In this paper, we present our experimental methodology, which was developed to assess and eliminate the excess moisture levels in the masonry of a Roman archeological monument, namely the Mensa Ponderaria of Tivoli, which is an important landmark dating back to the first century A.D. The need to keep interventions to a minimum were crucial factors for choosing microwave techniques as a non-destructive method for removal and moisture infiltration measurements in the walls. We used a microwave generator connected to a horn antenna to increase the temperature locally at the point of treatment and achieve the elimination of moisture. Additionally, to quantify the amount of eliminated water, we used a free space transmission measurement by two patch micro-strip fed antennas with a resonance at 2.62 GHz connected to a vector network analyser (VNA). S-parameters were measured at a frequency range 2 …