A shallow strip foundation (hereinafter referred to as MZLF) is one of the types of strip foundations, which is characterized by a small depth, significantly less than the depth of soil freezing, and a relatively low consumption concrete mixture. This article discusses the main advantages and disadvantages of MZLF, the most common mistakes in their construction, a simplified calculation method suitable for private developers (not professionals), and recommendations for constructing a foundation with your own hands.

The main advantages of MZLF are:

- economical - concrete consumption is significantly lower than during the construction of a conventional strip foundation. It is this factor that most often determines the choice of this technology when low-rise construction;

- reduced labor costs - less excavation work, less volume of prepared concrete (this is especially important when it is not possible to pour the finished mixture from a mixer);

- smaller tangential forces of frost heaving due to the reduced area of ​​the lateral surface of the foundation.

However, during the construction of the MZLF, it is necessary to strictly adhere to the technology; a frivolous attitude to the process can lead to the appearance of cracks, and then all of the above advantages, as they say, will go down the drain.

The most common mistakes made when installing MZLF:

1) selection of the main working dimensions of the foundation without any (even the most simplified) calculation at all;

2) pouring the foundation directly into the ground without covering it with non-heaving material (sand). According to Fig. 1 (on the right), we can say that in the winter season the soil will freeze to the concrete and, rising, drag the tape upward, i.e. the tangential forces of frost heaving will act on the foundation. This is especially dangerous if the MZLF is not insulated and a high-quality blind area is not equipped;

3) improper reinforcement of the foundation - choosing the diameter of the reinforcement and the number of rods at your discretion;

4) Leaving the MZLF unloaded for the winter - it is recommended to carry out the entire cycle of work (construction of the foundation, erection of walls, and arrangement of the blind area) one construction season before the onset of severe frosts.

Calculation of a shallow strip foundation.

The calculation of the MZLF, like any other foundation, is based, firstly, on the value of the load from the weight of the house itself and, secondly, on the calculated soil resistance. Those. the soil must withstand the weight of the house transmitted to it through the foundation. Please note that it is the soil that supports the weight of the house, and not the foundation, as some believe.

If an ordinary private developer can calculate the weight of a house if desired (for example, using our online calculator located), then it is not possible to determine the calculated soil resistance on your site on your own. This characteristic is calculated by specialized organizations in specialized laboratories after conducting geological and geodetic surveys. Everyone knows that this procedure is not free. Mostly, architects who design a house resort to it, and then, based on the data received, they calculate the foundation.

In this regard, it makes no sense to provide formulas for calculating the size of the MZLF within the framework of this article. We will consider the case when a developer carries out construction on his own, when he does not conduct geological and geodetic surveys and cannot accurately know the calculated soil resistance on his site. In such a situation, the dimensions and design of the MZLF can be selected according to the tables below.

The characteristics of the foundation are determined depending on the material of the walls and ceilings of the house and its number of storeys, as well as on the degree of heaving of the soil. How you can determine the latter is described

I. MZLF on medium and highly heaving soils.

Table 1: Heated buildings with walls made of lightweight brickwork or aerated concrete (foam concrete) and reinforced concrete floors.

Notes:

— the number in brackets indicates the pillow material: 1 — medium-sized sand, 2 — coarse sand, 3 — a mixture of sand (40%) with crushed stone (60%);

— this table can also be used for houses with wooden floors, the safety margin will be even greater;

— see below for foundation design options and reinforcement options.

Table 2: Heated buildings with walls made of insulated wooden panels ( frame houses), logs and beams with wooden floors.

Notes:

— the numbers in brackets mean the same as in Table 1;

- above the line value for walls made of insulated wooden panels, below the line - for log and timber walls.

Table 3: Non-buried foundations of unheated log and timber buildings with wooden floors.

Notes:

- above the line values ​​for log walls, below the line - for walls made of timber.

Design options for MZLF on medium- and highly heaving soils, indicated in the tables by letters, are shown in the figures below:

1 — monolithic reinforced concrete foundation; 2 — sand filling of sinuses; 3 — sand (sand-crushed stone) pillow; 4 — reinforcement frame; 5 - blind area; 6 7 — waterproofing; 8 - base; 9 — ground surface; 10 - sand bedding; 11 - turf.

Option a.— the upper plane of the foundation coincides with the surface of the earth, the base is made of brick.

Option b.- the foundation protrudes above the surface by 20-30 cm, forming a low base or being part of the base.

Option c.- the foundation rises 50-70 cm above the ground, while it also serves as a base.

Option d.- non-buried foundation-basement; Table 3 shows that such foundations are used for unheated wooden buildings.

Option d.- used instead of options b. or V. when the width of the base of the foundation significantly exceeds the thickness of the wall (more than 15-20 cm).

Option e.— a shallow strip foundation on a sand backfill is used quite rarely on weak (peaty, silted) soils with a high groundwater level for wooden buildings. Depending on the size of the building, bedding is done either under each strip or under the entire foundation at once.

Reinforcement of a shallow strip foundation.

MZLF reinforcement is made with meshes of working reinforcement and auxiliary reinforcing wire. The working reinforcement is located in the lower and upper parts of the foundation, and it must be immersed in the thickness of the concrete by about 5 cm. The lower mesh works to deflect the foundation tape downward, and the upper mesh works to deflect the tape upward. There is no point in placing the working reinforcement in the middle of the tape (as can sometimes be seen on the Internet).

Table 4: Options for foundation reinforcement.

MZFL reinforcement schemes are shown in the following figure:

A.— a mesh with two working reinforcement rods; b.— a mesh with three working reinforcement rods; V.— T-shaped joint; G.— L-shaped corner joint; d.— additional MZLF reinforcement with a large sole width, when the sole is more than 60 cm wider than the base (the additional mesh is located only in the lower part.

1 — working fittings (A-III); 2 — auxiliary reinforcing wire ∅ 4-5 ​​mm (Вр-I); 3 — vertical reinforcement rods ∅ 10 mm (A-III), connecting the upper and lower mesh; 4 — reinforcement for strengthening the corner ∅ 10 mm (A-III); 5 — connection with wire strands (twisting length is at least 30 diameters of the working reinforcement); 6 — additional working fittings ∅ 10 mm (A-III).

II. MZLF on non-heaving and slightly heaving soils.

Shallow strip foundations on non-heaving and slightly heaving soils do not have to be made only from monolithic concrete. You can also use other local materials, for example, rubble stone, red ceramic brick. MZLF is laid at 0.3-0.4 meters without a sand cushion. Moreover, for wooden buildings and one-story brick (or aerated concrete) foundations, they don’t even need to be reinforced.

For 2- and 3-story houses with walls made of stone materials, MZLF is reinforced. Concrete foundations are reinforced according to the 1st reinforcement option (see Table 4 above). Foundations made of rubble or brick are reinforced with masonry mesh made from BP-I reinforcement ∅ 4-5 ​​mm with a cell size of 100x100 mm. The nets are placed every 15-20 cm.

MZLF structures on non-heaving and slightly heaving soils are shown in the figure below:

1 - foundation; 2 - base; 3 - blind area; 4 — waterproofing; 5 — subfloor (shown conditionally); 6 - mesh made of wire reinforcement, 7 — reinforcement according to option 1 (see table 4)

Options a. and b.- for wooden and one-story brick (aerated concrete) buildings.

Options c. and Mr.— for two- and three-story brick (aerated concrete) buildings.

The width of the sole b is determined depending on the number of storeys of the building and the material of the walls and ceilings.

Table 5: Values ​​of the width of the sole of the MZLF on non-heaving and slightly heaving soils.

Stages of construction of a shallow strip foundation and recommendations.

1) Before starting construction of the foundation, if necessary, it is necessary to ensure high-quality drainage of surface rainwater from neighboring areas from the building site. This is done by cutting out drainage ditches.

2) The foundation is marked and trenches are torn out. It is recommended to begin excavation work only after all necessary materials have been delivered to the construction site. It is advisable to organize the process of cutting out the trench, filling the tape, backfilling the sinuses and constructing the blind area as a continuous process. The less it is extended in time, the better.

3) The dug trenches are covered with geotextiles. This is done so that the sand cushion and sand filling of the sinuses do not become silted over time by the surrounding soil. At the same time, geotextiles allow water to pass through freely and do not allow plant roots to grow.

4) A sand (sand-crushed stone) cushion is poured layer by layer (in layers of 10-15 cm) with careful compaction. They use either manual rammers or area vibrators. Tamping should not be taken lightly. Shallow foundations not as powerful as foundations poured to the entire freezing depth and therefore freebies here are fraught with the appearance of cracks.

5) The formwork is laid out and the reinforcement frame is knitted. Do not forget to immediately provide water and sewerage to the house. If the foundation is also a plinth, remember about the vents (does not apply to buildings with floors on the ground).

6) Concrete is poured. Filling of the entire tape must be done continuously, as they say, in one go.

7) After the concrete has set (3-5 days in summer), the formwork is removed and made vertical.

8) The sinuses are backfilled with coarse sand with layer-by-layer compaction.

9) A blind area is being constructed. It is advisable (especially with a small height of the foundation tape) to make the blind area insulated. This measure will further reduce the forces of frost heaving affecting the MZLF in winter. Insulation is made with extruded polystyrene foam.

As already mentioned at the beginning of the article, it is not allowed to leave the MZLF unloaded or underloaded (the building is not fully built) for the winter. If this happens, the foundation itself and the soil around it must be covered with any heat-saving material. You can use sawdust, slag, expanded clay, straw, etc. There is also no need to clear the snow on the construction site.

It is highly not recommended to build a shallow strip foundation in frozen soil in the winter.

In the comments to this article, you can discuss with readers your experience in the construction and operation of MZLF or ask questions that interest you.

Often, strip foundations are used in the construction of private buildings: cottages, bathhouses, garages, etc. Its main advantages are low cost, good strength, ease of construction and reliability of the finished building. In this article we will look at DIY strip foundation - step-by-step instruction .

How to make a strip foundation with your own hands?

The instructions consist of three important steps:

1. we determine the design and material from which the strip foundation will be constructed;
2. we calculate the width and depth of the foundation, depending on the thickness of the soil and the depth of freezing (according to SNiP 2.02.01-83 “Foundations of buildings and structures.”);
   
3. we carry out the design marks and dimensions;

   

4. Development of a trench in accordance with the selected width and depth. The bottom of the trench is compacted with sand and stones.

In the subheadings below we will describe the next two steps of the device - 5. reinforcement and 6. formwork.

Shallow strip foundation instructions on how to make it yourself

Shallow strip foundations are used on heaving and non-heaving soils. Its base is located above the level of soil freezing, due to which, when freezing, it rises much less than other types of foundations.

What is important to know:

• It is most popular in the construction of light frame and wooden houses.
• The depth of installation in the ground is usually equal to the width of the foundation.
• Reinforcement is mandatory; formwork panels are installed on the ground, forming one space with the trench(it is more expedient to develop the soil using the trench method rather than digging a pit) .

Instructions for deep strip foundation

An important aspect of the instructions for constructing a deep strip foundation is location of the bottom edge below the soil freezing depth. This is necessary to provide support on a denser layer of soil and increase the load-bearing capacity of the entire building.

Soil development is carried out:

• trench method with installation of formwork on the ground at the top;
• by digging a pit, with the installation of formwork at the bottom of the pit; in this case, the walls of the formwork must continuously extend above the level of undeveloped soil.

The placement of the frame should be carried out after the installation of the formwork walls. Remember that the walls need to be reinforced, so the frame must be installed before this step.

Below is an interesting selection of the design of a tape cushion for blocks.

Strip foundation deep burial withstands heavy loads and various deformations. In order to avoid tears and bends, it is reinforced with metal reinforcement - this makes the structure strong over the entire surface.

DIY T-shaped strip foundation instructions

Economically beneficial, since the area on which the load will be carried out is more than 2 times larger than the edge of a simple strip foundation. It is arranged in two main ways:

The second stage of constructing a strip foundation with your own hands with widening is reinforcing the frame; the general principle is presented in the diagram.

Construction of a non-buried foundation and a monolithic belt with your own hands

To be honest, I had already forgotten that such foundations and belts exist. But, remember that such a foundation is the soil under your foundation, therefore, if you prepare the foundation, then even a low monolithic belt will perfectly transfer the load to it. Here you need to choose: either rely on the foundation, or place additional pillars below the foundation strip for reinforcement.

Monolithic strip foundation - device steps, instructions

A monolithic strip foundation is a reinforced concrete strip that occupies the entire perimeter of the house. This type of foundation allows the construction of buildings of any shape and is suitable for solving non-standard design problems (for example, installing a trapezoidal bay window or a terrace with complex lines). Since this article is mainly about a monolithic foundation, there is no point in describing the steps of its construction again.

Prefabricated strip foundation - 3 installation steps, instructions

Very rarely used in European countries, but in Russia it finds a sufficient area of ​​application. A prefabricated foundation can almost be called a factory foundation; you can be confident in the quality of the concrete and the correct installation of the frame. The main advantage of this type is the speed of construction and reduction of construction time. The disadvantage is the need to use a crane to place the foundation blocks.

First, let's pay attention to the design diagram of a prefabricated strip foundation, so that when working with your own hands, you will not have any unnecessary problems.

Please note that in the first diagram there is no reinforced concrete belt above the foundation pad. I consulted with a specialist: nevertheless, its use is considered mandatory, so the load will be distributed more evenly.

Step 1: calculation and marking of the prefabricated strip foundation.

Open a drawing construction program that is convenient for you or take a pencil and ruler in your hand. First of all, draw the foundation blocks that are suitable as a foundation for your house (selected according to SNiP). Place the axes on the drawings and begin placing the foundation blocks so that the center of the axle runs through the middle of the foundation block.

Step 2: setting up axles and developing a trench

This step is no different from the steps for installing a brick or monolithic foundation. The only thing I would like to draw attention to is that there is a road near the construction site from which the crane could place the foundation blocks in the trench.

Step 3: installation of a sand cushion under the prefabricated foundation

Pay attention to the following photo, we see a sand bed, carefully leveled and foundation slabs installed on it. There is also a small formwork on the left, into which the frame will be installed and concrete will be poured, that is, places where there is a shortage need to be filled in, as well as the spaces between the slabs.

The next layer is the armored belt, see the diagram above. The armored belt already needs to be waterproofed.

After installing the foundation slabs, you can begin installing the basement wall blocks.

DIY brick foundation - instructions

Such a foundation is not built often, due to the high cost of bricks. Let's pay attention to the technological processes of constructing a brick foundation with our own hands.

Step 1 of installing a brick foundation - plan, removal of axes, excavation of the soil

Soil development can be carried out using both trenches and pits. Moreover, in the latter version it will be much more convenient for the mason to work. If ground floor If it doesn’t, then develop the trench so that a mason can work in it (+40 cm from the edge of the wall to the outside). Also keep in mind that the width of the foundation should be greater than the width of the outer wall.

Step 2 - pillow preparation and waterproofing

Diagrams often depict a cushion of sand, as can be seen in the top picture. Indeed, it should be there and it needs to be compacted well. But for reliability, you need to make a concrete preparation 10 cm high. At the same time, before laying concrete, it is necessary to spread waterproofing of such a width that its edges are wrapped and protect the concrete preparation from the sides.

If there is a basement floor, then you need to waterproof the foundation horizontally below and vertically from the outside. If there is no basement floor, then only the upper edge of the foundation needs waterproofing.

Step 3 - do-it-yourself bricklaying

To lay bricks, you can use any standard methods of tying rows.

Bricks are laid with longitudinal and transverse reinforcement. Moreover, after the first row it is simply mandatory to install longitudinal reinforcement or reinforcing mesh.

Bandaging the seams is mandatory; the seams themselves are no thicker than one centimeter. Slotted brick will not work; you need regular building brick.

The order should be approximately the same as in the diagram on the right. Very often this order is shown in articles about do-it-yourself brick foundations, but this is not true. This diagram shows the order of the walls of the first floor, not the foundation. But take the principle as a basis: alternating spoon and butt rows, the width of the foundation is not less than the width load-bearing walls, or better yet, more.

Do-it-yourself rubble foundation - 3-step instructions

A foundation with a rubble can be arranged in two ways:

Rubble strip foundation - step 1

Trench and soil compaction, according to the diagram above. For non-heaving soils, a bed of coarse sand is suitable under the tape. For heaving soils, you need a first cushion of compacted soil and a cushion of coarse sand.

Construction of a rubble foundation - step 2

Installation of formwork or rubble laying on a fishing line. If a rubble concrete foundation is used, then the trench is filled with concrete over the entire width, and the work is carried out from above.

Final work in installing a strip rubble foundation - step 3

The final work is waterproofing and backfilling the foundation.

A short video instruction for installing a strip foundation with your own hands

The photos are taken from the video below, in which you will learn or repeat where one of the 5 strip foundation designs is used.

Before, how to make a strip foundation with your own hands for a home, it is necessary to determine the operating conditions. Then it is enough to choose the type, design, dig trenches, pour concrete into the formwork or perform brickwork. At the last stage, the structure partially immersed in the ground should be protected from heaving forces, soil moisture, and groundwater.

Selecting the type of strip foundation

The main task of an individual developer is rational planning of the construction budget. Due to the variety of LF strip foundations, the principle from cheap to more expensive option is usually used. At the same time, a service life of 70–100 years, maintainability, and ease of use must be ensured. Thus, it is enough to consider all existing LFs and choose the option that suits you:

• monolithic belt - the width of the belt is greater than the height, there is no depth, suitable exclusively for log houses, outbuildings, half-timbered buildings, frame cottages on stable soils with low groundwater level
• non-buried LF - allows you to build a panel, frame, panel, log house on sandy loam, loam only on flat areas, the height of the tape is greater than the width, floors on the ground can be used
• shallow-depth MZLF tape – the volume of excavation work increases, there are no restrictions on wall and roofing materials (suitable for brick walls), trenches have a depth of 0.3 - 1 m depending on the soil
• T-shaped strip foundation - the strip is widened in the lower part by a slab, but the structure still cannot be built on slopes, swamps, or at a high groundwater level
• buried LF - there are no restrictions, this is the only option for a project with an underground floor; with a high groundwater level, a set of measures will be required to collect and drain soil moisture

Load bearing capacity Almost all strip foundations have a 2-3 fold margin with a strip width of 40 cm or more. The problem usually lies in heaving forces or is hidden in the soils themselves. On fresh embankments (former landfills, technogenic zones), the tape will have to be widened (T-shaped modification of the LF) or the bulk layers will have to pass through (MZLF 1 m deep or a deep belt 2 - 2.5 m).

If according to the results geological surveys the structure must be buried below 3 m, it is worth reconsidering the choice in favor of a floating slab or pile foundation with a monolithic hanging grillage of lattice or slab type. Since the budget will be approximately the same, labor costs are 50–70% higher.

Design selection

Depending on the prices of building materials and the skills of the individual developer, the strip foundation can be poured into formwork or laid out of brick. In the first case, it is advisable to lay the concrete mixture in one step.

For a deep-laying belt, this is not easy to do, even when ordering several mixers, since filling the formwork is tedious in 60 cm layers and compacting each layer with a deep vibrator. For MZLF such problems usually do not arise; the volumes here are 4–5 times smaller.

In the second option, you can do without special equipment; the strength of the masonry does not depend on the timing of its production. The solution can be mixed into the building spot yourself.

Brick LF is more resistant to swelling of individual areas:

• the structure consists of small-format beams
• each has two degrees of freedom without rigid pinching
• when individual areas are loaded, the forces are redistributed
• after the heaving soil thaws, the foundation returns to its original state

The main disadvantage is the complex waterproofing, and the much shorter lifespan of bricks compared to concrete. The calculation of the width of the foundation based on its bearing capacity is the same for all types of LF. For a monolithic tape, the cross-section of the reinforcement is additionally calculated, and a reinforcement diagram is drawn up taking into account the requirements of the joint venture:

The main measures to eliminate heaving forces are:

In addition, it is necessary to protect the underground structure from moisture with volumetric, lining, and coating waterproofing.

To transfer a drawing of a building to a building site while maintaining the scale, you will need a level or a plane builder (can be replaced with a hydraulic level with a laser level), a 12 m cord, cast-offs of two pegs with a crossbar 60 - 80 cm long between them. Before the full-scale removal of the axes of the dwelling, it is necessary to clarify its location in the building area, depending on external communications (power pole, septic tank, water supply wells, sewerage), parking for a car, and boundaries of the site.

The façade closest to the roadway must be at least 5 m from the center of the road. For minimal shading of the neighboring territory, it is enough to retreat 3 m from the fence:

• the first wall is laid parallel to the road
• the ends of the building extend from it at right angles, which are found using the triangle method
• with legs 4 m, 3 m, hypotenuse 5 m, the triangle is guaranteed to have an angle of 90 degrees

The axles are secured in place with cords/strings only after checking the diagonals (they must completely match in size), aligning the cast-offs to a single horizontal level (use a laser or hydraulic level, a plane builder).

To carry out excavation work, it is necessary to take into account the recommendations of specialists and SP standards:

After this, you can begin preparing the base for the foundation tape.

Preparing the base

It is especially important to manufacture a foundation cushion for shallow-depth MZLF belts. Sand (20 cm) laid on geotextiles, compacted in layers, and crushed stone (20 cm) will reduce the forces of frost heaving. Any of these materials can be used separately:

The bottom layer of geotextile prevents silting and mixing of non-metallic material with the soil. On a sand bed, rolled waterproofing material (TechnoNIKOL, Bikrost) is not subject to mechanical stress, allowing you to reduce the construction budget. If the top layer of the cushion is crushed stone, it is necessary to fill in a 5 cm concrete base, which will protect the hydroglass insulation from punctures by sharp stones.

The drains are laid in the lower trench, the bottom of which has a 4–7 degree slope, on top of a 10 cm layer of crushed stone over geotextile. Typically, smooth, corrugated pipes with point and slot perforations are used. They are wrapped with two layers of Dornit by default by the manufacturers.

Drains are laid between wells (vertical pipe with a plugged bottom) and are interrupted in them. This is necessary for normal cleaning from ground level with compressed air or steam. On the sides and on top, the drainage contour is filled with crushed stone and covered with geotextiles. The top filling of the drains and the foundation pad must match.

Self-concreting the foundation strip

The standard technology of monolithic strip foundation does not cause difficulties for individual developers. After preparing the base, all that remains is to mount the formwork panels, place the reinforcement inside, lay and compact the concrete mixture. Depending on the season and weather conditions, it must be cared for in the first three days.

Calculation of parameters

At this stage, you will need V.S. Sazhin’s reference book or SP 22.13330 standards with tables of snow + wind loads and calculated soil resistances. Next, the width of the tape is determined, sufficient for the load-bearing capacity of the prefabricated loads of the home. To do this, the value of the calculated resistance of sandy loam, clay, sand, loam on which the foundation will be built is taken from the tables.

The combined load is obtained by adding the wind and snow loads, the weight of all power structures, furniture, and residents. This figure is divided by the previous one, then by the length of the perimeter of the tape. The obtained result is adjusted according to the thickness of the wall so that timber, brickwork, or logs do not hang more than 10 cm from it. For light buildings, reinforcement of a periodic section of 8 - 14 mm with clamps made of a smooth rod of 6 - 8 mm is used.

Installation of formwork, reinforcement

The main characteristics of the strip foundation depend on the quality of work at this stage. Formwork uses rigid structural materials that can be reused. Most often, boards are made from edged boards (minimum 4 cm thick), multilayer plywood, or oriented strand board.

The shields are fixed vertically with jibs to the edges of the trenches, into the ground, and are tightened with jumpers and pins. It is necessary to leave ventilation ducts in the basement part (1/400 of the total area of ​​the above-ground part), and underground openings for the input of engineering systems.

Reinforcement occurs according to the following scheme:

• longitudinal rods (2 rows minimum for a width of 16 cm or more)
• 90 degree bend in corners, wall junctions
• overlap 60 cm when extending
• staggered order of joints in adjacent rows

Rods and clamps are immersed in concrete by at least 2–4 cm to provide a protective layer. Polymer cups, stands, and concrete pads are installed under the bottom row. The belts are fastened together with rectangular clamps.

Preparation and laying of concrete

The recommended mixture proportions for obtaining grades B25, B15 are 30/15 l or 42/25 l (crushed stone/sand), respectively, for a bucket of cement. For the footing, grade B7.5 is sufficient (61/41 liters of crushed stone, sand, respectively). When mixing manually, the characteristics of concrete are reduced by 20 - 30%.

The best option is to lay and vibrate the entire volume in one day. If the interval of 2 hours is exceeded, the concrete that has begun to harden is destroyed when the fresh portion is compacted with a vibrator. Filling is done in layers 60 cm deep along the ring. If it is unrealistic to fill the entire volume, partitions are installed inside the formwork. They cannot be tilted or moved after laying concrete. It is prohibited to cut reinforcement in these areas.

The time it takes for concrete to gain strength depends on the outside temperature. At + 5, +10, +20, +30 degrees, stripping can be done on days 29, 15, 8, 4, respectively. In the first three days, concrete requires care:

Used formwork is usually used in roofing and rafter systems. It is better to waterproof slightly damp concrete, so stripping can be done a day earlier, being careful.

Do-it-yourself LF brickwork technology

Marking, excavation work, bottom waterproofing, drainage are completely similar to the previous case. Instead of formwork, an individual developer lowers bricks into the trench, stacking them in periodic stacks. After that, all that remains is to prepare a reinforcement or wire mesh with a cell size of 3 x 3 cm or 5 x 5 cm, and mix the solution (the volume must be calculated to produce within an hour). The main nuances of brickwork are:

• the height of the corners for tensioning the cord - must correspond to the frequency of reinforcement, otherwise they will remain unconnected (usually 3 - 5 rows)
• dressing - classic (poke/spoon vertically + displacement of seams in adjacent rows by ¼ - ½ the length of the stone)
• seams - 1 - 2 cm, in reinforced rows they are thicker, filled completely in the underground part, partially in the basement part if plastering is planned

The vertical of the corners and the horizontal of the rows are controlled in each row. Experts recommend wetting the brick before laying to increase the correction time in the rows. Adding liquid soap (2 - 3 drops of Fairy per 100 liters of batch) will increase the plasticity of the solution without an expensive Superplasticizer, reducing the strength of the masonry.

Waterproofing

The main requirement for the protective layer of waterproofing is its continuity. The untreated area will become a source of corrosion of the reinforcement inside the tape, allowing the concrete to become saturated with moisture, which, when frozen, will lead to the formation of cracks in the structure of the structure. The following foundation waterproofing technologies exist:

The first two options are usually used in combination, providing a 50-80 year service life of structures. Penetron has an unlimited resource, since even a piece of foundation broken off after processing will retain water-repellent properties until complete destruction.

Regardless of the depth of the tape, it is recommended to insulate the foundation to solve several problems:

If you use the measures in a complex, the MZLF is guaranteed to last 80 - 120 years; non-buried foundations will increase the service life to 70 years.

The above selection, calculation, and construction scheme allows you to independently produce a strip foundation with a minimum construction budget. At the same time, a high service life and maintainability of individual structural fragments are maintained. T quality additional events Comfort of use depends on protecting concrete structures from moisture and heaving forces.

One of the most popular types of foundations in private housing construction has become strip foundations. It allows the construction of fairly massive buildings, both with and without a basement. There are two types of tape - prefabricated and monolithic. To do the work yourself, it is preferable to use a monolithic version, since it does not require complex lifting equipment.

Its distribution monolithic design received thanks to a serious list of positive qualities:

• possible installation on unstable soils;
• high reliability;
• possibility of arranging a basement;
• high load-bearing capacity;
• possibility of independent construction.

The disadvantages include:

• limited scope of application, not suitable for construction on marshy soils;
• high cost compared to columnar foundations or in some cases a monolithic slab.

Types of strip foundation

Depending on the depth of application, three types of tape can be distinguished:

• not buried;
• shallow;
• recessed.

The first two are used for light buildings, the third type can withstand the load from a stone house of a sufficiently large number of floors.

Based on the type of section, rectangular and T-shaped strip foundations are distinguished. T-shaped tape can withstand heavy loads and is used for masonry buildings.

Foundation structure

The technology for pouring a strip foundation is divided into several stages, which include:

• design work;
• terrain marking and axle alignment;
• soil development;
• installation of a pillow under the foundation;
• formwork work;
• reinforcement;
• pouring concrete mixture;
• care of concrete during the process of strengthening;
• stripping works.

To build a house without mistakes, you need to carefully study all stages of foundation construction.

Development of drawings and calculations

When constructing mass buildings, this work is performed by design engineers. They make full calculations of load-bearing capacity and stiffness. For a private home, this stage can be simplified. It is enough to draw a sketch of the tape and choose the right type. To do this, you can use the table.

Foundation type	Application area
Non-buried	Frame one-story houses when groundwater is located close to the surface of the earth, light outbuildings, terraces, sheds, gazebos
Shallow rectangular section	Frame and wooden buildings of no more than 2 floors, provided that groundwater is located at a depth of more than 1 m from the ground surface
Shallow T-section	Frame, wooden houses, buildings made of foam concrete blocks, it is possible to build a brick one-story house
Recessed rectangular	Individual houses from any materials
Recessed T-section	Apartment buildings residential buildings, public buildings

The laying depth is determined based on the depth of soil freezing and the presence of a basement. If a basement or technical underground is provided, the height of the tape is determined depending on the planned height of the room.

It is also necessary to pay attention to the groundwater level in the soil. If it is high enough, a shallow design should be considered. For the construction of brick buildings at high groundwater levels, I use buried foundations, but they require reliable waterproofing and drainage.

Bringing the design solution to the area

Once the type of construction has been selected and all the sketches or drawings of the house have been created, you can begin marking out the site. Before starting, it is necessary to clear the area of ​​debris and foreign objects. Next, the top fertile layer of soil is removed, with an average thickness of 150 mm. After this, you can proceed directly to markup in the following order:

• marking the outer corners of the house with pegs and checking the distance between them;
• connecting corner pegs using cord or slats;
• checking corners;
• checking the diagonals of the house;
• removal of the internal surface of external walls;
• marking internal walls and checking them using the method of angles and diagonals.

Soil development

After the main dimensions of the future construction are laid out on the ground, you can begin to develop the soil. It can be done in two ways:

• digging trenches for buildings without a basement;
• excerpt of a pit for buildings with a basement.

The fertile layer of soil is completely removed.

The second option is more labor-intensive, but allows you to make maximum use of the usable area of ​​the house. Soil excavation can be done manually or using earthmoving equipment. The depth of the passage is determined based on the sum of the depth of the foundations and the thickness of the cushion under them (further on preparation for the tape will be discussed in more detail).

Trenches under the tape.

Digging a trench or pit begins from the bottom corner, which allows you to control the evenness of the bottom. The walls must be smooth and not crumble. Depending on the type of soil, when digging trenches of a certain depth, it may be necessary to brace the walls. On average, this value is in the range of 1-1.5 m. This means that the construction of buried foundations requires the adoption of additional safety measures at the construction site.

During the construction process, it is necessary to periodically check the depth of the excavation and the evenness of the bottom.

Preparing the bottom of the excavation

Regardless of how the soil is developed (pit or trench), it is necessary to additionally level it using a foundation cushion. It performs the following functions:

• surface leveling;
• correct distribution of the load from the foundation to the ground;
• drainage system.

The construction of a pillow under the foundations is possible from the following materials:

• sand;
• gravel;
• crushed stone;
• slag.

For sand preparation of a monolithic foundation, a large or medium fraction is used. Fine sand will shrink during use. In addition to its main functions, the sand cushion also prevents the occurrence of frost heaving forces in the immediate vicinity of the belt.

The thickness of the sand preparation is taken from 30 to 50 cm. For bulk soils, the thickness of the cushion can reach 1.5-2 m, since the base with poor characteristics is being replaced. During installation, you must remember to compact the pillow layer by layer. It can be done in the following ways:

• vibration (best way);
• pouring water;
• compaction under load.

The use of a sand-gravel mixture increases the load-bearing capacity, but increases the costs of the construction process of a monolithic foundation. When deciding to use crushed stone as a cushion, it is better to choose granite material with a fraction size of 20-40 mm.

The most undesirable material for preparing the base of a monolithic foundation is slag. He has a very low price, but does not provide high reliability and can be dangerous to humans.

Formwork work

We install the formwork.

Foundation formwork can be removable or permanent. The following materials can be used as a non-removable material, which significantly reduces the labor intensity of the process:

• concrete;
• metal;
• expanded polystyrene.

Expanded polystyrene (penoplex and polystyrene) are perfect for non-recessed and shallow structures. It provides them with additional insulation when the ground freezes.

Reusable factory-made panels or wooden boards are used as removable formwork. When constructing a building yourself, the use of panel formwork is not economically profitable. You can also use sheets of moisture-resistant plywood.

Installation of formwork is carried out according to preliminary markings. For a wooden structure, a frame is first assembled from pegs and horizontal guides, to which boards or sheets of plywood will be attached. After installation is completed, plastic film is placed inside to prevent leaks.

The use of expanded polystyrene simplifies formwork work, since the internal and external panels are already connected to each other, all that remains is to assemble the tape according to the construction set.

Reinforcement

The tape is reinforced using three-dimensional frames. In most cases, two rows of longitudinal reinforcement are used, but with a large foundation height, reinforcement in a larger number of rows is possible. To strengthen the structure, rods with a diameter of 8-16 mm are used, which are prescribed according to calculation. Their length is selected based on the geometric dimensions of the tape, but it is necessary to provide a protective layer of concrete of 20-30 mm on each side, that is, the steel reinforcement should not reach the outer surface of the structure by 2-3 cm.

Pay attention to how the corner is reinforced, not just with intersecting rods, but according to a special anchoring scheme.

To fix the rods in the design position, it is advisable to use plastic clamps.

Connecting reinforcement bars by welding is less labor intensive compared to knitting, but is not recommended for use, because reduces the strength of the reinforcement. For small buildings, it is possible to weld longitudinal rods, but at the corners you still need to use a binding wire with a diameter of 3-4 mm.

Also pay attention to how the interface is reinforced with a U-shaped clamp.

Pouring concrete mixture

For the foundation, it is enough to use concrete M 200 - M 300. For massive brick buildings several floors high, stronger concrete may be required. Concrete can be factory-made or home-made. A better quality base will be obtained from a factory mixture, since it is difficult to follow the preparation technology on a construction site. Work can be carried out in two ways:

• continuous;
• layered.

The continuous method provides greater reliability of the structure. If it is necessary to take a short break in the work, it is performed in layers.

Important! Upper limit The layer cannot be leveled; for more reliable adhesion to subsequent pouring, it must have unevenness.

When ordering a ready-made mixture, the work should not cause difficulties. The solution is supplied by concrete mixers, from which it is placed into the formwork using special hoses, leveled and compacted by vibration.

A tray may be required for pouring the foundation with a mixer.

If possible, monolithic work is carried out at temperatures from +15 to + 25ᵒС. If it is necessary to fill the foundation during the cold period, they resort to the help of special modifiers and heating the construction site.

Caring for concrete during curing

During hardening, it is necessary to ensure normal temperature and humidity conditions. To prevent small cracks from appearing on the surface, it is necessary to periodically moisten the concrete. After pouring, the tape is covered with burlap or plastic film to prevent moisture evaporation and uneven hardening of the concrete.

The moistening process must begin no later than 12 hours after pouring, in case of heat or strong wind no later than three hours. Further, abundant moisturizing is done every 2 hours in hot or windy weather and every 3 hours in cloudy weather. At night, it is necessary to moisten the concrete at least twice. Watering is not performed at temperatures below +5ᵒC. For ordinary concrete, the duration of maintenance is one week.

Completion of work on making a monolithic tape

Concrete gains full strength within 4 weeks. When using removable formwork, it can be removed on average after ten days, but if you have enough time, it is better to wait until the monolith has completely hardened. The permissible time for stripping works depends on the outside temperature.

• at an average daily temperature of +20ᵒС - 1 week;
• at an average daily temperature of +10ᵒС - 2 weeks;
• at low temperatures, the time required to gain the required strength can reach 6 weeks.

After removing the formwork, waterproofing is carried out. When installing a strip foundation, three types of moisture protection are required simultaneously:

• vertical;
• horizontal;
• blind area.

Vertical is carried out using coating or welding materials on the outer surface of the buried part of the foundation. Horizontal made of materials guided along the edge of a monolithic tape. The blind area prevents rain moisture from penetrating the structure. After completing all work below zero, backfill with soil or sand.

Compliance with the technology of constructing a strip foundation and careful attention to all stages will guarantee a long service life of the structure and the absence of premature damage.

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Laying out the foundation is one of the first and most important stages of construction work. Any building needs its own foundation, be it a light barn made of boards, a compact bathhouse, a small frame house or a huge private mansion made of stone materials.

Among all existing varieties for supporting structures, strip foundations have gained the most popularity: they are suitable for use in a wide variety of conditions, are distinguished by their comparative simplicity of arrangement and, in general, conscientiously cope with all the tasks assigned to them.

File for download: SNiP 3.02.01-87 EARTH STRUCTURES, FOUNDATIONS AND FOUNDATIONS

After reading the information below, you will receive full view about the existing types of strip foundations and their areas of application, the requirements for such structures, study the theoretical aspects regarding each key stage in the construction of such a support and step-by-step practical instructions with illustrations.

• construction of relatively light (frame, log) and heavy (cinder block, brick, concrete, stone, etc.) buildings;
• construction of buildings with a basement, underground garage and other similar premises;
• construction of bathhouses and houses with attic floors;
• performing construction work on sites with heterogeneous soil.

The base under consideration is almost completely universal - a concrete strip cannot be installed except on a peat bog or subsiding soil. Be sure to take this point into account when arranging your own supporting structure and familiarize yourself with the key requirements for strip foundations.

File for download: SNiP 2.02.01-83. Foundations of buildings and structures

Basic requirements for strip foundations

The main characteristic of a strip foundation is its depth. When choosing a suitable value, one takes into account, firstly, the nature of the soil at the construction site, and secondly, the type of building for the construction of which a concrete support is being installed. Information regarding these points is given in the following table.

Table 1. Required depth of strip foundation for a bathhouse, cm

Building under construction	Rocky soil	Dense clay and loamy soils	Sandstones consisting of compacted dry sand	Silty soils, soft sandstones	Very soft sandstones, silty soils, sandy loams	Peat soils
Compact one-story bathhouse	20	30	40	45	65
Bath house with attic	30	35	60	65	85	Strip foundation is not used

The table shows average values. In general, it is better to clarify the required depth of the strip foundation on an individual basis, fully assessing the climate characteristics at the site of construction work and the characteristics of the site itself (soil type, depth of groundwater, etc.).

Types of strip foundations

Currently, there are many types of strip foundations. They are used in various construction works and have a number of design differences, but are generally built using similar technology.

The simplest type of support in question is monolithic ribbon belt.

The design is used mainly in areas with high level groundwater during the construction of small light buildings. Well suited for a compact frame bath, for example, 3x3 or 4x4, which does not create a significant load on the base.

Second type - non-buried strip foundation. In essence, it is the same monolithic belt belt, only the concrete part of the structure is placed on its edge.

This type of foundation is characterized by increased high bending strength, which makes it possible to support buildings with more serious characteristics, for example, from rounded logs.

Important! No stone buildings can be erected on a monolithic belt or shallow foundation.

The third type of supports under consideration is shallow strip foundation.

The design is used mainly in areas where the groundwater level is at a depth of more than 1 m. Approximately half the height of the concrete part is buried in the ground. If groundwater passes above the mentioned mark, there will be no point in arranging a shallow belt: in this case, drainage will have to be done, which is fraught with additional labor, financial and time costs.

The fourth type is .

The first tape here lies on its side, the second stands on the edge. Such a ligament forms a very rigid structure. Stone houses can be built on such a foundation. As a rule, there is no point in using a T-shaped foundation when constructing a small private bathhouse. Recommended depth: from 1 m. An important condition when arranging such a supporting structure there is a lack of groundwater throughout the entire depth of the tape, because under liquid pressure, the foundation will deform and collapse, which will make the operation of the structure installed on top impossible.

The fifth type of foundation under consideration is strip buried foundation.

The minimum depth is 1.5 m. The specific value is determined by the depth of soil freezing - the base of the concrete structure must be below the mentioned indicator.

Regions	Soil freezing depth, cm
Vorkuta, Surgut, Nizhnevartovsk, Salekhard	240
Omsk, Novosibirsk	220
Tobolsk, Petropavlovsk	210
Kurgan, Kostanay	200
Ekaterinburg, Chelyabinsk, Perm	190
Syktyvkar, Ufa, Aktyubinsk, Orenburg	180
Kirov, Izhevsk, Kazan, Ulyanovsk	170
Samara, Uralsk	160
Vologda, Kostroma, Penza, Saratov	150
Voronezh, Perm, Moscow, St. Petersburg, Novgorod, Ryazan, Tambov, Tula, Yaroslavl	140
Volgograd, Kursk, Smolensk	120
Pskov, Astrakhan	110
Belgorod, Kursk, Kaliningrad	100
Rostov	90
Krasnodar	80
Nalchik, Stavropol	60

Video - Types of strip foundations

Theoretical aspects of independent arrangement of strip foundations

Before you begin to consider the step-by-step technology for pouring your own foundation for a bathhouse, you are recommended to study in detail the theoretical aspects, key requirements and accompanying comments regarding each stage of the work ahead.

After determining the suitable parameters of the strip foundation in accordance with the conditions of a specific construction event (information on this matter was given in the table and on the diagrams of existing types of support), they begin to mark the site, having previously cleared it of debris and, in general, anything that could interfere with further work .

In addition to debris, the top ball of soil is removed to a depth of about 12-15 cm. Marking is generally done in the traditional way: wooden or metal pegs are driven into the corners of the future structure and a rope is pulled between them. The latter will make it easier
to navigate when determining the direction of the foundation strip.

A very convenient option is to mark using cast-offs. An example of marking using such devices is shown in the following image.

The marking begins with marking the outer contour of the base. In the example under consideration, a foundation for a bathhouse measuring 5x6 m is marked. On all sides, the area for arranging the foundation should be at least 40-50 cm wider than the supporting structure itself.

Specifically, in this example, the dimensions of the marked area were 6.6x7.6 m. The calculation is carried out according to the Pythagorean theorem, according to which the square of the hypotenuse is equal to the sum of the squares of the legs. The hypotenuse (AC) for this example is calculated as follows: √(5600²+6600²). The result is a value equal to 8656 mm.

We draw a base line equal to one of the sides of the future foundation. In the example under consideration, the segment AD equal to 5600 mm is defined as the base one. Most often, when performing this activity, the most important side of the future building is marked first - it is made parallel to a certain direction, for example, the line of another building, fence, etc. For example, let us define as an important line AB, which is being installed in parallel
in relation to the house at a distance of 5 m from it. We move corner point A 2 m from the fence. From point A we set aside segment AD and drive in pegs or reinforcement at its extreme points.

To determine point B we need a pair of ropes. We make loops at the ends of each rope. We throw the first loop onto the peg/rod located at the location of point D. We use such ropes in length so that after they are tensioned between the axes of the driven pegs, values ​​equal to the previously mentioned 6600 mm and 8656 mm are provided, in accordance with the above drawing.

After tensioning the rope, draw arcs on the ground. The first is to draw an arc with a radius of 6600 mm from point A, the second - 8656 mm from point D. At the intersection of the drawn arcs, point B is located. Here you need to drive in the second peg/rod.

To determine point C we use the same technology. The only difference is that from point A an arc is drawn along the length of the diagonal, from point D - along the side of the rectangle. We measure the diagonals of the resulting rectangle. Ideally, their length should be the same. The maximum permissible deviation is 1-1.5 cm. We pull the rope for marking, stepping back from the ground up about 20-25 cm, sequentially going around each block/rod. At this height of tension of the cord, it will not interfere with the installation of cast-offs.

To determine the remaining external nodal points, we simply measure the segments or use the technology discussed above in accordance with the foundation drawing, guided by the ropes. The internal contour, as well as the nodal points of the load-bearing walls, are marked after the demolition is completed.

Let's start installing the cast-off. It will provide temporary designation of axes outside the trench and will allow control of the zero level of the structure. In addition, the presence of cast-offs makes all preparatory activities simpler and more convenient.

Installation of cast-offs is carried out along the entire perimeter around the supporting structure. Between each side of the perimeter and the cast-offs being installed, a distance of about 1-1.5 m is maintained so that there is no inconvenience during the excavation work.

We find the highest corner point of our site, for example, A. The first cast-off will be installed here. We take three beams (10x10 cm in size are sufficient) and drive them into the ground in accordance with the drawing. It is important to ensure that the posts are secured as securely as possible. Using a pencil or other suitable device, mark the zero level of the future bath on the column. To do this, we step back 60 cm from the ground and draw a line indicating the zero level.

Armed with a screwdriver and a level, we fix a couple of boards measuring 4x15 cm on the driven posts. It is important that the upper edges of the fixed boards strictly coincide with the previously applied zero level and are located in a single horizontal plane. In a similar order, we install posts and boards in each corner and along the perimeter. We transfer the zero level to each installed column, focusing on the zero level of the very first cast-off. Finally, we make sure that the upper edges of the fixed boards are located in a single horizontal plane. To do this we use a level.

Let's start with the final markings. First, we pull the ropes one by one along the outer contour. To do this, we place the rope on the upper edges of the opposite cast-offs and pull it, orienting it strictly along the rope of the lower contour. After final leveling, we drive nails into the boards and tie the cords well. Using the same scheme, we mark the entire outer contour. As a result, the upper contour should coincide with the lower one. We make sure that our diagonals are equal. If there are no deviations, we stretch the remaining ropes along the extreme edges of the walls of the supporting structure being erected. We mark on the cast-offs the required thickness of the walls and the width of the spaces between them, drive in nails, pull and tie the ropes.

Marking the external and internal walls of the building. Scheme

At the same stage, you can mark the foundation for the sauna stove. In accordance with the requirements of construction technology, there should be no rigid connection between the supports of the furnace and the main building. Having completed the markings, proceed to excavation work.

Digging a trench

In accordance with the markings, a trench is dug to a predetermined depth - recommendations on this matter were given earlier.

Digging a trench

start digging from the bottom corner of the supporting structure - this way you will achieve the same depth of the pit along its entire length;

try to keep the walls of the trench as vertical and level as possible. In places where soil has fallen, install temporary supports;

regularly check the depth of the pit and the slope of its bottom to ensure there are no differences.

Having dug a pit, proceed to arranging the backfill. The thickness of the sand cushion is from 15-20 cm. The backfill is spilled with water and thoroughly compacted. Thanks to this structural element, the correct distribution of loads from the future building on the supporting structure will be ensured. The type of backfill included in the structure is shown in the following image.

Important! The backfill is done in several layers. The recommended thickness of each layer is 5 cm.

A layer of roofing material is laid on the finished sand cushion. The material will protect the backfill from erosion and prevent the concrete mixture from seeping into the sand while pouring the foundation.

In the photo - roofing felt under reinforcement

Additionally, roofing felt will take on the functions of waterproofing the lower part of the supporting structure. For greater efficiency, the insulating material should be rolled onto the walls of the pit by approximately 15-20 cm.

Installation of formwork is one of the most important stages of the work in question.

The structure can be collapsible (dismantled 3-10 days after pouring concrete) or permanent (remains part of the foundation, providing additional insulation).

Wooden boards are used to make collapsible formwork. The individual elements are screwed into panels of the required size. The finished panels are installed vertically in the trench. The height of the above-ground plinth part directly depends on the height of the formwork protrusion above the ground surface. As a rule, they adhere to the figure of 35-40 cm.

The individual panels are fastened along their crossbars. From the outside, the elements are supported by pieces of wooden beams. Be sure to check that the upper part of the formwork is in a single horizontal plane, i.e. there were no differences in height, otherwise the foundation would also be uneven.

A dense polyethylene film is laid into the finished formwork, covering the structure from the inside. Attach polyethylene to the end sides of the formwork panels.

To assemble permanent formwork, polystyrene foam blocks are used. The elements are installed on top of each other. The individual blocks are fastened using serrated cutouts and grooves. Blocks of different sizes are available for sale, which allows you to choose them for any foundation.

The blocks do not require additional fastening. Spacers are also not needed.

Reinforcement

Reinforcement is performed using steel rods with a diameter of 8-15 mm, depending on the expected load that will be created by the future bathhouse, the size of the foundation and the key characteristics of the soil.

The reinforcement is cut into rods along the length of the walls and tied into a mesh using special wire. It is strongly not recommended to use welding for this - during the process of shrinkage of the structure, the reinforcing mesh may collapse.

At the owner's request, the rods can be fastened with special plastic clips (clamps) - this is a simpler and faster option.

Fill

It is better if the concrete is poured in one go, but in self-construction conditions it is often extremely problematic to prepare the required amount of mixture at once.

In view of this, concrete will either have to be ordered ready-made, or look for other solutions to the problem by pouring the solution in layers. The standard scheme is as follows: on the first day, a horizontal layer of 15-20 centimeters thick is poured and carefully compacted using a wooden beam. It is important that the layer thickness is the same along the entire length of the formwork, and that the top of the fill is even. The next day the work is carried out according to the same scheme. The process will be repeated until the formwork is completely filled with concrete.

The poured structure is covered with plastic film - this will prevent it from drying out too quickly and cracking. Periodically, the plastic film is removed, the concrete is sprayed with water from a hose, and then covered again with insulating material. The base will dry for 4-5 weeks. The formwork is dismantled on average 5-7 days after pouring, sometimes after 10 days. Finally, the finished structure is waterproofed. This point will be discussed in more detail below.

To ensure that the finished foundation is of the highest quality, carry out the work on its arrangement in compliance with key construction recommendations.

Firstly, if you prepare the solution yourself, use materials that have been cleared of clay, soil and other impurities.

Secondly, choose the correct proportions of the solution specifically for your case. In general, crushed stone/gravel is always taken approximately 1.5-2 times more than fine aggregate, i.e. sand. Detailed information regarding possible concrete compositions will be given in the practical part.

Thirdly, add the optimal amount of water to the solution - about half the weight of cement. Additionally, consider the moisture content of the raw materials. For example, if you are forced to use wet sand, the amount of water required will be reduced accordingly.

Fourthly, do not forget to treat the fill to remove excess air from it - this is important for thick solutions. It is enough to pierce the fill with a metal rod along its entire length.

Fifthly, after pouring the concrete, the formwork must be tapped with a wooden hammer - this will also remove excess air.

Practical aspects, or step-by-step instructions for pouring a foundation

As an example, let's look at the procedure for arranging a non-buried strip foundation - one of the most popular options, perfect for structures of a relatively small area. For example, your wooden bathhouse measuring 4x4 or 6x6 (sometimes even larger) will feel quite comfortable on such a base. If necessary, you can change the depth of the tape and its other parameters in accordance with the type of soil and the characteristics of the building being erected - the immediate procedure will remain the same.

The procedure for carrying out the event in question is given in the following table.

Table 2. Procedure for arranging a non-buried foundation

Work stage	Illustration and additional explanations
Cleaning a platform for the future foundation from debris.
We recycle the collected garbage. TO for example, it can be taken out to a landfill or just burn it.
Let's start preparing the markings for the trench	Marking in progress in a standard way: a cord is stretched around the perimeter of the future structure, pegs are driven into the corners Using a hydraulic level, we mark the points of the horizontal plane on the pegs. In accordance with the marked points, stretch the cord. In the future, this will help us ensure that the bottom of the trench is horizontal - we will dig to the same depth from the stretched rope. Mark the inner perimeter of the tape. To do this, again, we install pegs. They can be driven into the ground, for example, reverse side axe. We pull the rope, thereby ensuring the marking of the inner wall of the trench.
We dig a trench in accordance with markings. The minimum permissible depth is 60 cm.	We cover the bottom of the finished trench with geotextiles, roofing felt or polyethylene film for waterproofing.
	For this we use a sand-gravel mixture. The recommended layer thickness is 15-20 cm. Thoroughly pour the backfill with water and compact it thoroughly You can compact it manually. Align the top of the finished backfill horizontally.
	The width of each must correspond to the height of the foundation being built. In the example under consideration, a foundation with a width of 300 mm and a height of 400 mm is being built.
	Let's start from the inside. To make it easier to disassemble the formwork in the future, we use screws to connect the elements. It is important that the top of the finished formwork lies strictly in a horizontal plane. To check we use a hydraulic level. If necessary, we immediately level out any detected deviations. On the back side of each shield we drive 3 pegs into the ground. This will ensure rigid and reliable fixation of the structure. We use screws to fasten the driven pegs to the shields. We install at least 3 spacers on each side of the structure. They will prevent the formwork from expanding under concrete pressure. The spacers are secured using screws.
	Thanks to the reinforcement, the necessary rigidity indicators of the finished foundation will be ensured. The reinforcement bars are connected using tying wire. If desired, a crochet hook can be bent from an old one. screwdrivers. First the nets are knitted. Afterwards, the finished meshes are connected into boxes. Cell sizes are usually maintained at 10x10 or 15x15 cm. The finished boxes are installed at each wall of the formwork, and then connected into a single structure using already known technology. Additional reinforcing reinforcement is installed at the joints.
Pouring concrete	To do this, we use a ready-made composition of the M200 brand or prepare the solution ourselves (the proportions are indicated in the table below). We fill the space in the formwork with an even horizontal layer of concrete and compact it carefully, you can do it manually. In the image you see that the foundation walls are at different levels - this option is very convenient when building a bathhouse from a log. This feature will allow the first crown to be laid with the highest possible quality in the future. Select the amount of difference in accordance with the size of the logs used. When building a foundation from other materials, you don’t have to make such a difference - there’s no point in it. The technology for doing the work remains the same.
So that all the cement reacts and the hardened concrete is as strong as possible, we periodically spill the fill with water, and then cover it with polyethylene or roofing felt.
The formwork is usually dismantled 5-7 days after pouring, but depending on the condition of the concrete, this period can increase to 10 days. Further construction work can begin at least a month after pouring the foundation.

Table 3. Concrete proportions

Cement brand	Concrete M300 (H 22.5)	Concrete M250 (B20)	M200 (B15)	M150 (B10)	M100 (B7.5)
400	1:1,6:3,4	1:1,8:3,6	1:2,4:4,4	1:3:5,3	1:4:6,5
500	1:1,8:3,9	1:2:4	1:2,6:5	1:3,5:6	1:4,5:7,3

Video - How to properly pour a foundation for a bathhouse

A completely hardened and strengthened foundation is subject to mandatory waterproofing. Most often, roofing felt is used for this. The material is laid on the upper part of the foundation, previously cleared of debris and, at the owner’s request, coated with an acrylic primer. After cleaning and priming (if planned), the top of the foundation is covered with mastic.

The first layer of roofing material is laid on top, pressed and simultaneously smoothed.

Video - Foundation waterproofing