The most common material for building a foundation is reinforced concrete. The optimal structure in terms of labor intensity and cost is a structure made of a monolith. This method avoids the need for lifting equipment, but requires strict adherence to technology. Pouring the foundation with your own hands should begin only after a detailed study of the stages of the process.
The design and construction of the supporting part of a building begins with a study of the soil characteristics. There are two options for performing this task:
- contacting a specialized company that will perform a full geological study with laboratory tests;
- self-study using test pits or hand drilling.
The first option will allow you to determine the strength characteristics of the soil most accurately. Before pouring the foundation of a multi-story building, such an event is mandatory. For buildings with a low degree of responsibility and private buildings, you can study the soil visually using GOST 25100-2011 “Soils. Classification"" determine its type. Based on which group the base belongs to, its approximate strength is assigned. The method does not provide high accuracy, but can be used to save money.
Marking axes and dimensions of the structure
An important stage that affects all other building structures. If you make a mistake in marking the foundation, the distance between the walls will change. This is especially critical if prefabricated elements are used for walls and ceilings. Marking is carried out correctly using the following technology:
- removal of the fertile soil layer, which is from 30 cm;
- designation of the first side of the house (most often marked parallel to the front boundary of the site or fence);
- then mark the points on the first side, which will be the corners of the house;
- From the marks, right angles are built using the Egyptian triangle method; all walls and corners of the building are marked using the same method.
Marking the foundation using cast-offs.
Marking the foundation can be done using pegs or full cast-offs made of vertical posts and horizontal lintels. The elements are installed at a certain distance from the axes of the building so that they do not interfere with the work when excavating trenches or pits. After completing the excavation work, a thread or cord is attached to the wooden markings, which will mark the contours of the supporting structure of the house.
It is important to control the following points related to geometry:
- compliance of the design lengths of the sides with the actual ones;
- the equality of the diagonals of structures that have a rectangular or square shape in plan (deviation of no more than 20 mm is allowed), the coincidence of the diagonals indicates that all angles of the rectangle are equal to 90°.
Development of the soil and laying of the cushion
The most difficult excavation work is if you fill the foundation yourself using tape technology. To dig a trench or pit yourself (if there is a basement), in this case you will need quite large penetrations into the ground. In this case, the following recommendations should be observed:
- The width of the trench is set to be 0.8-1 meter greater than the width of the foundation to provide access to the structure when performing waterproofing and insulation.
- It is important to correctly brace the walls of a pit or trench. If you miss this moment, filling work can become dangerous to life and health. This is especially true when constructing buried foundations. The maximum height of a trench with vertical walls without reinforcement depends on the type of soil. More detailed information is presented in the table below.
- It is also important to take into account the angle of internal friction of the soil (natural slope). When constructing an angle equal to this value from the bottom of the pit, a minimum distance is obtained at which massive equipment can be installed or materials can be stored.
After excavation of the pit or trenches, the need for backfilling under the base is considered. According to SP 50-101-2004, it can be made of sand (medium or coarse), sand-gravel mixture or gravel. Before pouring the foundation, it is worth laying the bedding in the following cases:
- depth below freezing in heaving soil;
- the presence of a bulk layer (it is replaced with a more durable material).
In other cases, there is no urgent need to lay the substrate. In general, bedding performs two functions:
- leveling the base under the base of the foundation;
- prevents capillary moisture from rising to the structure.
This element is necessary to remove excess moisture from the supporting part of the house. It is carried out even when the groundwater level is low to prevent troubles when liquid rises in the spring or during large amounts of precipitation. Work on laying drainage pipes must be carried out in accordance with the following recommendations:
- depth relative to the base of the foundation by 30-50 cm;
- the distance from the foundation of the house is no more than 1 m;
- the slope of the pipes in one direction is assumed to be 3-4 degrees so that the liquid moves by gravity;
- To prevent silting, the crushed stone laid around the pipes is wrapped in a layer of geotextile with an overlap of 30 cm.
Formwork work
Formwork for pouring concrete according to GOST R 52085-2003 is classified according to the following criteria:
- design;
- materials;
- turnover (possibility of reuse);
- possibility of use at different ambient temperatures;
- impact on the concrete mixture.
In addition, the filling mold can be removable and. One of the most common removable options is wooden; among non-removable ones, polystyrene foam is most often used. It is also possible to manufacture from materials such as metal, plastic, foam concrete, and moisture-resistant plywood.
When installing formwork, you need to control:
- accuracy of geometric dimensions and installation;
- shield stability;
- tightness (seams no more than 2 mm).
The placement of reinforcement is necessary to increase the structure's ability to resist bending loads. Reinforcement of strip and column bases is performed with spatial frames. Meshes are used for the slab. If the structure thickness is more than 150 mm, the mesh is laid in two layers. The following are the main recommendations for reinforcement:
- calculations for a private house can be performed in a simplified form, assigning the total area of the rods depending on the cross-section of the structure; the minimum diameters differ for different types and sizes of foundation, so this issue requires separate consideration;
- for the manufacture of frames and meshes, reinforcement of a strength class not lower than A400 can be used, but the use of rods A500 and higher is not economically justified;
- it is important to observe the protective layers of concrete; in general, it is worth remembering the following numbers: foundations without concrete preparation - 70 mm, with concrete preparation - 40 mm;
- reinforcement should be provided in the corners; usually the pitch of transverse horizontal and vertical reinforcement is halved, and the main reinforcement is also reinforced with U or L shaped clamps.
After installing the formwork and reinforcement cage, they begin filling with concrete mixture. The following are recommendations on how to properly pour a foundation for a house:
- Filling is done in one step. Breaks are allowed only during the setting period of the solution, which depends on the type of binder and weather conditions. On average, a break is allowed for 1-2 hours.
- It is best to carry out work at a temperature of 20°C. At lower values, the period of strength gain by the material increases. When the temperature rises to 30°C, the characteristics of concrete may deteriorate. It is important that there is no dry weather during pouring, since high-quality pouring requires air humidity of approximately 80%. Also, you should not carry out work in the rain, if it started during the work process, use plastic film. It is laid immediately after pouring.
- The formwork is filled so that 2-5 cm remains from the top edge of its panels to the mortar level.
- Liquid concrete is poured by moving the mixer from point to point. Pouring from one point followed by manual movement reduces the quality of the material.
- Concrete mixture cannot be dropped from a height of more than 2m.
- After pouring, thoroughly compact the solution using deep vibrators. Such a tool provides compaction to a depth equal to 1.25 of the length of the tip. It is recommended to first pour the mixture into the formwork to a height of 60 cm, then compact it and pour another 60 cm. The operation is repeated until the design mark is reached. It is important that all stages occur before the previous layer finishes setting.
Concrete maintenance and formwork removal
Recommendations on how to properly pour the foundation for a house are not limited to laying the mixture. The process of gaining brand strength will take an average of 28 days. During the first weeks, the structure will require maintenance to prevent cracks from appearing on the surface. Its first stage is covering it with plastic film, tarpaulin or burlap, which will not allow moisture to evaporate too quickly.
- in the daytime, moisturizing is carried out every 2-3 hours;
- During the night it is enough to perform the operation 1-2 times.
Formwork according to SP 70.13330 can be removed only after the concrete has gained 70% strength. When justified, it is allowed to perform work at 50% of the brand value. The time spent on this process depends on the outside temperature. Concrete using a normally hardening binder gains the required strength at a temperature of 20°C in 5-7 days, at 10°C in 28 days, and at lower temperatures the process slows down significantly.
Read more about stripping.
backfilling
When making a strip or columnar foundation, or less often a slab foundation, it is necessary to backfill the cavities of the pit or trench after removing the formwork. It is important to observe the following principles:
- work begins only after the soil reaches optimal moisture content;
- for backfilling, soil that is denser and has better strength characteristics is used compared to the extracted soil (coarse sand is often used);
- the work is performed in layers, the maximum thickness of the material at each stage is 30 cm;
- each layer must be compacted before laying the next one;
- The backfill material should not contain foreign components or organic inclusions.
Compliance with technology at all stages of concrete pouring will allow you to obtain a reliable and durable structure that will last for many years.
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Pouring the foundation is one of the first stages of building a house. Theoretically, there is nothing complicated about this - you dug a hole, filled the bottom with sand, poured concrete on top, and all you have to do is wait until the cement hardens. But in fact, only professional builders know how to properly pour the foundation for a house; There are quite a lot of nuances here - from the installation of formwork to the correct vibration of already poured concrete, not to mention the fact that this work is hard and dirty.
Pouring a strip foundation - this job definitely cannot be called clean
Information about the soil and nearby buildings
Starting to do something without prior preparation is simply unwise. The beginning of all beginnings in construction is the preparation of project documentation; and designing a house and foundation, in turn, can only be done based on the results of a geological examination of the site, which will reveal the individual characteristics of the soil and take into account the relief.
The lowest freezing point of the soil in winter will allow you to determine the type of foundation and its depth. It is better to entrust a detailed analysis of the soil and the choice of foundation type to qualified specialists.
Landscape design will help you choose the most convenient location of the house, auxiliary buildings, paths and gazebos. Modern technologies allow you to see your future home from all angles.
The linear dimensions of the base are only part of the foundation design
Preparatory work
The preparatory work stage occupies an important place in the process of building a house. First of all, it is necessary to clear the area of construction debris, cut down excess trees and uproot stumps, and remove dry grass.
Preliminary zoning of the site will allow you to effectively use every corner during operation. It is best to level the surrounding area before starting construction work and laying the foundation. This will not only give the site an attractive appearance, but will greatly facilitate construction work at all stages. The terrain with large differences requires stepwise leveling of the territory.
Next, the exact location of the house is determined and the foundation is marked. To do this, pegs are installed in all corners of the future building. If the house is a standard rectangular shape, the result should be a figure with perfectly equal angles of 90°. If the angle is not maintained, it is necessary to achieve this result by moving the limit cord in one direction or another.
Along the future walls, at the same distance from each other, pegs are also installed and a rope or cord is pulled between them. The diagonals drawn between the corners of the building must be exactly equal to each other.
An example of checking angles in markings - if the diagonals are equal, then all angles are 90°
When marking for a strip foundation, it is necessary to retreat from the walls of the house at a distance equal to the width of the foundation. Most often this figure is no more than 20 cm.
You can dig a trench either by hand or using specialized equipment. It is formed at least 20 cm below the freezing point of the ground, characteristic of the area in winter. It is necessary to dig a trench strictly following the markings and forming a flat bottom.
Methods for saving a house foundation
One of the exciting questions when building a house is how to lay the foundation for a house cheaply and efficiently. There are several ways to save at least a little:Digging the soil and pouring the foundation for a house with a concrete mixture is the most expensive stage in the construction of a country house. Whether to do all the work yourself or entrust it to professionals - everyone decides for themselves.
Forming a shallow foundation will save a significant amount of money. However, it is only suitable for the construction of low-rise buildings made of lightweight materials. In all other cases, a deep foundation is used, erected below the freezing point of the ground.
The formwork is assembled from boards, which can later be used as a subfloor or for other work in which the appearance of the material will be of secondary importance.
After the concrete has hardened, the formwork boards are removed and can be reused
On our website you can find contacts of construction companies that offer foundation construction and repair services. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.
When pouring a slab foundation, you can save money by using a thinner base with the formation of stiffeners.
The possibility of using fiberglass reinforcement instead of steel materials will also allow for minor savings.
Features of pouring a slab foundation
Slab foundations are most often used in the construction of brick, frame and stone country houses. In this case, the slab is located not only under the load-bearing walls of the house, but also under the entire structure and requires the formation of a perfectly flat surface.
To fill a slab foundation, a sand cushion up to 30 cm high is poured, reinforced concrete slabs are laid, a reinforcing frame is formed and a concrete screed is made.
It is the most expensive, but it fully ensures the strength and reliability of the foundation during the operation of the facility.
The slab foundation has a rather complex structure
Features of pouring a columnar foundation
A column foundation is often confused with a pile foundation, but in fact these are two completely different technologies. If the piles are necessarily screwed in below the freezing depth of the soil, then the columnar pile is a hole, about 50-70 cm deep, the bottom of which is covered with sand, and concrete is poured on top, mixed with some stones.
On a note! A columnar foundation is not suitable for a residential building, since it is designed for ultra-light buildings - small bathhouses without a stone stove, gazebos, sheds and similar outbuildings.
A columnar foundation does not require additional waterproofing work, but, like a pile foundation, it excludes the possibility of arranging a cellar or basement. Since it is laid at a shallow depth, it is mainly used on sandy soils and sandy loams, which are indifferent to heaving and natural soil movement.
To pour a columnar foundation, concrete blocks are used, fastened together with reinforcement and filled with ready-made concrete mixture. Any material is suitable for forming concrete blocks:
-
cobblestones;
ready-made reinforced concrete blocks.
Columnar foundation - a shallow budget foundation for outbuildings
Poles are installed in all corners, as well as at the intersections of walls and points with increased load at a distance of no more than 2 meters from each other. In this case, formwork is formed, pillars are installed and pulled together with reinforcing material. The entire structure is filled with a mixture of concrete.
Technology for arranging the foundation for a house
The strip foundation is laid at a depth below the freezing point of the soil. Pouring a strip foundation includes the following steps:
preparatory work;
trench formation;
arrangement of a sand cushion;
formation of a reinforcing frame;
installation of formwork;
mixing the concrete mixture and pouring the frame.
Video description
To see all the work involved in preparing the site and pouring the foundation, watch the video:
Formwork
Before pouring the foundation for the house, it is necessary to form a strong, reliable formwork. To form removable formwork you can use:
wood;
Permanent formwork becomes part of the structure and avoids the dismantling stage. To form it use:
expanded polystyrene;
wood boards;
fiberboard
Permanent formwork block for strip foundation
Reinforcement
To form a reinforcing frame, reinforcing rods are installed in the corners. Longitudinal reinforcement is laid at the bottom of the trench and vertical rods are installed every 30 cm, the height of which exceeds the depth of the trench by the height of the foundation above ground level. This distance should be at least 25 cm.
Horizontal reinforcing rods are attached at equal distances from each other in several levels to the very top of the formwork. The frame fragments can be tied together using soft wire.
Drainage
A necessary stage of work when building a house is drainage. It allows you to remove excess moisture from the building during the rainy season or spring snow melting.
Corrugated pipes are used to form a drainage system. They are laid to a depth of up to 50 cm in pre-equipped trenches along the entire perimeter of the house at a distance of no more than one meter from its walls.
So that water and moisture can move by gravity through the pipes, they are laid with a slight slope and a geotextile winding is made.
Video description
Visually about foundation drainage in the video:
Ballast
To form the foundation, concrete grades M200 - M400 are usually used. When mixing a concrete mixture, a mixture of river sand and gravel is often used as a filler. For the construction of a country house, the ratio of these materials, taken in proportions of 3:1, will be sufficient to mix the total mixture.
Pouring the foundation
Preparing a high-quality concrete mixture and pouring the foundation is an important stage in the construction work of a country house.
sand cushion
A sand cushion is a necessary element in the construction of any structure. To form it, the bottom of the trench is covered with river sand to a height of at least 20 cm. Each layer of sand is thoroughly spilled with water and compacted.
Formwork
To reinforce the foundation, reinforcement and reinforcing rods of various diameters are used. It is better to use thicker reinforcement along the trench. Reinforcing elements can be connected using soft wire.
Work progress
If you purchase concrete from a factory, you won’t have to think about how to pour the foundation for a country house. The automixer will evenly mix the concrete mixture to a uniform, plastic consistency and unload the finished concrete directly onto the site prepared for the foundation.
The automixer will not only bring concrete to the construction site, but will also pour it directly into the foundation formwork
Work begins from the corners of the foundation, trying to tightly fill all the voids. The concrete is evenly distributed around the entire perimeter using a shovel, excess air and bubbles are removed.
The finished foundation is wrapped in film and the surface is periodically moistened. This will help prevent the formation of numerous cracks during drying.
Conclusion
We looked at all the nuances of how to properly pour the foundation for a house. From which it follows that strict adherence to all technological stages of work and their high-quality implementation will fully ensure the strength and reliability of the house during operation and will allow you to avoid irreparable mistakes, therefore it is strongly recommended to entrust this work to professionals.
Even novice builders can build their own foundation. The key to success is strict compliance with all basic requirements, from the creation of the project to the arrangement of the blind area.
The foundation for a structure is one of the most important structural elements, the quality of which will ensure a fairly long service life of the structure. You can often hear that you shouldn’t save on pouring the foundation. Today we’ll talk about how to properly build a foundation for a house and at the same time reduce costs, of course, within reasonable limits.
Main stages
There are different types of foundations, but each of them has certain stages of arrangement.
We note that the installation of foundations can be performed according to the following algorithm:
- Preliminary preparation of the site and marking it.
- Arrangement of trenches or recesses for supports.
- Providing a cushion for the foundation of the house.
- Carrying out the reinforcement process.
- Pouring with concrete mixture.
Each type of foundation is good in its own way in certain conditions. When deciding which foundation to choose for your home, we pay attention to the geological conditions and expected load.
Today we will focus on the most common type - strip concrete foundations.
They are suitable for almost any type of soil and can withstand considerable loads.
Technology for arranging the foundation for a house
It is easier to pour a shallow foundation than a shallow foundation
Strip foundations can be deep and shallow. The first is laid at a depth below the soil freezing level. The technology for pouring a shallow foundation is a little simpler, but the algorithm for performing the work is similar.
Preparatory work
- clearing the site of all kinds of debris and excess vegetation;
- leveling the construction site by removing part of the fertile soil;
- applying markings in accordance with the project.
To make accurate markings, we will stock up on such devices as a measuring tape, stakes and rope.
Drive the first stakes into the corners of the house We start by marking the outer wall. First of all, we hammer the stakes into the outer corners of the future house. The result is a shape - a rectangle.
To make sure that the process is performed correctly, we check the lengths of its opposite sides and diagonals. They must be equal in pairs. Otherwise, by moving the stakes we achieve the desired result.
It must be remembered that the more accurately the markings for the foundation are made, the fewer difficulties will arise when performing further work.
Construction of the trench
Digging a trench by hand is cheaper and easier There are two ways to prepare a trench for a strip foundation: using equipment and manually. Of course, using an excavator, the trench can be prepared faster and cheaper. But some nuances should be taken into account: the boundaries of the trench will be uneven, and much more concrete will be needed during pouring. It is clear that there is no need to talk about savings.
Arranging the trench manually with your own hands or with the help of hired workers will ensure its clear boundaries and the required width. In the future, the amount of concrete mixture will be consumed according to the project. This will help to accurately determine the volume of ready-made concrete when purchasing it.
We provide a sand cushion
For the sand cushion, use sifted clean sand. The sand cushion helps to more evenly distribute the load of the structure on the ground, so experts do not recommend excluding this process from the general sequence of actions.
It is best if the pillow is made of pure sand, which does not contain excessive clay impurities. Sand does not have the property of heaving, which makes it possible to reduce soil pressure on the base of the base. Also, water does not stagnate in it, but is evenly distributed over its entire surface. All this will ensure a more uniform shrinkage of the foundation.
When arranging a sand cushion, a layer of sand is poured into a 20 cm thick trench and compaction is carried out simultaneously with pouring.
Reinforcement process
The diameter of the rod depends on the planned loads We make a solid foundation for the house. This property can be ensured by the process of reinforcing the tape with reinforcing rods. To reinforce the strip base, steel reinforcing bars of various diametrical sections are used.
The cross-sectional dimensions of the rods depend on the expected load. Typically, reinforcement is purchased by weight. This table will help you understand the required quantity of rods to purchase depending on their cross-section.
Typically, rods that are installed vertically are used with a smaller cross-section than those that are laid horizontally. So, for example, if vertical rods have a diametrical cross-section of 8–10 mm, then horizontal rods have a diametrical cross-section of 12–14 mm. For more information about reinforcement, watch this video:
This feature is explained by the fact that more load falls on the horizontal part of the reinforcement frame.
It is better to knit the reinforcement cage on the surface, and not in the trench itself. This will make the process much easier and prevent the trench from collapsing.
Experts recommend knitting rods using a special soft wire. The use of welding is not encouraged, as the joints are not strong due to the burning of the crystal lattices, and during the subsidence of the soil, their damage may occur.
To give the strip foundation the correct shape and ensure its elevation at a certain height above the ground, it is necessary to install formwork.
Most often, it is assembled from wooden boards, the width of which is up to 20 cm, and the thickness from 2.5 cm to 4 cm, depending on the height to which the concrete foundation will be built.
The greater the height of the base, the greater the concrete pressure on the formwork walls.
When installing formwork, we pay attention to the following nuances:
- The boards should fit together as tightly as possible.
- The opposite walls of the formwork are connected to each other by special crossbars.
- On the outer sides, the walls are supported by supports, which ensure the rigidity of the structure.
It should be remembered that the most problematic places in the formwork are the corners, so we pay special attention to the corner fastenings of the base.
Pouring concrete
Pouring the foundation for a house with concrete is a very important moment. It is best to purchase ready-made concrete for this purpose. It has a uniform consistency and requires less time, which prevents the formation of concrete seams. Only in this case will the installation of a monolithic foundation be carried out at a high level. But for this it is necessary to ensure free access of transport to the construction site. See this video for all the details of the process:
If you decide to prepare concrete yourself, then we will try to tell you in detail how to pour the foundation for a house correctly. We start by determining the grade of concrete. A concrete mixture M-200 - M-400 is suitable for this.
It is necessary to start pouring the concrete foundation from the corners and only then fill the remaining voids formed.
In order for the work to progress and the strip foundation for the future house to be poured in the shortest possible time, it is necessary to ensure the free movement of the concrete mixer to any point on the construction site.
When pouring, concrete is distributed in parallel using a shovel, and then using an internal vibrator we compact the concrete mixture.
How to pour the foundation for a house in private construction without a vibrator? Its functions can be performed using a bayonet shovel. It is necessary to constantly bayonet and gently tap on the reinforcing frame. These simple steps will also help to distribute the concrete evenly. To learn how concrete is poured into a trench without formwork, watch this useful video:
As you can see, pouring a concrete foundation is not difficult, but you should still pay special attention to the method of distributing concrete along the foundation trench for a house. Concreting the base is completed by carefully leveling the surface.
Concrete should be poured into the trench continuously After this, we let the foundation settle. This will take at least a month. Don't forget to water it constantly. This will prevent cracking of its surface.
So, how to make a foundation for a house is clear from the recommendations presented in this article. It is only necessary to correctly assess the situation, decide on the project and strictly adhere to the order of the stages.
To make the foundation correctly, you need to carefully study the options for construction types and their features. The construction of the underground part is carried out taking into account the following requirements:
- economic expediency;
- reliability;
- strength;
- durability;
- sustainability.
Before starting construction work, a soil study should be carried out. The choice of the right type of foundation is influenced by the total weight of the house, the strength of the soil and the groundwater level. A foundation that is carefully made and built in compliance with technology will last a long time and will not cause problems during operation.
Preparatory stage
It’s worth starting with pits or drilling. The main goal of this activity is to find out what soils are located on the site, as well as to find out the level of groundwater. The foundation must be laid in compliance with the rule: the mark of the sole must be at least 50 cm above the level of the water horizon.
How to do soil testing correctly? Two methods are used for this:
- excerpts of pits (deep holes, dimensions in plan are usually 1x2 m);
- manual drilling.
In the first case, the soil on the walls of the pit is examined. They also check to see if water has left the bottom. In the second option, the soil on the tool blades is examined.
Once you have determined what kind of soil is on the site, you will need to find its strength indicators. This can be done using special tables.
The cost of laying the foundation for a house can be up to 30% of the estimate for the entire building. To avoid cost overruns, you need to perform a calculation that will allow you to find the optimal design parameters that will simultaneously guarantee minimum costs, strength and reliability. For your convenience, you can use online payment.
Types of foundations
Building a foundation with your own hands involves the use of several technologies:
- ribbon;
- combined options.
Columnar supports have a low load-bearing capacity. It is possible to install monolithic pillars or assemble them into compact concrete blocks. Both options are great for DIY projects.
There are three types of pile foundation for a house:
- driven (not recommended for private buildings due to the need to attract equipment);
- (suitable for building a brick or concrete house);
- (ideal for light wooden buildings).
Piles make it possible to reduce the amount of excavation work. There is no need to dig trenches or a foundation pit or transport large amounts of soil outside the site. Thanks to this quality, installing this type of foundation is a very economical choice. The main disadvantage will be the impossibility of equipping a basement or underground for utilities. In this case, the base of the building is covered with decorative materials.
Another advantage of piles is the possibility of using them in wetlands. Even if the groundwater level is located close to the ground surface, the supports provide the necessary load-bearing capacity.
The next option is tape. It can be made monolithic or from blocks. The second option is rational to use for mass construction. Strip foundations are:
- recessed (for buildings with a basement, brick and concrete structures);
- (for wooden and frame houses);
- non-buried (technology of pouring foundations for small buildings on a solid foundation).
Before making a tape, it is worth checking the groundwater level and compliance with the rule that the sole cannot be closer than 50 cm to the groundwater horizon. Otherwise, there is a high probability of flooding of the basement, reducing the load-bearing capacity of the foundation and destruction of the materials of the supporting part of the building.
What to do with high groundwater level? If the structure is made independently from brick or stone, screw piles will not be suitable, and for bored piles it will be necessary to lower the water level. An excellent option would be filling. In this case, a non-recessed or slightly recessed base is made. The thickness of the slab is determined depending on the load, on average 300-400 mm.
How to pour a foundation for a house
Monolithic foundation type is the best option for private housing construction. In this case, laying can significantly save on transportation and installation of structures. There is no need to hire a crane to install elements in the designed position or a KamAZ truck to transport concrete blocks and slabs.
Monolithic foundations can be made from factory-made concrete or you can mix the solution yourself using a concrete mixer. The first option is recommended. The fact is that it is very difficult to strictly observe the proportions of the composition in artisanal conditions. For factory-mixed concrete, such a guarantor will be a passport, which indicates the verified indicators of the material.
To make the material yourself, you will need to prepare clean water, cement, sand and crushed stone (or gravel). They are mixed with each other strictly observing proportions, which depend on what grade of concrete needs to be obtained. If you add a little more sand or crushed stone to the composition than required, the strength of the supporting part of the building will suffer.
To properly pour the foundation, you need to familiarize yourself with the basic rules of concreting:
- Concrete must be poured in one go at time intervals of up to 1.5 hours. If you take long breaks in work, the solution sets and concreting joints form, which weaken the structure. The technology allows making horizontal seams if absolutely necessary. It is unacceptable to install vertical seams on a monolithic foundation, since in this case the support of the house will not be able to resist soil deformations.
- The class of concrete is selected depending on the type of supporting part. For a columnar or pile foundation, class B 15 is sufficient. For tape, grades from B 15 to B 22.5 are needed. Construction of a house foundation using slab technology requires concrete grades B 22.5 or B 25.
- After pouring, the material should gain strength. On average, this takes 28 days. Construction work can continue after the structure reaches 70% of its original strength.
- It is better to carry out work in warm, dry weather. The ideal average daily temperature for concrete hardening is +25°C. At temperatures below +5°C the material practically does not harden. For normal hardening in this case, special additives and heating are used.
- The concrete must be maintained within 1-2 weeks after pouring. It involves wetting the surface with water.
- To mix the mixture yourself, you will need cement, sand, crushed stone (gravel) and clean water. The proportions depend on the strength class. The material is delivered from the factory using a concrete mixer truck - it allows you to extend the life of the solution and deliver it over relatively long distances.
How to pour the foundation correctly? In general, work is performed in this order:
- installation of formwork and reinforcement cage;
- laying waterproofing material in formwork;
- pouring concrete;
- its compaction by vibration or bayonet;
- curing;
- stripping works (if necessary).
To quickly complete the work, it is recommended to order a concrete pump together with a concrete mixer. Concrete manufacturers are usually willing to provide this technique. In this case, it is necessary to use a concrete mixture of grades P3 or P4 in terms of mobility. Otherwise, the equipment breaks down.
Step-by-step instructions for pouring a strip foundation
Concreting is considered using the example of a monolithic tape. To erect the supporting part of the structure, construction is necessary. To do this, use cast-offs and construction cord. You need to show the edges of the tape.
After marking, the soil is excavated. If there is no basement, it is enough to dig a trench. At its bottom you need to make a sand cushion. It performs several functions:
- ground leveling;
- prevention of frost heaving;
The edges of the trench must go exactly along the cord Next stage - . For this purpose, the material included in the estimate is used: boards (removable type) or polystyrene foam (non-removable). The second option serves not only as a form for pouring concrete, but also as insulation of the underground part of the building. When installing the formwork, I raise the base to the desired height.
The content of the articleOne of the cheapest methods for constructing a foundation is a strip structure. It can be made as a prefabricated structure (from individual reinforced concrete blocks), or a strip foundation for the house can be poured, done independently with the possible use of ready-made concrete mixtures.
Basic information about strip foundations
Strip foundations can be used in the construction of houses with or without basements. Either way, you get significant savings when choosing this type of foundation.
When constructing a basement, it is advisable to build a foundation in a ready-made pit using double-sided formwork; in this case, the foundation will play the role of basement walls.
A simpler method is to pour the structure into specially prepared trenches. In this case, you can save on the cost of formwork, because it is enough to install only its outer part, which, when using modern materials (formwork using extruded foam), will also become a reliable element of insulation and waterproofing.
The calculation of foundation parameters must be carried out by a civil engineer who will be able to calculate all design parameters depending on the condition of the soil, the presence of groundwater and other factors.
The entire technology of pouring a strip foundation can be divided into several stages:
- Preparing the base, installing formwork
- Manufacturing of reinforcing frame
- Pouring concrete mixture
Let's look at all these stages in more detail.
Preparatory and excavation work
The main issue of preparation is the calculation and purchase of necessary materials. If you decide to prepare the concrete mixture yourself, which will help somewhat reduce the cost of pouring a strip foundation, but will significantly increase the time of its construction, you need to bring the required amount of crushed stone, sand, and cement to the construction site.
In addition, before starting work, it is necessary to purchase formwork material and reinforcement; all this can be imported during the excavation process. In addition, to prepare concrete, you need to make sure you have a concrete mixer, which, in extreme cases, can be rented. But we would still recommend using ready-made concrete mixtures, which will greatly simplify the work.
As already mentioned, concrete can be laid either in trenches or in a foundation pit. In addition to the fact that constructing a pit will simplify the work on arranging the basement, in this case it is possible to arrange additional waterproofing of the building by installing a clay castle over the entire area, which will significantly reduce the access of groundwater to the building.
When performing excavation work, it is necessary to constantly monitor elevations; this will be the basis for the stability of the entire building.
The rules for pouring the foundation do not allow large differences in the base of the structure; of course, a small part can be corrected with the help of bedding, but for large volumes this will not give the desired effect.
In addition, trenches must be monitored along the axes of the building. To do this, they resort to the so-called cast-off, it is performed as follows. 2 m are retreated from the lines of the future walls, supports are mounted to which the boards are attached. Thus, we obtain a structure that follows the entire contour of the building, which facilitates excavation work.
Preparation of the base, installation of formwork
To reduce the impact of seasonal soil heaving, a sand cushion is installed along the entire perimeter of the foundation, which will serve as a shock absorber. It is performed to a height of 10-30 cm, followed by moistening and compaction; at this stage, the elevation marks of the base are finally adjusted.
The next stage is the construction of formwork; it can be made of various materials, in addition, the following types are distinguished:
- Fixed
- Removable
It is recommended to use expanded polystyrene formwork as a permanent formwork, which will act as insulation. Removable formwork is used mainly in large-scale construction and can be installed on a number of objects, although boards removed from the formwork can also be used in a private house.
Basic rules for installing formwork:
- Formwork panels must be installed vertically, this is checked with a plumb line or level.
- All structural elements must be carefully secured, otherwise, under the pressure of the mass of concrete, the formwork may lose its straightness or even collapse, which will lead to loss of concrete.
- When installing, do not forget to insert sleeves under future communications(electricity, water, sewerage).
- It is advisable to cover the surface of the formwork with inexpensive insulating material.
Pouring a strip foundation with your own hands will be more economical with high-quality formwork that prevents leakage of the concrete mixture.
The basis of a strip foundation, which increases its load-bearing capacity, is a frame made of reinforcement. Its diameter and location pitch must correspond to the project; it is not recommended to select such parameters independently.
The distance from the reinforcement to any external surfaces of the foundation must be at least 20 mm, thus forming a protective layer.
Reinforcement elements must be tied with special wire; welding is not permitted, since it deteriorates the structure of the reinforcement. You can tie the frame on the surface and, after installing it in the trench, connect its elements. This method allows you to perform work even in narrow trenches.
That, in principle, is all about the preparatory stages of pouring a strip foundation; you can proceed directly to the process.
