Installation of strip foundation. Do-it-yourself strip foundation. Step-by-step instruction. Reinforcement as a guarantee of strength

One of the most reliable, durable and simple foundation options for capital building any type - strip foundation. It is widely applied in low-rise buildings, as it is suitable for any buildings: baths, houses and even under fences with gates.

The technology of its construction is as simple as possible, so building it with your own hands is not so difficult, and not only a small option, for example, under a fence, but also under a two-story residential building.

The strip foundation has several design options, but all of them can be divided into two large groups:

• buried
• and shallow

Strip foundation options

Shallow version of the strip foundation

The simplest and most inexpensive option, the construction of which does not require a large amount of resources, both material and human.

It is used for houses of small mass and light area. building materials, as well as on hard ground: on rocky and close to it.

Basically, such a foundation is built for the following types of buildings:

• Any wooden houses small area, especially panel and combined. They do not weigh so much that they need a full-fledged massive base, and if the soil on the site is quite dense, and also has a low level of heaving or construction is taking place in a warm region, you can get by with a shallow version of the strip foundation.
• Small buildings made of sibit (aerated concrete) or foam concrete blocks. The reasons are basically the same as with wooden houses: buildings of one or two floors made of such materials have a low mass, so they do not need a deep and powerful foundation.
• Brick and stone buildings of a small area - for one car, a family bath, some outbuildings and other building options. The brick itself is a heavy material, but if the building is small and the soil is dense enough, then there will also be no serious load on the base and the simplest can be built.

Usually, a shallow foundation does not exceed 80 cm in height, and another 15-20 can be spent on creating a pillow and sole, on which the foundation stands in the trench.

The only drawback of such a foundation is the lack of a basement.

Since in the recessed version the foundation simultaneously plays the role of the walls of the basement, cellar or basement, this will not work in the shallow version.

For heavily heaving or moving soils with a high level of groundwater, you can use a combined version - pile-tape. In this case, the tape also remains shallow and is further built up with piles or "legs" to harder and more stable soil layers.

Recessed version of the strip foundation

A full-fledged version of the strip foundation is buried below the freezing level of the soil, reaching the hard ground. It is used as a base for large, massive buildings that need a stable and heavy support so that the building does not begin to sag and warp.

Therefore, the foundation itself must be deep, wide and heavy, standing firmly in the soil and not moving along with its freezing, with an increase in groundwater and in any other climatic and geological changes.

Typically, the depth of such a foundation falls 30-50 cm below the freezing horizon, due to which it turns out that the foundation and the building itself stand on solid ground, and the upper soft layer acts as a pillow.

Such a foundation is always built if the soil on the site freezes deeply, is wet and soft. A deep foundation requires a large amount of materials for its construction, therefore, in order to save money, it is possible to erect options in which the array of the foundation tape expands to the bottom or is a stepped structure. T

Which options are more difficult to build and design, but allow you to spend significantly less building materials, since the strip foundation is the most expensive foundation of all in terms of the amount of concrete, reinforcement and related consumables like sand and steel wire for dressing the reinforcing belt.

The recessed strip foundation according to the design of the tape can be monolithic or prefabricated.

Prefabricated strip foundation

The prefabricated strip foundation is a strip of prefabricated reinforced concrete blocks connected into a single array using concrete and reinforcement. In this case, the formwork is filled with ready-made blocks produced in the factory, and as a result, a solid array is obtained.

The advantages of this design include short construction times and the possibility of construction in any season and in any weather.

But there are a number of disadvantages: finished blocks are more expensive, and moisture penetrates into their joints. Therefore, the construction of this option requires the creation of additional insulation, and a drainage system that will remove excess moisture.

Monolithic foundation tape

The monolithic foundation tape is a reinforced trench filled with concrete. The result is a single concrete mass, that is, a monolith. This option is the most reliable and versatile, so its design can be any.

The advantages of a monolithic foundation: no need to involve equipment, the ability to carry out all the work on our own, as well as a wide selection of designs and options for the tape.

There is only one drawback - the high price and high consumption of materials, especially fittings.

Stages of work on the construction of a strip foundation

Step 1 - Material for the construction of the strip foundation

The construction of the strip foundation is carried out using cement grade 200. This is a rather laborious process. If it is not poured at the same time, the foundation structure will not be strong. It is better to use coarse sand, cement and crushed stone for the construction of such a foundation. At the same time, while starting the solution, strictly observe the proportion. 2:1:2:5

In addition, for the construction of the foundation, you still need:

• River sand. They put a pillow under the foundation.
• Several pieces of shovels, bayonet and shovels.
• Levels, small and large.
• A large number of ribbed reinforcement 10-12 mm for creating belts and smooth, with a diameter of 6-8 mm, for bandaging. You will also need steel wire to connect the reinforcement overlaps.
• Formwork boards. You can use slab, it is the cheapest and most available of all this type of lumber.
• Nails, hammers, a hacksaw, a grinder and preferably a vibrator for tamping concrete.
• Concrete mixer for half a cube or a cube.
• Materials for the manufacture of concrete.

Step 2 - Preparing to build the foundation

The first step in any construction is the preparatory work, and they begin with the design. Therefore, you first need to find out the depth of freezing by digging a test hole and looking at the cut of the soil layers, or look at the average value for the region in the corresponding SNiP.

Based on these data, the depth of the tape is planned. It is also important to consider that the foundation should be slightly wider than the wall, and if the soil is soft, an empty space should be left along the outer walls, which in the future will be covered with sand to create a cushion between the tape and the moving soil.

A ditch is being dug, clearly according to the markings for the foundation.

Step 6 - Formwork Installation

It is installed from wooden boards, in accordance with the size of the foundation.

For formwork, any boards are taken, in which at least one side is planed. You can use the old ones, the main thing is that they are strong enough and as long as possible.

The inner side of the formwork should be a flat surface without strong drops and cracks into which the mortar can begin to pour.

In doing so, be sure to:

• Installation of corner supports with wooden beams;
• With the help of edged boards, a formwork structure is assembled, which is fastened with metal corners and self-tapping screws. At the same time, the heads of the self-tapping screws remain inside the formwork, and the bars and corners are outside;
• The outer side of the formwork is fixed with supports. This will prevent deformation of the structure under the weight of the poured solution;
• The height of the formwork cannot be less than 30 centimeters from the ground level.
• Inside the formwork, a level is drawn for the level of pouring concrete.

According to all the rules, the formwork for a deep foundation is built from the bottom of the trench, but in some cases it is allowed to erect it only on the surface of the soil.

In these cases, the walls of the trench must also be even and dense enough not to deform under the mass of liquid concrete when it begins to fill.

If there are no boards, any durable panel material will do, even slate.

Above the ground surface, the foundation should rise at least 30 cm, so it is better to make the formwork 50 cm high just in case. You also need to remember to lay all the necessary pipes if communications enter the house through the floor. For this, large-diameter asbestos-cement pipes are used, into which water and sewer pipes will then be laid.

Step 7 - Reinforcing strip foundation diameter

After the construction of the formwork is completed, a reinforcing belt is knitted along the entire length and height of the trench. For longitudinal belts, reinforcement of maximum length is required, preferably six meters, if the length of the side of the foundation is not less, 10-12 mm thick with a ribbed surface.

Vertical rods and cross bows can be made from smooth, 6-8 mm in diameter. Between themselves, the longitudinal elements should overlap with the ends of at least 30-40 cm, and each of the rows is knitted from two rods together.

Such requirements are due to the fact that it is on this part of the foundation that the main load falls, and if you save on it, it will not be as reliable as it should be. All ends are tied with steel wire, it is undesirable to use welding, since it does not give the necessary strength inside the concrete block.

The step with which the vertical rods are installed and the internal and external horizontal ones are tied together is determined by the design calculations, but it is not advisable to make it less than 50 cm.

Metal rods are not less than 8-12 mm in diameter, cut into pieces up to two meters, but not less than 45 centimeters, which are laid out in no more than 40 centimeters.

At the same time, steel rods are attached to each other by tying with a wire. Some use welding for this. But you shouldn't do that.

Step 8 - Filling the formwork with concrete

It is desirable to carry out work on pouring the formwork with concrete in one day, since at the junction of the seized and fresh parts, the strength of the foundation will be lower, and it is here that large through cracks may appear.

For concrete, it is better to take crushed stone of medium or small formation, this option is stronger than large stones.

If the crushed stone is very small, you need to reduce the amount of sand, since it is present in the crushed stone initially. Concrete is poured in layers, 20-30 cm each, and after pouring each layer it needs to be compacted. It is best to do this with a construction vibrator to eliminate small air cavities.

If there is no vibrator, you can make a rammer from the boards, the main thing is that the concrete be rammed. In cases where he buys ready-made concrete and pours it from an industrial mixer, it must be turned when pouring with crowbar or thick reinforcement so that cavities do not form in it. The formwork walls must be tapped with a wooden mallet for better shrinkage.

The upper part is leveled in the same way as when pouring the screed.

Upon completion of concrete work, the foundation must be covered with roofing felt or plastic wrap from precipitation and left to set. In normal weather with a small amount of rain, the foundation for the house sets in about a month. In the case of a fence, a couple of weeks or less is usually enough, depending on its volume.

Before choosing concrete for construction, you need to pay attention to the following important factors:

• What will be the mass of the building
• What will be the type of reinforcement
• What soil

Very often, a concrete pad is made under the strip foundation, which has a thickness of 10 cm. In this case, concrete M100 and above is suitable.

If the future structure will have more weight, for example, a prefabricated panel house, then in this case concrete M200 will be enough.

During the construction of a small one, M250 concrete is suitable if the groundwater does not lie deep.

If the future house is large - massive, then in this case it is worth using M350 concrete. It is this type of concrete that is classified as a particularly durable class, since it contains granite.

The most reliable is the M450, which is considered durable.

Remember! If construction takes place in a region where the climate is harsh, then give your preference to a higher grade of concrete.

To prepare concrete, you will need the following materials:

• A concrete mixer, since it is very difficult to knead with your hands, especially if a lot of concrete may be needed
• Shovel
• Capacity
• Cement
• Sand
• rubble
• And water

Any concrete consists of the following components:

• cement
• Fillers - it can be crushed stone, sand, gravel, other bulk materials

As a result of mixing these components, concrete is obtained. The quality will depend on the content of various fillers in the cement.

Concrete markings:

• M - brand of concrete - this parameter shows how the frozen foundation will transfer loads after 30 days
• B - class of concrete - this parameter carries information about the degree of compression
• F - resistance to frost - this indicator shows how much frost and defrosting concrete can withstand
• W - water resistance - this parameter characterizes the water permeability coefficient of concrete. Usually the values ​​range from 2 to 12.
• P - mobility - this parameter characterizes the liquid of a homogeneous concrete mixture and the flow coefficient.

For example:

• Concrete M100 B7.5 - it is of very low quality and is used only in preparatory work during construction
• Concrete M150 B12.5 - this type of concrete is not of very good quality. It is mainly used in the construction of concrete paths.
• Concrete M200 B15 - this type of concrete is used in construction with low load. It could be stairs.
• M300 B22.5 concrete - this brand of concrete is considered the most popular in Russia. It is used for pouring foundations and in the construction of high-quality houses.
• Concrete M350 B25 - this brand of concrete is considered very good. It is used in the construction of buildings and structures that require extremely high strength.

Filling formwork with cement mortar

• For this you need: cook concrete mortar, bring it with continuous stirring to a creamy consistency, then add gravel to it and mix everything again;
• The pouring of the formwork with a solution takes place with a systematic tamping and flow over its area with a rod made of metal. Thus, air is removed from the foundation. It is better to use a construction mixer for this;
• The solution is poured to the designated level in the formwork;
• The top layer of concrete mortar is leveled with a special tool, that is, a rule. It is better not to do this with a trowel;
• The top layer of poured concrete must be crushed with dry cement. It is better to do this with a sieve. This will speed up the drying process of the top ball of concrete mortar.
• The finished foundation in the formwork must be covered until completely dry. Usually 3-4 weeks is enough for this.
• If it is very hot, the foundation should be systematically watered. This will keep the top ball of the foundation from drying out.

And when the foundation is ready, the formwork is removed, you can start building the walls. Just before doing this, you need to complete. This will extend the life of the foundation, protect the walls from moisture and keep the heat in the house.

Is it possible to fill the strip foundation in parts

Answer: yes. You can fill in parts. This method is perfect for a strip foundation, where the largest amount of grout is spent. At the same time, the quality of work will not decrease, since modern technologies and skilled craftsmen allow such work to be carried out perfectly.

What should be considered in this case?

One of the main parameters is time, since incorrectly adjusted work intervals can reduce the quality of the structure as a whole. Therefore, it is worth knowing that before the foundation becomes strong and reliable, concrete goes through stages. It is these two processes that have certain time intervals that you need to know and take into account in your work.

Minimum setting time– 3 hours if the temperature outside is 15 degrees. The maximum time is a day if the temperature is lower than prescribed. This is considered the most important process, since it binds all the components that enter the solution.

Therefore, remember! If it is necessary to fill in parts with an interval of 8 hours, then the layers themselves must be thick. Otherwise, the desired effect will not work.

solidification process it takes up to a month and only after the expiration of this period the foundation will be able to withstand the necessary loads.

If you need to fill the foundation in parts, then the next layer can be laid only after three days. If these time intervals are not observed, the foundation may eventually crack.

• Filling subsequent layers can be done after 8 - 10 hours in cold winter time and at least 5 hours in autumn and summer periods
• Before proceeding to the next layer, it is necessary to work on the previous one - to clean it of dust.

The construction of buildings begins with a load-bearing foundation, which determines not only the service life of the building itself, but also forms the comfort and microclimate inside the premises. The strip foundation is one of the most popular types of foundations used both for the construction of private housing and for the construction of technical buildings.

Features of the strip foundation

A strip foundation is a load-bearing base, which is a closed loop in the form of a strip of reinforced concrete, bricks and block building materials. The tape is erected under the bearing walls of the building, which contributes to the uniform distribution of the load and its further transfer to the underlying soil layers.

For the manufacture of a monolithic strip foundation, high-strength concrete grades are used

The design of the strip foundation allows you to build structures both from wood and foam concrete, and from brick and concrete blocks. When building a foundation, a large amount of land and construction work is required. Despite this, the strip foundation is popular both among summer residents and owners of suburban areas, and among professionals.

The arrangement of the foundation is carried out on a pre-compacted pillow of sand and gravel. After hardening, the carrier tape is covered with an insulating material that will protect the integrity of the reinforced concrete surface. If the total weight of the building being erected is small (up to 50 tons), then the preparation of the underlying cushion can be neglected.

The configuration of the carrier tape depends on the shape of the walls of the building under construction

The competitive advantages of the strip foundation include:

• technology proven and refined over the years. A properly executed base will evenly distribute the load exerted on it without the risk of collapse of the supporting structures of the building;
• strength. The monolithic construction of the foundation ensures high reliability and durability. Subject to technology, the service life of the foundation can reach 100 years or more;
• versatility. The strip foundation can be used both for heaving and moving soil types, and for loamy and clay soil types. To improve performance, it can be combined with vertical piles and supports.

The disadvantages include the fact that the construction of a strip foundation is a very time-consuming process, requiring the investment of a considerable amount of finance. On average, the cost of a supporting foundation is 15-20% of the total budget allocated for the construction of a house.

The foundation construction technology assumes that the tape will be poured in a work shift, and it is problematic to prepare such a volume of concrete mix even with a concrete mixer. Because of this, it becomes necessary to purchase concrete from the manufacturer, which is also a significant waste.

Types of strip foundation according to the depth of laying

According to SNiP 3.02.01-87 "Earth structures, foundations and foundations", tape bearing foundations are classified according to two criteria:

• by depth;
• according to the method of the device.

The depth of the foundation depends on the bearing capacity of the soil and the calculated load that will be placed on the foundation being built. The bearing capacity of the soil is determined based on its type, the depth of freezing and the presence of groundwater in the area where the building is planned to be built. Read about the design and method of strip foundation construction in the next section.

Shallow strip foundation

A shallow strip foundation is a strip of concrete and a reinforcing frame, located at a shallow depth in the ground. The minimum level of laying depends on the depth of soil freezing, its heaving and the height of groundwater.

A shallow strip foundation can be made of reinforced concrete, brick or foam blocks

For example, if the groundwater is high and the depth of soil freezing is large, then both lateral and tangential heaving forces will act on the foundation, which will compress and displace the shallow carrier tape. And vice versa - the lower the groundwater level and the higher the level of soil freezing, the less the impact of heaving forces.

The recommended minimum depth of the strip foundation can be found in SNiP II–B.1–62. For reference, we offer a table compiled on the basis of data from this document. On average in Russia, the depth of laying varies from 0.4 to 0.75 m. Additionally, you can consider the depth of seasonal freezing of the soil in the region where it is planned to lay the bearing foundation.

Table: foundation depth depending on the level of soil freezing

The depth of laying a shallow strip foundation in the central region of Russia should not be less than 0.5 m

The construction of shallow strip foundations is recommended in the following cases:

• in regions with high average annual temperature and shallow depth of soil freezing;
• in the construction of private houses using frame technology, as well as buildings made of aerated concrete, foam concrete and other materials with low weight;
• when warming the supporting base from the outside, coupled with the arrangement of a blind area made of crushed stone, sand and concrete.

The construction of a shallow strip foundation on soil consisting of peat, sapropel, silt and other organic deposits is strictly prohibited. It is not recommended to build this type of strip base on mixed and heaving types of soil that are oversaturated with moisture.

Buried strip foundation

A buried foundation or a deep foundation is a load-bearing reinforced concrete or prefabricated strip, which is 20–30 cm lower than the level of soil freezing.

The depth of the carrier tape can reach 1.5–2 m, depending on the level of soil freezing

The main idea behind the deep laying of the carrier tape is to rely on dense soil layers with a higher bearing capacity. This type of foundation implies even greater volumes of excavation and concrete mix costs.

The construction of a deep strip foundation is recommended:

• in regions with low temperatures in winter and freezing of the soil to a great depth;
• if it is planned to build a two- or three-story house made of bricks, reinforced concrete blocks and slabs;
• in the presence of fine-grained soil types supersaturated with moisture.

In addition, the recessed foundation allows you to equip the basement. With high-quality insulation and sufficient insulation, it is possible to equip a basement floor intended for living or storing things.

Types of strip foundation according to the device method

Depending on the design features, strip foundations are monolithic and prefabricated. They, in turn, can be divided into monolithic foundations with vertical supports and precast tapes made of brick or foam block.

Monolithic strip foundation

When constructing a monolithic strip base, reinforcement and pouring of the foundation are carried out directly at the construction site. As a result, the overall integrity and continuity of the carrier tape is achieved.

A monolithic strip foundation is an inextricable reinforced concrete strip around the entire perimeter of the building

Depending on the geology of the site, the depth of laying a monolithic foundation varies from 80 to 250 cm. When building private houses, the laying depth rarely exceeds 150 cm.

Monolithic types of foundations, regardless of technology, are used to build facilities for various purposes on heaving and mobile types of soil. Monolithic design provides high strength and reliability of the bearing base.

Pile and column-strip foundation

Pile-tape and column-tape types of foundations are a monolithic reinforced concrete strip located on supports buried in the ground. In fact, these types of foundations - nothing more than a modernized version of pile or columnar foundations with a grillage.

Pillars or piles are located along the perimeter of the foundation with a step of 2 m

In the first case, steel products in the form of piles of various lengths are used as supports, which are screwed into the ground manually or automatically. In the second, the supports are made from the same concrete mixture that is used to fill the carrier tape.

The arrangement of pile and column foundations of the strip type is justified only during the construction of facilities in areas with great depth soil freezing. Steel piles or reinforced concrete poles buried below the freezing level of the soil will distribute the load that is transferred from the reinforced concrete strip.

Prefabricated strip foundation

The main material for the construction of a prefabricated strip foundation are reinforced concrete foundation blocks (FBS), made of heavy grades of concrete. The foundation carrier tape is formed from the blocks, which is located along the perimeter and area of ​​\u200b\u200bthe future building. To connect the blocks to each other, concrete grade M350 and steel reinforcement Ø15 mm are used.

After assembling the foundation, the outer surface of the bearing base is treated with waterproofing materials. The most commonly used bituminous mastic and special bituminous membranes, which have a self-adhesive base.

Prefabricated strip foundation consists of reinforced concrete foundation blocks connected with concrete

The main advantage of the prefabricated strip foundation is the short construction time. Unlike a monolithic base, you do not have to wait for the minimum strength of the concrete mixture to set. You can start building a house within a few days from the moment the tape is assembled.

Despite this advantage, a prefabricated strip foundation is used for the construction of private houses a little less often than a monolithic concrete foundation. This is largely due to the fact that the prefabricated structure is not suitable for use on moving types of soil. With the same thickness, the strength indicators of a prefabricated structure are 20–30% lower than a monolithic one.

Brick strip foundations are a prefabricated structure and are often used for the construction of one-story houses using frame technology. For the manufacture of the tape, burnt solid brick is used. Depth of laying - 40–50 cm.

The strip foundation made of bricks is highly maintainable, but requires the arrangement of high-quality waterproofing

After assembly, as in the case of blocks, it is necessary to equip a full-fledged waterproofing layer. The benefits of this foundation include:

• structural rigidity;
• high maintainability;
• ease of arrangement.

If we make a more detailed comparison of bricks with reinforced concrete blocks, then the foundations of the blocks are less hygroscopic and higher strength. The brick is more fragile, which affects not only the frequency of repairs, but also the life of the structure as a whole. With this in mind, it is recommended to build a brick strip foundation in areas with dry and hard soil, as well as with low groundwater.

How to make a strip foundation for a house

In order to start building a strip foundation, you will need to perform settlement operations, during which it is necessary to find out the depth of the foundation and the width of the carrier tape. If possible, these works can be delegated and contacted by a design and construction organization, where all the necessary parameters will be calculated for you, on the basis of which a project for the future foundation will be drawn up.

Calculation of the strip foundation

If you decide to survey the soil and draw up a project yourself, then be prepared that even a small mistake made can lead to the destruction of the house. Especially if you are planning to build a two- or three-story building.

Table: the depth of the strip foundation, depending on the type of soil

Type of building	Depth of the strip foundation (cm) depending on the type of soil
		Rocky ground, flask	Dense clay, soft loam	Packed dry sand, sandy loam	Soft sand, muddy ground	Very soft sand, sandy loam, silt	peat bog
Barn, bathhouse, household the buildings	20	20	30	40	45	65
One-story cottage with an attic	30	30	35	60	65	85	Requires a different type of foundation
Two-storey cottage	50	50	60		Requires calculation of specialists	Requires calculation of specialists	Requires a different type of foundation
Multi-storey cottage	70	65	85	Requires calculation of specialists	Requires calculation of specialists	Requires calculation of specialists	Requires a different type of foundation

For low-rise buildings made of wood, garages, bathhouses, chicken coops and technical buildings, you can perform a calculation taking into account the recommendations given in SNiP II–B.1–62 “Foundations of buildings and structures”.

The simplest option is to check the known parameters with a special table that allows you to determine the depth of the strip base. The referenced table is shown above. For reference: 1 kN = 101.9 kg. The table has been compiled on the basis of European standards adopted in 2010.

To level the site, improvised means, hand tools and special equipment are used.

As an example, we will calculate the parameters of the strip foundation required for the construction of a one-story dacha made of timber, the length of which is 8 m and the width is 6 m. The height of the dacha, not including the roof, is 2.5 m. The building will be built on the ground of dry fine sand. The depth of soil freezing is 1.4 m, which corresponds to the central part of Russia.

The sequence for calculating the strip foundation is as follows:

1. Building weight - to calculate the total weight of a building, you must have a building design that describes what materials will be used to build it. On average, the weight of a one-story structure made of timber with an attic is no more than 70 tons. To this value should be added the weight of heat-insulating materials, ceilings and partitions, as well as snow load (160–240 kg / m 2). As a result, it turns out that on average a one-story dacha with the parameters announced above will weigh about 100 tons.
2. Foundation area - length of the carrier tape: (6 + 8) * 2 + 6 = 34 m. The width of the tape is selected depending on the weight, but not less than 20 cm. As a result, it turns out that the surface area of ​​\u200b\u200bthe foundation is: 28 * 0.2 m \u003d 6.8 m 2. This value may be adjusted later.
3. Depth of laying - the soil consists of dry sand, the freezing depth of which is 1.4 m. From this we can conclude that the soil in the area is non-porous. Therefore, for the construction of a one-story cottage, you can use a shallow foundation with a laying depth of 0.6 m.
4. The load on the carrier tape - according to SNiP 2.02.01-83 "Foundations of buildings and structures", the formula is used to calculate the load: P = total weight of the structure / foundation area. For fine sandy soil, the resulting value should be less than 20 tons (value taken from DBN V.2.1-10-2009). In our case, P \u003d 100 / 6.8 \u003d 14.7 t / m 2.

Based on this, we can conclude that the previously indicated width of the carrier tape (0.2 m) is ideal for a one-story cottage weighing no more than 100 tons. As a result, it turns out that for the construction of a timber cottage with an area of ​​​​48 m 2, a strip foundation 0.2 m wide is required, which will be buried in the ground by 0.6 m.

Using the tables given in this article and SNiP 2.02.01–83, you can perform a calculation for any strip base that will be built on non-rocky soil types. Data on the weight of building materials can be taken from open sources, and for an approximate calculation, use online calculators.

Site preparation

After all the design operations have been completed, the project of the foundation and the future building has been received, you can proceed to the preparation land plot. During preparation, it is necessary to clean and mark the surface of the site using improvised means.

The marking of the site for the strip foundation is carried out using wooden pegs and a strong rope that is stretched between them.

To prepare, you will need to do the following:

For the final check, it is necessary to measure the diagonals of the site under the foundation. To do this, the thread is stretched crosswise. If everything is done correctly, then the diagonals will be equal. Otherwise, it is necessary to double-check the corners with the device and rearrange the pegs.

trench digging

During earthworks, it will be necessary to dig trenches to the design depth, which is calculated taking into account the type of soil and the foundation being built. To do this, you can use both special equipment and hand tools in the form of shovels and scrap.

The trench for the strip foundation is dug to the design depth of the bearing base and the underlying cushion

To equip trenches around the perimeter of the foundation, you will need to perform the following activities:

Formwork device

For the manufacture of formwork, an edged board 20 × 150, 20 × 175 or 20 × 299 mm is used, which is fastened with wooden bars 50 × 50 mm. If possible, you can use moisture-resistant plywood, which is mounted on a pre-assembled frame from a bar. The principle of the arrangement of formwork panels is shown in the photo below.

The formwork is installed in the following sequence:

If the foundation provides for the laying of pipes for communications and the creation of ventilation gaps, then special holes of the desired section are sawn in the formwork. For this, an electric drill with a crown nozzle is used.

Video: formwork installation

Reinforcing frame installation

To reinforce the strip foundation, a frame made of steel reinforcement Ø12–15 mm is used. The frame is assembled by welding or using steel wire.

The knitting of the reinforcing frame is as follows:

When knitting, it should be remembered that the frame must be hidden under a layer of concrete to a depth of 5–6 cm. The maximum length of the jumper with a tape width of 40 cm should not exceed 30 cm.

To speed up the knitting process, you can purchase a special construction gun that works on the principle of a stapler, but instead of the usual staples, it uses steel wire of the desired section.

Video: how to knit a reinforcing cage

Pouring concrete mix

When erecting strip foundations for private housing, a concrete mix of the M200, M250, M300 or M350 brand is used. Concrete brand M200, as a rule, is used only for small frame baths and utility rooms. Concrete of higher grades - for pouring foundations for the construction of two- and three-storey houses, and concrete M350 - only for overall buildings.

The foundation is poured strictly in one step, so it is important to ensure the required volume of concrete mix, which is calculated based on the size of the foundation. If it is not possible to prepare the required amount of concrete, then the foundation is poured in layers with the obligatory tamping of each layer.

The proportions of the solution for independent mixing of the mixture are 1 part of cement, 2 parts of sifted sand and 4 parts of crushed stone of fraction 20–40. When changing the proportions of the solution, it should be remembered that there should be 1.5–2 times more crushed stone than sand.

Automated supply of concrete mix will greatly speed up the process of pouring the strip base

You can start pouring the mixture from any convenient place in the trench. Concrete is fed in portions so that it can be evenly distributed over the volume of the trench. To compact the mixture, a reinforcement rod or a wooden lath is used.

The last portion of concrete is leveled along a stretched guideline. To do this, raw concrete is covered with dry cement and rubbed with a wooden grater. After that, the foundation is covered with a plastic film and moistened 2-3 times a day with a small amount of water.

The concrete strip foundation will gain full strength no earlier than after 27 days, but after 14–17 days it is already possible to dismantle the formwork. After 27–30 days, the foundation is waterproofed and backfilled.

Despite the relatively high cost, the strip foundation is one of the most durable types of load-bearing bases. In addition, many owners of suburban areas prefer this type of foundation, as it allows you to equip a basement or even an entire basement.

Economically justified strip foundation for heavy buildings on difficult soils. This is due to the high budget for reducing heaving forces. Only monolithic structures have the maximum resource, the step-by-step technology of which will be discussed below.

Strip foundation technology step by step

For projects without an underground / basement level, shallow, shallow strip foundations, ground monolithic belts are preferable. Buried tape is effective only at a laying depth within 3 m.

If the soils at this depth do not meet the characteristics of the building (settlement from prefabricated loads), it is necessary to reinforce the tape with piles or revise the project in favor of a slab, pile grillage.

For the convenience of private developers without specialized education, regular practice is given below step-by-step instruction construction of a strip foundation.

Axle marking

The main problems of any reinforced concrete structure operating in underground aggressive environments are corrosion of internal reinforcement, cracking of the concrete structure, swelling of adjacent soils during freezing. Therefore, the main tasks of the designer, then the builder are operations that allow you to protect strip foundation from moisture, freezing. Bearing capacity is built into any project by default.

Thus, for a shallow MZLF tape, marking trenches is preferable, for a buried GZLF foundation - a foundation pit. In any case, it is necessary for workers to have access to the outer edges of the foundation (waterproofing, stripping), making drainage sewers. Therefore, the marking width increases by 1.2 m outward (pit), 0.8 m inward (trenches).

The best option for marking the axle is cast-offs of two pegs with a horizontal bar of 60 - 80 cm. Two cast-offs will be required for each internal / external load-bearing wall. The markup technology looks like this:

• installation of cast-offs one and a half meters from the pit
• alignment in a single horizontal plane 5 cm above the design mark
• tensioning strings, cords for the side edges of the tape, the axis of the wall (the line along which the floor slabs will be laid)

For ease of markup, the following scheme is used:

• the first wall (front facade) is parallel to the street, 5 m away from the axis of the carriageway (the red line in the land surveying project) (3 m from the axis of the alley / driveway), located more than 3 m from the borders of neighboring properties
• two walls adjacent to it depart at right angles, laid out in a triangle way (legs 4, 3 m, hypotenuse 5 m)
• reconciliation of the diagonals should show the same result, the permissible error should be within 1 cm, ideally absent

It is enough to outline the edges of the pit, trenches with chalk, lime mortar on the ground.

Important: If the project includes MZLF with floors on the ground, the fertile layer inside the perimeter of the trenches will have to be completely removed. The slab cannot be concreted on this soil; it is guaranteed to sag after 2 to 6 months of operation.

Excavation

For MZLF, it is enough to remove the arable layer in the trenches (roofing along the beams) or from the entire perimeter (ground floor). If needed strip foundation deep laying, it is easier to rent special equipment, make a pit with a depth of 2 - 2.5 m with an excavator. In the latter case, additional soil will have to be removed. The side walls have an outward slope, which protects against rock collapse during further work.

foundation pit

When using with an excavator, it is recommended to dig just above the design level in order to trim the bottom manually. If the bucket goes deep in some areas, later you will have to remove the entire layer to this mark - it is strictly forbidden to level the pits with the same soil, even rammed.

trenches

The minimum construction budget provides strip foundation MZLF. The arable layer is removed from the trenches to a depth of 60–80 cm. Then a trench-in-trench for drainage sewage with a section of 50 x 50 cm is made.

Underlayment

The purpose of backfilling from inert materials is to replace heaving soils, level the perimeter, and ensure drainage of the sole of the tape. Step-by-step instruction work of this stage is as follows:

• bedding layer - thickness 10 cm, material sand at low groundwater level, crushed stone at high groundwater, twice the width of the tape
• compaction - with hand rammers, vibrating plates, so that there is no trace on the sand

The operation is repeated until reaching 40 - 80 cm, depending on the nature of the soil. Then, strip foundation it is necessary to protect from moisture, the concrete laid in the formwork from dehydration, the reinforcement from corrosion. All these problems are solved by the footing with the fusing of a waterproofing carpet:

Drains should be located outside the perimeter of the footing, otherwise the efficiency of groundwater drainage is reduced.

Reinforcement

Unlike concrete, reinforced concrete composite material, reinforced at two levels with bars of variable cross section, withstands both compressive and tensile forces. Fabrication of frames with which to reinforce strip foundation, is produced according to the scheme:

Longitudinal rods are cut from 8 - 16 mm A400 reinforcement of a periodic profile. Anchors, clamps are made of smooth 6 - 8 mm A240 reinforcement. L-shaped, U-shaped anchors reinforce the corners, T-shaped interfaces of the walls. Structural reinforcement is used in deep-laid tapes - additional bars in intermediate chords, necessary for the rigidity of spatial frames, ensuring a minimum percentage of foundation reinforcement.

It is better to connect frame elements with wire twists with a special tool - a hook. The overlap when increasing the length is 40 - 60 cm, the run-up in adjacent rows of adjacent joints is 60 - 80 cm. Welded frames from special reinforcement are allowed, in the marking of which there is a letter C after all the numbers.

formwork

Concreted strip foundation usually in removable formwork, the panels of which are made of oriented strand board, multi-layer plywood, edged board 4 cm minimum. This sheet, lumber can be useful in the future, so the inner plane of the shields is covered with polyethylene, which additionally prevents dehydration and leakage in the formwork cracks.

The shields are installed close to each other, fixed in a vertical position by internal ties, external supports. It is mandatory to control the alignment with the walls of the building. The upper board is set along the cords, that is, 5 cm above the design level. This will prevent splashing of concrete during the work.

At a depth of 1.5 - 2 m, it is necessary to install sleeves for the nodes for entering communications into the cottage. At the level of 40 cm from the blind area, it is necessary to provide for the installation of void formers (only for projects with ceiling beams). These holes are underground ventilation products, prevent rotting, corrosion of the elements of the load-bearing frame, remove harmful radon. Their total area should be approximately equal to 1/400 of the size of the basement of the foundation.

fill

Strip foundation they are concreted according to standard technology, laying a layer of 60 cm along the perimeter, compacting it with the tip of a deep vibrator. It is difficult to pour deep foundations at one time, to withstand a technological break of less than 2 hours. Therefore, phased concreting is often used:

In the first three days, side stripping is prohibited, a moisturizing compress is applied to the upper edge of the tape from regularly wetted sawdust, rags, and sand. This allows the hydration of the cement inside the mixture to be completed, to ensure the branded strength of concrete, to prevent the opening of cracks, the formation of shrinkage funnels.

Additional protective measures

Strip foundation must be protected from heaving forces, soil / ground water, freezing. Comprehensive protection is provided in the following ways:

Pasting the outer edges of the deep-lying tape to bring the dew point outward, eliminating fogging of the inner walls of the basement. Installation of extruded polystyrene foam on the surface of the tape of any level of penetration allows to reduce the tangential heaving forces. This method is called sliding-crumple protection, has the following scheme:

• high-density XPS expanded polystyrene is glued onto the waterproofing film
• its surface is covered with two layers of polyethylene, fixed only in the basement of the foundation
• PSB 25 low-density polystyrene sheets, not fixed to the foundation, are pressed vertically to the polyethylene with backfill material (sand)

The resulting heaving forces crush the PSB, displace it on a smooth film top in winter, without destroying the main contour of the insulation. After thawing, the structure, together with the reduced volume of soil, returns to its original position.

The classical strip foundation technology, regardless of the depth of the foundation, has the indicated form. For an individual developer, all the secrets of manufacturing on their own are given. This will reduce the construction budget, avoid mistakes, and ensure the maximum possible operational resource.

If you want to build a high-quality foundation for a house that will last for many years and will withstand heavy loads, then, undoubtedly, a strip foundation for a house is the best option. Since it is quite popular, there is a lot of information on how to do all the work. All that is required of you is to study it and bring it to life.

We have collected for you useful information, which will help you figure out how to build the right foundation yourself.

Features of the strip foundation

Let's start with a brief overview and description. The strip foundation is a monolithic structure that runs under the walls of the house. The tape itself can be made from blocks, slabs, or concrete. A feature of the building is that it can withstand heavy loads. The tape evenly transfers the load to the ground. In addition, this is the only foundation option in which you can make a garage or cellar under it. But, working with such a foundation is not easy.

The thing is that the device takes a lot of time, effort and investment. The main part of the work comes down to digging a trench. If you use special equipment, then there will be no problems. But for manual digging with shovels, you need to try. Not only is it long, it also takes strength, especially if the ground is rocky. As for pouring concrete, you will need to mix a quality mortar, build a formwork and wait about a month until the concrete mortar dries. And we don’t even mention how much money will go to materials.

If this information did not scare you, and you continue to have the goal of building it, then you should know that the strip foundation for the house is a reliable structure that will last you for many years. And thanks to the presence of a basement, the room will be warm. So, let's look at where the construction of the strip foundation begins.

Preparation of tools and materials

The first thing you need to do is to take care of the arsenal of tools and raw materials for working with the foundation. What does this list consist of? If we talk about materials, then it is as follows:

• river sand of medium fraction;
• crushed stone or gravel;
• boards or plywood for formwork;
• reinforcement bars Ø10-12 mm and knitting wire;
• pegs and rope for marking;
• concrete mortar consisting of sand, water and cement.

Now let's look at the list of tools:

• crowbar and shovel;
• tape measure, level, plumb line, level;
• hammer and nails or screwdriver with self-tapping screws;
• concrete mixer;
• buckets, wheelbarrow, shovel;
• vibrating plant for concrete compaction;
• Master OK.

As you can see, the list is long, but all strip foundation materials are readily available.

Note! If you do not want to prepare concrete for the foundation yourself on the site, you can order it in advance from a specialized company. They will deliver you the right amount of quality mortar for pouring the foundation.

Preparatory work

If you have already stocked up with everything you need, then you can start practicing. You must have a foundation plan in advance, which indicates its layout, width, depth of the tape and other features. All this depends on the type of soil, the depth of soil freezing and the occurrence of groundwater. It is better to entrust such work to an experienced specialist who can draw up a quality plan.

Now you can tackle the area where the foundation will be built. Rate it. Does it have trees, bushes, or other structures that will get in your way? They need to be removed. The work area should be free of debris, remnants of old buildings, etc. It is desirable that the surface be relatively flat.

Advice! On the site you need to make lighting, take care of sockets and water supply.

After that, you can start marking the future foundation. Good markup is essential. So, you will make the future foundation perfectly even and regular in shape. The ropes will serve as guides. You can read more about how you can mark up a strip foundation on our website. In general, the scheme looks like this.

We are engaged in a trench of the foundation

Well, if you are making a strip foundation for a country house. Then the depth of the tape will be small, since such houses are small, so the amount of work is reduced. Basically, the average depth of the tape reaches 70 cm. Maybe 40 cm, or maybe 1.5 m. It all depends on groundwater and freezing. Be that as it may, work on digging a pit will have to be done.

If funds allow you, then you can simplify your task. How? Hire special heavy equipment that will do all the work in a matter of hours. The trench under the foundation will be perfectly flat, and you can quickly get to work. But, there may not be such a possibility. And the reason for this is not only funds, but also the lack of the possibility of heavy equipment arrival. In this case, everything will have to be done manually.

To reduce labor costs and increase the speed of work, you can ask for help. Doing work with friends or relatives is much easier and more fun. As for the process itself, make sure to focus on the markup. It is important to make the walls and bottom of the trench even, checking everything with a plumb line. And with a tape measure you can control the depth.

Foundation cushion device

When the pit is ready, you can proceed to the next step. The process is the following:

1. Sand falls to the bottom.
2. Water is added to thicken it.
3. The surface is rammed with a special ramming tool to compact the sand.
4. It is important to ensure that the sand level reaches 10 cm. You can make indicative marks on the walls.
5. A layer of rubble or gravel is poured on top.
6. They are also amenable to ramming. Required layer - 10 cm.

Thanks to such a substrate, the foundation will not move, it will become more reliable and durable.

Foundation formwork device

It's time to go upstairs and build the formwork. This is the ground part of the structure that will form the basement of the building. Its height depends on the desired base. For cold regions, this figure can reach 50 cm, for warm regions 20-30 cm. The structure itself can be made of different materials, such as boards, plywood, asbestos-cement pipes, etc.

Formwork types are also different. There are two options:

1. Removable formwork, which is simply removed after pouring concrete.
2. Fixed, which becomes part of the plinth.

As you can see, the first option is cheaper. But, it will take more time to build it. The fixed design will serve as additional protection, and play the role of a heater.

You can see the formwork diagram in the figure below. The main task is to make it perfectly smooth and reliable. Supports are installed on the sides, and a screed is stuffed on top. So, the concrete will not fall out of it.

Advice! To make the process of removing the formwork after pouring easier, and the concrete itself does not seep through the holes, you can cover it from the inside with a film.

Reinforcement as a guarantee of strength

To give the strip foundation rigidity, it must be reinforced with reinforcement. Everyone knows that reinforced concrete is many times stronger than simple concrete for the foundation. Therefore, a frame in the form of a grid is made from the reinforcement bars. It is better to connect elements not by welding, but by knitting wire. The made frame is installed in the formwork. There are several nuances here.

The frame must not be placed on the ground. It should be at least 5 cm from the ground. The same applies to the side walls. Use stands on which you can put the frame. This is what the reinforcement of the strip foundation looks like ideally.

Filling the strip foundation

To make the strip foundation of the house yourself, it remains only to fill it. Here you will need concrete, lots of concrete. The solution is made in a concrete mixer. It is advisable to install it near the trench itself, which will need to be filled. The process is the following:

That's all, now you know how to make a strip foundation with your own hands. It remains to wait until the concrete dries. This will take a month. After 15 days, you can remove the formwork, just do it carefully so as not to damage the foundation.

Advice! While the concrete is drying, cover it with polyethylene to protect it from external factors. After all, the rain can wash it away.

Summing up

As you can see, the process of building a strip foundation is really long and laborious. But, making a foundation with your own hands is not difficult at all. You must adhere to the technology and follow the instructions. The main thing in this work is to design everything correctly so that the finished strip foundation can withstand the load of the house and is not eroded by groundwater. Consider the depth of soil freezing and get to work!

When building a house or other buildings, strip foundations are most often preferred, since such a foundation has many advantages. The strip foundation for the house is quite simple in device and, if necessary, it can be poured without the involvement of construction equipment. Such a foundation is a universal design and is used in the construction of light wooden and heavy stone buildings on various types of soils. In more detail, what is a strip foundation, its types, and how it is equipped, we will consider in our article.

Strip foundation in section Source bayanay.info

Types of strip foundation

Before proceeding with the construction of such a foundation, it is necessary to carefully consider its features and varieties. This will allow you to choose the right foundation for the construction of a particular structure. It will also make it possible to properly carry out all the necessary work. A strip foundation is not just one way to make a foundation for a house, there are several types of them:

1. One piece

A monolithic or solid strip foundation is being built directly at the construction site. To begin with, a formwork is being constructed, into which a reinforced belt is laid along the entire length. After that, concrete is poured.

The base is a closed monolithic contour made of reinforced concrete. Thanks to this, it is possible to create a solid frame that is suitable for any soil, including unstable ones. On this basis, it is easy to build Vacation home or stone fence.

Among the advantages of this design are ease of construction and reliability. In this case, the base can have a different shape. As for the shortcomings, there is a large mass monolithic construction.

Solid cast strip foundation - concrete is poured in one step into the prepared formwork Source sazhaemvsadu.ru

2. Prefabricated

For the construction of the foundation, ready-made reinforced concrete blocks are used. Of these, a tape of the desired shape is laid out directly on the site. They are fastened with cement mortar. They are optimally suited for the construction of low-rise buildings. Buying ready-made blocks is quite simple, since many factories are engaged in their production.

Among the advantages, it is worth highlighting the ease of assembly, which can significantly save time on the construction of the base. But, at the same time, prefabricated structures have some disadvantages. Not a solid structure and the need to attract heavy construction equipment reduces the popularity of this type of strip foundation.

For reference! If we talk about the price of the issue, then the difference between prefabricated and monolithic strip foundations is insignificant. Therefore, when choosing, it is worth focusing on the features of the structure.

The prefabricated strip foundation is assembled from ready-made slabs, and the joints between them are sealed Source kinozavr.info

3. Shallow foundation

This type of foundation is mainly used in the construction of light buildings. So, it can be frame houses and structures made of timber and logs. The peculiarity of such a base is that it is located slightly above the level of soil freezing. Therefore, it is often used on less problematic soils.

Shallow structures easily tolerate heaving of the soil, which occurs in winter. During construction, special attention is paid to waterproofing and thermal insulation. This will protect the base from the negative effects of the environment.

The advantages of a shallow foundation include its low cost of construction. At the same time, there is no need for complex earthworks. He has several shortcomings. First of all, it is worth noting that such a design can not be used on all types of soil and for the construction of not all structures.

The design of a shallow foundation is standard - it just goes deep into the ground by no more than 50-70 centimeters Source novostroika93.ru

On our website you can find contacts of construction companies that offer foundation design and repair services. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

The construction of a strip foundation of this type is carried out below the level of soil freezing. This makes it possible to distribute the load from the future structure on a stable layer of soil. Due to this, deep foundations are used for the construction of multi-storey buildings that have significant weight.

The advantages of this design is that they are suitable for the construction of heavy structures. It is also possible to equip the basement and basement. Of course, for the arrangement of the foundation, significant physical and material costs will be required. This is especially true for earthworks.

A deep strip foundation is buried below the freezing level of the soil - this can be 1.7-2.2 meters or lower, depending on the region Source diagnostics.spb.ru

Online foundation calculator

To find out the approximate cost of a strip foundation, use the following calculator:

Pros and cons of strip foundation

When choosing a foundation, you should pay attention to the advantages and disadvantages of one or another option. This also applies to the monolithic tape structure. The benefits include:

• the possibility of arranging a basement;
• ease of construction;
• low cost;
• high strength and reliability;
• possibility of application on heaving soils.

Unfortunately, the strip foundation has some disadvantages:

• in some cases there is a need for complex earthworks and the use of heavy construction equipment;
• the need for waterproofing and thermal insulation works.

It should be borne in mind that the concept of pros and cons is ambiguous, since everything here depends on the depth of the structure. Therefore, each type of foundation must be considered separately.

Materials for the manufacture of strip foundation

For the manufacture of the base will need various materials. It all depends on its type. So, for the construction of a prefabricated foundation, the following materials are used:

• concrete blocks and slabs of a certain brand;
• concrete for sealing holes between blocks;
• materials for waterproofing and thermal insulation.

Photo of the foundation with collapsible formwork:

One of the waterproofing options - it is laid even in the process of formwork assembly Source readmehouse.ru

Laying out a tape exclusively from blocks is almost impossible. Therefore, concrete mortar and even bricks are used to fill gaps. It is also recommended to arrange a reinforced concrete tape, which will allow you to connect all the elements into one.

As for the monolithic structure, for its construction you will need:

• boards or polystyrene foam for the construction of formwork;
• fittings for the manufacture of the belt and connecting elements;
• concrete of a certain class;
• heat and waterproofing materials.

When constructing a strip foundation for a house, it should be borne in mind that there is a need to carry out certain work. This applies to the arrangement of the pillow. To do this, you need sand or gravel, as well as waterproofing material.

Strip foundation design process

Foundation design is a very complex and responsible task, the solution of which is best left to professionals. In doing so, you need to determine:

• Soil type.
• Its calculated resistance.
• Linear loads.
• Burying depth.
• The width of the sole of the tape.
• Purpose and features of reinforcement.
• The possibility of arranging drainage.

Scheme for arranging drainage of a strip foundation Source krovli-zabori.ru

In order to determine these values, it is necessary to have certain knowledge. That is why it is better to entrust this work to professionals. Only they can do it well. It is worth remembering that the strength and durability of not only the foundation, but also the structure erected on it will depend on this.

Basement in a house with a strip foundation

The arrangement of the basement in a house with a strip foundation is a very time-consuming and costly process. To resolve this issue, it will be necessary to involve construction equipment and carry out false earthworks and concrete works. The arrangement of the basement is carried out in the following sequence:

• A pit of established dimensions is dug. If it is being built under the whole house, then heavy construction equipment will be needed for this. The process must be carried out very carefully so as not to bring down the ground.
• A crushed stone pillow is made along the bottom of the pit and concrete is poured. To give the floor strength, reinforcement is performed. The fittings should stick out a little around the perimeter, in those places where the walls will be installed.

Source doka-metal.ru

• When the floor is completely hardened, the walls are reinforced and the formwork is installed for further concrete pouring. If the basement is installed only under a part of the house, then reinforcement is produced, which will later be connected to the reinforced belt of the strip foundation.

When constructing walls, special attention should be paid to their height. They must match the top of the foundation. After the construction of the foundation, the basement is covered by pouring a monolithic slab.

The depth of the strip foundation for the house

The depth of the foundation is calculated at the design stage. The recessed structure is installed so that its sole is 25 cm below the freezing level of the soil. This will protect it from uneven deformations that occur during frost heaving of the soil.

The height of the structure depends on the climatic features of a particular area. The freezing depth is determined by the formula. But, there is a ready-made table where you can find these values ​​for a particular region.

Approximate depth of soil freezing in various regions of the Russian Federation and the CIS Source izchegopostroit.ru

If speak about shallow foundation, then it is located at a distance of 85 cm from the level of soil freezing. When constructing a structure, it is worth considering that it will have a low bearing capacity. Also, when constructing the foundation, it is worth considering the level of groundwater. The sole should be located at a distance of 20 cm from it. So, how to make a strip foundation?

Stages of erection of a strip foundation

Making a strip foundation is not such a difficult task. But in order to do the job correctly, you need to carefully study all the nuances and requirements. And it’s worth starting with drawing up a design diagram. It indicates the dimensions of the elements, which will make it easy to carry out its construction. Also, according to this scheme, you can calculate the required amount of materials.

The strip foundation technology looks something like this:

• ground preparation;
• work with formwork;
• waterproofing;
• frame reinforcement;
• concreting of the strip foundation;

Foundation preparation

At the preparation stage, calculation, marking and other equally important work are carried out. It is worth starting with a geological recovery - this work is entrusted exclusively to specialists.

Competent geological surveys require special equipment and specialized knowledge Source ro.decorexpro.com

In the process of geological recovery, the following should be determined:

• type of soil at the level of the sole of the base;
• ground water level;

After that, the occurrence mark and the thickness of the monolithic tape are calculated. When the geological penalties are over, they begin marking the site. To do this, use a wooden board and cord. You can also use lime mortar. With its help, a mark is made on the ground where the tape will pass. To simplify the task, the work is carried out using a pre-prepared foundation scheme.

Marking starts from one corner. After that, a side is planned. It is better to do it parallel to the fence or the road. Next, the other side is outlined, and so on. In this case, it is worth carefully checking the angles and diagonals. This will avoid problems with the construction of walls. The allowable error between the diagonals is 2 cm.

According to the markings, digging a pit or trenches is carried out. The first option is used in the construction of houses with a basement. Here you will need the use of heavy construction equipment.

Video description

Why the foundation is being prepared, see the following video:

At the bottom of the prepared pit or trench, a sand cushion is arranged. The thickness of the embankment can reach 50 cm. This parameter depends on the characteristics of the soil. The pillow is carefully compacted. This is done by vibrating or pouring water. A prepared layer is made on top of the pillow. For this, lean concrete is poured with a thickness of not more than 10 cm.

Formwork and waterproofing

The device of the strip foundation is carried out using the following types of formwork:

• removable, which is made of wooden boards;
• fixed, made of expanded polystyrene.

The peculiarity of the second option is that polystyrene foam plays the role of a heat and waterproofing layer. The formwork is set strictly according to the applied markings. It rises 10 cm above the foundation. To ensure the stability of the structure, it is supported by props from the inside and outside. A plastic film is laid in the formwork, which will prevent the flow of cement laitance.

On the inside of the formwork, mark the top point of the concrete. To do this, use a marker. In the process of carrying out this work, a hydraulic level is used. This will allow the concrete to be poured evenly.

Video description

What a fixed waterproofing formwork looks like, see the following video:

Frame reinforcement

For the manufacture of the frame, three types of reinforcement are used that perform a specific task:

• working longitudinal reinforcement with a diameter of 12 mm or more;
• horizontal clamps - from 6 mm;
• vertical clamps - from 8 mm.

Before you buy reinforcement, you need to calculate how much it will take to build the frame. In this case, it is worth considering the features of its design. The distance between the clamps is on average 25 cm. In the corners and at the joints of the walls, the step is somewhat reduced. When reinforcing, it is worth observing certain norms and requirements.

Video description

For more about reinforcement, see the following video:

Strip foundation concreting

Now you need to decide how to fill the strip foundation? If it is of considerable size, then it is better to order a ready-made concrete solution, which will allow you to pour the formwork in one go.

When concreting, you should follow some rules:

• Filling is carried out in one day. The break should not exceed two hours.
• It is necessary to drain concrete from the mixer from different points. If you stretch the solution, it will slightly reduce its quality.
• Concrete mortar can be dropped from a height of no more than two meters.
• The concrete solution is compacted with a vibrator or by baying.

It is better to fill the strip foundation at an average daily temperature, which is about 20 ° C. After completion, the structure is covered with a plastic film, which will slow down the loss of moisture.

Video description

Visually about the entire technology of creating strip foundations, see the following video:

Conclusion

The construction of a strip foundation, although it seems to be a fairly simple matter, but a lot of effort and materials are spent on it, and in terms of cost, this is about a third of the entire construction budget. A good foundation is calculated for the project of a particular house and it is better to entrust this work to professionals. Do not forget that the life of the building will depend on the quality and strength of the foundation.

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