The foundation is the foundation of any building, and the safety of the entire structure depends on its condition. However, over time, cracks, deformations and other damages may appear on the foundations, which may threaten the stability of the structure.
But problems with the foundation are not a verdict for a building, if they are detected in time and measures are taken. Understanding the causes of damage, proper diagnostics and the correct choice of repair methods can extend the service life of the structure and ensure its safety.
Let’s look at the main types of damage, their causes, diagnostic methods, as well as repair and reinforcement methods to ensure that the building remains strong and reliable.
Types and classification of damages, defects and deformations of foundations
Any damage to the foundation is an alarming signal that requires attention. However, in order to correctly identify the problem and choose a method for its elimination, it is necessary to understand what types of defects there are and how they differ from each other. In this section, we’ll look at the main types of cracks, sediments, and fractures, as well as how dangerous they are to a building.
The foundations of buildings are subject to various types of damage, which are classified according to the following criteria:
By the nature of the damage:
Cracks:
Vertical – they occur when uneven precipitation of individual parts of the foundation.
Horizontal – indicate the influence of lateral ground pressure or frozen water.
Inclined – they are associated with subsidence of the angular parts or deformation of the base.
Stepped foundations are typical for brick or block foundations.
Fine hairline cracks – appear due to concrete shrinkage or minor temperature deformations.
Detachment and destruction of concrete:
It is expressed in the form of peeling, formation of voids, separation of the upper layers.
It is associated with carbonation, leaching of cement stone, corrosion of reinforcement.
Rebar corrosion:
The oxidation of metal rods inside concrete leads to its cracking and loss of strength.
Precipitation or uneven subsidence:
It manifests itself in the form of slopes, rolls, and redistributed loads.
It may be accompanied by the formation of secondary cracks in the walls of the building.
Erosion and leaching of soil:
It leads to the formation of voids, reducing the bearing capacity of the base.
For the reason of occurrence:
Technological defects:
Design errors (insufficient depth of foundation, incorrect selection of materials).
Violation of construction technologies (poor concrete compaction, reinforcement errors).
Geotechnical reasons:
Changes in soil properties (softening, freezing, subsidence).
Karst phenomena, quicksand, rock weathering.
Operational factors:
Increased loads (superstructure of floors, installation of equipment).
Exposure to water, chemicals, and temperature changes.
According to the degree of danger:
Minor damage:
Fine surface cracks without threat of bearing capacity.
Slight peeling of the concrete.
Moderate damage:
Deep cracks that require repair.
Local corrosion of the reinforcement.
Rebar corrosion:
The oxidation of metal rods inside concrete leads to its cracking and loss of strength.
Critical damage:
Deep through-cracks, leading to loss of strength.
Loss of stability of the foundation, formation of cavities in the base.
Causes of cracks and deformations
All injuries have their own causes. Some are related to construction errors, while others are related to changes in the ground, weather conditions, or improper operation of the building. Here we will look in detail at what factors can lead to cracks and precipitation of the foundation, and why it is important to take them into account at the design stage.
The main factors leading to damage to foundations:
Uneven subsidence of the soil:
One of the main causes of cracks is uneven subsidence of the soil under the foundation, which can be caused by the following factors:
Insufficient soil compaction during construction.
Different types of soil under different areas of the building (for example, sandy and clay areas).
Discharge of water in the base due to leakage of utility networks.
Prolonged drying of clay soils, which leads to their shrinkage.
Design errors:
If the characteristics of the soil or the load on the foundation were not taken into account at the design stage, defects may occur.:
Insufficient depth of foundation, leading to its displacement.
Non-compliance of design loads with actual operating conditions.
Errors in the selection of fittings and insufficient structural rigidity.
Exposure to moisture:
Water has a significant impact on the condition of the foundation and foundation:
A rise in the groundwater level leads to the washing away and leaching of soil particles, which weakens the foundation.
Freezing and thawing in seasonal soils causes cyclical movements that create stresses in the foundation structure.
Capillary suction of moisture leads to corrosion of reinforcement in reinforced concrete foundations.
Load changes:
The foundation may receive additional loads if the building is undergoing renovation.:
Completion of floors without taking into account the bearing capacity of the base.
Installation of heavy equipment that creates point loads.
Changing the functionality of the building (for example, transferring from residential to industrial use).
Seismic and vibration effects:
In areas with high seismicity, regular tremors can cause gradual destruction of the foundation.
Vibrations from transport, railways, and industrial machinery can lead to a loss of stability of the soil under the foundation.
Reinforcement corrosion and concrete destruction:
The ingress of water and chemicals into reinforced concrete accelerates the corrosion of reinforcement.
Leaching of the cement stone leads to weakening of the monolith and cracking.
Methods of diagnosis and defect search
Before starting to repair the foundation, it is necessary to determine exactly what the problem is and how serious it is. Various examination methods are used for this purpose, from visual inspection to complex instrumental examinations. In this section, we will talk about the most effective diagnostic methods that help identify hidden defects and prevent further destruction.
Foundations are diagnosed using the following methods:
Visual inspection:
The primary method for assessing the condition of the foundation. Defined by:
The presence of cracks, their width and direction.
Precipitation, misalignment, and tilting of structures.
Traces of concrete destruction, reinforcement corrosion, and soil erosion.
Geodetic monitoring:
It is used to control building deformations and includes:
Leveling to determine the precipitation of the foundation.
Total station measurements of the slopes of walls and columns.
Installing beacons on cracks to determine their dynamics.
Laser scanning:
It is used to create an accurate 3D model of the foundation and identify deformations. Allows you to determine the geometry of defects.
Ultrasound diagnostics:
The method is based on the passage of ultrasonic waves through concrete. Allows:
Determine the depth of cracks and voids.
To identify material heterogeneities and stratifications.
Acoustic emission method:
It is used to detect active destruction processes inside concrete. Sound signals from microcracks are recorded.
Seismic exploration:
Allows you to examine the soils of the base and identify:
Decompression zones and karst cavities.
Weak layers that can cause foundation precipitation.
Thermal imaging examination:
It is used to identify wet areas, waterproofing defects and places of heat loss in the foundation.
Investigation of the foundation soils:
Includes:
Static and dynamic sensing to determine the density and bearing capacity of soils.
Laboratory analysis of soil samples.
Methods for determining the causes of damage
Knowing what exactly caused the damage to the foundation plays a key role in choosing a method to fix it. Design errors, poor–quality materials, soil features – all this requires a different approach. In this section, we will look at which studies help to establish the root cause of the defect, and how this affects further repair work.
The following methods are used to determine the causes of damage to foundations:
Analysis of design and executive documentation:
Comparison of design solutions with actual data.
Verification of compliance of design loads with actual operating conditions.
Analysis of the history of construction and repair work carried out.
Geotechnical research:
Assessment of the composition and bearing capacity of the soil.
Detection of changes in humidity, density, and the presence of movable layers.
Checking the groundwater level and its effect on the foundation.
Laboratory studies of materials:
Analysis of concrete properties (strength, porosity, water permeability).
Examination of rebar for corrosion and loss of strength.
Determination of the chemical composition of soils to identify aggressive media.
Instrumental examinations:
Ultrasound diagnostics is the detection of internal defects in concrete.
Acoustic emission is the recording of sounds of destruction inside a structure.
Seismic exploration is the detection of voids and weak zones in the base.
Geodetic monitoring is the measurement of precipitation and slopes of a building.
Monitoring of dynamic impacts:
Measurement of vibrations from transport and industrial machinery.
Fixing vibrations of structures using sensors.
Possible consequences of damage
If you do not pay attention to cracks and foundation deposits, the problem will only worsen over time. As a result, serious damage to walls and ceilings may occur, and in the worst case, the building may become an emergency. In this section, we’ll talk about what foundation problems can lead to and why it’s important to fix them on time.
Damage to the foundations can lead to various consequences affecting the safety and operation of the building. Consider the main risks:
Static and dynamic instability of the building:
The weakening of the base can lead to a gradual increase in the slopes of structures.
Deformations of the foundation cause an uneven load on the bearing elements, which leads to their damage.
In critical cases, individual parts of the building may collapse or be completely destroyed.
The appearance of secondary defects:
Cracks in the foundation can be transmitted to walls and floors.
The tilt and skew of the building can lead to jamming of door and window openings.
Destruction of load-bearing walls, partitions and finishing layers.
Loss of thermal performance:
Cracks and fractures degrade thermal insulation, contributing to heat loss through the foundation.
Cold bridges appear, and the risk of condensation and mold formation increases.
Increased exposure to water and moisture:
The destruction of the waterproofing leads to the penetration of water into the structures.
Water-saturated materials lose their strength, contributing to the accelerated destruction of the foundation.
Fungus and mold may occur, which worsens the sanitary condition of the building.
Increased operating costs:
Reinforcement and repair of the foundation require significant financial costs.
Increased structural deformation requires regular monitoring and additional examinations.
Deterioration of living conditions or operation of buildings, reduction of their market value.
Danger to human life and health:
Sudden structural collapses pose a direct threat to people in the building.
Reducing safety during operation can lead to emergencies.
The destruction of foundations in buildings with high traffic (shopping malls, office complexes) poses a serious risk.
Ways to strengthen, repair and eliminate the causes of damage
When the problem is identified, the stage of repairing and strengthening the foundation begins. Depending on the degree of damage, different methods can be used – from simple injections to a complete reconstruction of the building’s foundation. In this section, we will look at the most effective ways to repair and strengthen the foundation, which will help extend the life of the building.
Various reinforcement and repair methods are used to repair damage to foundations, depending on the type of defect, its scale and causes.
Reinforcement and repair of cracks in foundations:
Injection sealing: filling cracks with cement, epoxy or polyurethane compounds to restore the solidity of concrete.
Installation of reinforced concrete clips: installing clips around damaged areas to evenly distribute the load.
Replacement or reinforcement of reinforcement: it is used in case of corrosion of reinforcement inside the structure.
Banding with metal plates: prevents further development of cracks.
Reinforcement in case of uneven precipitation:
Pouring concrete mortar under the foundation: fills voids caused by soil erosion.
Soil injection: reinforcement of the substrate by introducing binders (cement mortar, polymers, silicate mixtures).
Installation of additional piles: transfer of load to more durable layers of soil.
Load distribution: installation of additional reinforced concrete belts and grillings.
Reinforcement of the foundation during the destruction of concrete:
Facing with reinforced concrete slabs: increasing the cross-section of the foundation.
Application of shotcrete: applying a layer of concrete under high pressure to restore the protective layer and increase strength.
Deep injection of polymer compounds: strengthens the structure of the destroyed concrete.
Methods of combating water exposure
Waterproofing of the foundation: application of bitumen, polymer, cement-polymer coatings.
Drainage systems: the installation of ring, wall and reservoir drains for water drainage.
Replacing the soil around the foundation with less water-saturated material.
Strengthening the foundation under dynamic loads:
Anchoring: increased resistance to vibrations and loads.
Installation of damping pads: reduction of vibration vibrations.
Replacement or reinforcement of grillages: redistribution of loads between supports.
Complete reconstruction of the foundation:
Dismantling of the old and construction of a new foundation: in case of critical damage.
Installation of an additional foundation contour: redistribution of loads and prevention of further destruction.
The lifting method: lifting the structure and replacing damaged sections of the foundation.
Regulatory documentation
During the construction and repair of foundations, it is important to comply with the requirements of regulatory documents that regulate all work. In this section, we will explain what regulations apply in the construction industry, and what requirements must be taken into account when examining, repairing, and strengthening foundations.
The calculation, diagnosis, repair and reinforcement of foundations are regulated by the following regulatory documents
The main regulatory documents:
GOST 31937-2024 – regulates the procedure for inspection and monitoring of buildings and structures, including the frequency of inspections and requirements for assessing the condition of foundations.
SP 22.13330.2016 (Code of Rules for the foundation of buildings and structures) – establishes requirements for the design of foundations, calculation of the bearing capacity of soils and ensuring the stability of foundations.
GOST 25100-2020 – contains the classification of soils, their physical and mechanical characteristics and methods for determining the properties necessary for the calculation of foundations.
SP 50-101-2004 (Design and construction of foundations and foundations of buildings and structures) – includes rules for selecting types of foundations, calculations of their bearing capacity and methods of protection against deformation.
SP 45.13330.2012 (Earthworks, foundations and foundations) – defines the requirements for construction work, including rules for the development of soil and the installation of foundation structures.
GOST 12730.1-2020 – describes methods for determining the strength of concrete used in foundations, which is important when conducting surveys and assessing load-bearing capacity.
Regulation of examination and monitoring:
According to GOST 31937-2024, an inspection of the foundations is carried out:
The first time is no later than 2 years after the building is put into operation.
Then – at least once every 10 years for normal operating conditions.
In difficult conditions (aggressive environments, seismic areas, high humidity) – at least once every 5 years.
Permanent monitoring mode is provided for unique and especially important objects.
The examination includes visual inspection, instrumental diagnostic methods and laboratory tests, the results of which are recorded in the technical report.
Standards for the design and calculation of foundations:
The design of foundations should take into account:
Geological conditions of the construction site (SP 22.13330.2016, SP 50-101-2004).
The type of building and its load on the base (SNiP 2.02.01-83).
Methods of strengthening the base soils, if necessary (GOST 25100-2020).
Requirements for the strength and durability of concrete (GOST 12730.1-2020).
Methods of protection of the foundation from water and corrosion (SP 45.13330.2012).
Regulatory requirements for the repair and reinforcement of foundations:
When carrying out repairs and strengthening of foundations, it is necessary:
Perform a full technical inspection with an assessment of the bearing capacity (GOST 31937-2024).
Conduct geotechnical studies to assess the condition of the soil (GOST 25100-2020).
Use only certified materials and technologies (GOST 12730.1-2020, SP 50-101-2004).
Ensure that new structural solutions comply with current building regulations (SP 22.13330.2016).
Control and responsibility for compliance with standards:
The introduction of construction control (design and technical supervision) to comply with regulatory requirements.
Development of certificates of the technical condition of foundations and maintenance of survey history.
Liability for violations of building regulations: in case of non-compliance with the requirements, penalties, emergencies and urgent repair orders are possible.
Results
The foundation is the foundation on which the entire building rests, and its condition directly affects the durability and safety of the building. Damages and cracks that occur in the foundation pose a serious threat to their reliability and safety. They not only worsen its operational characteristics, but can also lead to serious consequences, including the destruction of the building. Therefore, it is important to identify problems in a timely manner, understand their causes and apply effective methods of elimination.
Compliance with regulatory requirements and the use of modern technologies will extend the service life of structures and minimize the risks of destruction.
The main conclusions:
Damage to foundations can be different – cracks, precipitation, deformations, concrete destruction, reinforcement corrosion, and many others. Each of them requires an individual approach and timely elimination.
The causes of damage can be related to both external factors and errors during construction. This may be uneven load distribution, insufficient bearing capacity of the soil, design errors, aggressive external conditions, or even just natural aging of materials.
Diagnosis of the foundation condition is an important step to prevent serious problems. A simple visual inspection is often not enough, so geodetic surveys, laboratory soil analyses, ultrasound diagnostics of concrete, thermography and other modern methods are used.
Determining the causes of damage plays a key role in their elimination. Without an accurate understanding of what caused the cracks or precipitation, any repairs may turn out to be temporary measures. In-depth analysis and research of the factors affecting the foundation helps to avoid repeated problems.
The consequences of damage can be very serious. In addition to reducing the strength of the foundation, wall deformations, misalignment of door and window openings, destruction of load-bearing structures, and eventually recognition of the building as an emergency are possible.
The methods of repairing and strengthening foundations are diverse and depend on the type of damage. These include injecting cracks, reinforcing the structure with clips, injecting soil, installing additional supports, and even completely reconstructing the foundation. The choice of method depends on the degree of damage and the specific operating conditions of the building.
The foundation requires not only competent design and construction, but also regular monitoring during operation. It is important not to ignore the first signs of damage – small cracks or minor precipitation can eventually develop into a serious problem. Timely inspection, high-quality repairs and compliance with regulatory requirements will help keep the building in a safe and stable condition for many years to come.
Building owners, planners, and builders need to remember that the sooner a problem is discovered and remedial measures are taken, the lower the costs and risks in the future. A reliable foundation is the key to the strength and durability of any structure.
EUCLID provides comprehensive solutions for preparing for reconstruction, repair, modernization of existing and implementation of new projects. Our team is ready to take on the tasks within the framework of project and investment activities in construction:
Pre-design study and analysis;
Engineering surveys and design;
Technical and financial support for the implementation of projects;
Inspection of finished objects and completed stages of work;
Construction inspection of buildings, structures and engineering systems;
Technical expertise and audit.
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