Foundation pit - how to make, technology, features + Video

Foundation pit - how to make, technology, features + Video Pit for the basement - how to make, technology, features. The foundation is exactly the base on which the building stands. It is for this reason that one should take seriously its arrangement. You should consult with experts, make a lot of calculations, and then check them more than once and analyze. Often, to save money, people try to pull out a foundation pit for the foundation and basement floor with their own hands, but then you should know what and how to do.

Digging a pit is the last stage of manufacturing, but first you need to make calculations, which will be the preparatory stage. It also includes the search for special vehicles, the purchase of tools, special clothing and equipment, the recruitment of workers (if necessary). At each of the stages, great attention should be paid to how well the work is done, since the safety and reliability of the work will depend on it.

Time to complete the work

Builders who are just starting to learn often think about the best time to make a pit for the basement floor. There is only one obvious fact - it is not worth doing this in winter, since it is very difficult to dig the frozen ground.

But that doesn't mean that all other seasons will be perfect. Excellent advice from experts says that autumn and summer are suitable for digging. In no case should it be possible to carry out this kind of work in the spring, since it is at this time that thawing begins, and after that a large amount of water is released, which will have to be additionally pumped out. As a result, you will also have to spend money on calling special equipment.

Note that picking a good season to get started is a great way to save money, but if you do have to work on wet ground, remember that a special system should be used to drain water (for this, drainage from rubble is often done).

The autumn season is also not fully suitable for this activity. You can work only at the beginning, when it is still warm and relatively dry. In late autumn, frosts will begin, because of which the soil will behave unstable - it will freeze at night and thaw during the day. This, to some extent, will leave an imprint on the stages of work and quality. Naturally, it is impossible to unequivocally prohibit digging a foundation pit during the cold season, because sometimes there are circumstances or just an irresistible desire, and in this case everything is possible.

But still, you have to consider that such a rush will cost you 2 times more. So, to make a pit, you will have to prepare drawings and a work plan.


Before you start work, you should clearly define for yourself what kind of foundation pit you need. This will depend on the type of foundation and base.

There are parameters that must be taken into account when dividing the pit into categories:

  • Foundation pit - how to make, technology, features + Video presence / absence of slopes, their number.

  • The presence / absence of fasteners at the corners.
  • The presence / absence of inclined, upright walls.
  • Pit or trench (this will be determined after you select the type of foundation - slab or strip).

If you plan to create a strip foundation, then you will need to dig a pit-trench that will run along the perimeter, and also in those places where the bearing walls will be located.

Interestingly, that if you plan to make a slab foundation (it is he who is suitable for making a basement floor), then the pit should be dug around the perimeter of the building and in the place where you plan to make basement.

First of all, you will need to do such land work in order to dig a pit for the basement floor:

  • Determine what type of soil in the dacha site, conduct an examination (this is necessary in order to plan the depth of the foundation).
  • Conduct a study of the technical characteristics of the building in order to determine what will be the load on the foundation (to the maximum, take into account all the specifics that will affect the weight, even the weight of roofing materials).
  • Calculate the depth of the pit (it is better to entrust this type of calculations to specialists).
  • Analyze the prevailing climate for the strip to identify possible seasonal ground movements.

Preparatory work and calculation

Before starting to dig, calculate the width and length.

Naturally, they will depend on the parameters of the building itself (width and length), and also on the depth of the base of the structure. There is a rule in order to determine the dimensions of the building - the size of the foundation should be larger than the length and width of the facade by 0.4 meters, since a foundation is also required for finishing the facade. Therefore, add 0.2 meters to each side.

As already mentioned, the size of the pit will also depend on the depth of the foundation, because in cross section it (the pit) should be shaped like a trapezoid. Such requirements are due to safety engineering. The walls (when getting the earth out of the pit) should be with slopes. The size of the house, increased by 0.4 meters, will only be projected onto the lower part of the pit.

Please note that the upper must exceed the dimensions by an amount equal to the depth of the sole. This will help you proportion with a 45 degree slope of the wall. This is necessary so that the walls are safe, and they are not threatened with shedding of the soil.

The zero level looks like this - the dimensions of the pit (width and length) should be equal to the size of the house, but increased by the size of the depth of the pit. At the level of the sole, the size will be the same as for the facade, but larger by 0.

4 meters.If you deepen the sole by 50 cm, you do not have to adhere to this rule, and then the walls in the pit will be vertical.

In order to determine the area of ​​the sole, we recommend a pre-calculated load for a certain soil indicator and the level of the maximum permissible load (such data can be obtained after an examination). After the size is calculated, we begin to dig a pit.

The digging process is divided into several stages:

  1. Foundation pit - how to make, technology, features + Video For start preparing the site, you should remove 0.

    4 meters of soil from above.

  2. Moisture is pumped out (in case of its formation), and then removed from the site.
  3. The soil is removed to a predetermined depth. If the pit is deeper than 1.25 meters, then special support beams should be installed, which help prevent the earth from sliding along the walls.

  4. Make steps in the pit if the depth is 5 meters (leave the calculation of the depth of steps for an experienced specialist).

Development for types of bases

For a strip foundation

If you have planned the construction of a strip foundation, then the pit in appearance it will be like a trench buried in the ground, in which formwork is provided in the inner part. the dimensions should be calculated according to the following scheme - the dimensions of the house (width and length) should be increased by 0.4 meters. The width of the trench will be the sum of the width of the gap and the walls of 50 cm (this is when calculating for the manufacture of formwork).

It is important to understand that the size of the trench should in no case be less than 1 meter (the fact is that the minimum tape is 0.4 meters).

First, outline the dimensions of the future foundation pit, remove the soil layer, which will be from 0.2 to 0.3 meters for leveling work.

Select the highest angle and start digging (with an excavator or by hand), and you should go deeper along the perimeter and control the depth with poles.

Important! The walls of the pit, which are made with a deepening of more than 50 m, should be reinforced with shields on struts, which will be removed after the completion of installation work. The soil that you extract should be stored nearby in order to be used in the future for filling and making drainage.

For a slab-type foundation

In this case, in order to dig a pit for the basement floor, other rules:

  • For shallow depths, the parameters are the same as for the building facade (length and width). In case of significant deepening - the sum of the length / width of the facade and the height.

  • Development is carried out in such steps - the soil is removed in layers of 50 cm. Each of the layers will be smaller than the previous one. As a result, there should be steps on the walls with a height of 50 cm and a width of about 25 cm.
  • No digging is required for manufacturing, only the use of special equipment will do.

The first stage is the removal of 0.

3 meters of soil.After that, the dimensions of the pit should be applied to the surface. Along the borders, you need to make an initial notch with a depth of 50 cm, while removing the soil from the center to the edges. From the first layer, you can go to the second, but reduce the border by 25 cm, and so we continue to the bottom. The soil that has been extracted can be sorted into sand and other constituents.

Be sure to leave the sand in order to make the bedding.

For a columnar foundation

In this option, a small trench should be made (up to 50 cm) around the perimeter of the facade. At the bottom, it is required to install pits for installing pillars. They begin to remove soil from the site at 0.2-0.

3 meters, and at the bottom, simultaneously making pits. Using the rods, you can check the depth using standard methods. If you make a pile foundation, then the foundation pit is simply not needed. For him, you will need to drill wells, and then install piles in them. In this case, no digging is required.


To begin with, the first recommendation is that the pit should be made in accordance with all the regulatory and legal provisions that are specified in SNiP. They have all the norms for the size of the pit for various types of soils and more.

Any work that will be carried out in the manufacture of the foundation pit must be carried out in accordance with safety precautions and technological methods. Ideally, such work should be entrusted to professionals who have the necessary training, experience, education and documents that give the right to perform such work. Unfortunately, life loves to adjust all plans in its own way.

It is indisputable that by doing the work yourself, you can save significant amounts.

But there is also a reverse side of the coin. With self-production, there is a high risk of errors that cannot be corrected in the future. And it's good if everything will only result in material losses, but sometimes the wrong process even leads to a threat to the safety of health and life. For this reason, if you are not confident in your abilities, contact the professionals.