The quality of the restoration work is directly affected by the competencies of the workers at the construction site. Workers without the necessary skills, knowledge, or sensitivity tend to make irreversible mistakes in the conservation and restoration of architectural heritage.

The fundamental competencies of these workers are often not fully developed because the training provided to these workers is often in basic construction skills, not restoration skills. It is difficult to find qualified workers for restorations in almost all European countries. Skills and qualifications in Europe are not transparent and consistent with each other.