Depth of the laying of the ribbon foundation: basic provisions. How to determine the depth of the ribbon foundation

The foundation of any building is the foundation. From it, construction work begins. Tape foundation has found wide application in the construction of private houses and industrial buildings. It is put under construction with heavy walls or ceilings. The depth of laying the belt foundation is calculated in advance, before the beginning of the main construction. It depends on a number of conditions.

Determination of depth

The depth of the foundation of the basement is the distance from the lowest point of the foundation surface to the surface of the earth. In the section is a trapezoid or a rectangle. This value is calculated. For its calculation, certain knowledge is required - engineering, geological. A quality and reliable design of the future structure, taking into account all the nuances, can only be done by a specialist.

What depth of laying of the ribbon foundation is required in each specific case, it is possible to determine accurately a number of indicators. For all kinds of base, from whatever material it is made, they are always taken into account.

Depth of laying the ribbon foundation depends on them. The main provisions that are taken into account in the design:

• Type and characteristics of the soil;
• Load on the base (structural weight);
• Depth of soil freezing;
• Abrasion, or the property of the soil to change the indicators of its volume, depending on the temperature of the environment;
• Features of the structure (the presence of a basement, the number of floors);
• Groundwater level indicators.

Classification by species

Tape foundation is a continuous strip of durable material (mainly reinforced concrete) that runs along the perimeter of the entire structure. They lay it under all internal and external capital walls. Do this with such a calculation that the foundation foundation was wider than the walls themselves at least 10 cm.

They are of two types: monolithic and prefabricated, but both are called "ribbon foundation." The depth of the deposit is calculated for both types. Monolithic require more time for installation, but they can well protect the basement from moisture penetration and simulate any configuration of the basement. Concrete is used to make such a structure.

To equip the prefabricated strip foundation, take concrete or concrete blocks of standard dimensions. The depth of the lower layer of the blocks should be at least 15 centimeters below the freezing depth of the soil. Such a foundation is built:

• For the subsequent erection on it of walls from a stone, concrete or a brick with density above 1300 kg / m ³ ;
• For the construction on it of heavy structures and powerful reinforced concrete floors;
• If the walls of the prefabricated basement serve for the basement or basement;
• If the foundation is laid in a heterogeneous soil.

Classification by depth of deposit

There are also foundations for the depth of the deposit:

• The shallow shallow shall be used under light houses on loamy soils. The depth of the laying of the tape foundation of this type ranges from 50 to 70 centimeters.
• The recessed is used in the construction of houses on several floors, with heavy walls or with a basement on a bed of soil. Such a foundation is laid to a depth of 20 cm to 30 cm below the freezing level of the soil. This type of foundation is certainly more reliable and not subject to deformation. Accordingly, its service life is much longer than that of a shallow base.

Correctly calculated depth of the foundation will last for up to 70 years without any repairs. Above the ground, the ground should rise no less than 30 centimeters. This part can be made of brick, stone or concrete blocks.

Advantages and disadvantages

Each type of ribbon foundation has some advantages:

• Monolithic:

- strong;

- reliable;

- Any configuration is possible.

• Prefabricated:

- Simple in the assembly;

- reduce the time of manufacturing the base.

Disadvantages of all types of tape foundations are:

• A large amount of time for the production of all necessary work;
• Labor intensity of the process;
• Require significant capital investment.

The basis of reinforced concrete blocks is less practical. It is suitable mainly for buildings of simple forms (with a complex configuration of the structure it will be necessary to cut the blocks) and can pass water at the joints.

Whichever type of strip foundation is used for the construction of the building, it requires a careful calculation of the depth of the foundation of the building.

Dependence on soil

The type of soil layer is of great importance in calculating the depth of the foundation. This indicator is associated with the level of groundwater, on their ratio depends on how the strip foundation will be arranged. Depth of placement varies depending on the composition of the soil itself. This relationship can be seen in the table:

Ground freezing

An important indicator determining the need for the depth of laying the band foundation is the freezing of the soil. Due to such a physical phenomenon as an increase in the volume of moisture during cooling, it is necessary to know exactly the depth of freezing. In winter, the moisture contained in the soil freezing begins to increase in volume. The soil "puchitsya" and pushes to the surface of any structure immersed in it.

Neglect this phenomenon is impossible. Too much force of freezing water (remember, with what ease the ice breaks the pipes). Such movement of the soil can lead to the destruction of the base.

And the quality of the soil itself is important, as evidenced by the data given in the table.

With a high index of the soils, the band foundation must necessarily be monolithic. The depth of freezing depends on the climatic conditions of the terrain, its geographical location. For each individual location, it is necessary to calculate the depth of the foundation based on the average annual temperature indexes.

Neglecting this rule can lead to deformation of the walls and destruction of the building as a whole.

Groundwater

Practice shows that indications of the standing (average annual) groundwater level can seriously correct the calculation of the height of the laying of the tape foundation. If in winter the groundwater does not rise above 2 meters to the level (extreme) of freezing of the soil, the level of freezing of the ground is neglected.

Otherwise, the foundation is always laid lower than the freezing level of the soil, by 20-30 centimeters. Due to the proximity of water, the soil will be moist and will be strongly turbulent at low temperatures (frost).

Depth under the house

The basis under the house, except for all other conditions, must take into account the construction of the building itself. If it provides a basement room, then the depth of laying the basement under the house is arranged 40 centimeters below the level of the basement floor. It is necessary to take into account the level of ground freezing (in this case, the bottom of the base should be lower), as well as the level of ground water standing (the base of the base should be higher).

On a suitable ground and without a basement, the foundation is built at a depth much less - up to 70 centimeters. In wet soils, the minimum depth is 120 centimeters.

Outbuildings

Separately standing buildings on a suburban area require as much attention as an apartment building. When constructing small and light structures, the depth of laying the band foundation is also important. For a bath it can be made to a depth of 50 to 70 centimeters. This is enough to support the weight of the wooden structure.

For the reliable operation of utility rooms, not only the weight of the structure is taken into account. Take into account and all other indicators that affect the calculation of the depth of the foundation of the tape foundation.

Similar calculations for the arrangement of the foundation are recommended for other economic structures: a barn, a workshop, a garage, a hen house or a stable for keeping animals.

Depth and types of laying for a brick fence

The depth of laying the foundation for a brick fence should correspond to the weight of the proposed fence. If the construction is supposed to be entirely of bricks, then the calculation of the depth of the foundation is carried out in the same way as for the construction of an ordinary building.

Completely brick fence - the pleasure is very expensive. More often from a brick poles are made, and between them a cheaper fencing is established. There are two options for equipping the foundation for this type of fence :

• Tape, all around the perimeter;
• Columnar - only under brick pillars.

The pillar foundation also requires compliance with certain rules, all recommendations for soils are applicable to it, its depth should be below the freezing point of the soil.

Modern technologies

Modern technologies and the quality of the material (reinforced concrete) allow even small-buried foundations to be applied on problem soils. This significantly reduces both the time of erection of buildings, and their cost (the basis of the construction can cost 25% of the cost of the house).

If certain rules are observed, the finely-grooved ribbon foundation can be laid at a depth of only 50 cm, even on the soils. Obligatory conditions are:

• Use of reinforced concrete for a monolithic base of M200 or M300;
• In the trench, under the tape of the foundation, heat insulation (foam polystyrene plates) must be stacked and non-swollen materials poured;
• Tramble and level the drainage cushion from sand and rubble with a thickness of at least 2 cm;
• The side area of the base is waterproofed and insulated (with polystyrene foam plates);
• Cavities are covered with any non-heaped material (a mixture of gravel and sand, sand, gravel).

Such technologies are widely and successfully used in the construction of buildings in the US and some European countries. Many years of experience confirms the possibility of significant savings in construction work when laying the foundation.