Before erecting the foundation, in addition to preliminary calculations, it is necessary to prepare in a special way construction site. In particular, the placement of the pillow is an important point. The so-called concrete preparation for the foundation according to SNIP 50-101-2004 is carried out using crushed stone or lean concrete.
First of all, you need to figure out why you need preparation at all?
If we're talking about about pouring concrete, rather than erecting a structure from ready-made blocks, it allows you to solve several problems at once:
As mentioned above, several options for arranging the site for the foundation are allowed - using:
Now let's take a closer look at the features of each option.
This type of site arrangement is used to save money, since the price of crushed stone itself is low, and it also reduces cement consumption. The thickness of the pillow layer should be at least 20 cm.
This pillow is laid in the following order:
The disadvantages of this technology include the insufficient rigidity of the substrate. In addition, building a foundation on crushed stone is not very convenient. Therefore, such a pillow is used, as a rule, in the construction of technical and auxiliary buildings.
In the photo there is a concrete pad
This option for arranging the substrate provides the most correct process for constructing the foundation. In addition, it eliminates the possibility of soil subsidence.
It should be noted that lean concrete is far from the cheapest option, but it is used quite often. The peculiarity of a lean mortar is that it contains no more than 6 percent cement, the rest being sand, gravel and crushed stone.
The thickness of the substrate is 50-100 mm. This indicator depends on the weight of the future structure, the type of soil and the groundwater level.
Advice!
When constructing a cushion of crushed stone, it is better to use material of small and medium fractions.
Most often, a concrete pad is used in the construction of strip and slab reinforced structures. This is due to the features technological process, which provides for rigid installation of meshes and frames into the body of the future foundation.
In addition, construction on concrete is much easier, especially in winter time of the year.
This technology is modern version preparation for the foundation, which is an alternative. Its peculiarity is the absence of wet work. In addition, this method allows you to speed up construction process and save money.
Now let's take a closer look at how concrete preparation is performed using lean concrete.
So, the instructions look like this:
This completes the pillow preparation process. All that remains is to wait until the concrete has completely hardened and then you can begin building the foundation.
Advice!
Once the foundation is built, it may be necessary to mechanical restoration– leveling, making holes in it, etc. similar operations are carried out with a diamond tool, for example, diamond drilling of holes in concrete or cutting reinforced concrete with diamond wheels is often performed.
From the video in this article you can get Additional information on this topic.
Laying the foundation is one of the most important components construction work. Not least important in this process is the construction of a special concrete footing, which should be located under a solid foundation. The quality of its execution determines the stability and durability of the structure. Before carrying out work, it is necessary to determine what density of concrete or crushed stone layer is needed for the construction of a particular building.
The footing is a layer of concrete mortar that must be prepared for the economical, convenient laying of the main foundation. This thin layer is poured to the main mass (for example, during the installation of the base using concrete slabs).
Preparatory concrete or crushed stone foundation is made using different methods, means and building materials. But with any device, its purpose will remain the same - it consists in preparing and leveling the surface. Due to this, the main concrete pour is consumed more economically due to uniform placement, which does not require additional consumption of the mixture for unevenness and depressions in the ground. Concrete and crushed stone footing, which is required for construction work, is used in the following cases:
In addition, the presence of shock absorption increases the strength of the structure due to the fact that the base is better preserved. As for the thickness of the foundation monolith, it will depend directly on the dimensions and weight of the structure. On average, this figure is in the range of 0.15-1 meter.
Preparation can be made of concrete, bulk or film materials. Before starting the main work, it is necessary to carry out preparations. The work package includes the following three stages:
First preparatory stage involves careful calculations and work with documentation. Then you need to clear the site. You will need to remove debris from the area, cut down and uproot trees, dig up bushes and other plants. The next step involves creating a “cushion” on the surface, which will be located under the foundation of the future building. The following building materials are used for this:
First you need to clear the soil surface and make a pit. Proper preparation of the depression involves a number of works aimed at bringing the soil to the desired state. In other words, the soil must withstand the heavy loads specified in the project. It is necessary that after the foundation is laid, the soil tightly grips the foundation from below. First, you should form a pit, clean its bottom with a bulldozer, and then thoroughly compact the base. In addition, during compaction of the pit, the soil should be moistened or dried. Most often, trenches are dug by hand. In addition, builders visualize the surface of the base itself and set the corners of the walls using pegs. After the pit is dug, specialists begin the following stages of construction:
You can install a reinforced frame in concrete, but you can do without this material. In practice, the two options have almost no differences. The only difference is that a pillow created without reinforcement is limited in size. will strengthen the bottom of the cushion, which absorbs the pressure arising from the load of the structure and transmitted through the base.
Before building the foundation, in addition to preliminary calculations, you need to prepare the construction site. The so-called concrete preparation for the foundation is needed first of all. It consists of erecting a pillow under the base.
Before building the foundation, in addition to preliminary calculations, you need to prepare the construction site. The so-called concrete preparation for the foundation is needed first of all. It consists of erecting a pillow under the base.
There are a number technical requirements regulating the technology of preparatory work, the choice of material and the thickness of the layer used for the pillow. The list of basic standards and requirements for pre-foundation preparation is set out in SNiP 52-01, SP 52-101/2003 and SP 50-101/2004. They contain a lot of information on the topic that interests us. Basically, the role of fundamental preparation comes down to the following.
If the foundation is planned to be poured locally, and not built from ready-made blocks, preparation for the foundation will help:
According to SNiP 52-01, for concrete preparation for the foundation, crushed stone, lean concrete (it has a low content of binders, and therefore a low grade - from M50) or profile membranes are used as the main material.
Crushed stone preparations are used to reduce the overall cost of the foundation and reduce cement consumption. The thickness of the crushed stone layer should be from 20 cm. After thorough compaction, the crushed stone is filled with bitumen. Crushed stone preparation is used in cases where it is necessary to fill the base of a pit with bitumen until the soil is maximally saturated or a bitumen film is formed.
The use of crushed stone preparation of the foundation cannot provide sufficient rigidity of the substrate. In addition, building a foundation on a crushed stone base is not entirely convenient. Therefore, it is used in the construction of auxiliary utility and technical buildings to minimize costs.
It is needed to ensure correct process construction concrete foundation and eliminating soil subsidence. Skinny concrete is not at all cheap option However, it is used quite often. Such concrete contains no more than 6% cement, the rest is crushed stone and gravel. The thickness of the concrete preparation layer should be 50 - 100 mm. It depends on the weight of the future building, the groundwater level and the type of soil.
Concrete preparation for the foundation is used primarily in the construction of strip reinforced structures. This is due to the peculiarities of the technological process, which involves the rigid installation of frames and steel mesh into the body of the future foundation before it is poured. concrete mixture. In addition, it is much easier to build a foundation on concrete, especially in winter period.
A modern method of preparing a foundation that can replace crushed stone and concrete preparation. When installing them, “wet” types of work are eliminated, money is saved, and the construction process is accelerated.
Work must be carried out in the following sequence:
On each side of the perimeter you must retreat beyond foundation slab by 10-15 cm, thereby increasing the size of the concrete preparation area. For a base made using the method concrete pouring there are no restrictions in use. It is considered so reliable that it is not necessary to reinforce it. In practice, both options have proven themselves with the most positive side. Their only difference is that the non-reinforced concrete pad has limited dimensions.
Construction requirements provide minimum height concrete layer, which should rise above the ground surface by no less than 15 cm. This allows for optimal placement of the mesh for reinforcement. The mesh is needed to strengthen the lower part of the concrete pad, which experiences tensile forces. They are transmitted from the foundation, which experiences the weight load of the entire structure.
To understand why concrete preparation for the foundation is needed, you need to carefully study the existing regulations. They say that any concrete preparation option is better than no concrete preparation. It will provide the building with the best strength and stability, helping the foundation to maintain the entire structure in good condition for a long time.
The foundation is one of the most important components of every building. The durability and reliability of the entire building will depend on the quality of its execution. The concrete under the foundation also plays an important role. In this article we will tell you more about this element and everything that is connected with it.
First, it is necessary to carry out a set of preparatory work. This includes three main stages, including the following:
Everything is clear with the first stage - documentation work is being carried out. As for the second step, within its framework the area under the foundation must be thoroughly cleared. There should be no debris left behind, and shrubs, trees and other plants should also be removed. The third stage involves arranging a special pillow for the foundation. For this purpose, crushed stone is used, which must be constantly compacted. To provide such a cushion, lean concrete can also be used. In any case, all the steps are not that complicated, so it is quite possible to do it on your own.
More details about the features of such a pillow are described below. Anyway, as for technological requirements regulating the thickness of layers and others important points, then they are set out in the relevant SNiP. Regarding the main goal, the achievement of which is the main task of this type of work, it consists in direct preparation for the construction of the foundation. There are several types of preliminary work, including concrete footing.
The footing is designed to fulfill a number of various tasks. These include the following:
Preparation for the foundation is carried out in two ways. This includes crushed stone and concrete. Thus, crushed stone preparation has an undeniable advantage, which consists of significant savings on the total cost of construction work. This is due not only to the low cost of crushed stone, but also to significant savings in the cement component. As for the crushed stone layer, its thickness should be twenty centimeters. This layer must be compacted and then thoroughly compacted.
It should be remembered that this technology is not the most reliable, since it has serious weak side. It lies in the insufficient rigidity that the substrate will have. As a result, the arrangement of the best convenience in the process of further work on installing the foundation is called into question. It is better not to use this kind of operation in cases where serious buildings are being erected. In the event that, for example, it is necessary to install a utility block or other ancillary structure, then the use this method quite justified. Thus, it will be possible to significantly reduce the costs of construction operations.
As for the concrete preparation for the foundation, its arrangement is especially important in cases where there is a need to build tile and strip type structures. This is due to the fact that when using the above technologies for building a foundation, they usually resort to using a rigid frame made of steel rods. Such a frame is most often used before pouring the structure with concrete mortar. There is also another reason, which is that it is much easier to build a foundation on a hard surface. It is also worth noting that foundation footing becomes especially important in winter. This is explained by the fact that it is at this time that the soil deteriorates its characteristics.
Here are the most important points contained in the instructions:
The sand cushion under the foundation performs the task of ensuring the best redistribution of the load. It becomes especially relevant in the autumn-spring period. This is due to the fact that the soil at this time undergoes changes caused by the change of seasons. Using a sand cushion, the lower part of the foundation is raised above the groundwater level. At the same time, any deformation effects emanating from third-party materials and objects are also smoothed out.
A sand cushion is usually installed in cases where the bottom of the pit is located in an area of problematic soil. IN in this case it is necessary to remove some layer of soil and fill in its place with coarse soil river sand. Its layer should be at least one and a half centimeters thick. Then, using a level, the resulting pillow must be leveled. After this, all that remains is to compact it thoroughly. For this purpose, a specialized tool is used - a tamper.
A sand cushion can be considered to be of high quality only in cases where the level of groundwater is taken into account. In addition, it is extremely important to take into account possible changes in this indicator that occur with the change of season. If you are dealing with high level, then there is a need to arrange a drainage system. In principle, its construction will not hurt in other cases. For this purpose, it is necessary to dig a trench along the entire perimeter of the building being erected. It will protect the structure from melt water. In addition, with heavy rainfall, the groundwater level also rises, drainage system will cope with this problem too. It is necessary to properly waterproof the trench. The resulting drainage will also prevent water from entering the basement.
Instead of sand, crushed stone footing can also be used under strip foundation. Compared to the previous type, it boasts better strength qualities. For its arrangement, crushed stone is used, which is poured into a twenty-centimeter layer. It would not be superfluous to provide a small layer of coarse sand, the thickness of which will be about ten centimeters. Using a vibrating plate crushed stone cushion must be compacted.
This is exactly how the construction of the concrete under the foundation is carried out. In order to guarantee best quality execution of the structure as a result, all work is required to be carried out in accordance with all norms and rules. Neglecting technology is unacceptable; a lot really depends on it.
