The base of a traditional monolithic strip foundation is a reinforced concrete platform designed to evenly distribute the load that the house's foundation creates on the ground.
The width of the footing is usually at least twice the width of the foundation. In the United States, footing structures are required by most local building codes for foundation installations on loose sandy and silty soils.
The height of most soles for foundations that we have to construct is 30 and the width is 60 cm. Usually, unless the project provides otherwise, we reinforce such a sole with two rows of 012 mm steel reinforcing bars. In our case, the soil at the bottom of the pit was such that for a two-story house with plan dimensions of 8x12 m, it was impossible to do without an additional base that would increase the area of support for the foundation. This is a common occurrence in the state of Rhode Island where we operate. Before you start construction soles, it was necessary to mark the exact location at the bottom of the pit house foundation.
We always rely on the markers installed by surveyors when marking the construction site before the excavation begins. Usually, at the bottom of the pit, it is enough to determine the position of two base points - the two extreme corners of one of the foundation walls. In most cases, we find the position of these corner points using a cord, stretching it between the poles installed by surveyors and a plumb line. We hammer in two of our stakes along the plumb line at the bottom of the pit, using scraps of reinforcement for this purpose, so as not to remove them when it comes to pouring concrete. The distance between these two poles must exactly correspond to the length of the wall indicated by the architect on the plan. To quickly mark the position of the other two corners of the foundation, you need to calculate the length of its diagonal. Using a regular calculator, this is not so difficult. And knowing the length of the diagonal and the dimensions of the foundation in plan, you can easily and accurately determine the position of the remaining two corners and mark them with poles. We do this as follows. Two members of the team hold the ends of the tape of two tape measures at the base points, already marked with stakes, while the third member of the team, pulling the tapes of both tape measures, crosses them at the marks of the length of the diagonal and the length of the wall, and at the point of intersection hammers another pole into the ground. To eliminate possible errors, we always double-check the distances between all the stakes driven into the bottom of the pit, checking them with the dimensions indicated on the plan. After the poles are hammered into all the corners, we pull the cord from one corner to the other and get the outline of the entire foundation.
Now, having installed all the poles, you can begin construction formwork. For this we use boards with a cross-section of 5x30 cm, connected to each other using steel U-shaped brackets driven into the ground, which hold the inner and outer walls of the formwork at a distance of exactly 60 cm from each other. These brackets are our know-how brigades. We specially made them to order, since these are not available for sale. They turned out to be so convenient that, as a rule, we no longer use any other devices for fixing the formwork.
We install the formwork in such a way that foundation walls were located exactly in the center of the sole (the width of the foundation walls of this house according to the project was 25 cm). We begin work on the construction of the formwork by fastening two boards with a cross-section of 5x30 cm at an angle of 90° with nails to form an outer corner and installing them at a distance of 17.5 cm from the cord. Then, parallel to the boards of the outer formwork, we install and fix the boards of the inner wall of the formwork using steel U-shaped brackets. So, gradually moving from one corner to another, we continue this process until the installation of all external and internal walls of the formwork is completed.
We place the U-shaped brackets that secure the formwork on straight sections in increments of 100-120 cm. At the junction of two boards, we connect their edges using nails driven at an angle and install the fastening brackets on both sides of the joint.
We rarely have to adjust and cut formwork boards to length. When, for example, two boards do not join tightly enough, we close the gap using a short overhead board, nailing it from the outside. And if one or another board turns out to be a little longer than necessary, we simply nail it to the adjacent board with an overlap. We simply do not pay attention to the small irregularities that form on the side edges of the sole. In the end, it is not the appearance of the sole that is important, since it will still be completely buried in the ground. The main thing is that the finished sole has strength not lower than the design one and successfully copes with the functions assigned to it. Once the formwork is fully installed, we carry out partial backfilling of soil near its potential weak points, for example, at the junction of individual boards or in areas where it was impossible to install U-shaped fastening brackets. In addition, backfill prevents concrete from seeping under the formwork and lifting it.
Next, using a theodolite, we set the level of the top edge foundation soles. It must be located, firstly, strictly horizontally, and secondly, exactly at a given depth indicated on the plan by the architect. We fix the level marks with small 2.5x50 mm nails, hammering them in half their length at a distance of 0.5-1.0 m from each other along the entire perimeter from the inside of the formwork boards. When laying concrete, they serve as a guide for us to determine to what height the formwork should be filled.
Now everything is ready to lay the concrete. The best pits are those that can be easily reached by a concrete truck at any point. But, unfortunately, this happens very rarely. Therefore, we usually start laying from the areas that are most difficult for a concrete truck to reach, moving concrete along the formwork with shovels until these areas are filled to the required height - to the level of the nails that fix the height of the foundation base.
After pouring concrete When the formwork is completed, we begin laying two rows of D12.5 mm steel reinforcing bars along the entire perimeter of the sole. To do this, we first lay out the reinforcement bars in two rows on top of the wet concrete at a distance of approximately 15 cm from each wall, sliding them under the crossbars of the U-shaped brackets. And then we sink them into concrete to a depth of about 20 cm, using ordinary bayonet shovels as a tool. We carefully and carefully “pierce” the concrete above the recessed reinforcement bars with the same shovels to remove the air that has gotten into it.
Having leveled the concrete surface to the height of the nails that fix the level of the upper edge of the sole, we carefully lift all the steel U-shaped brackets a few centimeters. Usually 5-7 cm, no more, in order to easily perform the last two operations.
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| We carefully level and rub the upper edge of the sole. On all straight sections of the sole, exactly along the center line of the top edge, we make a keyway 2.5-3.0 cm deep and 7-8 mm wide. We mark the positions of the corners of the foundation walls directly on the upper edge of the base, drawing marks with the tip of a nail on the slightly hardened surface of the concrete. | ||
The first of them is grouting the upper edge of the sole. In addition to facilitating all subsequent work on the construction of foundation walls, the smooth surface facilitates the removal of dirt and debris that inevitably falls on the upper edge during dismantling of the formwork.
And finally, the final stage in construction of the foundation base is the cutting or extrusion of a keyway along the center centerline of the top edge. This groove should ensure strong and reliable adhesion of the sole to the foundation wall that will be built on it in the future. Typically we make a keyway 2.5-3.0 cm deep and 7-8 cm wide by simply pressing a short block of appropriate cross-section into the concrete along the center line of the top edge of the sole. By the time this work begins, the concrete has usually already hardened sufficiently, so the block leaves behind a groove, which by itself does not “float” and does not change its shape and size. We make such grooves only on straight sections of the sole, not bringing them to the corners by about 0.5-0.7 m. Since the corners are the strongest parts of the foundation wall, there is no need to worry about violating the integrity of the foundation at these points.
Before removing the formwork, we transfer from it the position marks of the corners of the foundation walls directly to the upper edge of the base, drawing marks with the tip of a nail on the slightly hardened surface of the concrete. They will serve as a guide for installing the formwork when constructing the foundation walls.
Support sole is a stepped expansion at the bottom of the strip foundation structure. It is used in the construction of foundations for heavy buildings erected on weak-bearing heterogeneous soils. This sole allows you to distribute the weight of the structure more evenly, thereby reducing pressure on the ground. Depending on the magnitude of the loads, as well as the size of the building and the characteristics of the soil, the foundation on the supporting base can be single-stage, two-stage, or three-stage.
Construction of a strip foundation with a support base
The design of this foundation is not particularly complicated. The walls of the building being erected rest on a strip support, which is buried in the ground. The tape is laid under all the internal and external walls of the building, while maintaining its identical cross-section along the entire perimeter of the foundation. All these tapes together create a foundation that transfers the load to the ground.
buried to a depth of 30 cm below the soil freezing level. Such a foundation can be made of various materials, such as:
Rubble or brickwork;
Monolithic concrete;
Reinforced concrete blocks.
In modern construction the most common are monolithic concrete strip foundations. While foundations made of rubble stone and brick, although they were widespread in the middle of the last century, today have already lost their relevance. In turn, prefabricated foundations made of reinforced concrete blocks are used in large-scale construction, because this technology requires the use of special construction equipment.
Advantages of a strip foundation with a support sole:
Ease of construction;
High durability;
High load-bearing capacity;
Used for a wide variety of soil types;
Suitable for any buildings;
There is an opportunity to arrange a basement.
Disadvantages of a strip foundation with a supporting sole:
It is impossible to build on deep-freezing and highly swelling soils;
A foundation made of monolithic concrete will require more time and labor compared to other types of foundations;
High consumption of materials (formwork, reinforcement or concrete);
For buried types of strip foundations, the use of special construction equipment is required;
High cost of foundation construction.
Even with all the existing shortcomings, strip foundation with support base is the most popular and widespread in modern construction. By choosing this type of strip foundation, you guarantee your future construction high reliability and durability.
Prices for strip foundations
The cost of building a strip foundation with a support base includes:
Terrain marking, georeferencing;
Digging a trench for the foundation 10 cm;
Sand cushion 10-20 cm, compacted;
Installation of reinforcement cages;
Installation of formwork;
Pouring concrete grade M250.
|
№ |
Foundation type |
Unit |
Cost in rubles |
|
1 |
Shallow strip foundation |
m/n |
4400 |
|
2 |
Recessed strip foundation |
m/n |
7000 |
|
4 |
|
m/n |
7600 |
For an additional fee you can order:
- Change of concrete grade M300-M450
- Increasing the diameter of the reinforcement
- Changing the height or width of the strip foundation
The foundation of a house is a very important part that affects the performance and durability of the building. The comfort of living in a building depends on its strength. A strip foundation with a support base is a fairly popular option in house construction.
Advantages and disadvantages:
- The main advantage of this option is the ability to build at any time of the year, including winter.
- Another plus is its versatility; it is used for building houses from timber, concrete, stone, logs, and bricks.
- Disadvantages include the difficulty of following the technology.
A strip foundation with a sole is suitable for most soils. However, if the site has unstable soil or peat, then it is necessary to fill it with earth. For an average structure you need 10-14 support points.
Features of the technology
The base of a monolithic strip foundation is a platform made of reinforced concrete. Its task is to distribute the load evenly. The width should be at least twice the width of the base itself. Height - about 30cm. In the traditional version, the sole is reinforced with steel reinforcing bars.
The technology consists of several stages. First, mark the bottom of the pit for the foundation of the house. The poles are installed, then the formwork is constructed. Most often, boards are used, connected by steel brackets sunk into the ground. The formwork is installed so that the walls are located in the center of the base. The boards are usually not trimmed; the gaps are sealed with short overhead boards, nailing them from the outside.
The next stage is partial backfilling of soil near potential problem points. The event helps the concrete pass under the formwork, lifting it up. Next, the level of the top of the sole of the strip foundation is established. The edge must be located horizontally, at a given depth. The marks are fixed with small nails.
It's time for concrete. They begin laying it in areas inaccessible to a concrete truck. Then comes the turn of reinforcement with steel rods. The final stage of sole construction is cutting a keyway along the center line along the top edge.
With careful adherence to technology, the strip foundation with a sole turns out to be strong and durable. It will ensure trouble-free operation of the building for many years. The Project company provides construction services in the Moscow region and Moscow at a professional level.
The foundation of a building is its main element. He provides existence. The whole house as a whole. To prevent the foundation from starting to fall apart, it should be filled very efficiently.
We will help you complete this task correctly; to do this, you just need to follow our recommendations. 
Before you start pouring the foundation, you should make the necessary preparations. First of all, you will need to clearly determine the position of your home. Then thoroughly clean the area and level it well.
You should not carry out the breakdown of the building yourself. It is better to entrust this matter to a professional. Using special devices and instruments, he will accurately mark all external corners with pegs. This is done to visualize the outer line of the foundation wall.
The main thing you must fill out is that it is necessary to determine whether your house is rectangular. 
This is quite easy to do. To do this, simply measure its diagonals. They must be identical; if not, it means the house is not of the rectangular type.
Once the external catch mark has been completed, you can begin driving in the pegs. Three pegs should be driven in for each corner. The distance between them should be about 1 m from the marked foundation line. Then you should start nailing the boards.
This must be done so that their edge, which is considered the top, shows the level of the end of the foundation walls. The level will help you achieve high-quality leveling. 
Next you will need to stretch the cord. This should be done through the board top edges on a pair of opposite catches. To correctly adjust the position of the cord you will need a plumb bob. This should be done so that the cord is directly under the mark that the professional will make. You will need to make notches in those.
In places where the cord comes into contact with the board, this is done in order to measure the position of the board. Remember that the notches you make must be completely identical to each other. The cords you pulled will help you in the next stages of construction. Namely, in determining the most even line for installing house walls. During the digging process, you can remove the cord. This is where the notches that you previously made on the surface of the boards come in handy. 
They will always help you decide where the edges of the outer type of foundation walls are located. You will also need to determine the load-bearing type of center beam. This will be required to correctly lay out the line of the external type of foundation. It's not that hard to do, you just need to accurately measure the distance from the pieces of the catch. Then it will be necessary to drive in the pegs.
After this, you will need to lay horizontal boards. Please note that they must be of the same level. It is very important. The next step is to place the cord. This must be done by following previous recommendations. While you will be digging a pit directly under the foundation, you can optionally remove the pegs if they begin to interfere with you. After all the steps taken, you can begin to build the foundation walls and its base.
The base of the building and foundation
Now you have come to creating the base of the building. We have prepared some tips for you to make this process as successful as possible. Remember that before you start digging a ditch for the foundation, you must remove a layer of soil. The removed layer should be from the entire surface at once. You will need to dig additional ditches. 
As for the size of the ditches, they should be approximately half a meter. Remember the important information that the base of the foundation should be about 10 cm thick. No less. In case the foundation in the non-existence is not of a very good level, you must widen it and also reinforce it. The wedge, which is located at the top of the foundation, performs important functions.
It helps the foundation wall to withstand lateral loads. Such loads can arise in the event of soil displacement. You may encounter uneven ground pits. In this type of situation, you should resort to leveling the pit with concrete. Never use soil that has already been dug up. 
You will, of course, need to lay a foundation for the pillars and columns. To easily determine the line on which the pillars are located, the main function of which is to support a load-bearing beam, you need to use a cord.
On the house plan you should find the coordinates for the placement of the pillars, as well as their sizes. The foundations under them must be poured so that the parts that are on their surface are in the center of the foundation itself
The size of the foundation will depend entirely on the pressure of the foundation itself, as well as the load. Typically, the dimensions of the foundation for pillars and columns are 60 by 60 for a building with one floor, and 80 by 80 for several floors. Be sure to take this nuance into account. On the issue of soil density, it is better to consult directly with a professional.
He will give good advice. You must take into account that the smallest thickness of a foundation that cannot be reinforced is 0.1 m for columns. You must take into account that the thickness of the foundation itself cannot be narrower than the distance between the edges of the foundation and the column. It is important to take into account the time of pouring the foundation for fireplaces; it must coincide with the time of pouring the chimney. I would like to say a few words about the stepped foundation.
These foundations are very common when the ground is sloping, or in houses in which the presence of different levels can be seen. Remember that the base of the foundation and the vertical step part should be poured at the same time. The placement of the lower part of the sole is of particular importance. It will be better if it is placed on a base without disturbances.
Concrete is perfect for connecting to a vertical type sole. Its thickness should be approximately 15 cm, and its width should fully correspond to the parameters of the base of the foundation. If you know that there is a large enough slope, do not just one step, but several.
This is an important point. Please note that the distance of the steps in a vertical position should not be more than 60 cm. This does not apply to a rocky base. If the base is made of gravel or sand, the distance should not be higher than 40 cm. You need to follow our advice, and pouring the base of the building will be successful.
And you can also look video Start of construction. Excavation
from 7600/m.p.
The supporting sole is an increase in the bottom of the strip foundation in the form of a step. Such structural reinforcement perfectly supports massive houses, the construction of which is carried out on weak-bearing heterogeneous lands. When using a sole, the pressure of the structure is distributed more evenly, which reduces soil pressure.
Prices for a foundation with a support base
The cost of erecting a foundation on a supporting base consists of prices for the following types of work:
- marking the territory, reference to the terrain;
- excavation of earth for a trench under the tape - one decimeter;
- filling a cushion of sand (one to two decimeters) with further compaction;
- construction of a frame from reinforcement;
- production of formwork from boards;
- casting concrete solution (M 250).
This type of foundation has subtypes that are selected in accordance with the amount of pressure, the dimensions of the structure and the nature of the soil:
- with one stage;
- with two stages;
- with three steps.
Foundation structure on a supporting base
This foundation is not that complicated structurally. A strip foundation buried in the ground is being erected under the walls of the future building. It is necessary to use absolutely all the walls of the house, not only load-bearing, but also interior. The cross-sectional size of the strip support must be identical along the entire length of the perimeter. All this ribbon weave, which creates the foundation, holds the building and transfers the load to the ground.
The depth of the foundation with the supporting sole can be up to thirty centimeters deeper than the freezing line of the soil massif. The constituent materials of this foundation can be different:
- masonry made of rubble or bricks (in the modern world it is no longer relevant, although it was popular in the mid-twentieth century);
- concrete monolith (the most common option among modern developers);
- sections made of reinforced concrete (as a rule, they are used for large-scale development, since special construction machines are required to manipulate this type of material).
Advantages of a foundation on a support sole
- simplicity of construction;
- durability;
- excellent load-bearing capabilities;
- variety of types of soil mass for installation;
- no restrictions on building type;
- This implies the arrangement of a basement.
Disadvantages of a foundation on a supporting sole
- not suitable for lands with deep levels of freezing, as well as with severe swelling;
- the option with a concrete monolith, unlike the other two types, requires a significant increase in work time and labor costs;
- too much material is used (form boards, reinforcing bars and concrete mortar);
- special construction machines are required for buried types of foundations;
- quite expensive.
However, despite a decent number of disadvantages, a strip foundation on a support base is most popular among modern developers, because it guarantees the structure many years of life and reliability.
