knitting wire? As many houses will be built, there will be as many discussions on this topic.

Pouring the foundation. You can fill the foundation manually. Using a concrete mixer. You can call a mixer with ready-made concrete and pour everything in 1 day. Factory concrete is homogeneous, of high quality and will be poured without layers. The main thing is to vibrate it well at full depth. You can use banal pieces of fittings for this process.

In the event that you will put a frame or timber house on the tape, at this stage embedded elements - anchors are introduced into the concrete, which will fasten the lower piping of the walls and the foundation.

Standing the foundation. The concrete will harden within 7 days, and will gain full strength after 28 days. To prevent the tape from cracking when the concrete hardens, you need to cover it with burlap and moisten it in hot weather. Some craftsmen cover the tape with foil.

Dismantling of the formwork. If you had a formwork from a board, then you can let this board in the future for any rough work. I have a rough ceiling made of this board in the house.

Waterproofing tape. If you have not installed a penoplex in the form of a permanent external formwork, then now is the time to waterproof the tape. Any bituminous material will do.

Backfilling of the foundation. After the waterproofing of the strip foundation is done, you can backfill the sinuses of the foundation. You need to fill up the sinuses with non-porous soil. Sand is best suited for these purposes.

That's basically all. The ribbon is ready. The first rows of bricks can be laid out as early as the 2nd week after the final pouring. The concrete has not yet gained all the strength, but it has hardened enough to lay out a block or brick.

If you are making a frame house on a strip foundation, then wait for the concrete to gain strength, and only then tighten the nuts on the anchors embedded in the concrete.

DIY step-by-step instructions for installing a strip foundation

If you plan to make a strip foundation with your own hands, step-by-step installation instructions will help you complete all the work at the highest level, without even resorting to the help of specialists. It is quite simple to prepare such a foundation for a house - the main thing is to follow the technology and not break the stages.

The strip foundation is by far the most popular type. It can be used both as a base for large structures and for small architectural forms - arbors, arbours and other buildings.

Therefore, we will consider in more detail how to build a strip foundation for a house, what is worth considering, and what are the main points and stages of the installation process.

Preparation of the land site and its marking

The device of the strip foundation begins with planning work. The area where the concrete will be poured must be completely cleared of debris and plant roots.

After the planning work is completed, you can start marking. For this purpose, it is necessary to prepare wooden pegs (or pieces of reinforcement) and lacing (you can use a special construction line). With the help of this inventory, the marking of the inner and outer boundaries of the future strip foundation is made. Immediately you need to determine the location of all load-bearing walls and internal partitions, since the foundation will be poured at the same time.

To set the angles accurately, it is imperative to use a building corner, which will allow you to accurately set the angle to 90 degrees. When all the cords are taut, check the diagonals. This can be done using a long tape measure.

When the markings are completed, it is worth assessing all the unevenness of the site. The lowest point must be selected. It is from her that it is necessary to start counting the depth of the foundation.

Pouring the strip foundation can have different depths; for an accurate determination, you need to find out the level of soil freezing and the presence of groundwater. For example, for the construction of a small structure, it will be enough to pour concrete mortar into a depth of 40 cm. More details about the calculation of the strip foundation here.

To dig a trench for filling, you can use an excavator, or you can do the work yourself. But manual labor will take more time, but it will also save money.

When the required depth has been reached, the entire bottom must be checked with a water level. If there are irregularities, they must be corrected without fail - this will prevent unpleasant moments in the future.

Not only the bottom should be flat, but all the walls should be strictly in a vertical plane, the foundation itself should be flat along its entire length and not taper towards the bottom.

Formwork and foundation reinforcement

So, the workflow on how to make a strip foundation continues. When the trench of the right size is made and ready, you can proceed with the installation of the formwork. But before installing it, you need to make a sand pillow. For this purpose, sand is poured into the bottom of the prepared trench, the layer thickness must be at least 15 cm. The compaction must be carried out together with water (the surface of the sand is filled with water). This will make it possible to seal the base much better.

For the best effect, the next layer can be crushed stone. So that the foundation does not conduct moisture to the walls from the ground in the future, it is necessary to lay a layer of waterproofing. In this case, the strip foundation device involves the use of roofing material. It is best used in several layers; a dense plastic film can become an alternative replacement for roofing material. More details about waterproofing strip foundations can be found here.

But for the manufacture of formwork, you can use:

The most important thing is that the material is strong enough to withstand the load of concrete.

Having reached this point, it is already clear that the do-it-yourself foundation tape task is quite doable. The structure of the formwork can also be made by yourself. Self-tapping screws or nails can be used to connect all the elements, if the formwork for the strip foundation is made of boards. All connections should be made from the inside so that the ends of the fasteners do not damage the surface of the foundation itself. Before installing the formwork, it is worthwhile to install a sleeve in advance, which will become the place for the supply and output of communications.

Armopoyas must be made of reinforcement with a diameter of 12 mm. This size is sufficient to ensure the strength and reliability of the structure.

A do-it-yourself strip foundation also implies the device of a metal frame. To connect the parts of the reinforcement, it is necessary to use a thin wire, which is knitted with a special device - a hook. By the way, there should be no more than 30 cm between the rods. It is better not to use welding as joints, since it will not give the structure the required flexibility. Read more about strip foundation reinforcement here.

Pouring concrete

This moment in the process under consideration, how to make a strip foundation with your own hands, is almost the main stage. It is performed when the formwork has already been installed, and the reinforcement frame is mounted in the trench.

To find out the amount of concrete, it is worth multiplying the required height by the width and the length. It is very important to make calculations if the concrete is ordered from special firms and delivered to the construction site in mixers. Correct calculations will help avoid acquiring unnecessary material.

Before pouring the strip foundation, it is worth preparing all the tools and materials:

• water bucket;
• shovels;
• concrete mixer (manual or electric)
• cement;
• sand;
• crushed stone.
• additionally, you can use plasticizers.

Pouring the strip foundation with your own hands begins with the preparation of the solution. You need to take 1 part of cement, 3 parts of sand and 5 parts of crushed stone. Mix everything thoroughly with a little water. The liquid should be added gradually to avoid making the solution too thin. To improve the performance of concrete, it is worth adding special plasticizers. It is necessary to fill the foundation at a time, so it is better to do the work not alone.

After the concrete has hardened, the formwork is disassembled. In the future, it can be reused.

So, considering the strip foundation, the technology of its installation is quite understandable and accessible to everyone. The main thing is to follow all the recommendations. But remember that the finished base can only be used after a while, when the concrete has hardened.

Basically, a do-it-yourself strip foundation will not only be reliable, but will also significantly save money.

As a conclusion

When performing concrete work, it is very important to do everything in accordance with the norms. Otherwise, the quality of the foundation will be poor.

1. It is important to respect the proportions of the ingredients. If you use less cement, the concrete will begin to crumble over time.
2. If it is not possible to fill the solution in one go, it is best to fill it in layers of at least 20 cm each.
3. Use sand and crushed stone for the solution only in its pure form without any impurities, clay and debris.
4. All materials from which the formwork is made must be even.
5. Do not forget to leave room for plumbing and sewerage before pouring the concrete.

Larger diameter pipes are best suited for this purpose. If they are not installed in advance, in the future you will have to violate the integrity of the foundation by making holes.

1. It is necessary to carry out work on pouring the foundation when there is no rain or snow outside.

The ambient temperature should be positive. If the foundation is poured at negative temperatures, it is imperative to use a plasticizer, which will prevent the crystallization of the solution and give the material greater strength.

Knowing how to correctly make a strip foundation, the work can be done quickly and efficiently.