Specifying the technical value of a building is a very important factor in the process of searching for effective conservation measures.. It is not only about determining the characteristics of the changes, that occurred in the structural organism, but also to determine the effects of these changes on endurance, durability and safety of use. Determining the nature of the damage and its gradation is closely related to the size of the expenditures., which will have to be incurred to save the monument lB).

Depending on the quality of the technical condition and the degree of danger in historic buildings or their structures, the following six states can be distinguished:

I. Normal condition - characterized by the lack of changes of essential importance to the materials or the entire structural system or its elements. The technical quality of the building or system does not raise any objections as to the load-bearing capacity and usability.

II. Safe condition - at which some changes in the materials or construction system of the masonry substance are noticed, but these changes do not affect the cohesiveness of the structure and stability of the system and do not cause adverse technical and functional phenomena, unless different working conditions are foreseen.

III. Dangerous condition - with local damage in the form of cracks, dissections and stabilized cavities, destruction of the structure, etc.. Damage of this kind partially weakens the building or reduces the bearing capacity of major structures, and also reduce resistance to their further destruction, which is a clear symptom of the hazard and danger of use in the further period of operation, if appropriate remedial measures are not taken.

IV. Severe condition - in which the features and symptoms of destruction are similar to the previous case, except that cracks and processes of changes in the masonry structure are of an active nature, therefore, there is a gradual weakening of the carrying capacity and loss of resistance to destruction. The measure of the dangerous state are deformations or a decrease in load capacity to passive tension, at which the structure of the wall is capable of transferring only its own load.

Continued use of the structure in this condition poses a potential threat to public safety.

V. Catastrophic state - in which the process of structure destruction as a result of chemical or mechanical factors has led to a serious reduction in the mechanical properties of materials, deprived them of their carrying capacity or at which there were changes in the static system to such a extent, that assemblies or structural elements still exhibit stability, but it can easily be violated by trivial factors, and thus an active danger of imminent danger arises.

WE. The state of irreversible destruction - characterized by this, that the process of destruction of a structure or system is of a permanent nature, and therefore no technical measures will be able to rehabilitate the substance of the masonry.

The introduction of this classification is essential for crystallization in the first stage of conservation guidelines, and in the following years, for the technical development of the programme of the conciliator works, their nature and scope, and to establish a hierarchy of their urgency.

Brick buildings or structures, whose technical condition has been qualified to condition I, do not require construction and conservation treatments.

Buildings and elements classified as State II should be subject to observation for the development of preventive measures to prevent change.

Buildings and elements classified as State III should be subject not only to permanent observation, but also technical control for the development of measures to protect at least against further build-up of damage.

Buildings classified as IV and V require very urgent intervention, and masonry substances classified in category VI — due to the lack of effective rehabilitation measures — require separate decisions. In search of technical ways to save monuments in situation IV, V and VI, efforts should be made to reduce the adverse effects of damage and, above all, to inhibit the progress of degradation.

Taking into account, therefore, the above considerations on the nature of the genetic transformations, the quality of the technical condition and the degree of danger can be determined, that technical restoration works should be undertaken all the faster and more effectively, the more unique the type of monument or structure we are dealing with and the more serious the symptoms of danger.

In renovation and construction practice, the criterion of the percentage of damage is sometimes used to assess the technical condition of the building., usually determined on a visual basis. For this purpose, in the relevant tabular forms containing the constituent parts of the building (load-bearing structures, Roofs, Equipment, installations and others) the fixed percentage of destruction shall be entered (Consumption). As a result of such an operation, the assessment of the value is sometimes determined (for example. very good, good, satisfactory, Disappointing, bad, completely bad (Safe). However, such criteria do not take into account the cultural values of the object..