Cracks in part of the wall (e.g. pillars, columns) vertical course in most cases can be caused by the breaking load, which crushes and splits its cross-section. Vertical lines across the entire height of the building or a significant part thereof may be caused by parts of the building separating from each other. In long massifs, similar cracks appear as a result of elongation or thermal contractions.
If horizontal cracks are clearly visible in the wall, and it is grouped on a certain surface, this may be a sign that the tensile stress has been exceeded. Such a state often occurs when working conditions change, e.g. due to increased eccentric load, horizontal pressure, etc., and sometimes due to thermal phenomena.
In masonry structures, damage is not only caused by scratches and cracks. In many cases, the damage may not be visible, e.g. caverns in the cross-section of walls, loosening the cohesiveness of masonry layers, detachment of facing layers, etc.. Therefore, there is a need for research, even during the inspection of the facility, with the use of tapping the wall, mock poll, sclerometric tests or using other precise measuring equipment (e.g. acoustic, radiological, electromagnetic, etc.). Non-destructive methods are of significant importance in structural research. Using ultrasound equipment, these parts can be detected in the walls, which are the most damaged and require a quick protective intervention. Using the SIR method, it is possible to locate any changes in the structure of walls up to one meter thick (voids inside the wall, material type changes, stone and brick joints and any other discontinuities). Using the AGA thermovisual equipment 750 can be accurately selected on the plaster surface, without opencasts, picture of the facts (types of threads, liners, the outline of the arcades, lintels, cracks, etc.). The electronic equipment of KPG allows with an accuracy of ± 2 % determine the thickness of the walls up to three meters with the accessibility of the walls on both sides, if, on the other hand, the walls are only accessible from one side, for measurement, GSSI radar equipment is used, which gives measurement accuracy within ± 5 %, The electromagnetic apparatus "FEMETER" allows to detect the size in the flesh of the wall, depth and location of steel elements. Using an AGA camera, as well as the IFJ isotope apparatus, it is possible to determine the extent and degree of moisture in the walls, ceilings and others.
The course of research on cracks and revealed structural deformations should be constantly confronted with the description of the initial state.
Some data for a preliminary analysis of the causes of building deformation
| Lp. | The nature of the damage | The reasons |
| 1 | Open horizontal cracks, separation of parts of the building horizontally | Vertical displacements due to subsidence, foundation collapse, disadvantages of funding |
| 2 | Open vertical cracks, vertical separation of parts of the building | Horizontal displacements due to wall inclination from the vertical, weakening of buttresses, excessive deflection of the ceilings, trench neighborhood, slope, disadvantages of funding |
| 3 | Open horizontal and vertical cracks | Lateral displacements of building parts, turning, loosening spatial ties, anchors for ceiling beams, ties, imbalance of the roof truss |
| 4 | Scratches and cracks directed upwards divergent (divergent) | Settlement of the side parts of the building as a result of subsoil surrender, the formation of sinkholes, soil removal, foundation defects, deformation of the hatch in the headboard when the side parts are overloaded, vertical displacement of supports |
| 5 | Scratches and cracks converging upwards (convergent) | Settlement of the central part of the building as a result of soil surrender, west, leaching soil under the foundation, disadvantages of funding; subsidence of lintels, hatch in the jumper when overloaded, horizontal displacements of supports |
| 6 | Scratches and horizontal cracks, bulge (buckling) walls | Eccentric compression, excessive expansion of the arches, vault, excessive deflection of the ceilings, loosened tension of the bowstrings, anchors, loosening of the anchors of the ceiling beams; lateral ground pressure |
| 7 | Minor vertical scratches and cracks in the window pillars, slupach, columns | Overload, turning, violation of the stable balance of construction links |
| 8 | Parallel very thin vertical jumping cracks | Forced shocks, Vibrations, vibration. Horizontal displacements |
| 9 | Small features on the casting wall, bulges or concavities in the walls, chipping off corners, violation of bondness of welds, cracking of cornices | Thermal movements and deformations, systolic; structural defects of materials |
| 10 | Distortion of horizontal lines, vertical lines, cracks and diagonal scratches, cracks between the walls of buildings of equal height | Uneven load, insufficient bearing capacity, no dilatation, breach and rotation of support links |