The research discusses the problems related to the studies of the reconstruction of historic buildings, which are completely scattered (missing) in the light of scientific determinants and controls that are integrated to develop the methodology for implementing these works. The first part of the research focused on the consolidation of the concept of the term " Recoverable " in general, in the context of the differences between the Recoverable operations on the one hand and the work of restoration and the fall of the specialized operations on the other hand. In the second part of the research, a technical study of the recovery process was carried out on the building of the Royal Opera House in Egypt where the previous studies of the reconstruction process and the obstacles encountered were discussed in the presence of the opera garage building in the Royal Opera House. The obstacles to overcoming these obstacles were discussed through an innovative work to restore the building of the Royal Opera House on the same Opera Garage building without the removal of the garage building.