How to install a strip foundation with your own hands. How to make a strip foundation with your own hands: a step-by-step guide

A foundation is laid at the base of any building so that the house stands firmly, provides heat and withstands all atmospheric loads. The foundation bears the brunt of the partition walls and ceilings, so the strength and durability of the building under construction depends on it. Of all the many different types of foundation, reinforced concrete monolithic tape is used for laying under walls, which ensures the safety of further operation of any building. The prevalence of pouring the strip foundation lies in the strength of the finished base, its simplicity, and the real opportunity to fill it with your own hands.

A do-it-yourself strip foundation is used to build low houses, kitchens for summer cooking, garages and bath rooms - sometimes it is also used to build large architectural forms, but then you need to take into account the condition of the land on which it is being built.

Factors affecting the depth of the foundation

The depth of pouring the foundation is calculated by the specialists of the construction agency. The magnitude of the immersion of the base of the house is affected by the massiveness of the structure, the use of foundation insulation and the depth of the spring waters. But, when installing the base, the depth to which the soil freezes is put at the forefront. Given the factors of freezing of the earth, the foundations are divided:

Shallow Do-it-yourself strip foundation is placed in the ground at 0.4-0.6 m. It can be used in regions with relatively warm air temperatures and a minimum depth of soil freezing. With external insulation of the foundation, the factor of soil freezing can be completely ignored. And, when a light house is built from frame shields sheathed with special materials, aerated concrete blocks and other light materials, it is the foundation with a shallow depth that is used;

deep-seated do-it-yourself strip foundation step-by-step instructions are more durable, and are placed at a depth of 1-2 m. It is designed for massive houses and for areas with a cold climate, for brick houses of several floors, with monolithic concrete floors. Such a foundation is poured for construction on heaving fine-grained and sandy soil. Under the influence of low temperatures, loamy and sandy soils repeatedly increase their volume and swell, destroying the foundation. In a similar way, the occurrence of spring waters close to the surface affects it.

The undoubted advantages and potential disadvantages of the strip foundation

The frequency of application of the strip foundation is dictated by a number of its positive qualities:

only concrete cannot provide strength to the foundation of the house, therefore it is reinforced - before pouring concrete, a frame is mounted in the formwork, which is connected from metal rods. They work in harmonious interaction - concrete provides resistance to compression of the foundation, and the frame resists tensile loads;
the wide base of the foundation, which is deepened into the ground, ensures its strength and evenly distributes the load on its total area;
the long service life of the foundation allows the house to stand on it for more than a hundred years;
the tape base of the foundation is used for any soil, even if they are able to crumble and absorb moisture - in winter, such soil can form ice crystals and begin to swell.

The unfavorable factors of the strip foundation device include:

the complexity of construction work associated with digging trenches, installing formwork, tying the frame from reinforcement and, in fact, pouring concrete;
at least 15-20% of the cost of all construction work is spent on materials for the foundation;
to reduce costs, the foundation goes deep into the ground at a shallow depth, but only such a depth does not affect the quality of construction.

Materials and tools for laying a strip foundation

To fill the base of the house, you will need the following consumables:

crushed stone or river sand for the base cushion device;
ready-made concrete from a cement plant, or cement grade M200, sand and crushed stone for self-mixing concrete mortar;
class A3 metal rod ribbed or smooth 12 mm in diameter for one-story houses, and larger diameter for high-rise ones;
steel wire material for twisting reinforcement into a frame;
waterproofing material - roofing material, or hydrosol;
for the device of the form for pouring a board 20 mm thick, slats and timber.

What tools will be required

Wooden pegs, construction cords, tape measure, square for marking the foundation;
plumb and building level for high-quality provision of horizontal and vertical position;
bayonet and shovel shovels;
apparatus for manual tamping;
concrete mixer with and without a drive, when mixing concrete manually;
hook, or pliers for knitting a frame from reinforcement;
a hammer for knocking down metal rods into a grate;
trowel for leveling concrete after pouring.

Foundation depth calculation

Construction begins with the calculation of deepening the foundation and sparing it around the perimeter: construction agencies can do this work. In order to avoid errors at the design stage, the calculation is ordered from the architecture bureau. Correct calculation of all factors during the construction of the foundation of the house will protect against possible deformation of the foundation.

In addition to a competent miscalculation of the size of the foundation, they take into account the peculiarities of the climate, soil properties and adhere to all construction standards. To build a small structure, you can take ready-made schemes and standard drawings. Pouring a strip foundation with your own hands video helps in determining the sequence of work, preparing materials and tools.

Stages of correct pouring of the foundation

Work begins with clearing the area and calculating the size of the foundation. The construction site is leveled, removing the soil along with the vegetation by 15-20 cm. Then the territory is marked out, setting the boundaries of the building, and providing perfectly right angles and equal diagonals. To achieve the task, such stages of construction work on pouring the foundation are carried out.

Clearing and marking the site:

two cords are pulled perpendicularly through the center of the building, denoting the axes of the structure;
measure the length and width of the building, forming an angle and hammering the first wedge. A construction cord is wound to it, measuring strictly 90 degrees angles to the right and left of the primary peg;
the fourth corner is marked in a similar way, and the correctness of the corners is checked again;
measure the diagonals - with the correct markup, they are equal to each other.

Trench excavation and preparation

The width of the trench should not be more than 25-30 cm, and the depth is calculated depending on the type of foundation and the number of storeys of the future structure.

The sequence of land works:

the soil is dug to the depth of the foundation, taking into account the thickness of the crushed stone pillow;
digging a trench manually or with a rotary excavator level the bottom of the trench horizontally;
arrange the part of the foundation protruding from the ground high enough, or give it a stepped look;
installation of a half-shell of crushed stone 15-20 cm thick;
wetting and tamping the pillow to ensure isolation from groundwater.

Formwork device

From the outer and inner sides of the trench, supports are installed vertically from a bar of 40-50 mm so that the board is fully consistent with the wall of the pit. Formwork boards are strictly vertically attached to the supports using a level and a plumb line;
formwork is formed from the shields, which is attached to the wall supports with self-tapping screws;
the placement of the shields is done with the front side to the foundation - this way the boards are easier to separate after the concrete has hardened;
it is planned to install spacers on both sides of the boards outside the formwork so that the weight of the concrete does not displace the formwork;
forming boards are connected with wooden slats to ensure the same thickness of the foundation pouring strip;
on the inside, from the sides, a twine is stretched, which serves as a guideline for determining the height of filling the form with concrete.

Foundation reinforcement

The strip foundation needs to be strengthened, for which a frame is made inside the formwork from a ribbed steel bar with a diameter of 8-12 mm. To prepare and tie reinforcement:

the longitudinal and transverse parts of the frame are cut from a special wire - meshes of reinforcement consist of two rows along the rods and one transverse row each;
determining the size of the jumpers - they are covered with concrete to a height of 5-6 cm;
the reinforcement laid with a lattice is fastened with a thin steel wire, with a special hook - the loop is made tight, but it should not change the shape of the reinforcement lattice;
the vertical bars of the frame are placed in the formwork at a distance of 5-8 cm directly on the crushed stone pillow;
Finally, the horizontal and vertical rods are securely fastened together using a tying gun, which produces a fastening effect.

Concrete pouring process

In the correct scenario, simultaneous pouring is carried out in the entire formwork, but the foundation can also be poured in layers. To do this, it is necessary to prepare a concrete solution - for a bucket of M200 cement there are 2-2.5 buckets of sand, 2-3 buckets of gravel and 2 buckets of water, after which sufficiently liquid concrete is mixed. To prevent the formation of voids in the finished concrete, the formwork is tapped from the outside and pierced in depth with a metal rod. To prevent the formation of air bubbles in concrete, special additives, plammifiers, are mixed into it. The upper surface of the concrete is leveled along the cord, sprinkled with dry cement and smoothed with a plaster trowel. To prevent the appearance of cracks in concrete, it is watered once a day, especially when it is hot.

Waterproofing works

An important process in construction is waterproofing to protect the building from excessive moisture, and to prevent freezing, followed by swelling. Such processes lead to deformation and destruction of the foundation. Horizontally, they are isolated from moisture at the junctions of the foundation with the wall with roofing material and hydrosol. For such work, the surface of the hardened concrete is cleaned, and the insulating material is cut into pieces, taking into account allowances of 8-10 cm.

Methods for attaching horizontal waterproofing:

the roofing material is fastened in a cold way with the help of bituminous mastic - the concrete is smeared with this adhesive, it is allowed to grab a little and the roofing material is glued to the right place;
they use the hot method when it is necessary to attach a hydroisol - it is released from the roll, heated with a blowtorch and pressed with a roller;
modern insulating materials are also self-adhesive - for this, the protective film is removed and the material is pressed against the initially prepared surface.

Waterproofing work is carried out by coating the foundation walls of the bitumen-based coating - such work is carried out in several stages. Such a method of protection against moisture is also used, such as finishing the outer side of the foundation with tiles.

Foundation insulation

Today, a variety of insulating materials are provided. But you should know that work on the insulation of the foundation is done only after its waterproofing. There are several ways to insulate the base of the house:

during the installation of the foundation, it can be insulated with expanded clay, but after filling the expanded clay, it must be well insulated from moisture, because expanded clay absorbs moisture well and loses its heat-retaining properties. To insulate the lower part of the foundation, using expanded clay, a trench is dug, at least a meter deep. After that, the material is strengthened to protect against moisture and expanded clay is poured to the full depth. For wall insulation, expanded clay is poured into a special formwork with a thickness of at least 0.5 -1 m from the outer and inner sides of the foundation and work is carried out to waterproof it;
extruded polystyrene foam is fixed on the outside of the formwork, which counteracts moisture. Often, its sheets are used from the outside, as part of a fixed formwork - in this case, polystyrene sheets are firmly fastened so that they are not moved by heavy concrete mortar. When the finished foundation is insulated, the expanded polystyrene sheets are attached to it from the outside with plastic dowels in a hole drilled with a drill. The thermal conductivity of expanded polystyrene is different, therefore, when buying insulation sheets, they pay attention to their density - most often they pay attention to a heater with an average indicator;
reliable, but also the most expensive way of insulation is the spraying of polyurethane foam from the outside of the foundation. This process is carried out by specialists with special equipment - they evenly cover the outer side of the foundation with polyurethane foam, without missing a single place where moisture could leak. The process is carried out quickly and subsequent waterproofing, because under the influence of sunlight, polyurethane foam releases substances that have a bad effect on the human body.

Re-filling the finished foundation

When the foundation has already solidified and the formwork has been removed, sinuses, voids and all the internal space fall asleep around it. For backfilling, the soil that was taken out during the digging of the trench is used. After backfilling, work is carried out to compact the soil with a vibrating plate, which is a flat sole connected to a vibrator.

Evaluation of work during the construction of a strip foundation

Do-it-yourself strip foundation video can be poured with full confidence in your construction skills and the correct calculations of the foundation. Sometimes, it is easier and more profitable to hire a team of specialists, or order a service from a construction agency. The work of a professional builder compares favorably with:

compliance with all requirements of technological processes at each stage of construction;
ordering the pouring of the foundation on a turnkey basis, or performing individual processes for the preparation and pouring of the foundation itself;
the use of equipment and professional tools, due to which, high rates of construction are ensured;
guarantees for their services and the ability to redo poor quality work.

Final stage of work

After pouring the foundation, the reinforced concrete strip is closed from above to prevent it from drying out and left to harden for at least two weeks. During cold weather, special additives are used, since at sub-zero temperatures water turns into ice, which prevents the concrete from hardening even after the temperature rises above zero again. In hot weather, concrete that hardens is poured with water because if it evaporates excessively, it stops the hardening process and turns into dust.

The strip foundation is poured under a low house, a bathhouse, or a panel house. It is attractive in that it is possible to cover all four sides of the house with the foundation at the same time. Before the start of construction work on the installation of the foundation, the earth is cleared and markings are made for it. Construction cords indicate the place of the future formwork, after which they begin ground work. A trench is dug, at the bottom of which drainage from crushed stone is filled and compacted. Then the formwork is installed from the boards, where the concrete is poured. To make the foundation stronger, the concrete is reinforced by installing a lattice of metal rods in the formwork. The poured concrete is kept for at least a month, then the formwork is removed and waterproofing of the upper part of the foundation is carried out.

Do-it-yourself strip foundation: step-by-step instructions and video, pouring, shallow

★ Do-it-yourself strip foundation ✓ Step by step instructions ✓ Filling ✓ Shallow strip foundation ✓ Photo and video

There are many types of foundations for the construction of private low-rise buildings. But most often, under domestic cottages, an option is set up in the form of reinforced concrete tape under load-bearing walls. After all, to make a strip foundation with your own hands, you only need to have minimal skills in mixing concrete and follow the instructions. The technology for arranging such a foundation is simple, which is why it is chosen so often for independent execution.

What it is?

Structurally, a strip foundation is a reinforced concrete structure created along the perimeter of the future structure to redistribute the load on the ground. A similar support is used for the construction of residential buildings, garages, outbuildings, baths, garages and even fences. It's not difficult to make it yourself.

This is how he looks

However, when building such a foundation, it is extremely important to adhere to certain rules and recommendations. If the technology for manufacturing the strip foundation is not followed, the durability of the supporting structure itself and the building on it can be forgotten. They won't last long.

Seasonal heaving of soils, the effect of moisture on concrete without waterproofing, incorrectly calculated loads - there are many reasons for the destruction of the strip base on which the house already stands. All of them must be foreseen and taken into account in advance, otherwise a damaged or completely destroyed structure will have to be rebuilt.

Types and types of foundation

According to the depth of laying, it is MZLF (shallow) and simply buried. In the first case, the concrete belt for a low-rise building is buried only 200–400 mm into the ground, and in the second case, it is buried up to one and a half meters (below the ground freezing level).

If the soils at the construction site are rocky, and the groundwater is deep, then it is better to choose a cheap and shallow concrete option, small in volume. On heaving, high groundwater levels and sandy areas for the house, you will have to make a more powerful and expensive support. Often, the estimate for a similar basis for a dwelling is such that you generally have to choose a different type of foundation.

Scheme of walls with MZLF

Structurally, the tape reinforced concrete base is:

Monolithic;

The first type is performed by pouring a reinforced concrete belt. The second option is laid out from special factory-made foundation blocks (FBS) or bricks.

Pros and cons of strip foundation

It has three undoubted advantages

Extreme simplicity of the device - any novice builder can handle pouring concrete and laying blocks (there is a step-by-step instruction - to build everything correctly, you just need to follow it step by step);

The ability to withstand heavy loads both from below the ground and from above from the weight of the cottage and everything in it.

A reinforced concrete strip base will last for many years, even if not light aerated concrete blocks are taken for the construction of the walls of the house, but a heavy solid brick. In terms of cost, it is second only to screw piles, but in most cases it surpasses them in reliability.

Among the disadvantages of such a foundation are:

Mandatory thorough analysis of soils at the construction site;

The need to use lifting equipment (in the case of using FBS);

Long-term curing of concrete for at least 3 weeks (when choosing a monolithic option);

The impossibility of bookmarking on strongly heaving and watered soils.

Step-by-step instructions - do-it-yourself foundation

The thickness and height of the tape of the base under consideration, as well as the depth of its laying, are selected based on the analysis of the soil, the climatic conditions of the area and the number of storeys of the house being built. Without knowledge in this area, it is better to entrust this design stage to a professional. There are many nuances and requirements of GOSTs that must be observed.

But it is quite possible to create a support for your house according to an already finished project on your own. But in order to avoid mistakes, it is best to make the strip foundation yourself with the step-by-step instructions given below. It describes all the details of building a similar design for a typical one-story cottage.

Stages of work

The first stage is marking and earthworks. Regardless of the depth of laying, the sole must rest on solid layers of soil. It can be clays, sandy loams, stony layers or loams. Usually they are hidden under the turf and layers of ordinary earth. All this will have to be torn down and removed before starting to build the foundation of the house.

We prepare the site, distribute the main materials: fittings, insulation, formwork boards

To mark the site, you will need pegs, a tape measure and twine. If the soil is dense, then excellent formwork will be obtained from the walls of the dug trench. It will only be necessary to increase it then from above. If the soil is loose and constantly crumbling, then the trench will have to be dug a little more in width so that formwork boards can be placed inside the pit.

The second stage is the preparation of the pillow. The bottom of the excavated trench is leveled with sand and fine gravel. This sand and gravel layer should be carefully compacted, pouring water as it is filled. In height, it should turn out within 10–30 cm. This pillow serves to redistribute and reduce point loads on the strip foundation from below during seasonal swelling of the soil.

On top of the pillow, you can put a heater - this will avoid heaving from freezing of the soil

The third stage is the setting of the formwork. Here you will need bars with a cross section of 30 to 40 mm and boards 15–20 mm thick or laminated chipboard. The formwork created for the concrete foundation of the house will subsequently have to withstand a considerable mass of concrete poured into it. Make it strong and reliable. If, after filling with a concrete mixture, it collapses, then everything will have to be started anew.

We expose the formwork from the boards

If the groundwater at the construction site is high, then reinforced concrete will require waterproofing. From above, at the level of the basement of the house, it is usually coated. And to protect that part of the base that remains in the ground, a roofing material should be laid in a trench on the sides and at the bottom. It will reliably protect concrete from excess moisture in the soil at the stage of its solidification and after.

The fourth stage is the laying of reinforcement. For reinforcement, steel rods with a cross section of 14–16 mm and a thin dressing wire are usually used. You can also fasten the reinforcement by electric welding. But in this case, experience with a welding machine and he himself is necessary. Plus, when performing welding, one must be prepared for the appearance of metal corrosion in the future.

We knit reinforcement

Inside the trench, as a result, a frame of reinforcement with cells of 25–30 cm should be formed. Moreover, it is laid so that the steel is covered from all sides with poured concrete. Otherwise, the metal will inevitably begin to rust, then the house will definitely not stand idle for a long time.

The fifth stage is pouring concrete or laying out FBS. If it is decided to equip the foundation for the house being built using block technology, then this greatly speeds up the process of its construction. Here you do not have to make formwork and wait almost a month until the concrete setting is completed.

However, reliance on foundation blocks will cost more than a monolithic counterpart. Plus, they will have to dig a larger trench in width. To distribute loads for the bottom row, FBS masonry is made with an expanding base.

If a monolithic option is chosen for the support device, concrete should be poured immediately over the entire surface. No breaks in length and no layers in height. A monolith is a monolith. The house must be on a solid foundation.

Nails can mark the border of the pour in the formwork

When self-preparing the concrete mix, it is necessary to mix cement, sand and crushed stone in proportions of 1: 3: 3. But it is better to initially order a ready-made solution with the M300 brand and higher.

We fill

When pouring concrete, it is extremely important to ensure that no voids form inside it. There are special vibrators for compaction. However, you can also use a piece of reinforcement to pierce the filled mass and release air from it.

The sixth stage is waterproofing and blind area. It is allowed to start waterproofing work 3-4 days after pouring concrete. It takes about three weeks to complete its setting. But you can already begin to process with mastic, even if not completely frozen, the strip foundation for the house.

We are waiting for solidification

Also, around the entire perimeter of the building, you will need to make a blind area to drain rainwater away from its walls.

Finished foundation with basement rows of bricks

Use for building a house

Such a support can easily withstand private houses two or three floors high. To build a cottage on it, you can choose glued beams, logs, foam blocks or ceramic blocks. It is only necessary to correctly examine the soil and correctly calculate all the loads. At the end, the foundation will not hurt to veneer for additional protection from the weather. For this, natural stone or clinker tiles for the facade are ideal. But you can also choose an easier-to-install and inexpensive corrugated board or siding.

Each building must have a reliable foundation, this is a prerequisite for trouble-free operation for many years. If the instructions for the foundation were not followed during the construction of the building, the building may collapse.

The base of the structure is a key stage of construction, which takes up to 30% of the total budget. Future owners of private houses, wanting to save their money, make the foundation on their own.

It should be taken into account for what type of structure the foundation is being created - for a small outbuilding or for a large mansion with several floors, to which extensions adjoin.

The article discusses the main types of foundations, the proposed material will help you independently understand the question: is it worth building the foundation yourself or turn to experienced professionals.

Varieties of foundations

When erecting structures in the private sector, 4 main types of foundations are used:

tape;
pile;
slab;
columnar.

Each of the varieties has its own characteristics, they need to be known to the master, for whom it is important to figure out how to make the foundation with your own hands. Self-manufacturing of the base will not become a problem if you fully understand the process technology.

Strip foundations

Such a foundation is considered suitable for various construction conditions, with the exceptions of permafrost regions and areas where it is necessary to build "on the water".

Reinforcement of the foundation allows you to give it maximum strength, it is usually carried out in two geometric shapes: a square or a rectangle.

There are different types of tapes, but there is a common feature that unites them: the base strip is poured along the perimeter of the building and under its supporting structures.

A high-quality base must be closed, it is buried in the ground, having previously calculated the value, only the base part of the tape is visible above the ground. Look at the photo of the foundation, its width should be the same throughout its entire length, this parameter is calculated in advance before the start of construction work.

The tape is universal in that it is suitable for almost any structure - from a gazebo to a multi-storey residential building. This type of foundation makes it possible to build a basement, organize a basement, insulate the floors well, and place engineering communications conveniently for yourself.

Pouring the foundation with your own hands is a laborious task, you can make the solution yourself or order concrete made at the factory. The second option is preferable: it allows you to fill the base completely at once.

Tape bases have disadvantages: you have to perform labor-intensive types of work, in addition, high-quality materials for the foundation are required in large quantities. All costs are fully justified: a high-quality foundation is reliable and durable.

Pillar foundations

For the implementation of a lightweight building project with a minimum load on the base, a columnar foundation is ideal. Here, the saving of materials is visible to the naked eye: labor costs are not needed, as in the construction of the tape.

As for labor costs, it is easier to build a columnar base - the supports are not created in a solid line, but only in the corners, at the intersections with the walls, and in straight sections with a specific step.

For the manufacture of columnar supports, tree species that are not subject to decay, concrete, brick, rubble stone, reinforced concrete blocks are suitable. Pillars can be made using an integrated approach: the lower part is made of stone, and the upper part is made monolithic, the strength of the structure is given with the help of a binding grillage.

Formwork for the foundation can be used removable and fixed, the latter option is easy to make from a metal pipe of the desired diameter, and removable frames are made of wood and steel.

When determining the depth of the foundation of the supports, it is necessary to take into account the characteristics of the soil and the materials used. One of the main advantages of columnar foundations is that with a slight difference in height on the site, it is easy to correct it by changing the height of the supports.

The upper part of the pillars is connected with the help of a grillage, which can be reinforced concrete or from a channel, waste piping is used.

The columnar foundation is not suitable for massive structures; it should be abandoned if you want to equip a basement or basement. Such a base is not recommended for use on unstable soils, where groundwater rises close to the surface of the earth.

pile foundation

This type of foundation resembles a columnar one in its appearance, in fact, completely different supports are used here. Piles are installed to a great depth, they go deep into dense layers of soil that are not afraid of seasonal fluctuations.

Wells are drilled to install piles, and the piles themselves are driven using special equipment, another way is to create piles using bored technology, but if you wish, you can make the pile foundation yourself. The involvement of expensive equipment in the work is the main disadvantage of the pile variety.

slab foundation

In the construction of private country houses, this type of foundation is rarely used; it is also called "floating". Such a foundation is a reinforced concrete slab, which serves as the basis for the future structure.

Advantages of the technology - the foundation does not depend on the state of the soil, it rests on the surface, it is not subject to such a problem as frost swelling. Among the shortcomings are the high consumption of building materials and the inability to use on sloped terrain.

DIY foundation photo

The foundation, built in accordance with the technology, is the basis for the durable and safe use of any structure. There are enough varieties of foundations for buildings, but the most popular is the strip foundation. To make it, you do not need to use special equipment, which means you can save money. Moreover, everyone can build a strip foundation on their own, if desired.

The list of advantages of the strip foundation builders include the following:

Small construction cost. Do-it-yourself strip foundation rarely occupies a large area. Not much material is needed to create it. Of these, you will need the simplest ones that can be found in any store and even a garage.
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.

A trench around the perimeter can be dug, armed with a shovel. The formwork is equipped with a saw and a hammer. The armature is knitted with strong steel wire. The concrete mixture is kneaded at the construction site.

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

The strip foundation can withstand high loads. In fact, this base is represented by a concrete monolith. Therefore, on it you can safely build a house in 2 or 3 floors.
Great speed of work. If the house under which the base of the tape type is made has an area of 100 squares, it is realistic to build a foundation from scratch within a month. With the use of industrial mixers designed for concrete mixing, it is possible to reduce the working time to a record 1 day. The main stage is digging a trench and building a formwork reinforced with reinforcement.

Of the minuses of pouring a strip foundation, the following are distinguished:

To make the foundation strong and reliable, it is important to provide for the preparatory stage. Experts analyze the soil and calculate the required depth. If you take this step carelessly, there is a real risk that it will lead to the winter house to the side or it will sag. Soil heaving and its mobility are the main parameters that are determined before construction.
Large specific gravity of the base. The weight of the building itself rests on the ground, except for the base. Over time, the ground may sag, or the house will lean to one side.

Species and subspecies

Based on the depth of the foundation, the strip foundation is shallow and deep. There is no constant indicator of the depth of occurrence. It depends on the depth of soil freezing in a particular area.

A shallow base is called a base with an indicator of the depth of arrangement less than the depth of freezing of the soil. When the ground freezes, it expands, which is fraught with pushing the concrete mixture and the building up. The owner of the house may be faced with an uneven skew and even a break in the base. Suitable reinforcement will help to avoid this. It is calculated using construction calculators.

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

Under the building is not heaving soil.
Low level of groundwater penetration.
Near the building it is planned to build a drainage system to drain water.
A blind area with insulation is planned near the house.
The building weighs a little. For example, this is a wooden sauna, a greenhouse or a frame structure house.

Of the advantages of a recessed base - construction is inexpensive, and the level of strength is high. Although more often for a fortress, structures still use a recessed base. Its implementation involves the arrangement of a monolithic reinforced concrete tape. 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 a strip foundation

To build a monolithic base under the house, you may need the following materials:

Portland cement;
clean river sand;
crushed stone;
fragmentation 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 to be achieved. If you need to equip a strip base for a building of complex configuration, mix cement, crushed stone and river sand.

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

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

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

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

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

For a poured foundation of a strip type, concrete of grades is bought:

M100 - suitable for arranging a pillow made of concrete;
M200 - will withstand light buildings (baths, sheds, panel houses);
M300 - indispensable when pouring the base for a house made of wood or buildings 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 buildings and work on a construction site in a region with a harsh climate.

Read also an article about expensive money, but very durable, other types are described in the section, with a detailed description and recommendations.

Do-it-yourself strip foundation step by step instructions

First of all, the owner of the future home needs to contact the 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 does groundwater pass.

How to calculate the foundation

Well, if the company's specialists can calculate the foundation. It is not recommended to do this on your own, except perhaps only for the foundation for 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, mark the area.

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

How to mark up a site

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

The builder fixes the axis of the building, and where the first corner will be located. Using a plumb line, he puts a peg in this place. A peg can be a cut of reinforcement.
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, successively setting new pegs.
From the second and third corner stretch the rope in the direction of the fourth. The corners are set following the square.
As a result, the master should get a rectangle. It defines the outer boundaries of the future home. It is easy to verify the correctness of the form by carefully measuring the lengths of the diagonals - they must be the same.
Similarly, markings are applied to the internal outlines of the base, and then the contours for individual components - load-bearing wall ceilings, a porch, a terrace, supports designed for columns.
To finally align the markup, 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 markup is applied, they start digging a trench. It is dug out taking into account the depth calculated during the development of project documentation. When digging a trench, you need to advance from a low angle. This approach will avoid a situation where the depth of the pit is less than the calculated one.

The walls of the trench are vertical. When the soil sheds, partitions are mounted, they are temporary. The bottom of the trench is done carefully, for this it is leveled several times. Be sure to check the bottom of the building level, for the absence of a slope.

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

River sand is poured until a layer 15 cm thick is formed. Saving sand can lead to an uneven distribution of the load on the base. This is often seen in heaving soil.
Sand is distributed in layers. Before falling asleep the next, the previous layer is watered and tamped.

A strong waterproofing film is laid out 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 draft version. Before proceeding with the installation of the formwork, they wait a week. During this time, the concrete will just set.

Formwork arrangement

It is necessary to mount corner supports. For this, bars with a thickness of 50 mm are suitable. Before proceeding to the next step, check the length of the diagonals.
The edged board is assembled into the formwork. The fastening of the boards to each other is carried out at the expense of bars or a corner made of metal and self-tapping screws. The caps of the fasteners turn out to be on the inner surface of the formwork. Bars and corners are left outside.
The outer sides are reinforced with props. Then you can not be afraid of the deformation of the formwork during the pouring of the concrete mixture.
At a height above the ground, the formwork is constructed at a distance of 30 cm.
Inside the base, a level is fixed to which they are guided when pouring concrete.

We install fittings

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

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

Pouring and maintaining concrete

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

The consistency that should turn out in the end 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 thorough mixing of 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. Alignment of the top layer is carried out using a rule or a trowel. Sifted sand is poured on top of the mirror surface of concrete.

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

Be sure 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.

Do-it-yourself strip foundation should mature properly. Only then can you proceed to the arrangement of wall structures. The formwork is dismantled, waterproofing is laid on top. Waterproofing material will ensure the durability and reliability of the base, improve the thermal insulation properties.

How to make a solid 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 slippage. It is better to refuse the tape base if:

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

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

In order for the concrete to settle better, the formwork is carefully tapped from the outside. You can pierce the mixture in several areas with a rod and additionally tamp it with a block of wood. This will remove the remaining air from the voids. The procedure is easier to carry out, armed with a perforator with a nozzle or a construction mixer.
The supply of concrete is carried out from a small height. Otherwise, the mass will delaminate.
If the pouring of the strip base falls in the winter, special substances are added to the cement.

Do-it-yourself strip foundation - video instruction

Conclusion

The strip foundation is considered the strongest and most durable of all types of foundation. Having built a building or a garage on a strip base, 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 by hand. Do not neglect the step-by-step technology of laying the foundation and the recommendations of specialists. Having lost sight of important nuances, the residents of the house run the risk of facing unpleasant and dangerous consequences. An improperly constructed strip base is fraught with a warp of the house and its shrinkage, cracking of the walls.

The strip foundation is perhaps the most popular type of foundation used in low-rise construction. This is primarily due to its versatility, since it is possible to build a house on it from almost any material. Another question is that this is not always economically feasible, but more on that later. What is this type of foundation, it is clear from its name. This is a single structure in the form of a strip of a certain solid building material located under all the load-bearing walls of the building.

According to the design, monolithic and prefabricated strip foundations are distinguished. Monolithic - made of monolithic reinforced concrete, prefabricated - foundation made of FBS blocks or small-piece materials (brick, rubble stone).

According to the depth of occurrence, strip foundations are divided into deep and shallow, which were discussed separately.

In this article, it is the buried monolithic strip foundation that will be considered.

Main advantages:

high strength and ability to withstand significant weight of the house;
greater reliability and durability;
the ability to build on their own;
Possibility to build a basement (basement).

Flaws:

significant labor costs due to the large volume of earthwork and concrete work;
significant material costs for concrete and reinforcement;
frankly, the dubious prospect of making a high-quality foundation without the involvement of construction equipment (we will talk about this later).

You can not choose a deepened strip foundation when building on organic, loess soils, on peat bogs, on fatty water-saturated (even seasonally) clays, on fine and silty sands, which are especially susceptible to moisture.

Important: The groundwater level should ideally not rise closer than 2 meters to the base of the foundation. Otherwise, it is better to establish the possibility of choosing this type of foundation (especially when building a massive brick house) when conducting geological and geodetic surveys, because. it will be determined precisely by the composition of the soil and its homogeneity at the site. Perhaps this type of foundation will have to be abandoned or a drainage system will need to be made. Remember that for a number of soils, when moistened, the bearing capacity changes very much. This can lead to sad consequences.

The main mistakes in construction.

thoughtless and not justified by any calculation choice of the basic geometric parameters of the foundation tape, such as its height and width.
pouring concrete directly into the excavated trench, without taking measures for its waterproofing and insulation;
errors when reinforcing the foundation and when laying household communications in the tape;
other errors associated with the technology of work.

Now consider how these negative factors can be avoided.

Calculation of the strip foundation.

When calculating, it is necessary to compare the total weight of the entire house and the foundation itself with the bearing capacity of the soil. The first should be less than the second, moreover, with a certain margin. You can do this in the following sequence:

I) We examine the building site. All information on this subject is provided

Based on the data obtained, we accept the depth of the foundation by 30-50 cm more than the estimated freezing depth. At the same time, you must understand that, starting from the calculated depth, you will have to observe the chosen thermal regime in the house in the very first winter. In other words, the house must be heated. Otherwise, if the house stays cold in the winter, the standard freezing depth is taken into account.

The width of the foundation tape is initially taken equal to 20 cm. This is the minimum value, which will increase if necessary in the further calculation.

II) Determine the weight of the house, which will act on the bearing layer of soil.

The approximate specific gravity of individual structural elements of the house is given in the following table:

Also note that the snow load when the slopes are more than 60º is assumed to be zero.

III) We calculate the weight of the foundation itself. From the project of the house, we know the total length of the foundation tape. Its height and width are defined above, in paragraph I. We multiply these values, we get the volume of the tape. We multiply it by the specific gravity of reinforced concrete, equal to 2500 kg / m³, and thereby obtain the weight of the foundation.

We add this figure to the weight of the house (point II) and get the total load on the bearing soil (P, kg).

IV) Now we calculate the minimum allowable the value of the required width of the base of the foundation B (cm) according to the formula:

B \u003d 1.3 × P / (L × Ro),

where 1.3 is the safety factor of the bearing capacity;

P - the total weight of the house with the foundation (item III), kg;

L is the length of the tape (translated into centimeters), cm;

Ro is the resistance of the bearing soil, kg / cm². Its value is approximately taken from the table below:

Once again, we note that the bearing capacity values in the table are given for soils of normal moisture content. When the groundwater level rises to the bearing layer, the values of Ro will change greatly (for example, for oily clay it can decrease by almost 6 times, and for fine sand - by almost 4).

v) If the resulting value of the width of the tape turned out to be less than the 20 cm selected at the beginning, then we take the final width to be exactly 20 cm. compressive strength of the foundation will not be ensured.

If we got a width exceeding the initially selected 20 cm by more than 5 cm, then we need to repeat the calculation, starting from III point, substituting the new width when determining the mass of the foundation.

Such repeated calculations are performed until the increase in the width of the tape is less than 5 cm. For those who are a little confused, we will give a small example.

An example of a simplified calculation of a strip foundation.

Let us determine the minimum allowable width of the base of a recessed strip foundation for a 2-storey brick house (see Fig.) measuring 10 × 8 meters with one load-bearing partition in the middle of the long side. The height of the walls is 5 m, the height of the gables is 1.5 m. The thickness of the walls is 380 mm (one and a half bricks), the basement and interfloor ceilings are made of hollow-core slabs, the roof is metal. The bearing soil is loam with an estimated freezing depth of 1.1 meters.

I) Based on the depth of freezing, we accept the depth of the tape with a wound of 1.6 meters. To begin with, we take the width of the tape equal to 20 cm.

II) We calculate the weight of the house:

1. The total area of the walls of the house, together with the gables and with the internal load-bearing partition (also folded into one and a half bricks), minus the window and door openings, in our case will be 212 m², and their mass is 212 × 200 × 3 = 127,200 kg.

2. The total area of the basement and interfloor floors is 160 m², and their weight, taking into account the operational load, is 160 × (350 + 210) = 89,600 kg.

3. The roof in our example has an area of about 185 m². Its mass with a metal roof and snow load for central Russia will be 185 × (30 + 100) = 24,050 kg.

4. We sum up the figures obtained and get 240,850 kg.

III) The weight of the foundation itself, 1.6 m high, with a total tape length of 44 m and with a previously accepted width of 0.2 m, will be 1.6 × 44 × 0.2 × 2500 = 35,200 kg.

The total weight of the house will be 276,050 kg.

IV) Taking the Ro value for loam equal to 3.5 kg / cm² and converting the total length of the foundation tape into centimeters, we calculate the required width:

H \u003d 1.3 × 276 050 / (4400 × 3.5) \u003d 23.3 cm

v) We see that the obtained value does not exceed the initially accepted 20 cm by more than 5 cm. Therefore, the calculation can be completed on this and the minimum possible width of the base of the foundation, rounded, is 24 cm.

Conclusion: having made the width of the base of the foundation more than 24 cm, we can expect that this soil will withstand the house in terms of its bearing capacity.

Now, in a nutshell, what would happen if the bearing capacity of the soil was, for example, 2 kg / cm². Then the width of the tape would be 40.8 cm. After that, we return to point III. The mass of the tape becomes already equal to 71,800 kg, therefore the total weight of the house is 312,650 kg, and the specified width of the tape B = 1.3 × 312,650 / (4400 × 2) = 46.2 cm.

We see that the discrepancy with the previous value of 40.8 cm was again more than 5 cm, so we return to point III, we consider the mass of the foundation, the whole house and an even more refined width of the foundation tape. By the way, this time it will turn out to be equal to 47.6 cm. The discrepancy with the previous value is only 1.4 cm, so the calculation can be stopped and the minimum possible width of the base of the foundation is rounded to 48 cm.

Please note that 48 cm is exactly the width of the sole, and not the entire tape. It can be narrowed, up to 20 cm (depending on the thickness of the wall and the structure of the ceilings), and at the bottom it is only expanded (see the pictures below). By the same principle, heavily loaded prefabricated foundations are made from FBS blocks. First, wide foundation pillows are laid, and already narrower foundation blocks are placed on them.

At the beginning of the article, it was mentioned that almost any low-rise building can be built on a buried strip foundation, but this is not always advisable. Let's see why? Let's take for example a small wooden house for which the foundation was calculated in the article and try to calculate the tape for it. It turns out that its minimum allowable width will be only 7.1 cm. And you will have to do at least 20 cm. The overspending of only one concrete will be almost 200%, not to mention all related materials and work. Obviously, a columnar foundation in this case would be a better choice.

Thus, we have more or less figured out the calculation, now directly about the technology itself.

Stages of erection of a buried monolithic strip foundation.

1) What to dig - trenches or a foundation pit?

Sometimes the answer to this question is very simple. For example, if you are going to build a house with a basement, it is obvious that you need to dig a foundation pit. But if the basement is not planned, what then?

And then you need to take into account the features of your project, your building site, the possibility of mechanizing work and decide on your own (well, or on the advice of a more experienced builder friend). What you need to pay attention to:

Type of soil on the site, especially its flowability - you must admit, it is problematic to dig a trench with even walls that do not crumble at the slightest touch in dry sandy soil. In addition, with great depth and manual work, it simply becomes an unsafe occupation.
The thickness of the fertile layer- this is especially true if you are going to make floors on the ground. The fertile layer will need to be completely removed, because. it tends to decrease in volume over time due to decay processes. And due to the fact that in some regions of our country this layer is very thick, digging a foundation pit with its subsequent backfilling with non-porous material (sand) becomes inevitable.
Required width of the sole of the tape- it's one thing if the calculation requires a width of 20-30 cm, another if it's 50-60 cm. Filling the entire tape to such a width is a rather costly undertaking. It can be made already with an extension at the base, but for this it is necessary to build a formwork. Fiddling with formwork in a narrow deep trench is extremely inconvenient, so sometimes it's really easier to dig a pit.

2) Preparation and marking of the site.

Before starting construction, it is necessary to carry out measures to divert surface rainwater from the building site. It is not necessary to pour concrete into soil that has become muddy after rain, and no one is safe from bad weather. Given the terrain, dig small drainage trenches if necessary.

Try to bring the necessary building materials to the site before excavation. The shorter the cycle of foundation work (up to the construction of the blind area), the better.

The marking of the site will be discussed in detail in a separate article.

3) Further work order depends on whether we are going to pour concrete directly into the ground or into the formwork.

When pouring into a trench, you must:

level and clean the bottom of the trench;
lay insulation, if insulation of the foundation is required;
cover the trench with a layer of rolled waterproofing;
make concrete preparation - pour at least 5 cm of lightweight concrete into the bottom of the trench and let it harden (this prevents damage to the waterproofing layer by reinforcement and protects it from corrosion due to contact with the ground);
install a reinforcing cage on the concrete preparation that has set, lay household communications;
build a leveling plinth formwork;
to pour concrete.

When pouring into the formwork, the sequence is different:

level and clean the bottom of the trench or a section of the bottom of the pit under the future foundation;
mount the formwork;
make concrete preparation;
install a reinforcing cage, lay household communications;
pour concrete;
dismantle the formwork;
make waterproofing of the foundation;
make insulation of the foundation;
backfill the soil.

In the near future, a separate detailed article will be devoted to each main stage of foundation construction, such as, formwork, reinforcement. they all require special personal attention. And now at the end of a few more general recommendations:

carefully level and compact the base under the foundation tape, especially if this is done after the operation of the excavator. The sole must be flat and strictly horizontal. If there is no construction level, control the hydraulic level (it costs a penny, it is sold at any hardware store);
for insulation, use extruded polystyrene foam (EPS) with a thickness of 50-100 mm. Styrofoam is not suitable for these purposes. When laying insulation in a trench, you can attach it to the side walls, for example, with plastic umbrellas (fungi) or simply with pieces of thick wire, sticking it into the ground through the EPS. For temporary fixation before pouring concrete, this is quite enough;
when covering the trench with waterproofing, make sufficient overlaps (about 20 cm). An extra roll won't save a lot of money;
when mounting the reinforcing cage, use a knitting wire or plastic clamps. Welding is not recommended in this case;
the formwork must be strong and reliable. The buried strip foundation is quite high and when pouring concrete, it will experience tremendous pressure. Cases of formwork rupture are not uncommon in construction, especially when the concrete is compacted with a good industrial vibrator;
fill the tape with a mixer. A recessed strip foundation is a very massive structure, so in the example discussed above (the foundation for a 2-storey house 24 cm wide), the volume of the concrete mixture will be almost 17 m³. It is simply unrealistic to pour them yourself from a conventional concrete mixer so that unacceptable layer-by-layer hardening does not occur;
when pouring, it is advisable to use a vibrator for concrete, in extreme cases, do the bayonet with a pointed piece of reinforcement. Also, for better air removal, you can knock on the formwork with a small sledgehammer, unless of course you are sure of its strength;
you can remove the formwork and make waterproofing approximately 3-7 days after pouring (depending on the weather - the hotter and drier, the faster).
backfilling of a buried strip foundation can be done with native previously excavated soil with its layer-by-layer compaction. The use of coarse sand here, as in the construction of a shallow foundation, is no longer important;
try not to delay the construction of the blind area.

For now, let's stop there. We will be glad to see your questions and especially your personal experience in the comments.