Foundation work is not considered the most complex construction work, but in terms of responsibility it is one of the most critical building structures. Most mistakes during foundation construction lead to very serious consequences; correcting them is very difficult and expensive, and in some cases impossible. All foundation calculations must be carried out in accordance with the provisions of SNiP 2.02.01–83.

File for download. SNiP 2.02.01–83. Foundations of buildings and structures. SP 22.13330.2011

During calculations the following are taken into account:

• loads acting on the base of the foundation;
• soil indicators, presence and location of groundwater;
• maximum permissible deformations and load-bearing characteristics;
• characteristics of climatic zones and foundation depth.

These are very complex calculations, we will not dwell on them. For the simplest structures, builders take standard parameters for a given climate zone and soil characteristics as the foundation. They already have a large margin of safety, which ensures the reliability of the design.

Shallow strip foundation - parameters

Introductory table of the approximate width of the strip foundation

Tape width depending on wall material

A shallow strip foundation is one of the most frequently used options in private construction; in all respects it satisfies most developers. The construction of the foundation can be divided into three stages: marking, digging a trench and constructing formwork, pouring concrete and leveling.

Let's look at each stage in detail. We will talk about the stages of construction of a shallow reinforced foundation on a sand bed.

The work must be done carefully and slowly. It’s better to lose an extra hour or two during marking than to have problems later with the finished foundation tape.

Step 1. Drive wooden pegs around the perimeter of the foundation. In order to align the dimensions and angles of the tape, you need to prepare a basic device in the form of small benches. Drive two pegs into the ground at a short distance from the corners of the foundation and attach horizontal boards to them.

Step 2. Strengthen the nails in the boards and tie ropes to them. Try to first check the angle between the ropes with an ordinary large square. This will give you an approximation of the foundation lines.

Step 3. Align the corners of the tape; they should be exactly 90°. This must be done by checking the diagonals. The dimensions of the two diagonals cannot differ by more than two centimeters. Such scatter can be easily removed during the construction of the building box.

Step 4. Do not remove the ropes; use them to carefully mark the position of the tape with a shovel; it is advisable to dig a trench as deep as the bayonet of the shovel (about 20 centimeters).

Step 5. Now you can remove the ropes and continue digging the trench. Decide right away where you will put the land. It can be taken outside the perimeter of the building or leveled under it. In any case, the fertile layer must be completely removed.

Step 6. The width of the trench is equal to the width of the walls of the building. If the soil on the site is dense, then there is no need to do formwork in a trench; if the walls are crumbling, then you will have to do formwork along the entire height of the foundation.

The depth of the trench is within 60÷80 cm, taking into account a sand cushion up to twenty centimeters thick.

Video - Marking for the foundation

Foundation marking schemes	Description

Manufacturing

You can use second grade edged boards or special waterproof plywood. We will take boards 20÷25 mm thick and 20 cm wide; to assemble the panels we will use slats and scraps of boards.

Step 1. Production of formwork panels. There is no need to make them very large; then it will be difficult to install and dismantle. The length of the shields depends on their height, but in any case, try to ensure that the total weight of the structure does not exceed 50–60 kilograms. This weight can be lifted without much effort by two people. Try to fit the boards without large gaps, nail the vertical posts at a distance of 50–60 centimeters. More accurate indicators depend on the parameters of the foundation strip.

Shields – photo

Use nails for nailing; self-tapping screws will not only increase the cost of the formwork, but will also create problems during its disassembly. Almost all lumber after dismantling the formwork can be used for further construction of the building, it is advisable not to damage it again. You are unlikely to be able to accurately calculate the length of the shields; leave a margin of approximately 1.5÷2 meters in length; you will make this shield after accurately installing all the previous ones. In this position it will be possible to take exact measurements up to the corner and make the shield of the required length.

Step 2. Start laying out the formwork for the foundation. This kind of work cannot be done alone; you need to call an assistant. Lower all the panels one by one into the trench, fix the position with pegs and corner stops. Spacers should be inserted between the panels so that they do not change their position while fixing the formwork. Spacers do not work while concrete is being poured, they are only important during the assembly of the formwork. We advise you to immediately prepare spacers for the template; the quantity is determined taking into account the length and height of the foundation strip and the parameters of the boards.

Step 3. Fix the panels securely; it is better to place corner supports more often than to level the foundation later. Place your shields along the rope and constantly monitor their position. The joints of the boards are sealed with a board; fastening must be done in this place. Drive the pegs as deep as possible; the corner supports to the shields must be fixed with special small stops made from scraps of boards. You must exclude even the slightest possibility of violating the integrity of the formwork while pouring concrete. Such an “accident” always comes at a cost.

Step 4. During the installation of formwork, it is always necessary to provide for its subsequent dismantling. This means that the nails should be driven into places where they can be removed. Place all dismountable units only on the outer accessible side of the formwork.

Step 5. Check that the formwork is installed correctly. Pay attention not only to the linearity of the planes, but also to the reliability of fixation. Apply multidirectional forces to the formwork - if even slight vibrations of the structure are detected, immediately install additional stops. Remember that correcting formwork installation errors while pouring concrete is an extremely thankless task.

Assembled formwork - photo

Prices for edged boards

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Video - Making formwork

Step 6. Place plastic tubes in the formwork at the locations of ventilation ducts and utility lines. Secure the top boards of the formwork panels with boards or tie them with wire to prevent expansion.

Our foundation must be reinforced - its load-bearing capacity increases significantly. For reinforcement, construction reinforcement of periodic profile Ø 10 mm is used. The reinforcement can be tied together, which takes a very long time, but you can only lay horizontal bars while pouring concrete. We, of course, choose the second option. In terms of strength, a strip foundation loses almost nothing, and much less work and money will be required.

If everything is fine, you can start pouring concrete.

Pouring concrete

We will make the concrete ourselves from grade 400 cement, sand and gravel or crushed stone.

Nowadays, such heavy physical work is no longer done manually; you need to purchase or borrow a small concrete mixer with a drum volume of approximately 0.2 m3.

Before starting work, you need to calculate the required amount of building materials; calculations are made taking into account the total volume of the foundation tape. It’s easy to calculate the volume; multiply the length by the width and height. For one cubic meter of concrete you will need 325 kg of cement, 760 kg of sand and 1100 kg of crushed stone. These are approximate figures, they are needed only to guide the amount of materials. When purchasing materials, increase their quantity by 10%. You need to buy even more sand for a sand cushion.

No one weighs individual ingredients to the nearest gram when making concrete. When preparing concrete, take two shovels of sand and three shovels of crushed stone or gravel for one shovel of cement. Water is used as needed, the specific amount is determined experimentally, and the concrete must have optimal viscosity.

Step 1. Pour a layer of sand ≈15÷20 centimeters thick into the trench. The sand needs to be compacted well; use any available means for this or make a simple device.

Step 2. Pour the concrete mixture around the perimeter of the building, do not allow large differences in height. If you have an electric vibrator, great, it can compact the concrete along the entire height of the foundation. If tamping is done manually, then the concrete layer should not exceed 25–30 centimeters in height.

Step 3. Simultaneously with pouring, pay attention to the “behavior” of the formwork; if you detect any bulges or curvatures, immediately take measures to eliminate them.

Step 4. We decided that we would perform the foundation reinforcement in a simplified way. The rods are placed directly on the concrete. In total, we will have four rows of reinforcement in the tape, two in each layer. Cover the sand cushion with a layer of concrete approximately 30-40 centimeters thick. Level it horizontally and lay two rows of reinforcement. You shouldn’t try too hard, the rods will then become filled with mass, and a small angle of inclination (if any remains) will not have any negative effect.

Step 5. Continue pouring the foundation around the perimeter, when twenty to thirty centimeters remain to the top of the tape, lay the second row of reinforcement. Make sure that the ends of the reinforcing bars overlap by approximately 20÷30 centimeters.

Step 6. Align the zero level of the strip foundation; the variation in height in the corners cannot exceed two centimeters. Use a stretched rope; with its help you will perform the leveling faster and with better quality.

It is highly advisable to fill the entire foundation within one working day.

In most cases, this is possible for baths, but it all depends on the specific size, ability to organize construction work, professionalism and the number of workers. If you have to leave part of the work for the next day, then the liquid concrete in the formwork must be leveled horizontally as much as possible. The presence of “steps” with large differences in height significantly reduces the load-bearing characteristics of the foundation. The formwork should be removed two weeks after pouring the concrete. If the weather outside is hot and dry, it is recommended to moisten the concrete generously with water several times a day. A quickly drying foundation will not have the calculated strength indicators.

Why? Concrete is a unique material. Under ideal conditions, the strength of concrete structures constantly increases. During the first 14–15 days, concrete gains 70–80% of maximum strength, then the rate of increase in strength slows down and after 30–40 years its strength increases by only a fraction of a percent. But it is increasing! Of course, this only happens in cases where the structure is not affected by precipitation, temperature changes, external forces, etc. That is why it is not recommended to remove the formwork in less than two weeks. Do not rush to dismantle it; during this time it is better to prepare for the next stage of construction.

Prices for concrete mix M400

concrete mix M400

Video – Seminar on pouring the foundation

Now that you already have a general understanding of foundation construction technology, you can give some practical advice. With their help, it will be possible not only to simplify and facilitate a number of construction works, but also to improve their quality and reduce cost.

How to make concrete

A lot depends on the correct organization of work; we give advice from experts who have solid practical experience.

The concrete mixer must be in a stationary place, and ready-made concrete is transported to the foundation by wheelbarrows.

There are some “craftsmen” who advise dragging the concrete mixer along the foundation as it is filled. They transport water, sand, cement and gravel separately in buckets to each new location. Looking at this “technology” is both funny and painful. This organization of work increases the labor intensity at least twice and increases the time by the same amount.

What do we recommend? The concrete mixer must be stationary; install it taking into account the possibility of access. Place a barrel of water with a volume of approximately 200 liters near the concrete mixer. Bring sand and gravel to separate piles, and let the cement lie on pallets in bags. All materials must be available for filling into a concrete mixer without transfer.

Throw a bag of cement onto the pile of sand and use a shovel to cut it approximately in half. Half a bag of cement is just the norm for one batch of concrete. Turn on the concrete mixer, pour one and a half to two buckets of water into it, take half a bag of cement with your hands and pour it into the water. You can immediately throw gravel or crushed stone; the pebbles will break up small piles of cement well. Next, throw sand and gravel into the mixer one at a time. The calculation is simple - for one shovel of cement you need two shovels of sand and four shovels of gravel.

The specific amount depends on the size of your shovels; for the first batch, you can measure the amount of cement in half the bag, this will give you a rough idea. In the future, you will gain experience and you will already be able to determine the quality of concrete by eye by the viscosity of the mass. If the solution is too thick, add water in small portions. If it turns out liquid, add sand; gravel has almost no effect on the viscosity of concrete; it absorbs little water. I had to add a lot of sand - throw another shovel of cement into the concrete mixer. The cement that spilled onto the sand is picked up and used.

With water, you also can’t guess right away; the amount of water depends on the moisture content of the sand and gravel. For the first batch, it is better to take a little less water and then add it as needed. Too much water can cause trouble - there won't be enough volume in the concrete mixer to add large amounts of sand and gravel.

Ready concrete must be transported to the foundation by wheelbarrows. When planning the organization of work, it is necessary to provide for such a number of people that the work proceeds in an assembly line manner, without anyone expecting anyone. The time for pouring the foundation with concrete should be equal to the time it took to make it. These indicators are influenced by many factors: the distance to the foundation strip, the volume of the concrete mixer, the professionalism and hard work of the workers.

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Important

Perhaps this is all we can advise beginners; in the future you will gain your own experience and you will be able to change and improve the algorithm for making concrete.

How to assemble formwork

Absolutely all individual nodes work in bending or compression. Why are we talking about this? And then, when assembling the formwork, there is no need to use huge nails and then bend them five centimeters on the back side. Not a single nail works to pull out. In corner stops, the nails are subject to bending forces and very insignificant pulling forces. Using normal nails will not reduce the strength of the structure, but it will make your work much easier during its dismantling.

Most of the boards after formwork are used for further construction - after removing the formwork, immediately disassemble it and clean the boards. There are cases when high-quality boards are used for formwork - we recommend covering them with plastic film. Install the film on the inside of the formwork, fix it with an ordinary stapler. The cost of the film is pennies compared to the cost of lumber. No master will process boards contaminated with cement on machines, and polyethylene will keep the materials in their original condition.

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How to dig a trench

It would seem that nothing is simpler - dig deeper and throw further. But those who have never dug themselves think so. Each job has its secrets, here are just a few of them.

1. First you need to trim the grass roots along the entire length of the trench. Using a shovel, cut the turf along the line on both sides of the foundation strip to a depth of approximately ten centimeters. This will not only make it easier to remove the sod, but will also make the edges smooth.
2. The first excavated soil should be thrown away as far as possible from the edges of the tape. You will still have to throw it further than you might think. It's easier to do this before you get too deep. Over time, the trench will become deeper, and more effort will have to be spent to throw out the soil. And if you have already made a mound near the edges, then you will have to transfer it too.
3. Increase the depth by the spade bayonet along the entire length of the trench, immediately leveling the edges. Then clean up the loose soil with a shovel, starting work from the place where you finished digging with a bayonet shovel. This way you won’t be compacting the soil yourself. When you’ve finished clearing the ground, repeat it all over again, work with a bayonet shovel along the entire length, then clean the bottom of the trench.

Video - How to dig a trench for a foundation

We guarantee that in this way you will be able to dig the foundation much faster and without “heroic feats of labor.” It is impossible to talk about all the intricacies of construction work in one article. Do not perform monotonous work for a long time, this accelerates physical and mental fatigue; if possible, change it after an hour or two.

We can give one universal piece of advice: look for logic in every work. All actions should be aimed at one thing - obtaining maximum results with minimal losses. It doesn’t matter what the loss is: time, money or effort. If you listen to our advice, then work will always be a joy, not a punishment. Especially if it is done with your own hands and for yourself.

Video - Do-it-yourself shallow strip foundation

Construction of a house begins with the foundation. Building materials for its construction are often selected taking into account regional availability. In some areas, the cost of a strip foundation is comparable to a reliable foundation structure built from granite. Such a foundation firmly holds any house of any size, even built on black soil and other unstable soil. Taking into account modern construction requirements, the main purpose 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 an “airbag” for a house made of high-strength material, craftsmen recommend that novice builders use ready-made foundation blocks. This construction option will help to avoid a number of mistakes, which for a number of reasons are not taken into account in cases where the strip foundation is built with your own hands.

Classic mistakes when building strip foundations

The strip foundation remains the most affordable option for constructing the foundation of a house with your own hands and is 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. Let's look at the main mistakes when constructing strip foundations, as well as how to avoid them.

Geological and hydrological works

Before starting work, it is recommended to obtain geological and hydrological survey data, which, when developing a project, will allow making calculations based on the location. Most standard projects, as expected, were made without taking into account the characteristics of the soil, so in some regions one can observe abnormal behavior of the foundation.

Strip foundations installed on black soil are not considered a solid foundation for any residential building. Typically, areas of black soil under the foundation are selected, covered in layers with sand, carefully compacted using water and covered with a bed of crushed granite stone.

Features of Extreme Design

When building a house yourself, you can conduct a soil analysis on your own. To do this, you need to drill the area 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 sliding on slopes.

Errors during work and installation

Construction of foundations in autumn-winter

Foundations are not installed on waterlogged and frozen soil, or on snow. The construction of a concrete foundation in winter is undesirable or must be carried out using strict technology using construction equipment. When concrete is laid in a trench on snow, voids filled with water are formed.

Heaving soils and their features

A standard error is the lack of soil when digging a trench under 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 strip-buried (strip-pile type) foundations are not installed. Piles hold the foundation in place, and heaving forces push it to the surface, as a result of which the concrete strip is very likely to crack or the pile to break 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 filled with sand and crushed stone, eliminating the source of heaving. On such soils, the blind area must be insulated, which prevents the foundation from freezing and eliminates the possibility of heaving.

Pasting and thermal insulation of the outer side allows you to shift the dew point beyond the boundaries of the foundation, which eliminates the influence of tangential heaving forces.

Foundation protection includes:

• gluing waterproofing film;
• installation of XPS polystyrene foam (high density);
• cover with 2 layers of dense polyethylene;
• Additionally, sheets of polystyrene PSB 25 are pressed to the foundation by backfilling with soil.

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

Do-it-yourself strip foundation photo: step-by-step instructions

Basic strip foundation structures: their appearance and design diagrams

Depending on the characteristics of the soil and the type of construction, choose the design of the future concrete foundation of the house. When building houses on black soil, buried and deep-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.

Trench and sub-concrete waterproofing

Communications

Simultaneously with the removal of soil for the foundation, the preparation of communications that must be connected to the house is carried out. At this stage, special attention should be paid to the house sewer pit and the waste drainage device. If water will be supplied from a well, it is necessary to make simultaneous preparation of communications, since the laying of water supply pipes is carried out at a depth of 1.5-2 m.

After removing the soil to the design level, sand is poured in layers of 10 cm with water. In some cases, the cushion can reach 40-80 cm; with high groundwater or a desire to make a safety cushion at low cost, the thickness of the backfill is 40-80 cm, of which up to 2/3 of the height can be crushed stone.

Next, formwork is laid 10 cm deep; it should be twice as wide as the base of the tape and filled with “lean” concrete (B7.5 mixture). After the mixture reaches 70 strength, a waterproofing membrane or polyethylene 0.15 mm thick is laid with a margin of 20-30 cm from the edge of the tape - drains.

A reinforcing belt made of reinforcing wire 10-12 mm (on moving soils up to 16 mm, grade A400) is laid on top and bottom of the trench, fastening it with a spatial wire frame (grade A240, 6-8 mm). Laying is done on plastic spacers 2-4 cm wide. The upper level of the frame should be located close to the surface, no deeper than 5 cm, under the fastening layer of concrete.

The reinforcement is usually overlapped with a size of 50 diameters of reinforcing wire according to the new SNiP requirements (with 12 mm wire the overlap is 60 cm, previously the requirements assumed an overlap of 20-30 cm). At the corners, the reinforcement cannot be installed end-to-end; in the corners, L-shaped and U-shaped shapes are used and fastened according to the scheme shown in the photo.

• install sleeves in the reinforcing belt to enter communications into the cottage or carry out simultaneous installation of pipes;
• 40 cm from the blind area in the formwork of houses with beamed floors, it is necessary to provide for the installation of void formers to ensure ventilation of the subfloor, prevent corrosion, rotting and ensure the removal of harmful radon. The dimensions of the ventilation openings should be a total of 1/400 from 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 secured using internal ties, as shown in the photo. Ready-made formwork allows you to concrete structures with complex shapes.

Pouring the foundation

It is advisable to use ready-mixed concrete for foundations. In this case, it is possible to carry out winter work, since for these purposes a special brand of solution is used that hardens in the cold. The brand is selected depending on the type of structure:

• M100 – for wooden houses and outbuildings;
• M150 – for buildings made of foam concrete;
• M200 – for one- and two-story cottages with light floors;
• M250 and M300 - for buildings up to 5 floors, as well as for monolithic floors;
• M400 – 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 foundations are poured in several stages, with a break between them of no more than 2 hours. Concrete can be poured after 12 hours, but the surface film must be cleaned off with brushes or removed with water pressure. Concrete must be placed in the trench with a vibratory compactor. Loose concrete does not gain the declared brand 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 provide the required level of strength and also avoid the formation of craters and cracks.

When laying a concrete foundation, it is not advisable to neglect vertical waterproofing (of the base walls), this will help protect it from damage and ensure long-term operation. This is especially important for those areas that are characterized by winter thaws, during which the foundation is moistened and goes through several freezing cycles.

Do not neglect horizontal insulation, the absence of which can lead to the appearance of fungus on the walls and increased humidity, since moisture from a 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 foundation is a monolithic slab. The technology for constructing a monolithic insulated Swedish slab (USP) is an innovative development that is becoming increasingly popular. And it can also be made with your own hands.

The base of the house is a reliable sandwich structure, which 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 retained to reduce energy costs. Above we showed how to make a foundation with your own hands, video, now we offer technology for constructing USP.

The construction issue is covered in detail in the video.

A foundation built in accordance with technology is the basis for the durable and safe use of any structure. There are many types of foundations for buildings, but the most popular is the strip foundation. To make it, you don’t need to use special equipment, which means you can save money. Moreover, anyone can build a strip foundation on their own if desired.

Builders include the following in the list of advantages of strip foundations:

1. Low construction cost. A do-it-yourself strip foundation rarely takes up a large area. You don't need a lot of materials to create it. Of these, you will need the simplest ones, which can be found in any store and even garage.
2. Simplified design compared to other types of bases. The principle of arrangement is clear even to a beginner and does not involve working with equipment, a crane, etc.

You can dig a trench around the perimeter using a shovel. The formwork is equipped with a saw and hammer. The reinforcement is knitted with strong steel wire. The concrete mixture is mixed at the construction site.

If making concrete by hand seems like a labor-intensive process, you can always ask your friends for an economy-class concrete mixer, designed for half a cube.

1. The strip foundation can withstand high loads. In fact, this base is represented by a monolith of concrete. Therefore, you can safely build a house of 2 or 3 floors on it.
2. High speed of work. If the house for which a strip-type foundation is being made has an area of ​​100 square meters, it is possible to build a foundation from scratch within a month. Using industrial mixers designed for mixing concrete, you can reduce the operating time to a record 1 day. The main stage is digging a trench and constructing formwork reinforced with reinforcement.

The disadvantages of pouring a strip foundation are the following:

1. In order for the foundation to be strong and reliable, it is important to provide for the preparatory stage. Specialists analyze the soil and calculate the required depth. If you take this step carelessly, there is a real risk that the winter house will lead to the side or it will sag. Soil heaving and mobility are the main parameters that are determined before construction.
2. Large specific gravity of the base. The ground, in addition to the foundation, bears the weight of the building itself. Over time, the soil may sag or the house may tilt to one side.

Species and subspecies

Based on the depth of the foundation, strip foundations can be shallow or recessed. There is no constant indicator of burial depth. It depends on the depth of soil freezing in a particular area.

A shallow foundation is a foundation with a construction depth less than the depth of soil freezing. When the ground freezes, it expands, which can push the concrete mixture and the building upward. The owner of the house may encounter uneven distortion and even rupture of the foundation. Suitable reinforcement will help avoid this. It is calculated using construction calculators.

A shallow strip foundation for a house is suitable in the following cases:

1. There is non-heaving soil under the building.
2. Low level of groundwater depth.
3. It is planned to construct a drainage near the building to drain water.
4. A blind area with insulation is planned near the house.
5. The building weighs a little. For example, this is a wooden bathhouse, a greenhouse or a frame house.

The advantages of a buried foundation are that construction is inexpensive and the level of strength is high. Although more often a buried foundation is used for the fortress of a structure. Its implementation involves the construction of a monolithic reinforced concrete strip. You can make blocks from FBS. They are placed on a reinforced concrete pad. A reinforced belt is built on top; it will connect the individual parts into a single whole.

Materials used for the construction of strip foundations

To build a monolithic foundation for a house, you may need the following materials:

• Portland cement;
• clean river sand;
• crushed stone;
• fragmentary rock;
• fittings made of strong steel;
• broken brick;
• water.

Of course, not all of these components are used when mixing one portion of the solution. Much determines the result that needs to be achieved. If you need to equip a strip foundation for a building with a complex configuration, mix cement, crushed stone and river sand.

Rubble concrete base is suitable for sandy soils. It consists of large stones, cement and sand. For clay soil the option is a losing one.

Adding brick to the mass is required to fill foundations located under or above the ground. Also, a brick foundation is suitable for the construction of a basement. Brick cannot be used in areas with a harsh climate; it will quickly deteriorate and the house may settle. The brick mortar is protected with waterproofing material. It is recommended for use in the construction of a frame house with thin wall structures made of brick.

High-rise buildings are built exclusively on slab or block concrete foundations. They are manufactured at the factory and transported to the construction site in finished form.

When buying concrete, it is important to choose the required brand of substance. The choice of brand depends on the following parameters:

• the mass of the building that falls on the base;
• weight of the building plus the foundation;
• type of reinforcement used;
• type of soil;
• climate of a particular area.

For poured strip foundations, the following grades of concrete are purchased:

• M100 - suitable for arranging a concrete cushion;
• M200 - will withstand light buildings (baths, sheds, panel houses);
• M300 - indispensable when pouring the foundation for a wooden house or a building made of light blocks;
• M350 is a good and reliable choice for the construction of 1-2-story buildings.

It makes sense to buy the remaining grades of concrete if the project involves the construction of geometrically complex structures and work on a construction site in a region with a harsh climate.

Read also the article about expensive for money, but very durable; other types are described in the section, with detailed descriptions and recommendations.

DIY strip foundation step by step instructions

The first step is for the owner of the future home to contact a design and construction company. Specialists will conduct a geodetic analysis of the site. The study will show the type of soil and the depth of its freezing in winter, at what depth the groundwater flows.

How to calculate the foundation

It’s good if the company’s specialists can calculate the foundation. It is not recommended to do this yourself, except perhaps for the foundation of a small outbuilding, garage or bathhouse. When calculating a strip foundation for a house, they are guided by the data of SNiP 11-B.1-62. You can use construction calculators on the Internet. Next, the site is marked.

Important. Preparatory work includes clearing the soil of debris. The top layer of soil (15 cm) is removed. This will help prevent biological decomposition processes. After all, they can cause an unpleasant odor in the basement and its partial destruction.

How to mark a site

Correctly apply the markings with your own hands, following this technology:

1. The builder fixes the axis of the building and where the first corner will be located. Using a plumb line, he places a peg in this place. The peg can be a piece of reinforcement.
2. Next, you need to pull the string, leading it from the first peg, so that you get a perpendicular. Gradually fix the second and next corners, sequentially installing new pegs.
3. From the second and third corners, pull the rope towards the fourth. The angles are set following the square.
4. As a result, the master should end up with a rectangle. It defines the external boundaries of the future home. It is easy to verify the correctness of the shape by carefully measuring the lengths of the diagonals - they should be the same.
5. Similarly, markings of the internal contours of the base are applied, and then the contours for individual components - load-bearing wall ceilings, porch, terrace, supports intended for columns.
6. To finally align the markings, following the horizontal direction, wooden planks are mounted at the required height. A string is pulled through them.

Digging a trench and preparing the bottom of the pit

After the markings have been applied, they begin digging a trench. It is dug taking into account the depth calculated during the development of design documentation. When digging a trench, you need to advance from a low angle. This approach will allow you to avoid a situation where the depth of the pit turns out to be less than calculated.

The trench walls are designed to be vertical. When the soil collapses, partitions are installed; they are temporary. The bottom of the trench is done carefully; to do this, it is leveled several times. Be sure to check the bottom with a building level to ensure there is no slope.

When filling a trench, it is important to consider the following rules:

1. River sand is poured until a layer 15 cm thick is formed. Saving sand can lead to uneven distribution of the load on the base. This is often observed in heaving soil.
2. The sand is distributed in layers. Before pouring the next one, the previous layer is watered and compacted.

A strong waterproofing film is laid at the bottom of the pit. You can use special geotextiles. The material has good reinforcing characteristics and increases the reliability of the base. As an alternative, experts recommend pouring the concrete mixture in a rough form. Before starting to install the formwork, wait a week. During this time, the concrete will just set.

Arrangement of formwork

1. Corner supports must be installed. Bars 50 mm thick are suitable for this. Before moving on to the next step, check the length of the diagonals.
2. The edged board is assembled into formwork. The boards are fastened together using metal bars or corners and self-tapping screws. The caps of the fasteners appear to be on the inner surface of the formwork. The bars and corners are left outside.
3. The outer sides are reinforced with supports. Then you don’t have to worry about deformation of the formwork during the process of pouring the concrete mixture.
4. The height above the ground is constructed at a distance of 30 cm.
5. Inside the base, a level is fixed to which they are guided when pouring concrete.

Installing fittings

To install the reinforcement, use metal rods with a cross-section from 8 to 12 mm. The rods are cut into pieces of the required length. The reinforcement is laid following the following technology:

1. The segments are laid along and across the axis of the base.
2. If the base is buried 0.4 m or more, vertical placement of metal rods is also required.
3. The reinforcement is fixed using steel wire. It is better to avoid welding. It reduces corrosion resistance in welding areas and bending strength.

Pouring concrete and maintaining it

• 1 part concrete to 2 parts sand;
• 1 part concrete to 2.5 parts sand.

The consistency you should end up with is liquid sour cream. The mixture is added to crushed stone. The volume of crushed stone should be equal to the volume of sand.

After thoroughly mixing the components, the mixture is laid out in the formwork. It is necessary to pour the concrete mixture to the level fixed on the formwork. Leveling the top layer is carried out using a rule or a trowel. Sifted sand is poured on top of the mirror surface of the concrete.

Important. It is easier to do this using a sieve. Experts recommend a procedure for rapid hardening of the concrete mass and to avoid erosion or cracking of the base.

You definitely need to give the concrete time. It is left covered with burlap or other material for a month. If it is too hot and dry outside, it is recommended to wet the surface of the base so that it does not dry out.

The strip foundation with your own hands must mature properly. Only then can you proceed to arranging wall structures. The formwork is dismantled and waterproofing is laid on top. The waterproofing material will ensure the durability and reliability of the base and improve the thermal insulation properties.

How to make a strong strip foundation yourself is clearly shown in the video:

At the stage of planning a strip foundation for a building, it is important to assess the risks associated with soil sliding. It is better to refuse a strip base if:

• the soil is cracked or sinking;
• The site is located in the seasonal flood zone of a lake or river.

At the stage of laying out the concrete mixture into the prepared formwork, it would not hurt to take into account the following recommendations from experienced builders:

1. In order for the concrete to settle better, the formwork is carefully tapped on the outside. You can pierce the mixture in several areas with a rod and further compact it with a block of wood. This will remove any remaining air from the voids. The procedure is easier to carry out using a hammer drill with an attachment or a construction mixer.
2. Concrete is supplied from a low height. Otherwise the mass will separate.
3. If the strip base is poured in winter, special substances are added to the cement.

DIY strip foundation - video instructions

Conclusion

The strip foundation is considered the strongest and most durable of all types of foundation. Having built a building or garage on a strip foundation, you can be sure that the foundation will withstand the load placed on it.

Despite this, the construction of the foundation must be taken responsibly, especially if the construction is carried out with your own hands. You should not neglect the step-by-step technology of laying the foundation and the recommendations of specialists. By losing sight of important nuances, residents of the house risk facing unpleasant and dangerous consequences. An incorrectly constructed strip foundation can cause the house to warp, shrink, and crack the walls.

In essence, a strip foundation is a monolithic or prefabricated reinforced concrete strip running under all the load-bearing walls of the house. This structure collects loads from the structure and transfers them to the ground. This type of foundation is most often used when constructing a country house, cottage, garage or small outbuilding. The reason for the popularity of this type of structure is its ease of construction, reliability and reasonable price. You can make a strip foundation with your own hands if you know the manufacturing technology, the features of the device and some nuances. Step-by-step instructions from our article will help you complete this type of foundation. And thanks to photos and videos, it will be easier for you to understand the features of the manufacturing process.

Area of ​​use of the strip base

Strip foundations are used in the construction of the following buildings and structures:

• It is suitable for a house with massive load-bearing walls made of stone, brick or monolithic concrete.
• If the composition of the soil on the site is uneven and there is a possibility of shrinkage of building structures, then installing a strip foundation under the house will help protect the entire structure from cracks and uneven settlement.
• Pouring a strip foundation is often used when constructing a house with a basement or ground floor.
• A shallowly buried strip base can be used when building a house made of wood, foam blocks, or when constructing a frame structure.

The service life of such a base depends on the material from which it is made. Thus, solid monolithic strips made of rubble or reinforced concrete can last up to 150 years. Brick structures are the most short-lived and will last up to 50 years. And prefabricated belts made of reinforced concrete blocks can perform their functions for 75 years.

Types of design solutions

The manufacturing technology of the strip base may differ slightly depending on the design and type of foundation. They come in the following types:

1. Solid monolithic structures are made directly on the construction site. If you decide to make a strip foundation with your own hands, then this option is most suitable, since installation does not require the use of lifting equipment. These structures are more durable compared to prefabricated foundations. But installation takes more time, since you need to assemble the formwork, install the reinforcement cage and wait almost a month for the concrete to completely harden. The photo below shows an example of a monolithic foundation strip.
2. Prefabricated structures are assembled from ready-made factory reinforced concrete blocks and foundation pads. In this case, the pillow can also be prefabricated or monolithic. The main advantage of such structures is that the technology of assembly from ready-made products allows you to significantly speed up the work and not wait for the concrete to set before starting to lay the walls. However, its price will be higher, since you will have to use lifting equipment. You can see a photo of the prefabricated base below.

In addition, the technology for manufacturing strip structures involves dividing foundations into two types:

1. Shallow foundations. This type is suitable for houses made of lightweight materials - foam blocks, wood, as well as for frame construction and for one-story brick buildings with thin walls. When constructing such a foundation, the laying depth does not exceed 0.5-0.7 m.
2. Recessed structures are erected during the construction of a house with load-bearing walls made of stone, brick or reinforced concrete. Also, such foundations are used in the construction of buildings with basements and ground floors.

Important: buried structures are stronger and more reliable, since the foundation is constructed below the freezing point of the soil. As a result, the tape is not subject to deformation. However, the financial costs and labor costs for such a design are much higher.

Peculiarities

Before you make a strip foundation with your own hands, you should learn about some construction nuances:

• It is better to build the foundation of a house in the warm season. Then you will not need expensive construction equipment, as well as frost-resistant additives in concrete.
• If your site has sandy soil and low groundwater, then the strip base can be installed above the freezing point of the soil, but not less than 500-600 mm from the surface.
• On highly intumescent soils, as well as in permafrost conditions, it is better to use more reliable pile structures instead of a strip foundation.
• To save on the construction of a prefabricated base, you can use intermittent laying of reinforced concrete elements, that is, a small gap is left between the blocks in each row, which is then filled with concrete. However, this technology cannot be used on silty and peaty soils, as well as on weakened soils.

When installing a strip foundation, do not forget about utilities (water supply and sewerage), which must enter the house through the foundation or below it (in the case of using a shallow foundation). You can often encounter a situation where the step-by-step instructions for installing a strip foundation misses the point of laying utility networks. This is usually not shown in many instructional videos.

The place where utility networks enter the house must be provided at the foundation construction stage. Usually, for this purpose, a sleeve made of asbestos-cement or plastic pipe is laid in the foundation. It must be located below the freezing point of the soil and is installed before pouring concrete at the stage of constructing the reinforcement frame.

Important: the choice of location for installing the sleeve depends on the location of existing centralized utility networks from which the connection to the house will be made. This point must be taken into account at the design stage of the future structure.

Material selection

Before answering the question of how to properly make a strip foundation, you need to decide on the material. Most often, strip-type foundations for the construction of a country house are made from the following materials:

• Rubble concrete - this foundation is made of large stones (up to 30 cm in diameter) and cement-sand mortar. This type of foundation can be made on sandy or rocky soils, but not on clay soils. The width of the structure can reach 20-100 cm depending on the load. Rubble concrete is laid on a bed of sand or gravel with a height of at least 10 cm.
• Reinforced concrete is a structure made from a mixture of sand, crushed stone and cement in the required proportions. For reinforcement, reinforcement or steel mesh is used. This option is the most popular, so in our article we will look in detail at how to properly pour a strip foundation. The video at the end of the article is also dedicated to this process. The width of the structure is selected taking into account the width of the walls, for example, under a brick wall with a thickness of 510 mm, a foundation 600 mm wide is made with reinforcement with AIII reinforcement with a section of 1-1.2 cm. The advantage of using reinforced concrete is high strength, the ability to make curved walls in plan, as well as simplicity hand-made.
• Factory reinforced concrete blocks and foundation slabs. Since the installation of a prefabricated foundation requires lifting construction equipment, this material is less often used in individual construction, so in our article we will pay more attention to how to pour a strip foundation rather than how to assemble it from blocks.
• Brick can be used to make the basement of a building and shallow underground structures. However, the strength and durability of such bases is low, so they are practically not used.

Execution technology

Before properly pouring a strip foundation, it is necessary to prepare the land plot and lay out the layout of the future structure on the ground. To do this, the construction area is cleared of debris and unnecessary green spaces. Next, the axes of the future structure are laid out and linked to the boundaries of the site. After determining the location of one of the corners of the house, a cord is pulled at a right angle to it. From there, the next corners of the building are marked and pegs are driven in. A cord is pulled over the pegs. The width of the foundation is measured from it and the second cord is pulled.

Important: we calculate the depth of the trench from the lowest point of the foundation.

Our step-by-step instructions and video at the end of the article will tell you how to further build a shallow foundation:

1. We dig a trench using a shovel or construction equipment. We level the bottom of the trench. At the bottom it is necessary to make a sand cushion 200 mm high. After laying the sand, it is filled with water and compacted.
2. Then a layer of insulation is laid. To do this, you can use a dense film, a concrete layer 10 cm high, or roofing felt. It is not worth using geotextiles in this case, since it will only reduce the strength of the base.
3. Now we proceed to the construction of the formwork. To do this, you can use boards, moisture-resistant plywood, OSB or special boards. It is better to cover the inner surface of wooden formwork with film. This will make it easier for you to remove the boards after the concrete has hardened, and they will also become less dirty and can be used in the future.

Tip: you can make permanent formwork from extruded polystyrene foam. This way you can insulate the foundation and reduce the cost of constructing formwork. However, the outer side of the expanded polystyrene slab must be well strengthened so that it can withstand the pressure of concrete.

1. Now the reinforcement cage is being constructed. For these purposes, we make a spatial frame from reinforcement with a diameter of 1-1.2 cm. The pitch of the transverse rods is 20 cm. We install the frame in the formwork so that after pouring concrete from the edge of the concrete surface to the reinforcement there is at least 50 mm of the foundation body. This will reliably protect the frame from corrosion.
2. Don’t forget to install and tie pipes (sleeves) to the frame through which utilities will be brought into the house. It is also worth laying pipes to ventilate the space under the house. To prevent concrete from getting into them when pouring, sand is poured there.

After preparing or purchasing the concrete mixture, you can start pouring

1. 6.After preparing or purchasing the concrete mixture, you can start pouring. As a rule, pouring is done in layers. Air bubbles are removed in each layer using a deep vibrator. This will make the structure stronger. When pouring concrete, you should not pour it from a height of more than 1.5 m, so as not to cause a decrease in the strength of the structure.
2. 7.After pouring, the concrete strip is covered with plastic film to ensure uniform evaporation of moisture. In addition, in the summer it is necessary to wet the concrete for the first week to protect it from drying out. After a week, the film can be removed.
3. 8.The formwork can be removed when the concrete gains initial strength. This usually happens after two weeks. Complete hardening occurs after 28 days.
4. 9.The foundation walls are protected from moisture using bitumen mastic, which is applied in two layers.
5. 10. The base is insulated. For this, it is best to use extruded polystyrene foam. It is attached to the outer surface until the ground freezes. Thermal insulation of the foundation in a house with a basement is especially important.
6. 11. Now you can backfill the pit or trench. To do this, it is better to use a mixture of sand, clay and gravel, which is carefully compacted.
7. 12. To protect the foundation from precipitation, a blind area is performed.

DIY strip foundation step by step instructions

The foundation of a building is its most important part. The slightest mistake in the construction of such structures can end in disaster. It is necessary not only to correctly calculate its depth, quantity and cross-section of reinforcement, but also to ensure reliable and high-quality drainage, hydro- and thermal insulation. We will describe the process of making a strip foundation with your own hands and step-by-step instructions for its construction in detail.

What type of foundation should I choose?

The choice of type of foundation depends on the mass of the building, the type of soil and the depth of its freezing.

Based on the type of construction, all bases are divided into:

• tape: the most common, made in the form of a closed loop, due to which the load on the ground from the building is transferred evenly; it is laid not only under the walls, but also the partitions of the building; such foundations, in turn, are divided into shallow and deeply buried
• pile: the building is installed on vertical rods (piles) with a depth of 3-20 m; used in difficult terrain, deep soil freezing and in marshy areas; The disadvantages include the need to use special equipment for driving piles into the ground and the lack of basements; horizontal soil movements are unacceptable
• pile-grillage: with load-bearing horizontally located beams (grillage) connecting the piles in the upper part; to protect against frost heaving, it is never buried in the ground
• columnar: on pillars that have an extension in the form of a “sole”; construction on soils with deep freezing is allowed; supports connected by jumpers (rand beams) are placed every 3 m
• slab: a rather expensive structure in the form of a monolithic slab 20-30 cm thick, lying on the surface of the ground, which simultaneously serves as the floor of the building

Heavy buildings and multi-story structures are usually constructed using strip foundation. Columnar foundations are more economically profitable, and it is allowed to build light frame or wooden houses on them, but only if the soil is not peaty or heaving clay.

Pile structures can be used even with a significant mass of the structure. But they are used mainly on land plots with weak sandy or peat soil, as well as in regions of the Far North with a large depth of soil freezing. To avoid movement, the piles are not installed in holes, but driven or screwed into the ground.

Slab shallow foundations It makes more sense to use it in problem areas with high soil mobility. Such a “floating” foundation can withstand even significant soil displacements without damaging the building.

Pouring the foundation is allowed at temperatures from +5 C. Work at low temperatures to avoid cracking of concrete is unacceptable.

VIDEO: Choosing a foundation for a house

Although the cost of such a support is quite high and averages 25-30% of the price of the entire object, Due to its high strength and reliability, this option is most often used. Below you will find detailed step-by-step instructions for making a strip foundation.

Laying depth

Tape bases have two types:

• shallow with 50-70 cm embedded in the ground; used only for light buildings
• deep-buried up to 2 m: should go into the ground 20-30 cm below the soil freezing level

Finding out how deep the soil freezes in your area is easy. There are special cards for this. However, teach that this meaning is normative. In practice, it is necessary to take into account the type of soil and the average monthly temperature of the region of residence. Also remember that wet, swampy soil always freezes more than sandy soil. Dense soil freezes more than loose soil.

In the Moscow region, the standard freezing depth is 140 cm. When laying the foundation, another 10% is added to these figures. For unheated rooms you need to add another 10%. If there is a basement, the base is lowered 40 cm below the floor. It is also necessary to take into account the height of the drainage layer and sand cushion.

Ideally, only geologists can answer the question of what the foundation depth should be. Neither tables nor maps can show the presence of dangerous quicksand, the level of groundwater, various violations of the soil composition, etc.

On soft soils, it is better to build a strip foundation in the shape of a trapezoid or make it stepped. Such a foundation will be more reliable.

Trench width

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Types of foundation trench

The width of the structure is calculated based on the width of the walls plus 10 cm. 40-60 cm is added to this value to allow the passage of people when installing and pouring the formwork. On average, the width of the trench is 0.7-0.8 m. When installing a drainage system, this parameter is increased by another 20-30 cm.

To avoid height differences, the trench begins to be dug from the highest angle. It is advisable to do this manually - when digging with an excavator, you will not be able to get perfectly smooth walls without shedding the soil.

The crumbled soil is completely removed - after all, even compacted, it is inferior in density to soil that has compacted over the years. There is no need to remove part of the earth - it will be used for backfilling.

If the ground crumbles heavily, dig a trench at a slight angle. You can further strengthen it with plywood or board panels with spacers. If there is a basement, a pit is immediately prepared for it.

Before starting work, the plant layer of soil (turf) is completely removed to a depth of 20-30 cm. The construction of a foundation on chernozem soil is unacceptable. The layer of loose soil must be completely removed.

When marking, the width of the walls is added to the design dimensions of the building. It starts from the corners where pegs or reinforcement bars are hammered. A string or fishing line is pulled tightly between them. The horizontal and vertical sides must be verified using a building level. The angles must be strictly straight. It is also necessary to double-check the diagonal dimensions.

If winter is approaching and there is no way to wait for the concrete to gain strength, you can assemble a foundation from ready-made concrete blocks. However, keep in mind that their joints are a weak point. If the soil moves, gaps may form in these places.

Sand and gravel cushion

Before building a foundation for a house, you should take care of arranging the pillow. Materials such as sand, crushed stone and gravel almost do not absorb moisture, and therefore are less susceptible to frost heaving. Using a cushion based on them allows you to protect the area from uneven shrinkage of the soil. The pillow allows you to more evenly redistribute the load from the mass of the building over the entire area. The soil underneath will settle more evenly.

The layer of such a pillow should be 20 cm. To prevent it from silting, a layer of film or roofing felt is laid before filling it. The same layer of waterproofing must be laid after backfilling with crushed stone and sand.

The sand must be spilled with water and then compacted with a vibrating rammer or using a special device in the form of a wooden block with a vertical handle.

“Correct” formwork

The most common problems when arranging a foundation are:

• formwork fracture
• her distension
• concrete leaks

To avoid such mistakes, you should not rely on chance and use waste lumber. To make formwork for the foundation, a flat board 25 mm thick without significant defects, grade 2, is required. Later, after disassembling the formwork, it can be used to arrange the sheathing.

Shields that are too large will be inconvenient to use - they are made 3-4 m long and assembled with nails. For cross racks, a rail or the same board is used. To avoid leakage of the solution, there should be no space between the boards.

After lowering into the trench and leveling, the shields are fixed with pegs driven into the ground. In the future, they do not need to be removed - they remain in the concrete. From the outside, the formwork is additionally strengthened with supports. The distance between them is at least 1 m.

All panels are connected to each other by wooden slats. To protect the formwork from swelling, the boards are tied with wire, which is screwed to the vertical crossbars. During the dismantling of the formwork, it is cut off and left in the concrete.

Roofing felt is often used as a waterproofing layer. It is secured with slate nails.

Installation of fittings

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In a strip foundation, the reinforcement should be placed in the shape of a rectangle. There is a logical explanation for this. Two forces act on the support of the structure at once: heaving forces from below and the mass of the structure itself from above. There is practically no load in the middle of the belt. To compensate for these two loads, two belts are prepared: upper and lower.

When deepening the foundation to a depth of 1 m, this is sufficient. For a deep foundation, three belts are prepared: the third is required for reinforcement when the reinforcement frame is high.

Smooth rods are permissible only when creating jumpers. For the main frame, reinforcement with a ribbed surface with a diameter of 8-16 mm is used, able to withstand tensile loads. The ribbed surface can provide better adhesion to concrete. Steel grades of reinforcement for foundations are SGS, 25G2S, 32G2Rps.

To protect the metal from corrosion, the reinforcement should only be located in the thickness of the concrete. Therefore, along the edges and bottom of the formwork it is necessary to retreat 5 cm. According to SNiP, the reinforcement spacing is 30-35 cm.

Corners and walls, which bear the load from neighboring walls, are the weakest point. To avoid the appearance of cracks, the rods in these places are bent onto each other at an angle of 90 degrees with an overlap of 60-70 cm. If the length of the rod is not enough, they are connected with L-shaped clamps.

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It is not advisable to use welding for fittings. Firstly, in places where welding occurs, the steel partially loses its strength. Secondly, the load-bearing frame of the foundation must have a certain degree of freedom so that it does not break when the soil moves.

Therefore, it is necessary to fasten the reinforcement using ties. For this purpose, a special wire is used. Knitting is done manually, and for large volumes of work using a gun. To work with wire, it is more convenient to use a special hook.

If there is a significant difference in height, it is better to divide the foundation into sectors, where each sector is located in the ground at a different depth.

Checking the quality of cement

Before we give detailed instructions for building a foundation, let's talk about the quality of cement. When pouring the foundation for a house, you definitely shouldn’t skimp on cement. According to GOST, it must be no less than grades M200-300. But it’s better to play it safe and use M400-500 cement. This is especially important when constructing heavy or multi-story buildings. Indeed, in practice, today's cement is often not of the best quality.

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High-quality concrete has a dark gray color. It should be fresh and not caked - when squeezed in a fist, it should easily fall out between your fingers.

Since this material can quickly absorb moisture, if purchased in advance, store it in a dry place, covered with plastic wrap for no more than 1-2 weeks.

It is difficult to focus on the manufacturer - after all, each region produces its own cement. Therefore, it is better to do a test batch of the solution.

After it hardens, you need to place a chisel on the surface of the concrete and hit it with a hammer. You should only be left with a small mark in the form of a scratch. The breaking off of small pieces means that, even if the manufacturer assured you otherwise, the brand of such cement is no more than M200. Holes in concrete after impact appear when pouring M100 cement. The inside of the dried concrete should be darker than on the surface.

After a month, it should be difficult to hammer a nail into high-quality concrete. In the conditions of Siberia and the North, it is important to pay attention to the frost resistance of the material. Such concrete is marked ML.

The correct foundation must be made from high-quality mortar. E The proportions are directly dependent on the brand of cement. So, when using M400 grade cement, the volume ratio will be 1.0: 1.2: 2.7 (cement, sand, crushed stone are used for mixing).

Sand is used dry, without admixtures of clay and debris. To remove large particles, sand must be sifted through a sieve. Crushed stone will need a fine fraction with a particle size of 5-20 mm. Using river gravel instead, which has low strength, is undesirable. Plus, its grains have a too smooth surface and do not adhere well to concrete.

First, you need to thoroughly mix the dry mixture together, and only then add water to it. If kneading is done manually, then this must be done in small portions, otherwise, if not kneaded, lumps will form in the solution. The resulting solution should be thick enough and not run off the trowel.

The formwork is removed no earlier than a couple of weeks after pouring. Any work before the expiration of this time is unacceptable.

Pouring the foundation

The strip foundation is made in the form of a continuous concrete sheet running along the perimeter of the walls and internal partitions. When constructing light buildings, the construction of brick foundations is allowed.