This study presents the methodology focusing on the analysis and repair works during the reattachment of the archaeological findings at the Venizelos Metro Station in Thessaloniki, Greece. The investigation discusses the compatible materials and techniques to reposition the antiquities to their initial place after being removed for the construction of the metro. The antiquities, primarily from the Roman, Early Christian, and Byzantine periods, were uncovered during the construction of the metro station. The proposed methodology includes a geometrical, structural and architectural analysis of the current state, documentation of existing materials, pathology, and recommendations to restore their structural integrity and continuity. The bearing capacity evaluation is based on laboratory measurements. Samples were collected from the site to quantify the physical and chemical characteristics of the mortars and stone units, along with their mechanical properties. Based on these tests, compatible mortar compositions were proposed for deep repointing and grouting of the structural members. As the antiquities were removed and relocated to their original positions, further support work is studied, with considerations for safety, compatibility, reversibility keeping minimal intervention.