Strip foundation is one of the favorite types of foundation for developers. It is characterized by its durability and the possibility of making it yourself. There are many variations of this base. Strip foundations can be prefabricated or pile-strip. But the most common is considered to be a monolithic strip foundation. This is a classic that has been tested over the years.
What are the features of this type of foundation? What is it? What does a strip monolithic foundation look like? You can learn all this from this article.
What is remarkable about the strip foundation
If you look at the drawing of a strip foundation, you will see a characteristic strip that extends under all the walls of the house. It follows the contour of the box, making the base quite reliable. Why is it called monolithic? The fact is that this tape is made of a continuous layer of concrete reinforced with reinforced rods. This tape is unbreakable and durable.
If we compare a strip monolithic foundation with a columnar one, then we can say with confidence that its load-bearing capacity is much higher. Thanks to this, it is possible to build large houses with several floors. It doesn't have to be a tree. Aerated concrete and brick are used. Another advantage is the ability to perform installation without auxiliary heavy equipment. The same prefabricated version cannot be completed without a crane. Foundation slabs are heavy and you can’t lift them yourself.
To work, you definitely need to have a concrete mixer at the construction site. It will produce a concrete solution that will eventually fill the tape. As you understand, a lot of concrete will be required.
Advice! There is a simpler option: you can resort to the services of a specialized company that will deliver you the required amount of the mixture.
Also, for work you will need to take care of formwork materials. Without it, you will not be able to make the base of the building. As for the width and depth of the foundation for a house, it is selected taking into account many factors: the weight of the structure, the type of soil, the depth of groundwater and the freezing point of the soil. And the width of the foundation strip should be 10-15 cm greater than the thickness of the walls. The stock will be used for finishing. From all of the above it follows that the work on installing a monolithic strip foundation is quite expensive. This is true. It cannot be called cheap and fast. It will take a lot of materials, time and effort to build the structure. But there is one big plus - you have the opportunity to make a basement. The walls will be recessed strips, and the ceiling will be a monolithic ceiling in a strip foundation.
Types of strip foundations
Depending on the expected load on the foundation, the type of soil and the depth of soil freezing, strip foundations for a house can be of different types:
- Recessed base.
- Shallow base.
- Non-buried base.
A recessed strip foundation has the highest load-bearing capacity. Its use is rational when you are building a heavy brick house of several floors. In addition, the edge of the tape should be located 10-15 cm below the freezing point so that the foundation does not collapse. The sole must have a dense base. Therefore, the trench is deepened until the layer has good bearing capacity. For example, when the level of soil freezing is 1 m, and together with the fertile layer this figure is 1.2 m, then the trench is dug below 1.2 m.
Speaking about the shallow foundation, we can note the ease of operation. The foundation is suitable for ordinary soil, non-heaving, with excellent bearing capacity. As for the house itself. It can be made of wood or using frame technology. The depth can reach 70 cm or less.
But a non-buried strip foundation is used for light agricultural structures that do not place a large load on the foundation. Therefore, before installing a monolithic strip foundation, decide on the soil, freezing point and type of your building. Choose the type you need, make a drawing of it and get to work. Where does it all begin?
We begin the construction of a strip foundation: marking
You must take care of the necessary tools and materials in advance. Then the base is marked. To work you need to have:
- laser tape measure;
- hydraulic level;
- hammer;
- reinforcement bars;
- rope.
The work is performed as follows:
Digging a foundation pit
The markings were made so that you can quickly and easily dig a pit. When working, you should focus on the rope tape. Use shovel, crowbar and labor. Digging a pit yourself will be difficult and time-consuming. Dig until you reach the desired level. When working, it is important to make smooth walls and maintain verticality. Use a plumb line or hydraulic level.
When you dig to the desired point, you need to compact the bottom. Pour water over it and compact it. But that's not all the work. To protect your foundation from excess moisture and last longer, you need to make a base of sand and crushed stone. In addition, it evenly distributes the entire load from the monolithic tape. First, pour sand into the pit. Then pour water over it and tamp it down thoroughly. The dense layer should be 10 cm in size. Cover everything with crushed stone on top and compact it too.
Foundation formwork and reinforcement
This is an important structural part of the foundation, the construction of which requires attention. It will form the base of the building. The formwork is done on the ground. Since concrete mortar will be poured into it, it is important to make it sufficiently strong and airtight. Otherwise, the structure will collapse and concrete will leak out of it.
The classic forming option is the use of wooden boards and bars. The structure is connected to each other using nails or screws. Supports are made on the sides, and a screed of bars is stuffed on top. This foundation structure is removable. There are also permanent options in which the formwork will remain part of the base.
In order for a monolithic reinforced concrete foundation to be such, a mesh of reinforcement must be installed in the formwork. This is a frame that will make the concrete stronger. Metal wire is used for shaping. The frame is made of 4 longitudinal rods. The diameter can be 10 or 12 mm. For transverse and vertical parts of the structure, you can take reinforcement Ø8 mm. The recommended cell size of the reinforcing mesh is 20×25 cm.
Important point! The frame is installed in the foundation formwork, not on a substrate of sand and gravel. It should retreat 5 cm from the floor and walls of the trench. At the bottom it can be installed on bricks or other support.
Installation of fittings is a mandatory measure. Thus, the foundation will be much stronger and will not collapse at the first heaving of the soil.
Pouring a strip foundation with concrete
If you use factory-mixed concrete, it will undoubtedly be of better quality. But, if you cannot order it, you can prepare it yourself. For such work you cannot do without a concrete mixer. It will provide you with the required amount of concrete in the shortest possible time. For a high-quality mortar, use good cement, grade M400 and higher. One of the disadvantages of pouring it yourself is that you won't always be able to do it in one go. According to technology, it is better to build a monolithic foundation at a time so that expansion joints do not form between the layers. And pouring with a concrete mixer can take one or two days. In this case, it is done in layers. As a result, these cold seams can cause the foundation to collapse.
The solution is supplied from any corner of the foundation trench. Ideally, make a tray through which the contents of the concrete mixer will be delivered to the formwork.
Fill the concrete evenly, gradually compacting it. Ideally, use a special vibrating unit. If there is none, make a bayonet with a rod to expel the air and compact the concrete. So, it will be much stronger. When you have filled the base to the desired level, all that remains is to level the surface and wait for your monolithic strip base for the house to dry. During this period, cover it with plastic wrap to protect it from precipitation.
Advice! When pouring the foundation, you need to insert cutting pipes into the indicated places. They will serve as openings for communications.
Conclusion
This is where the strip foundation technology ends. It will take about a month for the base to dry. After 10 days, the concrete will dry enough for you to remove the sheathing. Now everything is ready for the full construction of the house. The floor can be made from a reinforced concrete floor slab, and the walls are built from the material of your choice.
Any building, regardless of its purpose, is unthinkable without a reliable foundation. Construction of the foundation is one of the most important and natural tasks of the entire construction cycle as a whole, and this stage, by the way, is often one of the most labor-intensive and costly - often up to a third of the estimate is spent on it. But at the same time, any simplifications, unreasonable savings on the quality and quantity of necessary materials, and neglect of current rules and technological recommendations must be absolutely excluded.
Of all the variety of foundation structures, it enjoys maximum popularity as the most universal, suitable for the majority of houses and commercial structures being built in the field of private construction. Such a base is highly reliable, but, of course, with high-quality execution. And the key condition for strength and durability is well-planned and correctly carried out reinforcement of the strip foundation, drawings and basic principles of construction of which will be discussed in this publication.
In addition to the diagrams, the article will provide several calculators that will help the novice builder in performing this rather difficult task of creating a strip foundation.
Important features of a strip foundation
General concepts. Advantages of a strip foundation
So, briefly, a few general concepts about the construction of a strip foundation. By itself, it represents a continuous concrete strip, without breaks into door or gate openings, which becomes the basis for the construction of all external walls and major internal partitions. The tape itself is buried to a certain calculated distance into the ground and at the same time protrudes from above with its base part. The width of the tape and the depth of its placement, as a rule, are maintained the same throughout the entire foundation. This form contributes to the most uniform distribution of all loads falling on the base of the building.
Strip foundations can also be divided into several varieties. So, they are not only poured from concrete, but also made prefabricated, using, for example, special foundation reinforced concrete blocks, or using rubble filling. However, since our article is devoted to reinforcement, in the future only the monolithic version of the foundation strip will be considered.
Strip foundations can be classified as a universal type of foundation. This scheme is usually preferred in the following cases:
- When constructing houses from heavy materials - stone, brick, reinforced concrete, building blocks and the like. In a word, when you need to evenly distribute a very significant load on the ground.
- When the developer plans to have a full-fledged basement or even a ground floor at his disposal, only a strip scheme can allow this.
- During the construction of multi-level buildings, using heavy interfloor slabs.
- When a building site is characterized by heterogeneity of the upper layers of the soil. The only exceptions are completely unstable soils, when creating a strip foundation becomes impossible or unprofitable, and it makes sense to turn to another scheme. Strip foundations are also impossible in regions with permafrost.
A monolithic strip foundation has a considerable number of other advantages, which include durability estimated over many decades, relative simplicity and clarity of construction, ample opportunities in terms of laying utilities and organizing insulated floors on the first floor. In terms of its strength properties, it is not inferior to monolithic slabs, and even surpasses them, while requiring less material costs.
However, one should not think that a strip foundation is an absolutely invulnerable structure. All of the listed advantages will be valid only if the parameters of the foundation being built for the house correspond to the conditions of the construction area, the design load, and have a built-in strength reserve. And this, in turn, means that the design of a foundation (any foundation, by the way) is always subject to special requirements. And tape reinforcement occupies one of the key positions in a series of these problems.
The width of the foundation strip and its depth
These are two key parameters on which the reinforcement scheme of the future foundation strip itself will depend.
Prices for fittings
fittings
But the degree of penetration into the ground strip foundations can be divided into two main categories:
- A shallow strip foundation is suitable for the construction of frame structures, small country houses and outbuildings, provided there is sufficiently stable, dense soil on the site. The base of the tape is located above the soil freezing line, that is, it usually does not fall below 500 mm without taking into account the base part.
- For buildings constructed from heavy materials, as well as in areas where the soil condition is not stable, a deep tape is required. Its base already drops below the soil freezing level by at least 300÷400 mm, and if there is also a basement in the construction plans, even lower.
It is clear that the height of the foundation strip as a whole, including its depth, are by no means arbitrary values, but parameters that are obtained as a result of carefully carried out calculations. When designing, a whole array of initial data is taken into account: the type of soil on the site, the degree of their stability both in the surface layers, and the change in structure as they deepen; climatic features of the region; presence, location and other features of groundwater aquifers; seismic characteristics of the area. Plus, the specifics of the building planned for construction are superimposed - the total load, both static, created only by the mass of the structure (naturally, taking into account all its constituent elements), and dynamic, caused by both operational loads and all kinds of external influences, including wind, snow and others.
Based on the above, it would be appropriate to make one important remark. The fundamental position of the author of these lines is that the calculation of the basic parameters of the foundation strip does not tolerate an amateurish approach.
Despite the fact that on the Internet you can find many online applications for carrying out such calculations, it would still be better to entrust the issue of foundation design to specialists. At the same time, the correctness of the proposed calculation programs is not at all disputed - many of them fully comply with the current SNiP and are capable of truly producing accurate results. The problem lies on a slightly different plane.
The bottom line is that any, even the most advanced calculation program, requires entering accurate initial data. But in this matter it is impossible to do without special training. Agree that it is simply beyond the capabilities of a non-professional to correctly assess the geological features of the construction site, take into account all the loads falling on the foundation strip, and with their distribution along the axes, and provide for all possible dynamic changes. But every initial parameter matters, and underestimating it may well then “play a cruel joke.”
True, if you plan to build a small country house or outbuilding, then inviting a specialist designer may seem like an excessive measure. Well, at your own peril and risk, the owner can build a shallow strip foundation, using, for example, the approximate parameters given in the table below. For light buildings, a deeply buried tape is not required (large deepening can even play a negative role, due to the application of tangential forces during frost heaving of the soil). As a rule, in such cases they are limited to a maximum depth of the sole of 500 mm.
| Type of building being constructed | Barn, bathhouse, outbuildings, small garage | One-story country house, including one with an attic | One- or two-story cottage designed for permanent residence | Two or three story mansion |
|---|---|---|---|---|
| Average soil load, kN/m² | 20 | 30 | 50 | 70 |
| TYPES OF SOIL | RECOMMENDED DEPTH | TAPE LAYINGS | (EXCLUDING BASEMENT | FOUNDATION PARTS) |
| Pronounced rocky soil, opoka | 200 | 300 | 500 | 650 |
| Dense clay, loam that does not disintegrate after compression with the force of the palm | 300 | 350 | 600 | 850 |
| Packed dry sand, sandy loam | 400 | 600 | Professional foundation calculation required | |
| Soft sand, silty soil or sandy loam | 450 | 650 | Professional foundation calculation required | Professional foundation calculation required |
| Very soft sand, silty soil or sandy loam | 650 | 850 | Professional foundation calculation required | Professional foundation calculation required |
| peat bog | A different type of foundation is required | A different type of foundation is required | A different type of foundation is required |
Let us emphasize once again that these are only average values that cannot be considered as the ultimate truth. In any case, if an amateur builder uses such sources, he takes a certain risk on his own responsibility.
Now - about the width of the foundation strip.
This also has its own characteristics. Firstly, to ensure the rigidity of the foundation structure, it is customary to adhere to the rule that the total height of the tape should be at least twice its width - but this rule is not difficult to follow. And secondly, the width of the tape in the area of the sole should be such that the distributed load is less than the calculated soil resistance parameters, naturally, also with a certain design margin. In a word, a foundation strip with a full load should stand stably, without sagging into the ground. In order to save materials, the base of the strip foundation is often made wider to increase the support area.
There is probably no point in presenting here formulas and tabulated values of soil resistance for carrying out independent calculations. The reason is the same: not so much the difficulty in performing calculations, but problems with the correct determination of the initial parameters. That is, again, it is better to turn to professionals on such issues.
Well, if you are building a light structure or a country house, then you can be guided by the fact that the width of the tape should be at least 100 mm greater than the thickness of the walls being built. As a rule, when planning the foundation yourself, round values are taken that are multiples of 100 mm, usually starting from 300 mm and above.
Foundation strip reinforcement
If a specialist is designing a strip foundation, then the finished drawing will, of course, include not only the linear parameters of the concrete belt itself, but also the characteristics of the reinforcement - the diameter of the reinforcing bars, their number and spatial location. But in the case when a decision is made to independently erect a foundation for a building, when planning the structure it is necessary to take into account certain rules established by the current SNiP.
Cement prices
What fittings are suitable for these purposes?
For proper planning, you need to have at least a little understanding of the range of reinforcement.
There are several criteria for classifying reinforcement. These include:
- Production technology. Thus, the reinforcement can be wire (cold-rolled) and rod (hot-rolled).
- According to the type of surface, reinforcing bars are divided into smooth and having a periodic profile (corrugation). The profiled surface of the reinforcement ensures maximum contact with the poured material.
- The reinforcement can be designed for conventional or prestressed concrete structures.
To create a reinforcing structure for a strip foundation, as a rule, reinforcement is used that is produced in accordance with GOST 5781. This standard includes hot-rolled products intended for reinforcing conventional and preloaded structures.
In turn, these fittings are distributed into classes, from A-I to A-VI. The difference mainly lies in the types of steel used for production and, therefore, in the physical and mechanical properties of the products. If low-carbon steel is used in elementary-class fittings, then in high-class products the metal parameters are close to alloy steels.
It is not necessary to know all the characteristics of reinforcement classes when building independently. And the most important indicators that will influence the creation of the reinforcement frame are given in the table. The first column shows the classes of reinforcement according to the two designation standards. Thus, in brackets there is a designation of classes, the digital designation of which shows the yield strength of the steel used for the production of reinforcement - when purchasing the material, such indicators may appear in the price list.
| Valve class according to GOST 5781 | steel grade | Rod diameters, mm | Allowable bending angle in a cold state and the minimum radius of curvature when bending (d – diameter of the rod, D – diameter of the mandrel for bending) |
|---|---|---|---|
| A-I (A240) | St3kp, St3sp, St3ps | 6÷40 | 180º; D=d |
| A-II (A300) | St5sp, St5ps | 10÷40 | 180º; D=3d |
| -"- | 18G2S | 40÷80 | 180º; D=3d |
| AC-II (AC300) | 10GT | 10÷32 | 180º; D=d |
| A-III (A400) | 35GS, 25G2S | 6÷40 | 90º; D=3d |
| -"- | 32G2Rps | 6÷22 | 90º; D=3d |
| A-IV (A600) | 80C | 10÷18 | 45º; D=5d |
| -"- | 20ХГ2Ц, 20ХГ2Т | 10÷32 | 45º; D=5d |
| A-V (A800) | 23Х2Г2Т, 23Х2Г2Ц | 10÷32 | 45º; D=5d |
| A-VI (A1000) | 22Kh2G2AYu, 20Kh2G2SR, 22Kh2G2R | 10÷22 | 45º; D=5d |
Pay attention to the last column, which indicates the permissible bending angles and curvature diameters. This is important from the point of view that when creating a reinforcing structure, you come to make bent elements - clamps, inserts, legs, etc. When manufacturing jigs, mandrels or other devices for bending, it is necessary to focus on these values, since reducing the bending radius or exceeding the angle can lead to the reinforcement losing its strength qualities.
Class A-I rods are available in a smooth version. All other classes (with some exceptions, which, however, depend more on the individual requirements of the customer) are with a periodic profile.
The construction of a high-quality foundation for a house is the key to the strength and reliability of the building. A properly developed foundation plan becomes an excellent basis for work. When creating it, a large amount of initial data is analyzed, which can have an impact on the foundation.
The foundation plan, in addition to tables, accompanies the drawing. This document shows in detail all the geometric characteristics and connections to the existing site and the contours of the area.
The classic and popular strip foundation also has a drawing, which is the starting point for the work.
The task of a correctly drawn up foundation plan is to provide a well-developed and justified transfer of calculated characteristics in graphic form. Using a drawing simplifies and speeds up work on site and ensures that the designed parameters of the building are achieved.
The following parameters of the future building are determined on the plan of the strip foundation:
- Configuration of the base tape section.
- Type and arrangement of the “concrete” layer.
- The depth of the foundation strip in each section of the construction site.
- Utility exit points.
Developing a drawing of a strip base requires special attention to individual elements. Thus, it is important to specify the coordinates and parameters of the reference block as accurately as possible. It is this that is installed first, and subsequent blocks are already tied to it. An error in its position leads to significant deviations in the configuration.
When producing foundations that are monolithic or monolithic, their boundaries should be drawn as accurately as possible and transferred to the site in kind.
There are numerous requirements for the foundation plan, including:
- Simple and unambiguous readability of the material.
- High information content and transmission of all key data on the plan.
- Additional information that is not of decisive importance is conveyed in the attached diagrams and documents so as not to overload the main plan.
- Comprehensive data for starting construction.
If the foundation plan is carried out according to established rules, then construction is not difficult and will be accurate and reliable.
The strip foundation plan with a drawing includes detailed horizontal and vertical sections of the base. They are intended to clearly show the configuration of the support elements. The most popular and practically useful scales for drawings are M1:100 and M1:200. Sometimes they move to smaller scales.
Marking the area for a strip foundation
Alignment axes and support axes must be marked on the plans.
The strip foundation plan always has a drawn outline of the base. Each structural element must be indicated in detail on the drawing. Here they designate not only the base of the foundation, but also such elements as bedding and preparation. The vertical elevations of each base horizon are always indicated.
The laying of communications for the operation of the building deserves special attention. When laying the foundation, you should provide for the location of the outlets of utility networks - this way you will initially equip technological holes in the foundation and avoid subsequent work. Making such holes after the foundation has been erected has several negative aspects:
- High labor costs.
- Reduced foundation strength.
- Possibility of partial collapse.
Therefore, already at the design stage, the locations for laying technological passages are determined. These places are tied to the axes of the building, so that later they can be simply and unambiguously taken out into nature.
All points on the plan have an elevation mark. The drawing also indicates the “common zero” of the project, relative to which the vertical position of all points of the project is plotted.
A monolithic strip foundation, produced strictly according to the drawing, has high strength characteristics and allows you to rationally spend money and work time.
How to make a foundation plan, basic calculation parameters
The developed and approved specialized GOST standards define the requirements for projects and the rules for creating and calculating plans for foundations of various types.
According to established practice, when developing design drawings, a scale of 1:100 to 1:400 is selected. These dimensions optimally reflect the required precision.
Basic parameters for strip foundation calculations
Before constructing a drawing, be sure to mark along the main and auxiliary axes.
If the base has, then they must be detailed on the plan.
The main lines of the structure are drawn with lines 0.5 - 0.8 mm thick.
Technological openings for the entrance of utilities are indicated:
- full detailed diagram,
- indicating data on the lowest point,
- with axial removal of the data necessary for the production of work.
To unambiguously identify these points in the drawing, they are designated by special symbols.
Foundation calculation diagram
The foundation plan is always accompanied by detailed calculation tables. When performing this work, the following parameters are taken into account:
- Total weight of the building.
- Possible increase in load during operation of the constructed structure.
- Characteristics of soils at the construction site.
All these indicators determine not only the geometry of the structure, but also the technical characteristics of building materials that will be used at various stages of construction.
Conditions for accurately transferring the plan to the area
The foundation drawing is the basis for the subsequent outlining of the construction project. Therefore, all the necessary dimensions must be conveyed here, but the materials should not be oversaturated with data - extra numbers only interfere with the work.
If the established scale is observed and the structural elements are correctly linked to the axes of the structure, the transfer of the plan to the area is carried out quickly and accurately. For this purpose, surveyors with the necessary equipment are involved. In some conditions, when accuracy is not so critical (outbuildings, etc.), the removal can be done independently. It is important to accurately observe the geometric shapes of the structure.
The foundation plan of a residential building and the drawing of all the geometric characteristics of the structure determine the quality of installation work, and, consequently, the quality and reliability of the future building.
It is impossible without project documentation construction country cottage. A project is not required to build a garden house. However, without a sketch it will not be possible to mark the construction site. Therefore, the owner of the site needs minimal knowledge in design and professional advice for individual stages of construction.
How to make a foundation drawing?
At the initial stage, it is necessary to determine the dimensions of the building, obtaining the four axes of the external walls. Then the axes of internal load-bearing walls and heavy partitions are added to the project, taking into account the following factors:
Then on the sketch it is enough to add two lines (inside, outside the perimeter) from the axes tape foundation. The formwork panels will be mounted along these cords; the string along the axial lines will allow you to control geometry deviations monolithic foundation.
The simplest design method
When calculating individual elements strip foundation you will need tables SP 22.13330 or V. S. Sazhin’s Guide. The technology for calculating the width of the tape is as follows:
The burial depth for MZLF is 0.3 – 1 m depending on the groundwater level. Recessed strips are lowered below the freezing mark by 0.4 - 0.6 m. The height of the basement part of the foundation depends on the preferences of the developer:
- by pouring the tape at 10 - 20 cm from the ground level, you can create a floor on the ground, sharply reducing the construction budget
- when lifting by 40 - 60 cm, a ceiling on beams or a slab is used; ventilation vents are required in the basement
- if an underground floor is planned, the height of the basement depends on the level of the finished floor in it
Based on the calculation results, it is possible to prepare a drawing for moving the axes to the building site and carrying out excavation work.
For precise drawing monolithic foundation You need access to professional graphic editors AutoCAD, Compass, Solid Work, Archikad. Therefore, paper sketches are often used for garden buildings. On it it is necessary to mark the axes of the walls, auxiliary structures (stove, internal staircase, porch, fireplace), and draw the contours of the foundation strip. 
For anyone strip foundation Reinforcement is necessary if it is planned to manufacture a monolithic structure on site. The layout of the lower and upper reinforcement frame can be depicted in the same drawing. You will need it to draw up estimates when purchasing rods, wire, spacers, and stands. When drawing a diagram, you must consider:
When the belt width is less than 15 cm, one rod in each belt is sufficient. In wide tapes, the minimum distance between the rods (in the clear) should be more than 35 mm (bottom), 40 mm (top). Reinforcement is needed in the lower part at the sole, near the upper edge of the structure. In the middle part, the tape is reinforced only when it is high (from 0.7 m).
Construction technology
For monolithic foundation A standard construction methodology is used, consisting of the following stages:
- full-scale axle offset
- trench/pit excavation
- filling the foundation cushion
- sole waterproofing
- installation of formwork
- reinforcement
- concreting
- surface waterproofing
To reduce heaving forces, the blind area and the side surface of the tape are insulated, and drains are laid at the level of its sole. At each stage there are nuances that make it possible to reduce the amount of work and increase the service life of the structure.
Before moving the axes into the construction site, it is necessary to place the building on the site for normal operation of engineering systems, fertile soil, and the dwelling itself. For example, there is often parking on the street side; an external sewage septic tank requires periodic emptying, so it is also located closer to the street. It must be at least 4 m away from the foundation to ensure a sanitary zone. 
Power transmission poles and wells with shut-off valves for connection to central life support systems are also installed here. The front facade is most often turned towards the roadway. After this, it is enough to mark strip foundation according to the scheme:
- first wall – starting corner 3 m from the boundaries of the site, spine 5 m from the red line (street road)
- side walls - perpendicular to the first axis (construction of a triangle with 4.3 m legs, 5 m hypotenuse)
The corners of the last wall (the rear facade of the house) are obtained automatically. During excavation work and the manufacture of the foundation pad, the cord must be periodically removed. To avoid repeated measurements, castoffs are recommended - a horizontal block between two pegs. You need 2 of them for each axis; three strings can be pulled across wide slats at once (the side edges of the foundation, the axis of the wall).
Cushion, formwork
A layer of non-metallic material under the sole of the belt monolithic foundation Designed to replace heaving material and level the bottom of the trench. The most popular underlying scheme is:
- sand 20 cm + crushed stone 20 cm – laid on geotextiles, wrapped with it on top after compacting every 10 cm
- crushed stone + sand (the thickness is similar) is a more convenient option; an extra layer of geotextile is added between these materials, but there is no need to fill the footing when laying roll waterproofing
- sand 40 cm or crushed stone 40 cm - the first option only for low groundwater levels, the second for high groundwater
Rolled waterproofing (usually hydroglass insulation) is laid in 2 - 3 layers with a release so that after concreting it can be rolled onto the side edges of the tape. The formwork is mounted on top of it; it is better to use materials that can be reused (OSB, plywood, edged boards).
Vertical panels, the height of which is 5 cm greater than the design mark, are supported against the sides of the trench, the ground, and fastened with jumpers (pins, bars). In the underground level it is necessary to leave openings for the introduction of engineering systems, in the basement part of the ventilation duct. To do this, pipes are passed through the shields, which remain in the concrete for sleeves or are pulled out when stripping. 
Reinforcement, filling
Aroma frame tape The foundation is usually two-level. For light buildings, two corrugated rods in the upper chord and two in the lower are sufficient. To fix the rods inside the formwork, rectangular clamps are used, curved from smooth 6-8 mm reinforcement, to which longitudinal reinforcement is tied with wire. The main requirements are:
The bottom bars rest on polyethylene supports or concrete pads to provide a protective layer. pouring occurs according to standard technology with compaction along a ring of every 60 cm of concrete to remove air.
For monolithic foundation, partially or completely immersed in the ground, protection from moisture is necessary. This is done in several ways:
A storm drain (storm inlets + surface gutters) is built into the outer perimeter of the blind area, with the help of which melted rainwater is drained.
The above technology is suitable for tape foundation of any type, deepening. Recommendations from experts will help avoid mistakes and reduce the labor intensity of construction operations. The housing will have a high service life, despite independent calculations.
Prefabricated strip foundations have become widespread in civil, industrial, and individual construction. Externally, strip foundations are a closed structure in the form of a strip, which is installed along the entire perimeter of the building, under all the walls of the structure.
The main task of such a foundation is to uniformly distribute the weight of the building throughout the entire support, as well as throughout the entire soil located under the building. In addition, the foundation must maintain the structure and geometry of the building no matter what external forces, ground shocks or other conditions affect the building.
What are prefabricated foundations?
A prefabricated foundation is a foundation that is constructed from individual structural elements produced on an industrial scale. Such products include:
- Foundation pillows. This part of the base is one of the most significant. Since it is from this that the load is transferred - from the structure to the ground. In terms of its appearance and design features, this product is a reinforced concrete slab, which has a trapezoidal cross-section. You can find foundation pillows in a variety of sizes. Considering that the pillow plays a very important role in the design of the building, increased demands are placed on the manufacture of this element; for example, the pillow is made using a durable reinforcement frame.
- Foundation blocks. In the construction industry, this product is often referred to as FBS. The appearance of the foundation block is an elongated parallelepiped, which is also made of reinforced concrete. At the ends of the block there is a place for filling its liquids during installation. Reinforced concrete block can have different sizes.
Prefabricated reinforced concrete foundation is most often used in construction because it has several advantages:
- It is much faster to erect the foundation of a building thanks to the use of ready-made products in this process. After the foundation is assembled, you can almost immediately begin to erect the walls of the structure, which is impossible to do when arranging monolithic foundations.
- Prefabricated foundation strips are of high quality, since they are constructed from ready-made parts, the quality of which is confirmed by the GOST standard. Such products are produced at industrial-scale enterprises where quality control is carried out quite strictly.
However, despite its great popularity, it is still necessary to take into account some of the disadvantages inherent in reinforced concrete products and prefabricated foundations in general:
- Prefabricated strip foundations are less durable than monolithic foundations.
- Prefabricated strip foundations include seams that remain between the products. Due to this feature, ensuring thermal insulation, as well as protecting the building from moisture, is much more difficult than when installing a monolithic foundation.
- Sometimes the arrangement of prefabricated strip structures is more expensive for builders, since the delivery of products to the construction site requires quite large expenses. In addition, when installing a prefabricated strip foundation, the services of a crane may be required to place heavy structures in the right places. Therefore, experts recommend carrying out calculations at the stage when a drawing of the building is drawn up and the type of foundation is selected.
Today in construction practice, variants of a combined foundation have become widespread, when the base of the structure itself is made in the form of a monolith, and the walls in the form of a prefabricated strip foundation. You can see this option for constructing a support in more detail in the photo. It should be noted that the combination of a monolith with a prefabricated strip structure is more durable than the use of conventional prefabricated strip foundations.
Design from reinforced concrete blocks
A foundation drawing must be drawn up when creating a project for the entire structure. It is worth noting that this type of work in any case should be carried out only by specialists, since the drawing must also comply with the construction standards set out in the regulatory documents. These include not only GOST rules, but also other state-issued documents.
When drawing up a drawing of a prefabricated strip base, the following parameters must be taken into account:
- The distance over which the soil freezes. This indicator is for reference and differs depending on the region. For example, within the Moscow region the freezing depth is 120 centimeters, and in the Krasnodar Territory it is much less - 60 centimeters. An important point is that the base of prefabricated strip foundations or any other type of foundation should be located slightly below the freezing depth of the soil. This is necessary to avoid adverse consequences that may arise due to heaving forces that occur when the soil freezes or thaws.
- Location of groundwater. The foundation drawing must take into account the depth of ground flows. In construction practice, a well is usually drilled, through which the depth of water flows is measured.
- Dimensions of the structure being constructed. In this case, the building diagram must necessarily include not only the length and width of the base, but also the width of the walls, the materials that will be used to construct the walls, as well as the number of storeys of the building and the total load on the foundation and soil.
- The topography of the construction site and the location of the structure as a whole.
- The structure and condition of the soil at the site of construction. In this case, it is important to take into account the degree of soil subsidence, its heaving and other indicators.
- Features during the construction of a building. In this case, such a parameter as the seismicity of the region is taken into account. In areas with an increased risk of earthquakes, the most durable foundations are installed.
- Construction of a prefabricated strip foundation.
After all the designer’s work is completed, the customer receives a ready-made construction plan, with which he applies to special organizations to obtain a construction permit. The drawing must include a plan for the prefabricated strip foundation made of reinforced concrete products.
Block foundation diagram
The building foundation plan in the drawing represents the entire structure in section at the foundation level, thanks to which it can be seen quite well and all the features of the structure can be understood. The support structure plan must include the following indicators:
- Parameters and dimensions of support pads or monolithic sole.
- The depth of the location of absolutely all foundation elements relative to the zero level, which is usually considered to be the floor level of the first floor of the building.
- The drawing must include an image of the cross-section of the base, which shows in detail the bedding, its type and thickness, the depth of the base and other elements, the height of the foundation above the ground level, the type of waterproofing and the use of insulation.
- The plan must necessarily show the location of all types of communications, be it water supply, gas pipes, electrical cables, sewers, etc. The diagram must contain all the holes through which this or that communication will be laid. In addition, the plan must be accompanied by an explanatory note, which should describe in detail the method of organizing all types of communications.
- The foundation drawing must necessarily contain the location of all foundation blocks, as well as pillows. If a monolithic structure is used as a sole, its location and structure must also be indicated.
- The foundation plan necessarily contains an explanatory note, which will describe in detail all the design features of the foundation, as well as the technology for the construction and installation of all elements.
The finished foundation plan is a completed document, according to which you can immediately begin to calculate the cost of all building materials, as well as the necessary construction work, and then begin purchasing everything necessary for construction.
Construction of a prefabricated foundation
- Work on the installation and construction of the foundation begins with carefully carried out markings. The marking is carried out using special construction equipment and strictly by professionals. In this case, the marking includes the determination of the axes of the future building, as well as the determination of trenches or a place for a foundation pit if construction of a basement is planned.
- Most often, when preparing a construction site for the construction of a foundation, an excavator is used, since prefabricated strip foundations are generally always located below the freezing level of the soil. After the excavator operator’s work is completed, the area is cleaned manually. In addition, it is important to check the density and structure of the soil so that the foundation of the house is placed on solid and stable soil.
- Before installing the base cushions, a backfill of gravel and sand is made in a layer of at least 10 centimeters. All layers of bedding are carefully compacted and spilled with water. These materials are used as bedding, since when moisture appears, neither sand nor gravel absorb water and do not increase in size.
- Trenches or foundation pits are dug along the axes of the future building. It is imperative to check the rectangularity of the shape for the base, as well as exact compliance with all the dimensions indicated in the plan. Next, special identification marks are placed where reinforced concrete pads are placed.
- After all the cushions have been laid, you can begin laying the reinforced concrete blocks. The products are installed using special equipment on a pre-laid mortar. Mortar is also poured between the blocks. Do not forget about the holes that are necessary for installing communications. It is imperative to level the surface of the base so that the remaining elements of the structure stand level. Once all the blocks have been installed, only minor work remains to fill the empty space with concrete or brickwork, as well as to provide waterproofing.
As you can see, the process of constructing a prefabricated strip foundation is quite simple, however, one should not forget about all its features. This type of foundation is quite versatile and allows you to cope with construction work much faster.
