Restoration is a scientific, technical, and ethical intervention process aimed at preserving the authentic value of historical buildings, monuments, and cultural heritage elements to pass them on to future generations. The international framework of the modern conservation approach was established by the 1964 Venice Charter, defining the preservation of cultural heritage not merely as a physical repair activity, but also as a historical and cultural responsibility.
In order to carry out restoration practices in a sound and scientific manner, it is necessary to act in accordance with certain fundamental principles.
1. Respect for Authenticity
The value of a cultural property is directly related to its original material, design, craftsmanship, layout, and historical context. During the restoration process, these authentic qualities must be preserved, and interventions that would change the identity of the structure should be avoided. The original material should be kept in situ as much as possible; when replacement is unavoidable, the new material must be compatible both technically and aesthetically.
Authenticity encompasses not only physical elements but also the cultural and symbolic meaning the structure carries.
2. Minimum Intervention
The fundamental approach in restoration is to provide the highest level of preservation with the least amount of intervention to the structure. Unnecessary renewals, attempts to make the structure look "new," or extensive reconstruction practices can lead to a loss of historical value.
The principle of minimum intervention focuses on consolidation, conservation, and improving the current state. Interventions should only be made in compulsory situations and with scientific justifications.
3. Documentation and Scientific Basis
The restoration process begins with a detailed research and documentation phase:
- Measured Survey (Rölöve): Scaled drawing of the existing condition.
- Restitution: Scientific proposal regarding the past periods of the structure.
- Restoration Project: Implementation decisions.
These documents must be based on scientific data such as archive scans, old photographs, engravings, written sources, and material analyses. Every stage of the intervention process should be recorded and archived. This creates a transparent and traceable information infrastructure for future studies.
4. Reversibility
New elements added or techniques applied during restoration must be reversible without damaging the structure when necessary. This principle allows for the application of more advanced conservation techniques that may develop in the future.
For example, a system used for reinforcement should be removable when a more appropriate method is found in the future.
5. Distinguishability
Newly made additions or completions must be distinguishable from the original parts of the structure. The approach of "reproducing the old exactly" through imitation can mean deceptively reconstructing the historical process.
However, the principle of distinguishability does not mean creating extreme contrasts that will disrupt visual integrity. The goal is an intervention that is both honest and aesthetically balanced.
6. Material and Technical Compatibility
The materials used in restoration must be physically, chemically, and mechanically compatible with the original material. For instance, using cement-based mortar in a historical masonry structure can cause long-term damage to stone and brick.
Therefore, traditional materials and construction techniques should be researched; materials with the same or similar properties should be preferred whenever possible. This preserves both the durability and the historical character of the structure.
7. Respect for Historical Layers
Historical structures often bear the traces of different periods. The mentality of returning a structure only to its "original state" can mean ignoring the historical contributions of subsequent periods.
The conservation approach evaluates the phases the structure has undergone as a whole. Each layer is part of the historical memory value of the structure.
8. Functional Continuity and Preservation through Use
One of the most effective methods in preserving a structure is to keep it functionally alive. Unused structures deteriorate rapidly. However, during the process of assigning a new function (adaptive reuse), the layout, load-bearing system, and spatial organization of the structure must not be damaged.
The choice of function must be compatible with the scale and identity of the structure.
9. Interdisciplinary Work
Restoration requires the collaborative work of disciplines such as architecture, art history, archaeology, engineering, materials science, and urban planning. A sound conservation process can only be carried out by expert teams.
Unilateral interventions lacking a scientific basis can cause irreversible losses.