Survey of foundations and foundations of buildings: description of the procedure, features and recommendations

A survey of the foundations, especially its underground part, is carried out during the reconstruction, overhaul or construction of the building. For its implementation, there are special bodies and special tools. Such methods are used that will not lead to the destruction of the base in the field of research. In addition, sampling for laboratory samples is possible. The result of the audit is the expert’s conclusion on the condition of the foundation, as well as some recommendations for addressing the shortcomings.

In what cases is a check performed?

A foundation survey is mandatory if:

• It is planned to purchase a land plot on which a partially erected building is located for a long time.
• There is a need for additional floors.
• Cracks appeared in the walls, and the door or window openings warped.
• Visual drawdowns are present, although deformations of the supporting structures are not visible.
• There are doubts that the construction of the base of the building was carried out correctly and accurately according to technology.
• The load on the foundation has been greatly increased.
• There is a need for reconstruction of the old structure.
• The base is physically worn out.
• In the basement of the building is constantly present water.
• It is necessary to go to court to resolve disputed claims.

A proper survey of the foundation makes it possible to determine whether it is possible to use the old building in the future and erect the unfinished. In addition, the examination allows you to obtain information about existing invisible defects and to eliminate them in time.

Reasons for the loss of strength

The foundation is the foundation of the entire building. If it collapses, then the integrity and reliability of the entire building is at stake. A survey of the foundation allows you to determine the reasons for the loss of its strength:

1. Subflooding of the base, which may occur due to leakage from an underground pipeline or excessive rainfall.
2. Uneven or very heavy load.
3. Flushing soil from under the foundation sole.
4. Carrying out construction work near the facility, which are accompanied by strong vibration or ground vibrations.
5. Non-compliance with the installation technology of the base.
6. Earthquake.

What is the examination for?

So, a survey of the foundation of the building implies such goals:

• Determination of the real state of all structures of which the base is constructed, as well as soil.
• Finding out the degree of damage to the metal parts of the foundation.
• Establishment of the present margin of safety of the base.
• Assessment of the integrity and general condition of waterproofing.
• Determination of operational properties.
• Finding out the reasons that led to the destruction or settlement of the building.
• Clarification of the geometric parameters of the base, as well as determining the location of the reinforcement cages.
• Check for voids inside the foundation.
• The choice of the most effective methods to eliminate the shortcomings.

Features of the survey

So, a survey of the foundations and foundations is carried out by a special organization, in the arsenal of which there are various methods of inspecting the structure. In some cases, only a visual inspection is sufficient. Although it is desirable for greater reliability to carry out the whole range of studies using instrumental and laboratory samples.

As a result of quite complex calculations, specialists can find out the margin of safety of the structure, which is located underground.

For example, if cracks formed in the wall, this indicates a shift in the foundation or that the foundation began to crumble. In this case, a technical examination of the foundations should be carried out necessarily. This will make it possible to eliminate the problem in time and avoid a collapse and tragic consequences.

Often the examination is carried out upon acceptance of the zero cycle of the construction of the facility. Information on the basis may be used in resolving disputes in court.

Visual inspection features

Inspection of the foundations of buildings and structures is carried out primarily by visual inspection. With its help, video or photographing of defects is carried out, an act of work done is created in which recommendations are written on how to eliminate existing problems. Such an examination requires only 1 day, although its results may be insufficient and inaccurate.

Most often, this method is used in visible areas, although in some cases the basis has to be dug up. This method is used to inspect the upper part of the foundation, basement, pit and grillage.

During the survey, particular attention is paid to:

• Destroyed places in the masonry.
• Violation of the integrity of a monolithic structure.
• Corrosion of concrete.
• Bare reinforcement (this occurs as a result of cleavage of the foundation).
• Rusty spots.
• Cracks and gaps that appeared during the use of the structure.

Features of instrumental research

A survey of the foundation of the house using special devices is used if:

1. A shift, draft, or other spatial disturbance of the structure has occurred.
2. There are chips whose size exceeds 1.5 cm.
3. The total area of ​​destroyed sites exceeds 10%.

There are such instrumental research methods:

• Ultrasonic.
• Squeezing under the press.
• Impulse-shock.
• Tear-off, with chipping.
• Elastic rebound.

During the examination, frost resistance and water permeability of the base are also checked. Since reinforced concrete is reinforced with metal, the degree of reinforcement is also checked. Attention is paid to the protective layer.

It should be noted that the cost of the procedure presented cannot be low. The instrumental check takes 5-10 days. If laboratory tests are also present, the process may be delayed.

Features of the study

So, a survey of the foundations and foundations of buildings is carried out along the walls, near underground poles and at corners. To do this, experts dig holes, the depth of which should be greater than the foundation. That is below the depth of his sole.

Next, a visual inspection of the structure is carried out, during which a documentary recording of all existing defects is made, as well as video or photo recording of the damage.

During the procedure, linear measurements of the foundation are also carried out to determine the correctness of its geometric parameters. Naturally, additionally it is necessary to take soil and base samples for laboratory research. It is advisable to use methods for this that will not harm the overall integrity of the structure.

During the examination, the following parameters are taken into account:

• The presence and condition of waterproofing.
• Soil properties.
• The strength of all parts of the base.
• The current state of the reinforcing frame.
• The geometric parameters of the foundation.
• Basement condition.

What are the recommendations after the study based on?

So, after the inspection of the base has occurred, experts give a detailed conclusion with a description of all existing defects. The act should also contain those recommendations that will help get rid of defects and strengthen the foundation. They are given based on:

1. Acts of visual and instrumental examination.
2. Archival documents containing information about the underground part of the base, as well as hydrogeological data.
3. Expert evaluation results.
4. Protocol of laboratory research of samples taken.
5. Certain technical calculations.

What determines the price of research?

Naturally, the foundation inspection procedure is not free. However, its cost depends on many factors:

• The construction volume to be examined.
• Type of foundation, as well as a variety of its design.
• The level of responsibility of the structure and building.
• The complexity of the work.
• Forms and design complexity.
• The presence of documents that contain all the information about the depth of groundwater, the bearing capacity of the soil, geological features of the area.

The cost of the survey is from 12,000 rubles or more per object. That's all the features of the procedure, which can help maintain the building structure for many years. Good luck!